Chapter 5. Diagnosis of Pain States Flashcards

Question

276. Which of the following statements regarding postamputation pain is correct? (A) Vascular conditions are the leading cause of both lower and upper extremity amputations (B) There is no relationship between persistent stump pain and phantom limb pain in amputees (C) The intensity of pain and the length of the phantom increases with time (D) Phantom breast pain is a common cause of postmastectomy pain (E) Phantom pain was first described in the American Civil War

Answer 1

276. (D) Phantom breast pