Chapter 6. Types and Pain Flashcards

Question

356. Preamputation pain (A) is more likely to lead to phantom pain if the amputation is traumatic (B) may sensitize the nervous system, explaining why some individuals may be more susceptible to development of chronic phantom pain (C) is more likely to lead to phantom pain if the amputation is secondary (D) is similar in character and localization to the subsequent phantom pain in 80% of patients (E) is less likely to lead to phantom pain if the amputation is in the upper extremities

Answer 1

356. (B) Some retrospective studies, but not all have pointed to preamputation pain as a risk factor for phantom pain. It has been hypothesized that preoperative pain may sensitize the nervous system, explaining why some individuals may be more susceptible to development of chronic pain. A. It has been noted that patients with traumatic amputations, who had no pain prior to the amputation, develop pain to the same extent as patients with preoperative pain who endure amputations after significant medical pathology. C. There is no correlation between the development of phantom pain and whether the amputation was primary or secondary. Primary amputation is when the limb is lost at the time of the injury. Secondary amputation is when the limb is surgically removed in a hospital. D. Phantom pain may mimic preamputation pain in both character and localization. Preamputation pain may persist in some patients, but it is not the case in the majority of patients. E. Site of amputation has not been found to have a role in determining whether preamputation pain leads to phantom pain.

Answer 2

357. (E) A. Amputees who experienced a long delay between the amputation and return to work, had difficulty in finding suitable jobs, and had fewer opportunities for promotion. B. The use of a functionally active prosthesis as opposed to a cosmetic prosthesis may reduce phantom pain. C. Spinal anesthesia in amputees may precipitate transient, difficult to treat phantom pain. Given the low incidence of recurrent phantom limb pain with spinal anesthesia, its transient nature, and the fact that it can be treated if it occurs, it has been concluded that spinal anesthesia is not contraindicated in patients with previous lower limb amputation. D. While there is no evidence that phantom pain represents a psychological disturbance, it may be triggered and precipitated by psychosocial factors. It has been shown that coping strategies are important for the experience of phantom pain Research has indicated that the way individuals cope with pain may influence pain, and physical and psychological adjustment.

Answer 3

358. (E) Stump pain is located at the end of an amputated limb’s stump. Unlike phantom pain, it occurs in the body part that actually exists, in the stump that remains. It typically is described as a “sharp,” “burning,” “electric-like,” or “skinsensitive” pain. Some patients have spontaneous movements of the stump, ranging from slight, hardly visible jerks to severe contractions. Stump pain results from a damaged nerve in the stump region. Nerves damaged in the amputation surgery try to heal and may form abnormally sensitive regions, called neuromas. A neuroma can cause pain and skin sensitivity. Percussion of neuromas may increase nerve fiber discharge and augmentation of stump and phantom pain. No one treatment has been shown to be effective for stump pain. Because it is a pain caused by an injured peripheral nerve, drugs used for nerve pain may be helpful. If the stump pain affects a limb, revision of the prosthesis is sometimes beneficial. Other approaches also are tried in selected cases, including: nerve blocks, transcutaneous electrical nerve stimulation, surgical revision of the stump, or removal of the neuroma (this procedure may fail because the neuroma can grow back; some patients actually get worse after surgery), and cognitive therapies. Stump pain is common in the early postamputation period. Stump pain can also persist beyond the stage of postsurgical healing. Stump pain and phantom pain are strongly correlated. Phantom pain subsides with resolution of stump pain and that it is more prevalent in patients with phantom pain than in those without it. Careful sensory examination of amputation stumps may reveal areas of sensory abnormalities such as hypoesthesia, hyperalgesia, or allodynia. However, a correlation between phantom pain and the extent and degree of sensory abnormality has not been established.

Answer 4

359. (E) The ectopic and increased spontaneous and evoked activity from the periphery is assumed to be the result of an increased and also novel expression of sodium channels. Local anesthesia of the stump may reduce or abolish phantom pain temporarily. Decreasing peripheral output by locally anesthetizing stump neuromas with lidocaine reduced tap-evoked stump pain. On the other hand, there was a clear increase in pain when the potassium channel blocker, gallamine was injected in the perineuromal space. Both findings support the premise that abnormal input from peripheral nociceptors plays a role in pain generation.

Answer 5

360. (A) The pharmacology of spinal sensitization entails an increased activity in NMDA receptor–operated systems, and many aspects of the central sensitization can be reduced by NMDA receptor antagonists In amputees, the evoked pain from repetitive stimulation can be reduced by the NMDA antagonist ketamine B. Terminating the stimulation is not the only way to reduce the pain. C. After a nerve is injured, there is an increase in the general excitability of spinal cord neurons, where C fibers and A-δ afferents gain access to secondary pain-signaling neurons. D. Sensitization of dorsal horn neurons is mediated by release of glutamate and neurokinin. This sensitization may present in several ways including: lowered threshold, increased persistent neuronal discharges with prolonged pain after stimulation, and expansion of peripheral receptive fields. The central sensitization may also be a result of a different type of anatomical reorganization. Substance P is normally expressed in small afferent fibers, but following nerve injury, it may be expressed in large A-β fibers. This phenotypic switch of large A-β fibers into nociceptive-like nerve fibers may be one of the reasons why nonnoxious stimuli can be perceived as painful

Answer 6

361. (E) E. The sympathetic nervous system may play a role in generating and, in uparticular, in maintaining, phantom pain. After limb amputation and deafferentation in adult monkeys, there is reorganization of the primary somatosensory cortex, and while these changes may be unique to the cortex, they may also be, at least in part, the result of changes at the level of the thalamus and perhaps even brain stem or spinal cord. After dorsal rhizotomy, the threshold to evoke activity in the thalamus and cortex decreased, and the mouth and chin invade cortices corresponding to the representation of arm and fingers that have lost their normal afferent input. In humans similar reorganization has been observed. In the thalamus, neurons that normally do not respond to stimulation in amputees begin to respond and show enlarged somatotropic maps. A cascade of events seems to be involved in generating phantom pain and it starts in the periphery, spinal cord, brain stem, thalamus, and finally ends in the cerebral cortex.

Answer 7

362. (C) A. and D. Tramdol and amitriptyline have been found to be efficacious in treating phantom and stump pain in treatment naive patients. B. Gabapentin has been noted to be better than placebo in reducing phantom pain. Failure to pharmacologically provide pain relief should not be accepted until opioids have been tried. Intravenous (IV) and oral morphine have been shown to decrease phantom pain. Case reports have indicated that methadone may also be helpful. Other trials have not reported the same the success with an oral NMDA antagonist, memantine. Suggestions for the treatment of postamputation pain (no evidence) (Note: it is important to differentiate between early postoperative pain and chronic pain [pain persisting more than 4 weeks], and stump and phantom pain): Early postoperative pain Stump pain Conventional analgesics • Acetaminophen • NSAIDs • Opioids +/− combined with epidural pain treatment Stump and phantom pain If neuropathic pain clearly exists (paroxysms or abnormal stump sensitivity)—trial with TCAs or anticonvulsants. Chronic pain Stump pain • Local stump surgery: if obvious stump pathology is present, revisions should be considered; surgery should be avoided in cases of sympathetically maintained pain. • Local medical treatment: topical lidocaine or capsaicin can be tried in those who have stump pain but no obvious stump pathology. Stump and phantom pain (medical treatment, in order of preference) • Gabapentin 1200 to 2400 mg/d, slow titration. Max dose of 3600 mg/d. • TCAs (imipramine, amitriptyline, nortriptyline) 100 to 125 mg/d, slow titration. Check electrocardiogram (ECG) before starting. Monitor plasma levels with dose greater than 100 mg/d. If sedation is wanted, amitriptyline should be used. • If the pain is mostly paroxysmal, lancinating, or radiating: • Oxcarbazepine 600 to 900 mg/d. Start at 300 mg and increase by 300 mg daily. • Carbamazepine 450 mg/d. Start dose 150 mg, daily increments of 150 mg. Monitor plasma levels after 10 days on maximum dose. • Lamotrigine 100 to 200 mg/d. Start dose 25 mg/d, slow titration with increments of 25 mg/14 days (to avoid rash). • Opioids (long-acting) or tramadol. • If none of the above has an effect, refer the patient to the pain clinic. • In pain center: can perform IV lidocaine trial or ketamine trial. If the lidocaine test is positive—reconsider anticonvulsants. If the ketamine test is positive: consider memantine or amantadine. Physical therapy encompassing massage, manipulation, and passive range of motion may prevent trophic changes and vascular congestion in the stump. Transcutaneous electrical nerve stimulation, acupuncture, ultrasound, and hypnosis, may have a beneficial effect on stump and phantom pain.

Answer 8

363. (B) Surgery on amputation neuromas and more extensive amputation were accepted treatment modalities for stump and phantom pain in the past. Today, stump revision is probably done only in cases of obvious stump pathology, and in properly healed stumps there is almost never an indication for proximal extension of the amputation because of pain. Surgery should be avoided in cases of sympathetically maintained pain. Surgery may produce short-term pain relief but pain often reappears. The results of other invasive procedures such as dorsal root entry zone lesions sympathectomy and cordotomy have generally been nontherapeutic, and most of them have been abandoned.

Answer 9

364. (B) Classification of patients with phantom pain: Group I: Mild intermittent paresthesias that do not interfere with normal activity, work, or sleep. Group II: Paresthesias that are uncomfortable and annoying but do not interfere with activities or sleep. Group III: Pain that is of sufficient intensity, frequency, or duration to be distressful; however, some patients in this group have pain that is bearable, that intermittently interferes with their lifestyle, and that may respond to conservative treatment. Group IV: Nearly constant severe pain that interferes with normal activity and sleep.

Answer 10

365. (D) A. and B. The gate control theory of pain, put forward by Ronald Melzack and Patrick David Wall in 1962, and again in 1965, is the idea that the perception of physical pain is not a direct result of activation of nociceptors, but instead is modulated by interaction between different neurons, both paintransmitting and non–pain-transmitting. The theory asserts that activation of nerves that do not transmit pain signals can interfere with signals from pain fibers and inhibit an individual’s perception of pain. It has been used to explain phantom limb pain. Following marked destruction of sensory axons by amputation, wide dynamic range neurons are freed by inhibitory control. Self-sustaining neuronal activity may then occur in spinal cord neurons. C. If the spontaneous spinal cord neuronal activity exceeds a critical level, pain may occur in the phantom limb. This loss of inhibitory control may lead to spontaneous discharges at any level in the CNS and may explain the lack of analgesia in paraplegics with phantom body pain after complete cordectomy Pain increases after blocking conduction are in line with the theory, as continued loss of peripheral sensory input would lead to further disinhibition. Sodium thiopental perpetuates CNS inhibition and has been reported to end phantom limb pain during spinal anesthesia. Melzack R, Wall PD. Mechanisms: a new theory. Agate control system modulates sensory input from the skin before it evokes pain perception and response. Science. 1965;150(3699).

Answer 11

366. (D) Primary dysmenorrhea is defined as menstrual pain without pelvic pathology. Endometriosis and adenomyosis are the most common causes of secondary dysmenorrhea.

Answer 12

367. (C) The pain of endometriosis can occur with menses or sexual intercourse or can always be present. It can also mimic any known pelvic pathology. Answers A, B, D, and E are all correct.

Answer 13

369. (B) Opioids have the potential for addiction even when administered for acute pain. However, it is the exaggerated common fear of the potential for addiction to opioids that often interferes with adequate pain management. The rest of the answers are correct.

Answer 14

370. (E) It is recognized that long-term changes occur within the peripheral and central nervous system following noxious input. This neuroplasticity alters the body’s response to usual peripheral sensory input. In pathologic pain conditions, stimulation of A-β fibers, normally eliciting response to touch, may elicit pain.

Answer 15

371. (C) Even though there have been some concerns regarding the risks of perioperative NSAIDs, including intra- and postoperative bleeding, they continue to have a useful role. Combination of NSAIDs and opioids has a synergistic analgesic effect, as they act at the different sites of pain pathways. More new evidence is emerging that NSAIDs exert their analgesic effects also through the central mechanisms.

Answer 16

372. (B) It has been demonstrated that the administration of an NMDA antagonist reduces the development of tolerance to morphine. The rest of the answers are correct.

Answer 17

373. (A) The following are the usual features of the somatic pain: well localized, sharp and definite, often constant (sometimes periodic); it is rarely associated with nausea usually when it is deep somatic pain with bone involvement; it may be following the distribution of a somatic nerve. In contrast, the visceral pain: is poorly localized, diffuse, dull, and vague; it is often periodic and builds to peaks (sometimes constant); it is often associated with nausea and vomiting.

Answer 18

374. (B) It has been demonstrated that early postoperative pain is a significant predictor of longterm pain. The rest of the answers are correct.

Answer 19

375. (C) Multimodal analgesia makes it possible to significantly reduce the total consumption of opioids intra- and postoperatively. Therefore, opioid side-effects are minimized, including inevitable opioid-induced GI stasis that delays the resumption of normal enteral nutrition after surgery.

Answer 20

376. (B) PHN affects women more often than men, in a ratio of approximately 3:2. The rest of the answers are correct.

Answer 21

377. (B) PHN is defined as pain caused by herpes zoster for more than 1 month.

Answer 22

378. (A) As many as 40% of patients with PHN have either incomplete or no relief from treatment. Because of this, the future may lie with prevention through vaccination and early aggressive treatment of herpes zoster with antivirals and analgesics to reduce the extent of the nerve damage and sensitization that may correlate with PHN.

Answer 23

379. (B) Experience with serotonergic antidepressants, such as clomipramine, trazodone, nefazodone, fluoxetine, and zimelidine, in PHN has been disappointing. The evidence supporting the use of noradrenergic agents is more compelling. The rest of the answers are correct.

Answer 24

380. (B) There has been evidence that opioids do not relieve neuropathic pain as well as nonneuropathic pain. However, there is also evidence that opioids have been successfully used for the treatment of PHN.

Answer 25

381. (B) DM is the most common cause of autonomic neuropathy, and peripheral neuropathy in general, in the United States, as well as in the rest of the developed world. Leprosy is the most common cause of peripheral neuropathy in the world.

Answer 26

382. (C) Diabetic amyotrophy starts with pain and involves the lower extremities. It has a good prognosis and usually resolves spontaneously in 12 to 24 months. It is not directly related to hyperglycemia.

Answer 27

383. (E) Distal sensorimotor polyneuropathy is a symmetrical length-dependent process with dying-back or dropout of the longest nerve fibers—myelinated and unmyelinated. All other answers are correct.

Answer 28

384. (B) It is generally agreed that the prevalence of neuropathy is about 10% at diagnosis of DM, rising to 50% or more in patients diagnosed for longer than 5 years

Answer 29

386. (C) It is accepted that the most common cause of trigeminal neuralgia is arterial crosscompression of the trigeminal nerve in the posterior fossa, as suggested by Jannetta in 1982. Electron microscopy of trigeminal nerve biopsies taken from patients with trigeminal neuralgia has shown areas of axonal swelling and demyelination adjacent to the area of arterial compression. Although trigeminal neuralgia is more common in patients with multiple sclerosis, only a small portion of patients with trigeminal neuralgia suffer from multiple sclerosis and does not explain the majority of the cases.

Answer 30

387. (C) Carbamazepine is likely to be beneficial in up to 70% of the patients. Incidence of side effects is often higher in elderly patients especially if the drug escalation is too fast. Allergic rash is seen in up to 10% of the patients and high concentration of the drug may be associated with fluid retention promoting cardiac problems. Carbamazepine is a potent hepatic enzyme inducer which can potentially lead to undesirable drug-to-drug interactions. Although microsurgical exploration of the posterior fossa is the highly successful, it is a major surgery with 0.5% risk of mortality and major morbidity. The effectiveness of pimozide for trigeminal neuralgia is better than carbamazepine, but the high frequency of side effects limits its clinical use.

Answer 31

388. (C) The trigeminal ganglion receives sensation from the oral mucosa, scalp, nasal areas, face, and teeth. Proprioceptive information is transmitted into the ganglion from the mastication and extraocular muscles. The peripheral branches of the ganglion are the ophthalmic, the maxillary, and the mandibular, which are organized somatotropically, with the ophthalmic branch located dorsally, the maxillary branch is intermediate, and the mandibular nerve is located ventrally. The gasserian ganglion lies within the cranium, in the middle cranial fossa. The posterior border of the ganglion includes the dura of the Meckel cave. The landmark to perform the trigeminal ganglion block is the foramen ovale and not the foramen rotundum.

Answer 32

389. (C) The diagnosis of trigeminal neuralgia is eminently clinical and further tests are necessary only to rule out associated conditions. When the condition is found, MRI and evoked potential testing are strongly recommended to rule out secondary causes. Clinically the onset of trigeminal neuralgia is around the age of 50 years, more common in females, almost exclusively unilateral with a paroxysmal nature.

Answer 33

390. (D) The giant cell arteritis affects almost exclusively the white population although it can occur in worldwide. Unlike other forms of vasculitis it rarely affects skin, kidneys, or lungs. Females are affected 3 times more often than males. Visual loss is now considered to affect between 6% to 10% of patients in most series.

Answer 34

391. (D) Analgesic rebound headache resolves or reverts to its previous pattern within 2 months of discontinuing of the overused medication.

Answer 35

392. (B) The first statement better describes trigeminal neuralgia. Cluster headache affects more males than females with a 5:1 ratio and can begin at any age. Attacks are severe, stabbing, screwing, unilateral pain, occasionally preceded by premonitory symptoms, with sudden onset, and rapid crescendo. Therapeutic interventions for the acute attack include oxygen, triptans, dihydroergotamine, ketorolac, chlorpromazine, or intranasal lidocaine, cocaine, or capsaicin. Melatonin has been found to be moderately effective as a preventive treatment in episodic and chronic cluster headache

Answer 36

393. (D) Sterile neurogenic inflammation is often seen after stimulation of the trigeminal ganglion, which innervates large cerebral vessels, pial vessels, large sinuses, and the dura via unmyelinated C fibers. In acute attacks of migraine, substance P, CGRP, and nitric oxide mediate the neurogenic inflammation

Answer 37

394. (E) TTH is the most common type of headache. Aura is present in only 20% of patients suffering from migraine. Although chronic daily headache diagnostic criteria for probable TTH requires no nausea or vomiting as one of the criteria or absence of photophobia, or phonophobia, nausea may be seen in 4.2% of patients with TTH, while phonophobia is reported in 10.6% of them.

Answer 38

395. (D) Inhalation of 100% oxygen at 7 to 12 L/min is effective in treating the majority of cluster headache sufferers when used continuously for 15 to 20 minutes. Generally oxygen inhalation is not considered to be effective in any other form of primary neurovascular headache.

Answer 39

397. (C) PDPH and SIH are two distinct clinical entities with similar presentation. The headache is always bilateral, located in the occipital and/or frontal area. Although low CSF pressure is often noted, it is not necessary to confirm the diagnosis.

Answer 40

398. (C) New daily persistent headache is a chronic, unremitting headache of sudden onset, daily pattern. The duration of the headache should be at least 3 months. Some important features include its moderate severity, bilateral location, and lack of nausea, vomiting (N/V), photophobia, and phonophobia (P/P). On the other hand, status migrainosus is a severe debilitating migraine, associated with N/V, P/P, and with duration longer than 72 hours but that typically do not exceed 2 weeks. The other diagnoses are not consistent with the symptoms.

Answer 41

399. (A) The previously known classic migraine (migraine with aura) is preceded by visual aura that starts 20 to 40 minutes before the migraine and is characterized by spreading scintillations reflecting a slow propagation of neuronal and glial excitation emanating from one occipital lobe. Cortical spreading depression (CSD) presents with dramatic shifts in cortical steady potential (DC), temporary increases in extracellular ions and excitatory neurotransmitters (glutamate), and transient raise, followed by sustained decrease in cortical blood flow. The vascular theory proposed that migraine with aura is caused by intracranial cerebral vasoconstriction and the headache by reactive vasodilation. Despite that, the theory can not explain the prodromal symptoms or why some antimigraine medications are not effective. Hormonal fluctuations and estrogen withdrawal may explain the higher incidence of migraine in female patients during their reproductive years, but are not related to the presence of aura. Cerebral idiopathic hypertension is a form of headache of unknown etiology

Answer 42

400. (D) The published literature commonly states that 80% to 90% of low back pain resolves in about 6 weeks, irrespective of the administration or type of treatment, with only 5% to 10% of patients developing persistent back pain. Contrary to this assumption, actual analysis of research evidence shows that chronic low back and neck pain persist 1 year or longer in 25% to 60% of adult and/or elderly patients.

Answer 43

401. (C) Based on evaluations utilizing controlled diagnostic blocks, the prevalence of zygapophysial or facet joint involvement has been estimated to be between 15% and 45% in heterogeneous groups of patients with chronic low back pain.

Answer 44

402. (E) The clinical picture of metastatic epidural spinal cord compression is uniformly reported as pain, weakness, sensory loss, and autonomic dysfunction. Metastatic epidural spinal cord compression initially presents with severe back pain in 95% of cases. After weeks of progressive pain, the patient may develop weakness, sensory loss, autonomic dysfunction, and reflex abnormalities. Bladder and bowel dysfunction are rarely presenting symptoms, but may appear after sensory symptoms have occurred. The exception to this generalization develops with compression of the conus medullaris, which presents as acute urinary retention and constipation without preceding motor or sensory symptoms

Answer 45

403. (B) Patients with severe, persistent symptoms (discogenic in origin) that have been confirmed by other diagnostic evaluations do not need to undergo further evaluation by discography. Specific uses for discography include, but are not limited to: further evaluation of demonstrably abnormal discs to help assess the extent of abnormality or correlation of the abnormality with clinical symptoms (in case of recurrent pain from a previously operated disc and a lateral disc herniation); patients with persistent, severe symptoms in whom other diagnostic tests have failed to reveal clear confirmation of a suspected disc as the source of pain; assessment of patients who have failed to respond to surgical procedures to determine if there is painful pseudoarthrosis or a symptomatic disc in a posteriorly fused segment, or to evaluate possible recurrent disc herniation; assessment of discs before fusion to determine if the discs within the proposed fusion segment are symptomatic and to determine if discs adjacent to this segment are normal; and assessment of minimally invasive surgical candidates to confirm a contained disc herniation or to investigate contrast distribution pattern before intradiscal procedures.

Answer 46

404. (A) Gait disturbances are a feature of cervical myelopathy, not radiculopathy. Other signs and symptoms of cervical radiculopathy include upper extremity sensory disturbances and muscle weakness.

Answer 47

405. (D) Experimental studies have given support to the hypothesis that blood flow and nutrition to the disc are diminished in smokers, the pH of the disc is lowered, disc mineral content is lower, fibrinolytic activity is changed, and there are increased degenerative changes seen in the lumbar spine.

Answer 48

406. (B) There is strong evidence from randomized controlled trials that bed rest is not effective for treating acute low back pain.

Answer 49

407. (A) Narrowing of the intervertebral discs has long been considered one of the signs of pathologic aging of the lumbar spine, but recent data has shown that notion to be untrue. Large-scale postmortem analysis have shown lumbar disc height and diameter to actually increase with age. The anterior-posterior diameter increases by about 10% in females and 2% in males. Disc height has been shown to increase by about 10% in most lumbar discs.

Answer 50

408. (C) Radiculopathy is a condition in which conduction within the axons of a spinal nerve or its roots are blocked. It can result in numbness and weakness secondary to conduction block in sensory and motor neurons respectively. Conduction blockade can be caused by compression or ischemia. It is important to make the distinction that radiculopathy does not cause pain. It may, however, be associated with pain.

Answer 51

409. (D) The major theoretical complications of corticosteroid administration include suppression of pituitary-adrenal axis, hypercorticism, Cushing syndrome, osteoporosis, avascular necrosis of bone, steroid myopathy, epidural lipomatosis, weight gain, fluid retention, and hyperglycemia.

Answer 52

410. (A) Absolute contraindications to epidural steroid injections include sepsis, infection at injection site, therapeutic anticoagulation, and patient refusal. Relative contraindications include preexisting neurologic conditions, prophylactic low-dose heparin, thrombocytopenia, and uncooperative patients.

Answer 53

411. (B) L4-L5 disc herniation with L5 nerve root involvement involves: pain over the sacroiliac joint, hip, lateral thigh, and leg; numbness over the lateral leg and first three toes; weakness with dorsiflexion of great toe and foot; difficulty walking on heels; possible foot drop; and internal hamstring reflex diminished or absent. Numbness over the medial thigh and knee, and quadriceps weakness are indicative of L3-L4 disc herniation with L4 nerve root involvement. Difficulty walking on toes and lateral heel pain are common with L5-S1 disk herniation involving the S1 nerve root.

Answer 54

412. (B) Fifteen percent of patients with chronic low | back pain have sacroiliac joint pain.

Answer 55

413 to 417. 413 (B); 414 (D); 415 (E); 416 (A); 417 (C) Spondylolysis is an acquired defect that results from a fatigue fracture of the pars interarticularis (the part of the lamina that intervenes between the superior and inferior articular processes on each side). Spondylolisthesis is the displacement of a vertebrae or the vertebral column in relationship to the vertebrae below. Kissing spines (also known as Baastrup disease) affects the lumbar spinous processes. Excessive lumbar lordosis or extension injuries to the lumbar spine cause adjacent spinous processes to clash and compress the intervening interspinous ligament. This results in a periostitis of the spinous process or inflammation of the affected ligament. Radiculopathy is a neurologic condition in which conduction blocks the axons of a spinal nerve or its roots that results in numbness and weakness. Radicular pain is pain that arises as a result of irritation of a spinal nerve or its roots.

Answer 56

418. (E) In managing lumbar radicular pain with interlaminar lumbar epidural steroid injections, the evidence is strong for short-term relief and limited for long-term relief. In managing cervical radiculopathy with cervical interlaminar epidural steroid injections, the evidence is moderate. The evidence for lumbar transforaminal epidural steroid injections in managing lumbar radicular pain is strong for short-term and moderate for long-term relief. The evidence for cervical transforaminal epidural steroid injections in managing cervical nerve root pain is moderate. The evidence is moderate in managing lumbar radicular pain in post–lumbar laminectomy syndrome. The evidence for caudal epidural steroid injections is strong for short-term relief and moderate for long-term relief, in managing chronic pain of lumbar radiculopathy and post–lumbar laminectomy syndrome.

Answer 57

419. (A) The sources of the nerve endings in the lumbar discs are two extensive microscopic plexuses of nerves that accompany the anterior and posterior longitudinal ligaments. The nerve plexuses that innervate intervertebral discs are derived from the lumbar sympathetic trunks. The dorsal rami supply innervation to the muscles of the back and zygapophysial joints. In normal lumbar intervertebral discs, nerve fibers are only found in the outer third of the annulus fibrosis. Discs painful on discography and removed with operation have nerve growth deep into the annulus and into the nucleus pulposus. Disc fissuring is a trigger for neoinnervation and neovascularization of a disc.

Answer 58

420. (A) Development of an epidural abscess is a very rare complication of epidural steroid injections. It needs to be recognized and treated quickly to avoid irreversible injury. Symptoms of an epidural abscess include severe back pain that is followed by radicular pain 3 days later. The initial back pain may not become evident for several days after the injection.

Answer 59

421. (C) Plain x-rays are recommended for possible fractures, arthropathy, spondylolisthesis, tumors, infections, stenosis, and congential deformities. CT images are recommended for bone/joint pathologies, lateral disc herniations, stenosis (ie, spinal canal, neuroforaminal, lateral recess), and for those in which an MRI is contraindicated. MRI is recommended for disc herniations, spinal stenosis, osteomyelitis, tumors (ie, spinal cord, nerve roots, nerve sheath, paraspinal soft tissue), and cauda equine syndrome.

Answer 60

422. (D) The L2 nerve root is involved with hip flexion, L3 with leg extension, L4 with heel walking, L5 with first toe dorsiflexion (and heel walking), and S1 with toe walking

Answer 61

423. (C) Laminotomy with discectomy has a low infection rate, statistically. The most frequent complication is a dural tear. Neural injury may occur as a result of a dural tear and may cause long-term pain and neurologic deficit. Recurrence of the herniation occurs in approximately 5% of cases. Infection and neural injury occurs in less than 0.5% of cases.

Answer 62

424. (C) Conservative treatment is usually the first treatment of choice for patients presenting with FBSS. It consists of medical management of contributing factors (ie, depression, obesity, smoking), rehabilitation, and behavior modification (ie, alcohol or drug dependency).

Answer 63

425. (D) Many prognostic indicators have been implicated in patients undergoing repeat lumbosacral spine surgery. They may or may not be significant for each patient and should be taken into context for the particular patient. Women have been found to have better outcomes than men. Patients with a history of favorable outcomes from prior surgeries tend to have better outcomes as well. A history of few previous surgeries, operative/myelographic findings of disc herniation, and a history of working immediately prior to surgery are all favorable prognostic indicators. Less favorable prognostic indicators include epidural scarring that requires lysis of adhesions and pseudoarthrosis of a prior fusion.

Answer 64

426. (E) Waddell signs are used to help diagnose nonorganic low back pain complaints. Each of the five findings is considered positive if present. Three positive findings are considered highly suggestive of a nonorganic source of pain: 1. Tenderness: does not follow dermatomal or referral patterns and is hard to localize. 2. Stimulation testing: stimulating distant sites should not cause discomfort. 3. Distraction testing: findings when testing the same site are inconsistent when the patient’s attention is distracted. 4. Regional disturbance: motor and sensory testing yield nonanatomic findings. 5. Overreaction: inappropriate verbal remarks or facial expressions, withdrawal from touch,

Answer 65

427. (B) Ankylosing spondylitis is characterized by pain and stiffness in young males (typically ages 17-35 years) more often than females. It is worse in the morning and improves with mild exercise. The pain will typically last for at least 3 months and be diffuse in nature affecting the low back and spine. Rheumatoid arthritis is an inflammatory polyarthritis that affects middleaged women more often than men. It typically presents with morning stiffness that improves as the day progresses, and the spine is not affected until late in the disease. Psoriatic arthritis is characterized by inflammation of the skin and joints that typically presents in the fourth and fifth decades of life. Klippel-Feil syndrome is a congenital disorder that is characterized by abnormal fusion of two or more bones in the cervical spine. Reiter syndrome is a reactive arthritis that is characterized by a triad of symptoms: nongonococcal urethritis, conjunctivitis, and arthritis.

Answer 66

428. (C) The three major criteria for cervicogenic headache include (1) signs and symptoms of neck involvement (precipitation of head pain by: neck movement and/or sustained awkward head positioning, by external pressure over the upper cervical or occipital region on the symptomatic side; restriction of the range of motion in the neck; ipsilateral neck, shoulder, or arm pain of a rather vague nonradicular nature or, occasionally, arm pain of a radicular nature); (2) confirmatory evidence by diagnostic anesthetic blockades; and (3) unilaterality of the head pain without sideshift. Head pain characteristics include moderate-severe, nonthrobbing, and nonlancinating pain, usually starting in the neck, episodes of varying duration, or fluctuating, continuous pain. Other characteristics of some importance: only marginal effect or lack of effect of indomethacin, only marginal effect or lack of effect of ergotamine and sumatriptan, female sex, not infrequent occurrence of head, or indirect neck trauma by history, usually of more than only medium severity.

Answer 67

429. (D) Neurogenic claudication pain is secondary to nerve root compression rather than lack of blood supply that is seen with vascular claudication. The pain is exacerbated by standing erect and downhill walking. Improvement comes with lying supine more than lying in the prone position, sitting, squatting, and lumbar flexion. Neurogenic claudication is not made worse with biking, uphill walking, and lumbar flexion, unlike vascular claudication. It is not alleviated with standing.

Answer 68

430. (A) Neck pain has been suggested to have multifactorial etiologies. Risk factors for neck pain that cannot be modified include age, sex, and genetics. There is no evidence that normal cervical spine degenerative changes are a risk factor for neck pain. Modifiable risk factors for neck pain include smoking and exposure to environmental tobacco. Participation in physical activity seems to offer a protective effect. High quantitative job demands, low social support at the workplace, inactive work position, repetitive work, and meticulous work increases the risk of neck pain. There is a lack of evidence that workplace interventions are successful in decreasing neck pain in employees.

Answer 69

431. (D) In patients with neck pain, the physical examination is more predictive at excluding a structural lesion or neurologic compression than at diagnosing any specific etiologic condition in patients with neck pain. Other assessment tools (ie, electrophysiology, imaging, injections, discography, functional tests, and blood tests) lack validity and utility.

Answer 70

432. (B) Most people with neck pain do not experience a complete resolution of symptoms. Between 50% and 85% of those who experience neck pain at some initial point will report neck pain again 1 to 5 years later. These numbers appear to be similar in the general population, in workers, and after motor vehicle crashes. The prognosis for neck pain also appears to be multifactorial. Younger age was associated with a better prognosis, whereas poor health and prior neck pain episodes were associated with a poorer prognosis. Poorer prognosis was also associated with poor psychologic health, worrying, and becoming angry or frustrated in response to neck pain. Greater optimism, a coping style that involved self-assurance, and having less need to socialize, were all associated with better prognosis. Specific workplace or physical job demands were not linked with recovery from neck pain. Workers who engaged in general exercise and sporting activities were more likely to experience improvement in neck pain. Postinjury psychologic distress and passive types of coping were prognostic of poorer recovery in WAD. There is evidence that compensation and legal factors are also prognostic for poorer recovery from WAD.

Answer 71

433. (C) The reported complications of fluoroscopically guided interlaminar cervical epidural injections are increased neck pain (6.7%), nonpositional headaches (4.6%), insomnia the night of the injection (1.7%), vasovagal reaction reactions (1.7%), facial flushing (1.5%), fever on the night of the procedure (0.3%), and dural puncture (0.3%). The incidence of all complications per injection is 16.8%.

Answer 72

434. (E) Anterior spinal artery syndrome classically presents in older patients with abrupt motor loss, sphincter disturbance, and nonconcordant sensory examination with preservation of sensation to light touch but loss of pain and temperature. It may also occur during aortic procedures. When anterior spinal artery syndromes occur during or after transforaminal epidural steroid injection, the patient may have abrupt back or abdominal pain after injection. An MRI will demonstrate a T2 signal change consistent with cord ischemia/infarct. Anterior spinal artery ischemia may be caused by arteriosclerosis, tumors, thrombosis, hypotension, air or fat embolism, toxins, or other causes. Particulate (steroid) substances, arterial injury, or vascular spasm are other potential causes and have been implicated as significant possibilities for the occurrence of ischemic events after transforaminal epidural steroid injections.

Answer 73

435. (E) A spinal epidural abscess must be recognized promptly and treated quickly, otherwise extreme morbidity can result. It may be separate or associated with vertebral osteomyelitis. Diabetic, alcoholic, IV drug using patients, and immunocompromised patients are all at increased risk. Staphylococcus aureus is the most common organism involved. An affected patient usually presents with neck pain that rapidly progresses to radicular symptoms. Quadriplegia can result if left untreated. Treatment involves surgical removal and antibiotic management.

Answer 74

436. (B) The pathophysiology of HIV-related neuropathies is still not well understood. The current understanding is that it is not related to the direct effect of the virus itself. HIV is not found within ganglionic neurons of Schwann cells, but only in endoneurial macrophages, which may generate a tissue-specific autoimmune response by secretion of cytokines, which, in turn, promotes trafficking of activated T cells and macrophages within the endoneurial parenchyma.

Answer 75

437. (E) The predominantly sensory neuropathy of AIDS affects up to 30% of people with HIV infection and AIDS and is the most commonly encountered.

Answer 76

438. (E) The primary process that leads to vascular occlusion is the polymerization of sickle cell hemoglobin on deoxygenation, which in turn results in distortion of the shape of red blood cells (RBCs), cellular dehydration, decreased deformability, and increased stickiness of RBCs, which promotes their adhesion to and activation of the vascular endothelium.

Answer 77

439. (D) SCD is unlike other pain syndromes where the provider can make decisions on treatment based solely on the pain and its associated behavior. A primary care physician, for example, taking care of a middle-aged patient with job-related low back pain may decide to expel the patient from his or her care if the patient in question demonstrates suspicious drug-seeking behavior. Doing the same with patients who have SCD could be counterproductive. There are anecdotes of patients with SCD who were dismissed from certain programs only to be found dead at home within 24 hours after dismissal or to be admitted to other hospitals with serious complications. Sickle cell pain could be the prodrome of a serious and potentially fatal complication of SCD in some patients.

Answer 78

440. (C) Tissue ischemia caused by vascular occlusion resulting from in situ sickling causes infarctive tissue damage, which in turn initiates a secondary inflammatory response. The secondary response may enhance sympathetic activity by means of interactions with neuroendocrine pathways and trigger release of norepinephrine. In the setting of tissue injury, this release causes more tissue ischemia, creating a vicious cycle. It is the combination of ischemic tissue damage and secondary inflammatory response that makes the pain of SCD unique in its acuteness and severity.

Answer 79

441. (C) Objective signs of a painful crisis, such as fever, leukocytosis, joint effusions, and tenderness, occur in about 50% of patients at initial presentation.

Answer 80

442. (E) Pain is the hallmark of SCD, and the acute sickle cell painful episode (painful crisis) is the most common cause of more than 90% of hospital admissions among adult patients who have SCD.

Answer 81

443. (B) NSAIDs have potentially serious, systemic adverse effects. They include gastropathy, nephropathy, and hemostatic defects. It is advisable not to administer them continuously for more than 5 days to patients with SCD.

Answer 82

444. (D) Tramadol is a synthetic, centrally acting analgesic that is not chemically related to opioids. It acts as a weak agonist with preferential affinity to the μ-receptors. Moreover, it inhibits neuronal reuptake of both serotonin and norepinephrine and stimulates the release of serotonin. Thus, it has functional properties of an opioid and an antidepressant. This drug received an initial enthusiastic reception based on the perception that it was not associated with clinically significant respiratory depression or addiction potential. However, this enthusiasm waned after reports indicated that seizures may be an adverse effect and that abuse potential is increasing.

Answer 83

(D) Chronic pain is a major complication of SCI. Epidemiologic studies indicate that approximately two-thirds of all SCI patients suffer from chronic pain out of which one-third have severe pain. Pain interferes with rehabilitation, daily activities, quality of life, and may have significant influence on mood leading to depression and even suicide.

Answer 84

446. (C) Musculoskeletal pain is common in both the acute and chronic phase of SCI. Chronic pain secondary to overuse is common in shoulders and arm, and vertebral column pain may occur because of the secondary changes following fractures and fixation, mechanical instability, and osteoporosis.

Answer 85

447. (D) Autonomic dysreflexia may complicate SCI patients with a lesion above the splanchnic outflow (sixth thoracic level).

Answer 86

448. (E) Visceral pain usually presents as dull or cramping abdominal uncomfortable and painful sensations, which may be associated with nausea and autonomic reactions. It is likely that visceral pain may occur in the absence of any abdominal organ dysfunction, and may in some cases represent a neuropathic type of pain. SCI patients may not have the typical signs of abdominal illness, and they should be carefully examined whenever any new pain or changes in existing pain occur. Increases in spasticity, pain at any location, or autonomic reactions may be the only indications of abdominal organ dysfunction.

Answer 87

449. (E) Above-level neuropathic pain includes pain caused by compressive mononeuropathies (particularly carpal tunnel syndrome) and CRPS. While below-level pain is considered to be a central pain caused by the spinal cord trauma, at-level pain may have both peripheral (nerve root) and central (spinal cord) components that are difficult to separate.

Answer 88

450. (D) Answers (A), (B), (C), and (D) define allodynia, aftersensation, hyperalgesia, and referred pain, respectively.

Answer 89

452. (B) Central cord syndrome is one of the incomplete SCI syndromes. It is the most common pattern of injury, representing central gray matter destruction with preservation of only the peripheral spinal cord structures, the sacral spinothalamic and corticospinal tracts. The patient usually presents as a quadriplegic with perianal sensation and has an early return of bowel and bladder control. Any return of motor function usually begins with the sacral elements (toe flexors, then the extensors), followed by the lumbar elements of the ankle, knee, and hip. Upper extremity functional return is generally minimal and is limited by the degree of central gray matter destruction.

Answer 90

453. (D) Sensory symptoms and signs in CRPS include spontaneous pain, hyperpathia, allodynia, and hyperalgesia. Answer (A) is the definition of allodynia, answer (B) defines primary hyperalgesia, and answer (C) is secondary hyperalgesia. Answer (E) is the definition of dysesthesia. Dysesthesia maybe spontaneous.

Answer 91

454. (C) CRPS I is a painful condition following an injury, which may not even be a neuropathic pain, as not obvious lesion is present. Patients with this condition develop asymmetrical distal extremity pain, which is disproportionate to the intensity of the initiating event. Sensory abnormalities appear early in the course of the disease and are more pronounced distally. No clear relationship between the injury and the area of pain distribution exist. Sweating abnormalities, whether hypohidrosis or hyperhidrosis are present in nearly all patients with CRPS I.

Answer 92

455. (D) Trophic changes, particularly abnormal hair growth, fibrosis, decreased dermal blood flow, thin glossy skin, and osteoporosis are more common in long standing cases, while the others described present in acute phases of the disease.

Answer 93

456. (D) The diagnosis of CRPS I and II follows the IASP clinical criteria. Bone scintigraphy may be a valuable tool to rule out other conditions. CRPS I is more common than CRPS II and the female to male ratio is from 2:1 to 4:1.

Answer 94

457. (D) The symptoms of CRPS II are similar to those of CRPS I, except that in CRPS II, there must be a lesion of a peripheral nerve structure and subsequent focal deficit are mandatory for the diagnosis.

Answer 95

458. (A) The majority of patients with CRPS present with significant psychologic distress, being the most frequent anxiety and depression. Current evidence is against the theory that CRPS is a psychogenic condition. The pain in CRPS is the cause of psychiatric problems and not vice versa. When compared to patients with low back pain, CRPS patients showed a higher frequency of somatization, but other psychologic parameters were similar.

Answer 96

459. (D) Activation and sensitization of cutaneous C fibers elicit a response consisting of a wheal (local edema), a reddening of the skin at the site of stimulus, and a spreading flare, were the responses described by Lewis (1927). [Lewis T. The blood vessels of the human s

Answer 97

460. (A) Muscle pain tends to be dull, poorly localized, and deep in contrast to the precise location of cutaneous pain. The diagnosis of myofascial pain syndrome is confirmed when the myofascial trigger point is identified by palpation. An active myofascial trigger point is defined as a focus of hyperirritability in a muscle or its fascia that causes the patient pain. B. Myofascial pain syndrome is usually thought of as a regional pain syndrome in contrast to fibromyalgia as a widespread syndrome; however, as many as 45% of patients with chronic myofascial pain syndrome have generalized pain in three or four quadrants. Hence, regional pain syndromes should raise a suspicion of myofascial pain syndrome, but patients with widespread musculoskeletal pain can also have myofascial pain syndrome. C. The American Pain Society showed general agreement with the concept that myofascial pain syndrome exists as an entity distinct from fibromyalgia. D. Systemic palpation differentiates between myofascial

Answer 98

461. (A) The minimum criteria that must be satisfied in order to distinguish a myofascial trigger point from any other tender area in muscle are a taut band and a tender point in that taut band. The existence of a local twitch response, referred pain, or reproduction of the person’s symptomatic pain increases the certainty and specificity of the diagnosis.

Answer 99

462. (C) D. This statement is true. End-plate noise is characteristic of, but not restricted to, the region of the myofascial trigger point. Hence, an objective EMG signature of the trigger point is now available for diagnostic and research purposes.

Answer 100

463. (B) A. There is no reason to believe that the placebo effect is unusually high with this or other soothing sprays. B. The stretch and spray technique combines the use of a vapocoolant spray with passive stretching of the muscle. Application of vapocoolant spray stimulates temperature and touch A-β skin receptors, thereby inhibiting C fiber and A-δ fiber afferent nociceptive pathways and muscle spasms, myofascial trigger points, and pain when stretching C. The patient is positioned comfortably and the muscle involved is sprayed with a vapocoolant spray, and then the muscle is stretched passively. With the muscle in the stretched position, the spray is applied again over the skin overlying the entire muscle, starting at the trigger zone and proceeding in the direction of, and including, the referred pain zone. After, the area is heated with a moist warm pack for 5 to 10 minutes. The patient is encouraged to perform full range of motion exercises with the body part. This technique can be used in physical therapy as a separate modality or following myofascial trigger point injections. D. It is expected that therapists can be more liberal once the spray has been applied owing to less patient discomfort.

Answer 101

464. (C) Myofascial release techniques and sustained pressure may soften and relax contracted and hardened muscles. The principle of the least possible force is applied, instead of applying high stress to the muscle. Effective myofascial release techniques include strumming. Strumming is when a finger runs across a taut band at the level of the trigger point over the nodules from one side of the muscle to the other. The operator’s fingers pull perpendicularly across the muscle rather than along the length of the fibers. When the nodule of the trigger point is encountered, light pressure is maintained until the operator senses tissue release. Other techniques include perpendicular and oscillating mobilizations, tissue rolling, connective tissue massage, and deep muscle massage consisting of effleurage (stroking massage technique) and pétrissage (kneading massage technique). After superficially passing over the muscles and adjacent muscles, massage therapy can be applied directly to the taut band and trigger points. Exercise and massage helped to reduce the number and intensity of trigger points, but the addition of therapeutic ultrasound did not improve the outcome.

Answer 102

465. (C) When treating myofascial pain, the physician must evaluate and, if indicated, treat both soft tissue and joint dysfunction. Restrictions in joint capsules hinder the function of the muscles that overlie the joint, while muscle irregularities result in joint capsule restrictions. Zygapophyseal joints may have pain referral patterns that are analogous to myofascial trigger points. The limited range of motion and weakness that results from this somatic dysfunction that affects muscles and joints can be reversed easily by manual therapy.

Answer 103

466. (D) Answers A., B., and D. are the therapeutic, diagnostic, and adjunctive indications for myofascial trigger point needling, respectively, with D. being the most common appropriate use of this technique. Rarely is dry needling done to eliminate a trigger point permanently, although, this can happen when the myofascial pain syndrome is acute. Inactivation of the myofascial trigger point appears to be the result of the mechanical action of the needle in the trigger point itself, because it also occurs when no medication is used. However, using local anesthetics is more comfortable for the patients and results in longer lasting pain reduction. After pinpointing and manually stabilizing the trigger point in the taut band with the fingers, the needle is quickly passed through the skin and into the trigger zone. Alocal twitch response or a report of referred pain indicates that the trigger zone has been entered. One-tenth to 0.2 mL of local anesthetic can be injected. The needle is pulled back to just below the skin, the angle is changed, and it is once again inserted through the muscle to another trigger zone. In this way a funnel-shaped volume of muscle can be evaluated without withdrawing the needle through the skin. The trigger zone is explored this way until no further local twitch responses are obtained. By this time, the taut band is usually gone and the spontaneous pain of the trigger point has subsided. Experienced patients know when trigger points have been inactivated.

Answer 104

467. (E) A., B., and C. While direct needling of myofascial trigger points appears to be an effective treatment, there is insufficient evidence that needling therapies have efficacy beyond placebo. These researchers also found no evidence to suggest that the injection of one material was more effective than another. They found no advantage to adding steroids, ketorolac, or vitamin B12 to local anesthetic. Steroids actually have the disadvantage that they are locally myotoxic and that repeated administration can produce all the unwanted side effects associated with steroids. For those who are allergic to local anesthetics, saline or dry needling can be used. D. No studies have been done to confirm or refute that diphenhydramine increases the efficacy of myofascial trigger points.

Answer 105

468. (E) Complications of trigger point injections: • Local bleeding into muscle • Local swelling • Painful contraction of a taut band from inadequate myofascial trigger point inactivation (missing the trigger point) • Infection • Perforation of a viscous body, most commonly the lung • Nerve injury from direct trauma by the needle • Transient nerve block • Syncope • Allergic reaction from the anesthetic Torticollis is a contraction, often spasmodic, of the muscles of the neck, chiefly those supplied by the spinal accessory nerve; the head is drawn to one side and usually rotated so that the chin points to the other side. While missing the trigger point during needling can cause a painful contraction of a taut band, torticollis has not been noted.

Answer 106

469. (B) Answers (A), (C), (D), and (E) are all causes of trigger point failure. C. Myofascial adhesions can possibly develop with secondary or “satellite” trigger points in nearby muscles. Trigger points appearing in muscles that are part of a functional unit must be treated together. Muscles that work together as agonists or in opposition as antagonists, constitute a functional muscle unit. For example the trapezius and levator scapula muscles work together as agonists in elevation of the shoulder, but are antagonists in rotation of the scapula, the trapezius rotating the glenoid fossa upward and the levator scapula rotating it downward.

Answer 107

470. (A) The most common anatomic variations that constitute mechanical factors precipitating myofascial pain are: leg length discrepancy and small hemipelvis, short upper arm syndrome, and the long second metatarsal syndrome. The leg length disparity syndrome produces a pelvic tilt that results in a cascade of chronic contraction and activation of a chain of muscles in an attempt to straighten the head and level the eyes. The quadratus lumborum and paraspinal muscles contract to correct the deviation of the spine caused by the pelvic tilt. Unwarranted loading perpetuates myofascial trigger points and may result in low back, head, neck, and shoulder pain. Trigger points in these persistently shortened and constantly contracted muscles are not easily inactivated until the muscles are unloaded. The quadratus lumborum is less likely to develop trigger points during the teenage years, and typically, unilateral low back pain is located on the side of the shorter leg because of early shrinking of the ipsilateral annulus fibrosis. In adults, it occurs on the side of the longer leg, caused by later spondylitic changes and quadratus lumborum shortening. A true leg length incongruity can be corrected by placing a heel lift on the shorter leg. The asymmetry caused by a small hemipelvis is corrected by placing an ischial or “butt” lift under the ischial tuberosity. Short upper arms cause forward shoulder roll, pectoral muscle shortening, and abnormal loading of the neck and trunk muscles as the individual attempts to find a comfortable position when seated. Along second metatarsal bone obscures the stable tripod support of the foot produced by the first and second metatarsal bones anteriorly and the heel posteriorly. In contrast, in this condition, weight is carried on a knife-edge from the second metatarsal head to the heel, overstressing the peroneus longus that attaches to the first metatarsal bone. Diagnostic callus formation takes place in the abnormally stressed areas: under the second metatarsal head, and on the medial aspect of the foot at the great toe and first metatarsal head. Correction is accomplished with support under the head of the first metatarsal.

Answer 108

471. (E) A. In women with chronic coldness and myofascial pain, ferritin has been found to be below 65%, largely because of an iron intake that is insufficient to replace menstrual loss. GI blood loss caused by antiinflammatories and parasitic diseases can also cause ferritin to be low. Ferritin represents the tissue bound nonessential iron stores in the body that supply the essential iron for oxygen transport and iron-dependent enzymes. Fifteen to 20 ng/mL is low and anemia is common at levels of 10 ng/mL or less. The association between depleted iron and chronic myofascial pain hints that ironrequiring enzymatic reactions may be limited in these people, which may produce an energy crisis in muscle when it is overloaded and thereby produce metabolic stress. Myofascial trigger points will not easily resolve in such instances, and iron supplementation in patients with chronic myofascial pain syndrome and serum ferritin levels below 30 mg/mL prevents or corrects these symptoms. B. and C. Folic acid and vitamin B12 function not only in erythropoiesis but also in central and peripheral nerve formation. Preliminary studies have shown that 16% of patients with chronic myofascial pain syndrome either were deficient in vitamin B12 or had insufficient levels of vitamin B12, and that 10% had low serum folate levels. D. Hypothyroidism can be suspected in chronic myofascial pain syndrome when coldness, dry skin/hair, constipation, and fatigue are also present. One study, found that under these circumstances (chronic) it occurred in 10% of patients. The myofascial trigger points tend to be more extensive in hypothyrotic patients. Hormone replacement may resolve many myofascial complaints and perpetuate a more permanent healthy state by allowing the implementation of physical therapy and trigger point inactivation. Also common in chronic musculoskeletal pain: low vitamin D, recurrent candida yeast infections, elevated uric acid levels, parasitic infections (especially amebiasis), Lyme disease, osteoarthritis, rheumatoid arthritis, Sjögren syndrome, carpal tunnel syndrome, and peripheral neuropathy secondary to DM. The postlaminectomy syndrome is frequently caused by myofascial trigger points.

Answer 109

472. (D) Biologic abnormalities that are detected in most fibromyalgia patients include • Dysfunctional sleep by polysomnography • Physiological or biochemical evidence for central sensitization • Temporal summation or second pain • Lowered thresholds to pressure-induced pain detected by brain imaging • Low levels of the biogenic amines to drive descending inhibition of nociception • Elevated spinal fluid levels of substance P • In primary fibromyalgia only, elevated spinal fluid levels of NGF

Answer 110

473. (D) The American College of Rheumatology sanctioned a study that led to the criteria for diagnosing fibromyalgia: a history of widespread pain for at least 3 months and pain sensitivity to 4 kg of digital pressure at 11 or more of 18 anatomically defined tender points. The criteria displayed sensitivity and specificity of 88.4% and 81.1%, respectively, for patients with fibromyalgia against normal control and disease control subjects with other painful conditions.

Answer 111

474. (C) In addition to the four areas mentioned in the question stem, five other locations exist: 1. Trapezius, at the middle of the upper muscle border 2. Supraspinatus, near the origins, above the spine of the scapula 3. Second rib, upper surface just lateral to the second costochondral junction 4. Gluteal, in upper outer quadrants of buttocks in anterior fold of muscle 5. Greater trochanter, posterior to the trochanteric prominence

Answer 112

475. (B) A. and B. Fibromyalgia is no longer considered a psychogenic disorder, however, there is a subgroup of fibromyalgia patients with associated depression or anxiety. C. It is believed that fibromyalgia patients who have had medical treatment are more apt to exhibit symptoms of depression than those in the community who have not. D. Sexual abuse in childhood is no longer considered a legitimate hypothesis for the origination of fibromyalgia.

Answer 113

476. (E) The female urethral syndrome or irritable bladder syndrome constitutes urinary frequency, dysuria, suprapubic discomfort, and urethral pain despite sterile urine.

Answer 114

477. (E) A., B., and C. Most patients (90%) with fibromyalgia have trouble sleeping. Some have difficulty getting to sleep (initial insomnia), while the majority awaken feeling alarmingly alert after only a few hours of sleep (mid insomnia) and are then unable to sleep soundly again until near morning (terminal insomnia). They usually awaken in the morning feeling incredibly stiff (lasts 45 minutes to 4 hours), mentally listless, and unrefreshed by their sleep. Hence, it is surprising that they have difficulty napping during the day. Moldofsky (2002) observed that 60% of fibromyalgia patients exhibit an electroencephalogram (EEG) pattern of sleep architecture called alpha wave intrusions of deep, delta wave, non–rapid eye movement sleep, which relates to subjective fatigue and psychologic distress but is not specific for fibromyalgia. Its prevalence in the healthy general population or in those with insomnia or dysthymia is only 25%. [

Answer 115

478. (E) Approximately 80% of patients with fibromyalgia have fatigue, while a small percentage of these actually meet the criteria for chronic fatigue syndrome (CFS). CFS is thought to affect approximately 4 per 1000 adults. For unknown reasons, CFS occurs more often in women and in adults in their 40s and 50s. The illness is estimated to be less prevalent in children and adolescents, but study results vary as to the degree. CFS often manifests with widespread myalgia and arthralgia, cognitive difficulties, chronic mental and physical exhaustion, often severe, and other characteristic symptoms in a previously healthy and active person. There remains no assay or pathologic finding which is widely accepted to be diagnostic of CFS. It remains a diagnosis of exclusion based largely on patient history and symptomatic criteria, although a number of tests can aid diagnosis. The fatigue of CFS is a feeling of weakness, while the fatigue of fibromyalgia is a feeling of tiredness. Fatigue may result from sedating medications (ie, TCAs being used for the treatment of insomnia in fibromyalgia). The rest of the differential diagnosis is quite extensive and must take into account: • Sleep disorders • Chronic infections • Autoimmune disorders • Psychiatric comorbidities • Neoplasia

Answer 116

479. (B) The rest of the answers are blatantly wrong. Secondary fibromyalgia may not be clinically distinguishable from that of primary fibromyalgia. Examples of secondary fibromyalgia: • Rheumatoid arthritis patients have fibromyalgia 30% of the time • Systemic lupus erythematosus (SLE) 40% • Sjögren syndrome 50% • Lyme disease 20%; the symptoms of fibromyalgia may develop 1 to 4 months after infection, often in association with Lyme arthritis. The signs of Lyme disease will normally resolve with antibiotics, but the fibromyalgia symptoms can persist • Chronic hepatitis • Inflammatory bowel disease • Tuberculosis • Chronic syphilis • Bacterial endocarditis • AIDS • Hypothyroidism • Hypopituitarism • Hemochromatosis Patients with rheumatic disease and concomitant fibromyalgia experience joint pain out of proportion to their synovitis. The practitioner should treat each of the conditions separately, because increasing the dosage of antirheumatic medications in the absence of active inflammation might have minimal effect on the pain augmented by the fibromyalgia.

Answer 117

480. (A) A. There are several neurochemical mediators of pain that appear to be factors in the pathogenesis of fibromyalgia: • Substance P • NGF (elevated in primary fibromyalgia, but not secondary) • Dynorphin A (normal or elevated in fibromyalgia) • Glutamate • Nitric oxide • Serotonin (decreased in fibromyalgia) • Noradrenaline (its inactive metabolite is significantly lowered in fibromyalgia) Substance P, NGF, dynorphin A, glutamate, and nitric oxide are considered pronociceptive because they transmit or intensify afferent signals, leading to the brain perceiving increased pain. On the other hand, serotonin, noradrenaline, the amino terminal peptide fragment of substance P, and endogenous opioids are considered to be antinociceptive because they hinder the transmission of nociceptive signals. B. All studies on substance P in fibromyalgia patients have found significantly higher average concentrations (two- to threefold) of substance P than in the CSF of healthy control subjects. However, the levels in other bodily fluids like saliva, serum, and urine, have been normal in fibromyalgia. C. The increased substance P is not because of decreased CSF substance P esterase activity, because the rate of cleavage of labeled substance P was found to be normal. In primary fibromyalgia, it is believed that NGF may be responsible for the elevated CSF substance P through its effects on central sensitization and neuroplasticity. D. Increased CSF substance P is not specific to fibromyalgia as it is also seen in painful rheumatic diseases irrespective of whether they have fibromyalgia. In patients that were status post–total hip replacement, elevated substance P prior to the procedure normalized after the surgery when the pain was gone. Certain chronic conditions such as low back pain and diabetic neuropathy present with lower than normal CSF substance P levels.

Answer 118

``` 481. (E) There is no current cure for fibromyalgia, so its management is • Nonspecific • Multimodal • Expectant • Symptomatic The goals are to • Decrease pain • Enhance sleep • Reinstate physical function • Maintain social interaction • Restore emotional balance • Decrease the excessive use of health care resources The best way to achieve these goals is through a multidisciplinary approach of • Education • Exercise • Physical therapy • Medications • Social support ```

Answer 119

482. (B) The shared decision concept emphasizes the importance of simultaneous exchange of information until an agreement between the doctor and patient can be achieved concerning available diagnostic and treatment approaches. It improves both patient and physician satisfaction, is preferred by patients, and sets the stage for better outcomes. A. The shared decision concept involves the physician and the patient. C. The physician may outline the treatment options with associated risks and benefits, while the patient may disclose information about their culture, fears, expectations, beliefs, and attitudes.

Answer 120

483. (E) A. All these techniques have been recommended for some patients with fibromyalgia. Progressive muscle relaxation was developed by Jacobson, who argued that since muscular tension accompanies anxiety, one can reduce anxiety by learning how to relax the muscular tension. Jacobson trained his patients to voluntarily relax certain muscles in their body in order to reduce anxiety symptoms. He also found that the relaxation procedure is effective against ulcers, insomnia, and hypertension. Selfhypnosis is a naturally occurring state of mind which can be defined as a heightened state of focused concentration (trance), with the willingness to follow instructions (suggestibility). Biofeedback is a form of alternative medicine that involves measuring a subject’s quantifiable bodily functions such as blood pressure, heart rate, skin temperature, sweat gland activity, and muscle tension, conveying the information to the patient in real time. This raises the patient’s awareness and conscious control of their unconscious physiological activities. By providing the user access to physiologic information about which he or she is generally unaware, biofeedback allows users to gain control of physical processes previously considered an automatic response of the autonomous nervous system. B. Cognitive-behavioral therapies have improved pain scores, pain coping, pain behavior, depression, and physical functioning over several months in fibromyalgia patients. It is suspected that follow-ups with booster sessions may prolong the effects. While some think that support groups perpetuate griping, a resource-oriented selfsupport group can help a fibromyalgia patient come to terms with an illness and provide invaluable patient education. C. Aerobic exercise is one of the first nonpharmacologic strategies promoted for patients with fibromyalgia. Low-impact aerobics of sufficient intensity to produce cardiovascular stimulation can decrease pain, enhance sleep, improve mood, increase energy, advance cognition, and better a patient’s overall outlook. Fibromyalgia patients who exercise deal better with the disease. However, a fibromyalgia patient can also experience increased pain if the exercise regimen is too strenuous or carried out during an inopportune time in the treatment. These patients should begin with low-impact exercises (ie, aqua therapy). Continuing the patient on the exercise regimen becomes easier as the patient’s pain decreases. D. Heat helps fibromyalgia patients with tenderness, stiffness, and cephalgia. It can also calm muscles, ease exercising, and accentuate a sense of well-being. Cold application also works. E. Some patients do obtain relief by light massages that progress to more deep sedative ones.

Answer 121

484. (E) A. and D. Dopamine is a neurotransmitter best known for its role in the pathology of schizophrenia, Parkinson disease, and addiction. There is also strong evidence for a role of dopamine in restless leg syndrome, which is a common comorbid condition in patients with fibromyalgia. In addition, dopamine plays a critical role in pain perception and natural analgesia. Accordingly, musculoskeletal pain complaints are common among patients with Parkinson disease, which is characterized by drastic reductions in dopamine owing to neurodegeneration of dopamine-producing neurons, while patients with schizophrenia, which is thought to arise, at least partly, from hyperactivity of dopamine-producing neurons, have been shown to be relatively insensitive to pain. Interestingly, patients with restless legs syndrome have also been demonstrated to have hyperalgesia to static mechanical stimulation. Fibromyalgia has been commonly referred to as a “stress-related disorder” owing to its frequent onset and worsening of symptoms in the context of stressful events. It was therefore proposed that fibromyalgia may represent a condition characterized by low levels of central dopamine that likely results from a combination of genetic factors and exposure to environmental stressors, including psychosocial distress, physical trauma, systemic viral infections, or inflammatory disorders (eg, rheumatoid arthritis, systemic lupus erythematosus). This conclusion was based on three key observations: (1) fibromyalgia is associated with stress; (2) chronic exposure to stress results in a disruption of dopamine-related neurotransmission; and (3) dopamine plays a critical role in modulating pain perception and central analgesia in such areas as the basal ganglia including the nucleus accumbens, insular cortex, anterior cingulate cortex, thalamus, periaqueductal gray, and spinal cord. In support of the “dopamine hypothesis of fibromyalgia,” a reduction in dopamine synthesis has been reported after using positron emission tomography (PET) and demonstrated a reduction in dopamine synthesis among fibromyalgia patients in several brain regions in which dopamine plays a role in inhibiting pain perception, including the mesencephalon, thalamus, insular cortex, and anterior cingulate cortex. A subsequent PET study demonstrated that, whereas healthy individuals release dopamine into the caudate nucleus and putamen during a tonic experimental pain stimulus (ie, hypertonic saline infusion into a muscle bed), fibromyalgia patients fail to release dopamine in response to pain and, in some cases, actually have a reduction in dopamine levels during painful stimulation. Moreover, a substantial subset of fibromyalgia patients respond well in controlled trials to pramipexole, a dopamine agonist that selectively stimulates dopamine D2/D3 receptors and is used to treat both Parkinson disease and restless legs syndrome. B. Tryptophan is decreased in the serum and CSF of fibromyalgia patients. Serotonin is low in fibromyalgia serum. 5-Hydroxytrytophan, the intermediary between tryptophan and serotonin, and 5-hydroxyindole acetic acid, the by-product of serotonin metabolism, are both low in the CSF of patients with fibromyalgia. The excretion in urine of 5-hydroxyindole acetic acid was lower than normal in patients with fibromyalgia, lower in females versus males, and lower in females with fibromyalgia versus females who don’t have fibromyalgia. C. The numbers of active tender points in fibromyalgia patients directly correlated with the concentration of serotonin in fibromyalgia sera.

Answer 122

485. (C) Fibromyalgia, a common chronic pain condition characterized by widespread pain, is thought to originate largely from altered central neurotransmission. In this study, a sample of 17 fibromyalgia patients and 17 age- and sexmatched healthy controls, were compared using μ-opioid receptor PET. PET scans measure blood flow in the brain. It was demonstrated that fibromyalgia patients display reduced μ-opioid receptor binding potential within several regions known to play a role in pain modulation, including the nucleus accumbens, the amygdala, and the dorsal cingulate. The reduced availability of the receptors could result from a reduced number of opioid receptors, enhanced release of opioids that are produced naturally by the body, or both. These findings indicate altered endogenous opioid analgesic activity in fibromyalgia and suggest a possible reason for why exogenous opiates appear to have reduced efficacy in this population. The reduced availability of the receptor was associated with greater pain among people with fibromyalgia. Answers (A), (B), (D), and (E) have no merit.

Answer 123

486. (C) A. and B. The sedating tricyclic biogenic amine reuptake drugs, such as amitriptyline and cyclobenzaprine, are the most commonly prescribed medications for fibromyalgia insomnia. These medications are mostly used in low doses to improve sleep and to enhance the effects of analgesics (amitriptyline 10-25 mg at night and cyclobenzaprine 5-10 mg at night). Patients can develop tachyphylaxis to them, but a 1-month holiday from the drugs may help restore effectiveness. C. SSRIs are so stimulating that they can interfere with sleep, and should never be taken at bedtime. D. Benzodiazepine decrease anxiety and allow less troubled sleep (alprazolam, clonazepam). Clonazepam in particular can help control nocturnal myoclonus when it is associated with fibromyalgia. E. Pregabalin is a sedative in addition to an antinociceptive medication.

Answer 124

488. (B) In osteolytic bone metastases, the most commonly involved sites are vertebrae, pelvis, ribs, femur, and skull. Upper and lower extremity bones, except femur, are not commonly involved.

Answer 125

489. (A) Multiple sites of metastatic epidural spinal cord compression occur in 17% to 30% of all patients. This is particularly common in prostatic and breast carcinoma and uncommon in lung cancer.

Answer 126

490. (E) Bisphosphonates decrease resorption of bone directly, by inhibiting the recruitment and function of osteoclasts, and indirectly, by stimulating osteoblasts. In patients with bony metastases, they are the standard therapy for hypercalcemia after rehydration, and have the greatest effect in patients with breast cancer and multiple myeloma. Bisphosphonates also have an acute pain-relieving effect, which is thought to be derived from the reduction of various pain-producing substances.

Answer 127

491. (E) Both gabapentin, an antiepileptic drug, and amitriptyline, TCA, are widely used in treating neuropathic pain, which is often a significant component of a cancer pain syndrome. Samarium 153 belongs to the group of bone-seeking radiopharmaceuticals emitting medium- to high-energy beta particle radiation. The most commonly used agent in this group is Strontium 89 with a documented pain-relieving effect in patients with bony metastases. Samarium 153, rhenium 186, and phosphorus 32 are also available for clinical use.

Answer 128

493. (E) Both gabapentin (an antiepileptic drug) and amitriptyline (a TCA) are widely used in treating neuropathic pain, which is often a significant component of a cancer pain syndrome. Samarium 153 belongs to the group of bone-seeking radiopharmaceuticals emitting medium- to high-energy beta particle radiation. The most commonly used agent in this group is Strontium 89 with a documented pain-relieving effect in patients with bony metastases. Samarium 153, rhenium 186, and phosphorus 32 are also available for clinical use.

Answer 129

497. (B) In clinical practice, most peripheral neuropathies do not produce chronic pain as impairment of nerve fibers carrying nociception should result in decrease pain perception. In most neuropathies, all components of the peripheral nervous system are affected, presenting with variable sensorimotor deficit and autonomic dysfunction.

Answer 130

498. (B) The most commonly activated areas during acute processing of pain in humans are S-I, S-II, anterior cingulated cortex, insular cortex, prefrontal cortex, thalamus, and cerebellum.

Answer 131

499. (C) Many studies suggest that axonal injury along the nociceptive fiber in the peripheral nervous system is the main cause of neuropathic pain. Several conditions where the small fibers are spared support this concept. The Charcot-Marie-Tooth disease also known as hereditary motor and sensory neuropathy where the demyelination is limited to large myelinated fibers, do not manifest with pain. Segmental anhidrosis or Ross syndrome where only autonomic fibers are affected, is also not painful. On the other hand, conditions affecting the small nerve fibers, like diabetic neuropathy or Fabry disease, a rare lipid-storage disorder, commonly present with pain.

Answer 132

500. (A) Chronic renal failure is associated with selective loss of large nerve fibers which is rarely painful. Common symptoms include restless leg syndrome, distal numbness, and paresthesias, with distal weakness usually in the lower extremities.

Answer 133

501. (E) Cytokines, a heterogeneous group of peptides activate the immune system and mediate inflammation. They form a complex bidirectional system that communicates between the immune system and the CNS. IL-1 is the most extensively studied cytokine. Intraplantar as well as intraperitoneal injections of IL-1 reduce mechanical and probably thermal nociceptive threshold, which may be blocked by local cyclooxygenase inhibitors, supporting the role of prostaglandins in the process. The communicating pathway between the peripheral cytokines and the brain may involve vagal afferents terminating in the nucleus tractus solitarius and circumventricular sites that lack a blood-brain barrier.

Answer 134

502. (A) Blockade of the sympathetic innervation of the head can be documented by the presence of Horner syndrome, which is characterized by myosis, ptosis, and enophthalmus. Associate findings include conjunctival injection, nasal congestion, and facial anhidrosis. Horner syndrome is an expected finding after blockade of the sympathetic afferents to the face and can not be considered a complication.

Answer 135

503. (E) Behavioral studies have shown that activation of NMDA receptors are required for the development and maintenance of pain-related behaviors. Calcium channels are the key ion involved in the release of transmitters. Different subtypes of calcium channels (L-, N-, and P/Qtypes) may have a differential role depending on the nature of the pain state. The N-type voltagedependent calcium channels appear to be the predominant isoform involved in the pre- and postsynaptic processing of sensory nociceptive inputs. Animal and clinical studies have shown partial pain relief with the use of a specific N-type calcium channel blocker synthetically derived from a conotoxin, SNX-111. The generic name of this substance derived from the snail’s natural conotoxin is Ziconotide.

Answer 136

504. (A) The effectiveness of opioid agonists in the management of neuropathic pain has created significant controversy over the last two decades. Recent studies have increased our understanding about this topic. In patients with SCI and stroke, IV morphine showed poor effects in reducing spontaneous pain, but significantly reduced stroking allodynia. Other studies used alfentanil in the treatment of neuropathic pain independently of the etiology and observed decrease in dynamic, stroking allodynia, and spontaneous pain, while increase the temperature at which heat pain was detected and decrease the temperature at which cold pain was detected.

Answer 137

505. (A) Action potentials in the dorsal horn neurons are mediated by glutaminergic excitatory postsynaptic potentials, this activity may be inhibited predominantly by the inhibition produced by GABA and/or glycine which causes fast inhibition of postsynaptic potentials. GABAAand glycine receptors are ligand-gated Cl− channels, while GABAB, adenosine, and opioids exert their typically produced postsynaptic hyperpolarization by activation of K+ channels.

Answer 138

506. (C) More intense or sustained noxious peripheral stimulation induce primary afferent nociceptors to discharge at higher frequencies and to release from central nociceptor terminals neuromodulator peptides like CGRP, substance P, and glutamate. As more and more dorsal horn neurons get depolarized, NMDA receptors open by removing the Mg2+ blockade, allowing for intracellular calcium levels to increase. The end result of these intracellular signaling cascades is windup.

Answer 139

507. (B) Histopathological studies in patients with PHN have found ganglion cell loss and fibrosis and atrophy of the dorsal horn, DRG, dorsal root, and peripheral nerves. Up to 30% of patients with PHN have no loss of sensation in the affected dermatome demonstrating minimal or no loss of neuronal function and interestingly thermal sensory thresholds are not affected or even decreased. Antiviral drugs have shown disappointing results in patients with chronic PHN. Heat hyperalgesia is more common than cold hyperalgesia, which only occurs in less than 10% of the patients.

Answer 140

508. (B) Phantom pain is equally frequent in men and women and is not influenced by age in adults, side or level of amputation, and cause (civilian versus traumatic) of amputation. Phantom pain is less frequent in young children and congenital amputees.

Answer 141

509. (A) Phantom pain is usually intermittent. Only a few patients are in constant pain. Episodes of pain are most often reported to occur daily, or at daily or weekly intervals. Phantom pain is usually localized to the distal parts of the missing limb. Pain is normally felt in the fingers and palm of the hand in upper limb amputees and toes, foot, or ankle in lower limb amputees. This may be because of the larger cortical representation of the hand and foot as opposed to the lesser representation of the more proximal parts of the limb. The character of phantom pain is usually described as shooting, pricking, burning, stabbing, pins and needles, tingling, throbbing, cramping, and crushing

Answer 142

510. (D) Phantom sensations are more common than phantom pain, and are experienced by nearly all amputees. The incidence of phantom sensations ranges from 71% to 90%, 8 days to 2 years after amputation. Duration and frequency, but not incidence, decrease as time passes. Phantom sensations are less common in congenital amputees and in patients who underwent amputation before the age of 6 years Nonpainful sensations normally appear within the first days after amputation. The amputee often wakes up from anesthesia with a feeling that the amputated limb is still there. Just after the amputation, the phantom limb often resembles the preamputation limb in shape, length, and volume. As time passes, the phantom fades, leaving back the distal parts of the limb. For example, upper limb amputees may feel hand and fingers, and lower limb amputees may feel foot and toes. Commonly, upper limb amputees feel the fingers clenched in a fist, while the phantom limb of lower limb amputees is often described as toes flexed In some cases, phantom sensations include feeling of movement and posture; however, in others only suggestions of the phantom are felt. Telescoping (shrinkage of the phantom) is reported to occur in about one-third of patients. The phantom progressively approaches the stump and eventually becomes attached to it. It has even been experienced within the residual limb. Phantom pain does not retard shrinkage of the phantom.

Answer 143

511. (B) Changes occur in the DRG cells, after a complete nerve cut. Cells in the DRG show similar abnormal spontaneous activity and increased sensitivity to mechanical and neurochemical stimulation. Local anesthesia of neuromas abolished tap-induced afferent discharges and tapinduced accentuation of phantom pain, but spontaneous pain and recorded spontaneous activity were unchanged which is consistent with the activity in DRG cells. DRG cells exhibit major changes in the expression of sodium channels, with an altered expression pattern of different channels. The sympathetic nervous system may play a role in generating and especially in maintaining phantom pain. It was noted that application of noradrenaline or activation of the postganglionic sympathetic fibers excites and sensitizes damaged, but not normal nerve fibers. Injecting noradrenaline into the skin can reestablish neuropathic pain that has just been relieved with a sympathetic block and injecting into a neuroma is reported to be intensely painful. The catecholamine sensitivity may also manifest itself in the skin with a colder limb on the amputated side, and it has been implied that phantom pain intensity is inversely related to the skin temperature of the stump.

Answer 144

512. (A) 1. Numerous studies on preemptive analgesia using epidural, epidural/perineural, and just perineural administration have been conducted. Only two were noted to utilize proper patient randomization and blinding. 2. Persistent pain has been reported in up to 80% of patients after limb amputation. The mechanisms are not fully understood, but nerve injury during amputation is important, with evidence for the crucial involvement of the spinal NMDA receptor in central changes. The study objective was to assess the effect of preemptively modulating sensory input with epidural ketamine (an NMDA antagonist) on postamputation pain and sensory processing. 3. The aim of preemptive analgesia is to avoid spinal sensitization by blocking, in advance, the cascade of intra-neuronal responses that take place after peripheral nerve injury. True preemptive treatment is not likely possible in patients scheduled for amputation as most have been suffering from ischemic pain and are almost certainly presenting with preexisting neuronal hyperexcitability. To conclude: epidural blockade has been shown to be effective in the treatment of preoperative ischemic pain and postoperative stump pain.

Answer 145

513. (A) Acidic foods, such as orange juice, carbonated drinks, tomatoes, and vinegar may aggravate the symptoms of interstitial cystitis. Spicy food, alcohol, coffee, chocolate, tea, cola, and smoking should also be either restricted or completely eliminated.

Answer 146

514. (C) Sodium pentosan polysulfate (Elmiron) is an oral analogue of heparin. Inside the bladder, it acts as a synthetic glycosaminoglycan layer and fortifies bladder wall defenses from bacteria by increasing the antiadherent surface of the bladder mucosa.

Answer 147

515. (E) Endogenous opioid peptides as other neurotransmitters, such as serotonin, norepinephrine, and GABA, are thought to be involved in descending inhibition.

Answer 148

516. (E) Anxiety, fear, helplessness, and sleep deprivation are part of the vicious cycle of pain. Cultural background has been shown to play a significant role in the individual’s pain response.

Answer 149

518. (A) There is evidence that pain-related impairment of intestinal motility may be relieved by epidural local anesthetics.

Answer 150

519. (B) Pain in the area of sensory loss, also called deafferentation pain, or anesthesia dolorosa, is a prominent sign of a neuropathic pain. Neuropathic pain generally responds less well to opioid treatment than somatic pain. One of the significant signs of neuropathic pain is also allodynia-a painful response to nonpainful stimuli. Tapping of neuromas produces radiating electric shock sensation in the distribution of the damaged nerve is called Tinel sign— another feature of a neuropathic pain.

Answer 151

521. (E) Post–burn injury pain has two components: a constant background pain and an intermittent procedure-related pain. Continuous infusion of opioids is useful for control of the background component of pain. Pain related to wound care, dressing changes, and others (procedure-related pain) may require brief but profound analgesia. This may be achieved by administration of supplemental IV opioids, or addition of the adjuvant drugs, such as IV ketamine, IV benzodiazepines, inhaled nitrous oxide-oxygen mixture, or even general anesthesia.

Answer 152

522. (E) All answers are correct. Aconcomitant head injury may be associated with increased intracranial pressure, which could be considered a contraindication for an epidural catheter placement.6yt

Answer 153

523. (B) Two types of pain may be found in PHN: a steady burning or aching, the other, a paroxysmal, lancinating pain. Both may occur spontaneously and are usually aggravated by any contact with the involved skin.

Answer 154

524. (E) All of the listed groups of medication were found to be effective to some extent in the treatment of PHN. Amultimodal approach seems to be more effective because of the synergistic effect different modes of action

Answer 155

527. (A) Oral steroids may provide pain relief in acute phase of herpes zoster, as well as shorten the time to full crusting of lesions. However, controlled trials showed no benefit in the prevention of PHN. With the development of antiviral agents, the use of oral steroids is currently not recommended because of more frequent side effects

Answer 156

528. (B) Diabetic amyotrophy is a condition occurring in diabetic patients, more commonly with type-2 diabetes, which begins with pain in the thighs, hips, and buttocks. Weakness and atrophy of the proximal pelvic muscles groups, iliopsoas, obturator, and adductor muscles follows the painful manifestations. It usually does not involve sciatic nerve, or distal muscles of the lower extremity. The therapy for diabetic amyotrophy is primarily supportive.

Answer 157

529. (A) Neuropathic arthropathy (Charcot joint) develops most often in weight-bearing joints. The predominant cause is DM, but also associated with neuropathic arthropathy are leprosy, yaws, congenital insensitivity to pain, spina bifida, myelomeningocele, syringomyelia, acrodystrophic neuropathy, amyloid neuropathy, peripheral neuropathy secondary to alcoholism and avitaminosis, SCI, peripheral nerve injury, postrenal transplant arthropathy, intraarticular steroid injections, and syphilis. The etiology of Charcot joint is believed to be related to the destruction of afferent proprioceptive fibers and subsequent unrecognized trauma to the joint.

Answer 158

530. (D) Across-sectional, community-based survey of 255 patients with DPNP recruited through the offices of endocrinologists, neurologists, anesthesiologists, and primary care physicians found that NSAIDs were the most commonly used medications, with 46.7% reporting their use. This is despite the fact, that there is little evidence to support the efficacy of NSAIDs in DPNP, and that NSAIDs have a high potential for renal impairment in patients with diabetic neuropathy.

Answer 159

532. (A) Given the frequency of imperfect glycemic control, attempts have been made to identify oral medications which can target downstream metabolic consequences of hyperglycemia, thereby preventing production of reactive oxygen species, which are felt to contribute to diabetic neuropathy. Unfortunately, trials of aldose reductase inhibitors, which decrease aberrant metabolic flux, have been disappointing (eg, sorbinil, zopolrestat).

Answer 160

533. (B) The combination of trigeminal neuralgia and hemifacial spasm is known as convulsive tic. It is reported to be more severe in women than in men. Occasionally, strong spasms involve all of the facial muscles unilaterally almost continuously. Seldom, facial weakness may be present. Convulsive tic may indicate the presence of a tumor, vascular malformation, or ecstatic dilation of the basilar artery, compressing the trigeminal or facial nerves.

Answer 161

534. (A) The diagnostic criteria for trigeminal neuralgia are: shooting, electric-like, sharp, severe pain which last for seconds but sometimes experienced together with pain-free intervals. The pain is periodic with weeks or months without pain. The pain is typically unilateral and triggered by light touch, eating, talking, or washing.

Answer 162

535. (D) Rarely, trigeminal neuralgia is the presenting symptom of multiple sclerosis. More often, trigeminal neuralgia presents in patients with advanced stages of multiple sclerosis.

Answer 163

536. (C) Glycerol is a nonselective neurolytic agent. Although less common than with radiofrequency thermocoagulation, the frequency of patients affected by sensory loss is high. Recurrence rate is the highest among all ablative techniques.

Answer 164

537. (E) The trigeminal neuralgia is the most common cranial neuralgia and its most frequent form is idiopathic. The incidence of trigeminal neuralgia is 5.7 per 1000 females and 2.5 per 1000 in males. Patients with multiple sclerosis have a higher risk for trigeminal neuralgia. Other potential relation was found in patients with family history.

Answer 165

538. (A) The trigeminal neuralgia is a primary axonal degenerative disease. The ignition hypothesis combines the current knowledge of the role of ion channels in the development of neuropathic pain. Focal demyelination adjacent to the area of arterial compression has been shown by electron microscopy in patients undergoing posterior fossa surgery. In up to 30% of patients with arterial cross compression, there is a groove or an area of discoloration lateral where the root entry zone would be expected.

Answer 166

539. (C) SIH and PDPH have similar presentation, pathophysiology, and treatment. The most important distinction is the initiating event, which is obvious in PDPH. MRI of the brain with gadolinium enhancement in patients with SIH shows meningeal enhancement, and thickening, and a possible caudad shift of the brain toward the foramen magnum. The most common location of spontaneous dural tear is the thoracic region followed by the cervicothoracic and thoracolumbar junction regions.

Answer 167

540. (B) It has been shown that keeping a supine position for 2 hours after the EBP provides higher chances of success when compared with 30 minutes. Although initial relief is very high (close to 100%), the overall long-term relief of PDPH after EBP is between 61% and 75%. The effectiveness of EBP is reduced when the dural tear was caused by a large-size needle.

Answer 168

541. (C) Two important factors in the prevention of PDPH are the use of small and blunt bevel spinal needles. Other factors that may prevent the development of PDPH include the use of paramedian approach (with angles of 35° or greater) and the use of intrathecal catheters. Bed rest as a preventive measure is not effective.

Answer 169

542. (E) Cervicogenic headache is defined as headache that arises from painful disorders of structures in the upper neck, which generates irritation of the upper cervical roots or their nerve branches. The current classification by the IHS and the IASP accepts these headaches to be unilateral or bilateral. All the other options in the questions are true.

Answer 170

543. (E) According to the International Headache Society and the IASP, cervicogenic headache (CGH) is a pain originated in the neck, mostly unilateral although it may be bilateral, exacerbated by neck movement, and alleviated by local anesthetic block of the occipital nerve. The prevalence of CGH is 0.4% to 2.5% in the general population and may account for up to 15% to 20% of patients with chronic headache, more common in females with a 4:1 ratio and mean age of patients with 42.9 years.

Answer 171

544. (A) During the aura in classic migraine a decrease in cerebral blood flow decreases spreads from the occipital cortex. The variation in the cerebral blood flow causes the aura and activates trigeminal nerve endings. It is possible that cortical spreading depression may stimulate peripheral nerve terminals of the nucleus caudalis trigeminalis.

Answer 172

545. (B) During the aura in classic migraine there is a decrease in cerebral blood flow. In patients with classic migraine (migraine with aura), there is increase of cerebral blood flow that happens after the headache begins and this change persist until the headache resolves. In migraine without aura, there is no change in cerebral blood flow.

Answer 173

546. (E) Migraine is a risk factor for affective disorders. When comparing with nonmigraineurs, patients with migraine have a 4.5-fold increased risk of major depression, a sixfold risk of manic episodes, a threefold increase in anxiety disorder, and a sixfold prevalence in panic disorder.

Answer 174

547. (A) Although migraine begins in the first three decades of life, the higher prevalence is in the fifth one. Family history is a common finding, and pregnant females often experience worsening symptoms in the first trimester and improvement during the third. Many women experience improvement of their symptoms after natural, but not surgical menopause.

Answer 175

548. (C) Muscle tenderness is common in patients suffering from TTH, but is not secondary to pericranial muscle contraction or ischemic pain in response to emotion or stress. Increased EMG activity is independent of tenderness and pain. Reduced pain threshold observed in chronic TTH may be the result of low CNS levels of serotonin. Although TTH can begin at any age, the most common onset is during adolescence and young adulthood. The prevalence of TTH decreases with increasing age.

Answer 176

549. (E) For any structure to be considered as a source for low back pain it must have the following characteristics: a nerve supply, the capability of causing low back pain similar to what is seen clinically (ideally in healthy volunteers), a susceptibility to disease or injuries known to be painful, and should be able to be shown as a source of pain using diagnostic techniques of known reliability and validity

Answer 177

550. (A) There have been RCTs showing that lumbar supports and back schools are not effective in preventing back pain. Exercise has been proven by RCTs to prevent back pain. To date, there are no RCTs on the effectiveness of ergonomics in preventing back pain.

Answer 178

551. (E) The most significant anomalies of the lumbar nerve roots are aberrant courses and anastomoses between nerve roots. Type 1 anomalies are aberrant courses of which there are two kinds. Type 1A describes two pairs of nerve roots arising from a single dural sleeve, whereas type 1B defines a dural sleeve arising from a low position on the dural sac. Type 2 anomalies include those in which the number of roots in the intervertebral foramen varies. An empty foramen is classified as type 2A, and a foramen with extra nerve roots is known as a type 2B. Type 3 anomalies are those involving extradural anastomoses between roots in which a bundle of nerves leaves on dural sleeve to enter one nearby. Type 3 anomalies may coexist with type 2 anomalies.

Answer 179

552. (E) The IASP published standardized terms to define low back pain as pain perceived to arise for lumbar spinal pain and/or sacral spinal pain. Lumbar spinal pain is defined as pain perceived to arise from the region bordered superiorly by an imaginary line through the T12 spinous process, inferiorly by a line through the S1 spinous process, and laterally by the lateral borders of the erector spinae. Sacral spinal pain is that defined as pain perceived to arise from the region bordered laterally by imaginary vertical lines through the posterior superior and posterior inferior iliac spines, superiorly by a transverse line through the S1 spinous process, and inferiorly by a transverse line through the posterior sacrococcygeal joints.

Answer 180

553. (E) Transforaminal injections have been the cause of some of the most worrisome recent complications. These included cerebellar and cerebral infarct, SCI, and infarction, massive cerebral edema, paraplegia, visual defects with occlusion following particulate depo-corticosteroids, anterior spinal artery syndrome, persistent neurologic deficits, transient quadriplegia, cauda equina syndrome, subdural hematoma, and paraplegia following intracordal injection during attempted epidural anesthesia under general anesthesia.

Answer 181

554. (C) Despite its controversial history, disc stimulation (formerly known as discography) remains the only means by which to determine whether or not a disc is painful. The test is positive if upon stimulating a disc the patient’s pain is reproduced provided that stimulation of adjacent discs does not reproduce their pain. Discs are also considered to be symptomatic only if pain is reproduced at injection pressures less than 50 psi and preferably less than 15 psi. At injection pressures greater than 80 psi, some discs are painful in normal individuals. The stimulation of discs has been complemented by another approach, heating a wire electrode that has been inserted into a disc annulus. Heating a disc evokes pain that is perceived in the back. This pain may also radiate to the lower extremities and be responsible for referred pain in the thigh and leg.

Answer 182

555. (B) Chemonucleolysis is indicated for contained disc protrusions causing sciatic pain that have been unresponsive to conservative management. The injection is contraindicated for extruded and sequestered disc herniations, and in patients with cauda equine syndrome. Relative contraindications include previous chymopapain injections, previous surgery for lumbar disc herniation, spinal stenosis, severe degenerative disc or facet osteoarthritis, and spondylolisthesis.

Answer 183

556. (E) Inappropriate or premature selection of patients for surgery is the most common cause of FBSS. The second most common cause is persistence of pain secondary to irreversible neural injury. A less common cause is inadequate surgery. Lastly, a variant of FBSS results from new pathologic processes initiated by the initial surgery.

Answer 184

557. (A) The American Association of Neurological Surgeons and the American Academy of Orthopedic Surgeons have published criteria for patient selection for elective lumbosacral spine surgery. They are applicable to new patients, as well as FBSS patients. They include the following: 1. Failure of conservative therapy. 2. An abnormal diagnostic imaging study showing nerve root or cauda equina compression and/or signs of segmental instability consistent with the patient’s signs/symptoms. Radicular pain with one or more of the following: (a) corresponding dermatomal segmental sensory loss, (b) corresponding dermatomal motor loss, (c) abnormal deep tendon reflexes consistent with appropriate dermatomes.

Answer 185

558. (A) There are three main types of cervical spine involvement in rheumatoid arthritis: atlantoaxial subluxation, cranial settling, and subaxial subluxation. The inflammatory changes affecting synovial joints and bursae target structures lined with a synovial membrane in the cervical spine. Patients with cervical spine involvement are thought to have a more severe form of rheumatoid arthritis, and their prognosis is usually worse. Occipital condylar fractures result from a full-energy blunt trauma complemented with axial compression, lateral bending, or rotational injury to the alar ligament.

Answer 186

559. (E) The Québec Task Force (QTF) was a task force sponsored by the Société de l’assurance automobile du Québec, the public auto insurer in Quebec, Canada. In 1995, the QTF submitted a report on WADs which made specific recommendations on prevention, diagnosis, and treatment of WAD. These recommendations have become the base for Guideline on the Management of Claims Involving Whiplash- Associated, a guide to classifying WAD and guidelines on managing the disorder. The full report titled Redefining “Whiplash” was published in the April 15, 1995 issue of Spine. An update was published in January 2001. Four grades of WAD were defined by the QTF : Grade 1: Complaints of neck pain, stiffness or tenderness only but no physical signs are noted by the examining physician. Grade 2: Neck complaints and the examining physician finds decreased range of motion and point tenderness in the neck. Grade 3: Decreased range of motion plus neurologic signs, such as decreased deep tendon reflexes, weakness, insomnia, and sensory deficits. Grade 4: Neck complaints and fracture or dislocation, or injury to the spinal cord.

Answer 187

560. (A) The distraction test is performed with an examiner standing behind a seated patient, lifting their head from the chin and occiput, and removing the weight of the head from the neck. If relief of neck pain occurs, the test might point to foraminal intrusion on a nerve root as the source of pain.

Answer 188

561. (A) Spurling maneuver is used to identify nerve root compression or irritation. The head is tilted toward the affected side and manual pressure is applied to the top of the head. Radicular pain should be reproduced with this maneuver. Valsalva test allows a patient to experience painful or sensory changes when bearing down. The test increases intrathecal pressure and exacerbates compression within the cervical canal caused by tumors, infections, disc herniations, or osteophyte changes. The distraction test is performed with an examiner standing behind a seated patient, lifting their head from the chin and occiput, and removing the weight of the head from the neck. If relief of neck pain occurs, the test might point to foraminal intrusion on a nerve root as the source of pain. Adson test is used to assess vascular compromise because of subclavian artery impingement from thoracic outlet syndrome.

Answer 189

562. (D) Peripheral neuropathic pain syndromes in patients with HIV infection tend to be specific to the stage of HIV infection as outlined in answers (1) through (3).

Answer 190

563. (A) In patients with predominantly sensory neuropathy of AIDS, the complaints are mostly sensory. However, the NCV and EMG studies demonstrate both sensory and motor involvement.

Answer 191

564. (E) Psychostimulants, such as dextroamphetamine, methylphenidate, may be useful agents in patients with HIV infection or AIDS who are cognitively impaired. Psychostimulants enhance the analgesic effects of the opioid drugs. They are also useful in diminishing sedation secondary to opioids. In addition, psychostimulants improve appetite, promote sense of well-being, and improve feelings of weakness and fatigue in patients with malignancies.

Answer 192

565. (B) Tissue injury generates several major pain mediators, including, but not limited to IL-1, bradykinin, K+, H+, histamine, substance P, and CGRP. The pathway for painful stimuli is subject not only to activators, sensitizers, and facilitators but also to inhibitors. Serotonin, enkephalin, β-endorphin, and dynorphin are endogenous central pain inhibitors.

Answer 193

566. (E) SCD is a quadrumvirate of: (1) pain syndromes, (2) anemia and its sequelae, (3) organ failure, including infection, and (4) comorbid conditions. Pain, however, is the insignia of SCD and dominates its clinical picture throughout the life of the patients. Pain may precipitate or be itself precipitated by the other three components of the quadrumvirate.

Answer 194

567. (C) Avascular necrosis is the most commonly observed complication of SCD in adults. Although it tends to be most severe and disabling in the hip area, it is a generalized bone disorder in that the femoral and humeral heads and the vertebral bodies may be equally affected. Treatment of avascular necrosis is symptomatic and includes providing nonopioid or opioid analgesics in the early stages of the illness; advanced forms of the disease require total joint replacement. Core decompression appears to be effective in the management of avascular necrosis if performed during its early stages

Answer 195

568. (B) Leg ulceration is a painful and sometimes disabling complication of sickle cell anemia that occurs in 5% to 10% of adult patients with SCD. With good localized treatment, many ulcers heal within a few months. Leg ulcers that persist beyond 6 months may require skin grafting, although results of this treatment have been disappointing. Recent advances in management include the use of platelet-derived growth factor, prepared either autologously (Procuren) or by recombinant technology (Regranex).

Answer 196

.570. (A) Sickle cell anemia affects millions throughout the world. It is particularly common among people whose ancestors come from sub- Saharan Africa; Spanish-speaking regions (South America, Cuba, Central America); Saudi Arabia; India; and Mediterranean countries such as Turkey, Greece, and Italy

Answer 197

.571. (E) General management of vasoocclusive crisis during pregnancy begins with aggressive hydration to increase intravascular volume and decrease blood viscosity. Supplemental oxygen is essential in those patients with hypoxemia. Partial exchange transfusions are used to reduce polymerized hemoglobin S. Prophylactic transfusions may reduce the incidence of severe sickling complications during pregnancy.

Answer 198

572. (E) Some patients with SCD are opioid-tolerant secondary to their home opioid management. Therefore, the home opioid requirement should be taken into account for faster and more efficient pain control of sickle crisis pain. Opioid titration, however, may require some additional care because hypoxemia and hypercarbia further exacerbate sickling of erythrocytes.

Answer 199

573. (D) Autonomic dysreflexia is a potential lifethreatening condition, which is triggered by sensory input below the lesion and manifests itself with increased blood pressure, headache, and a risk of cerebral hemorrhage and seizure.

Answer 200

574. (C) Anterior cord syndrome is a common incomplete cord syndrome. A patient with anterior cord syndrome may exhibit complete motor and incomplete sensory loss, with the exception of retained trunk and lower extremity deep pressure sensation and proprioception. This syndrome carries the worst prognosis for return of function, and only a 10% chance of functional motor recovery has been reported.

Answer 201

575. (B) Posterior cord syndrome is a rare incomplete cord syndrome consisting of loss of the sensations of deep pressure and deep pain and proprioception, with otherwise normal cord function. The patient ambulates with a footslapping gait similar to that of someone afflicted with tabes dorsalis.

Answer 202

576. (E) Brown-Séquard syndrome is an uncommon incomplete spinal cord syndrome. It is anatomically a unilateral cord injury, such as a missile injury. It is clinically characterized by a motor deficit ipsilateral to the SCI in combination with contralateral pain and temperature hypesthesia. Almost all these patients show partial recovery, and most regain bowel and bladder function and the ability to ambulate.

Answer 203

577. (A) Anticonvulsants have several pharmacologic actions, such as modulation of sodium and calcium channels, increasing GABA inhibition, and suppressing abnormal neuronal hyperexcitability, which suggest an effect in neuropathic pain

Answer 204

578. (E) Patient with autonomic dysreflexia usually exhibit decline in heart rate, dramatic changes in blood pressure, flushing and sweating above the level of the injury, and a marked reduction on peripheral blood flow through the reflex pathways in the preserved vagus nerves.

Answer 205

579. (C) HO is the formation of mature, lamellar bone in nonskeletal tissue, usually occurring in soft tissue surrounding joints. The bone formation in HO differs from other disorders of calcium deposition in that HO results in encapsulated bone between muscle planes, not intraarticular or connected to periosteum. In neurogenic HO secondary to TBI or SCI, the hip is the most common joint affected. Even though the most common symptom of HO is pain, it may be painless in patients with complete SCI. Etidronate disodium, a bisphosphonate, is an osteoclast inhibitor. It is structurally similar to inorganic pyrophosphate and is shown to delay the aggregation of apatite crystals into large, calcified clusters in patients with TBI and SCI. The recommended prophylactic treatment for HO in SCI is 20 mg/kg/d for 2 weeks, then 10 mg/kg/d for 10 weeks. The current treatment recommendation for established HO is 300 mg IV daily for 3 days followed by 20 mg/kg/d for 6 months in spinal cord patients.

Answer 206

580. (E) Localized neurogenic inflammation may explain the acute edema, vasodilation, and sweating observed in early stages of CRPS. Increased protein concentration and synovial hypervascularization is observed in the intraarticular fluid of affected joints. Findings that support the role of neurogenic inflammation in the generation of CRPS include elevated systemic levels of CGRP and local increase of IL-6 and tumor necrosis factor alpha in artificially produced blisters.

Answer 207

581. (C) Up to 50% of CRPS patients show decrease range of motion, increase amplitude of physiologic tremor, and reduce active motor force, with dystonia of the affected limb observed in only 10% of the chronic cases. Those motor changes are unlikely associated with a peripheral process and more likely the result of changes of activity in the motor neurons which point to abnormalities of cerebral motor processing.

Answer 208

582. (C) It is estimated that the risk of CRPS after fractures is 1% to 2% and 12% after brain lesions. Retrospective studies in large cohorts shows a distribution in the upper and lower extremity from 1:1 to 2:1. CRPS following SCI are rare. Affected extremities after brain injury are more likely affected than unaffected ones.

Answer 209

583. (E) The three stages of the three-phase bone scan include the perfusion phase 30 seconds postinjection, the blood-pool is 2 minutes postinjection, and mineralization phases is evaluated 3 hours postinjection. Homogeneous unilateral hyperperfusion in the perfusion and blood-pool phase is consistent with CRPS and excludes the differential diagnosis of osteoporosis because of inactivity. The mineralization phase in patients with CRPS shows elevated unilateral periarticular uptake.

Answer 210

585. (A) The major peripheral pathologic findings in CRPS patients include (a) patchy atrophy of some muscle cells, secondary to disuse and nerve damage; (b) capillary microangiopathy, with accelerated turnover of endothelial cells and pericytes; (c) Wallerian degeneration of several types of axons; and (d) focal osteopenia in the territory innervated by a damaged nerve, and synovial cell disorganization and edema.

Answer 211

586. (B) Medical procedures are the second most common cause of CRPS. The finding of exaggerated deep tendon reflexes in CRPS patients has been attributed to cortical disinhibition. Focal deficit of touch (hypoesthesia) were present in 50% of patients. Brushing skin activates low threshold mechanoreceptors which under normal circumstances has no connections with central pain neurons. Brush evoked pain (cutaneous dynamic mechanical allodynia)is a hallmark of central sensitization.

Answer 212

587. (A) In contrast to CRPS II which has similar frequencies in boys and girls, CRPS I is more common in girls with a ratio of 4:1. The lower extremity is more affected (5:1 ratio). CRPS I is more common in Caucasians. There is also evidence that CRPS may have a genetic predisposition, with increase incidence in patients with HLAA3, B7, and DR2.

Answer 213

588. (B) The gender distribution of CRPS II in the pediatric population is roughly similar in boys and girls. Even though patients with brachial plexus injury during delivery (Erb palsy) is common and can lead to prolonged motor weakness, they rarely develop pain. Interestingly most of these patients do better without treatment.

Answer 214

589. (B) The diagnosis of CRPS remains a clinical decision based on findings in the history and physical examination. There are no laboratory tests that can absolutely confirm or exclude the diagnosis. Although controversial, most of the authors find that bone scans are quite nonspecific for the diagnosis of CRPS. Patients with a clinical diagnosis of CRPS may have bone scans showing hypofixation or hyperfixation or may be normal. The primary utility of the bone scan could be in ruling out some underlying orthopedic abnormality that might be triggering neurovascular changes that may confused the findings with those of CRPS.

Answer 215

590. (C) Movement disorders are an essential feature of patients with CRPS. Motor dysfunction is not simply a voluntary defensive response to protect the limb from painful stimuli, but may represent the interaction of peripheral and central mechanisms. Deep tendon reflexes are often brisk. The prevalence of movement disorders increases with the duration of the disease. One characteristic form of these movement disorders is the presence of inability to start a movement (akinesia).

Answer 216

591. (A) Dystonia in CRPS patients causes twisting movements or abnormal postures of the affected body parts. The most prominent motor feature is flexor postures (tonic dystonia) of the fingers, feet, and wrist. Extensor postures occur but are rare.

Answer 217

592. (E) Supraspinal mechanisms play a major role in the abnormal sensory perception of patients with CRPS. Segmental dystonia is characterized by spread of the cortical representation of the affected extremity and its corresponding synaptic connections to adjacent cortical areas. On the other hand, generalized dystonia have increased intracortical excitability to sensory stimuli, and motor cortex disinhibition has been confirmed in CRPS I. PET scan and SPET have shown increased activity of the contralateral thalamus in patients in early stages of CRPS and hypoperfusion in advanced stages.

Answer 218

593. (C) Myofascial trigger point characteristics: • Focal severe tenderness in a taut band of muscle • Referral of pain to a distant site upon activation of the trigger point • Contraction of the taut band (local twitch response) upon mechanical activation of the trigger point • Reproduction of the pain by mechanical activation of trigger point • Restriction of range of motion • Weakness without muscle atrophy • Autonomic phenomenon such as piloerection or changes in local circulation (regional blood flow and limb temperature) in response to trigger point activation Individual features of the trigger point are differentially represented in different muscles. An examiner should not expect to find each feature of the trigger point in every muscle by physical examination.

Answer 219

594. (A) Inactivation of the trigger point is a means to achieve pain relief, to improve biomechanical function, and then to improve the ability of the patient to better perform whatever tasks have been selected as goals. Relief (not elimination) of pain or increased range of motion, both of which can be the result of trigger point inactivation, are not in themselves the goals of treatment.

Answer 220

595. (E) While chronic myofascial pain syndrome is best treated with a multidisciplinary team approach including the patient, physicians, psychologists, clinical social workers, occupational therapists, physical therapists, ergonomists, massage therapists, and others actively involved in patient care; patients with acute myofascial pain syndrome may only require treatment by physicians and physical therapists. Too frequently, patients with chronic myofascial pain are started too soon on isotonic training and conditioning, causing further aggravation of active trigger points and an increase in pain and dysfunction. The acute treatment plan may be divided into a pain-control phase and a training or conditioning phase. During the pain-control phase, the most essential component is inactivation of the trigger point. Patients must change their behaviors and avoid overstressing their muscles without becoming excessively inactive. The pain-control phase must have a definitive endpoint. If patients do not move beyond the paincontrol phase to the conditioning phase, patients can be restricted in their functional abilities and be at greater risk of reinjury. The training or conditioning phase follows and it involves therapeutic exercises, movement reeducation, and overall conditioning

Answer 221

596. (C) Botulinum toxin has been tried successfully in myofascial trigger point inactivation; however, it can cause a flu-like myalgia that lasts days to a week and sporadically causes weakness beyond the area of injection. It functions as a long-lasting trigger point injection that can provide up to 3 months of relief in contrast to the days to 1-week effect of traditional trigger point injection with local or no anesthetic.

Answer 222

597. (A) 1. Japanese acupuncture or shallow needling reduced the pain of chronic myofascial neck pain in one study. 2. and 3. These have been found to be true. 4. While this study does not exist, a technique of dry needling called intramuscular stimulation does exist. It involves the insertion of the needle into the taut band without necessarily considering the actual trigger point. It may be combined with electrical stimulation delivered through the needle (percutaneous electroneutral stimulation).

Answer 223

599. (D) Fibromyalgia has been found among all cultures throughout the world with an incidence of 2% to 12% of the population. In adulthood, women are affected four to seven times as often as men. The frequency of fibromyalgia increases with age and peaks in the seventh decade of life. In childhood, boys and girls are affected equally. In contrast to adults, children’s symptoms may resolve with age.

Answer 224

600. (A) Although research is ongoing, the development of fibromyalgia appears to be increased if the patient has had a febrile illness, a history of physical trauma, or a family history of fibromyalgia syndrome. Approximately onethird of patients with fibromyalgia report that another member of their family has previously been diagnosed with fibromyalgia

Answer 225

601. (E) Greater than 90% of patients with fibromyalgia suffer from chronic insomnia. Some patients may have problems falling asleep. Other may awaken a few hours after going to sleep and feel alert, thus disrupting their sleep throughout the remainder of the night. After a night of sleep, patients with fibromyalgia may feel stiff, tired, and “cognitively sluggish.” These patients also encounter difficulty napping throughout the day. Patients with fibromyalgia have disrupted sleep architecture with alpha wave intrusions in deep, delta wave sleep.

Answer 226

602. (E) 3. In fibromyalgia patients, CT has revealed unusually low cerebral blood flow in the thalamic nuclei, the left and right heads of the caudate nucleus, and the cortex that correlates with spinal fluid substance P levels. 4. Windup is a frequency-dependent increase in the excitability of spinal cord neurons, evoked by electrical stimulation of afferent C fibers. Glutamate (NMDA) and tachykinin NK1 receptors are required to generate windup and therefore a positive modulation between these two receptor types has been suggested. Whatever the mechanisms involved in its generation, windup has been interpreted as a system for the amplification in the spinal cord of the nociceptive message that arrives from peripheral nociceptors connected to C fibers. This probably reflects the physiological system activated in the spinal cord after an intense or persistent barrage of afferent nociceptive impulses. On the other hand, windup, central sensitization and hyperalgesia are not the same phenomena, although they may share common properties. Spinal cord windup is abnormal in fibromyalgia syndrome. Physical trauma or a fever/infection may be provisionally related to the onset of fibromyalgia in over 60% of cases.

Answer 227

603. (B) The levels of serum IL-8 were higher in fibromyalgia patients, and IL-6 was statistically higher in cultures of fibromyalgia peripheral blood mononuclear cells compared with in controls. The IL-8 increase was most dramatic in depressed patients, but there was also a correlation with the duration of fibromyalgia and the pain intensity. The production of IL-8 in vitro is stimulated by substance P.

Answer 228

604. (D) Pregabalin has the potential to raise the threshold for pain fiber depolarization. It is a ligand for the α2δ subunit of voltage-dependent calcium channel receptors, which has analgesic, anxiolytic-like, and anticonvulsant activity. It decreases the release of numerous neuropeptides, including noradrenaline, glutamate, and substance P. It has already been approved for treating partial seizures, pain following the rash of shingles and pain associated with diabetes nerve damage (diabetic neuropathy). Two double-blind, controlled clinical trials, involving about 1800 patients, support approval for use in treating fibromyalgia with doses of 300 or 450 mg/d. It is effective in reducing the severity of body pain, improving quality of sleep, and reducing fatigue in fibromyalgia patients. Pregabalin was approved by the FDA for use in fibromyalgia patients on June 21, 2007. The most common side effects of pregabalin include mild to moderate dizziness and sleepiness. Blurred vision, weight gain, dry mouth, and swelling of the hands and feet also were reported in clinical trials. The side effects appeared to be dose-related. Pregabalin can impair motor function and cause problems with concentration and attention. The FDA advises that patients talk to their doctor or other health care professional about whether use of pregabalin may impair their ability to drive. 1. Cyclobenzaprine, have been used in the past with success in fibromyalgia patients, they have not been approved by the FDA. 2. Duloxetine is an FDA-approved treatment for major depression, neuropathic pain from diabetic peripheral neuropathy, and generalized anxiety disorder. The drug is a serotonin and norepinephrine reuptake inhibitor that exhibits nearly equal serotonin and noradrenaline reuptake inhibition. Atrial of duloxetine for patients with chronic pain and/or major depression indicated that for the fibromyalgia patients, 80% of the observed effect on pain is a direct analgesic effect rather than an indirect antidepressant effect. Common adverse events were: nausea, headache, dry mouth, insomnia, constipation, dizziness, fatigue, somnolence, diarrhea, and hyperhidrosis. Two placebo-controlled randomized studies on the treatment of fibromyalgia-associated pain with duloxetine have been published. Both studies demonstrated that duloxetine treatment improved fibromyalgia-associated pain in women. However, the medication has not yet been approved for the treatment of fibromyalgia. Another type of serotonin and noradrenaline reuptake inhibitor is represented by milnacipran, where noradrenaline reuptake inhibition is favored over that of serotonin. Some reports state that milnacipran may also be effective in treating fibromyalgia body pain. 3. Tramadol has only recently been shown to improve the pain of patients with fibromyalgia. It combines weak μ-agonist with NMDA antagonist and noradrenaline and serotonin reuptake inhibition. In the combination preparation that comes with acetaminophen, a considerable synergy has been noticed. Nausea and dizziness can be limiting at first in about 20% of patients, but starting with just one tablet at bedtime for 1 to 2 weeks can decrease the prevalence and allow later increases but about one tablet every 4 days to full therapeutic levels. Atypical tramadol regimen for fibromyalgia is 300 to 400 mg/d in three or four divided dosages, concomitant with acetaminophen at 2 to 3 g/d in divided doses. Administering 5-hydroxytryptophan can augment the synthesis of serotonin. Onehundred milligrams, orally, three times daily has been shown to be an effective dose in treating fibromyalgia.

Answer 229

605. (B) Central sensitization can be inhibited by NMDAreceptor blockade. Two NMDA receptor antagonists, ketamine and dextromethorphan (an oral preparation) have been found to exhibit favorable effects on pain and allodynia in fibromyalgia patients. With ketamine, 50% of patients benefited. Fibromyalgia subgroups of responders and nonresponders were perpetuated by these findings because all the fibromyalgia patients in the study were otherwise comparable. Ketamine’s effectiveness was limited because of its frequently occurring psychotropic side effects, such as feelings of unreality, altered body image perception, aggression, anxiety, nausea, dizziness, and modulation of hearing and vision. Dextromethorphan has a better side-effect profile than ketamine. It was administered with tramadol to increase the antinociceptive effect, to hold adverse effects low, and to decrease the development of opioid tolerance. A good response was obtained in 58% of the fibromyalgia patients who tried this regimen. It may be a consideration for the patients who respond positively to IV ketamine.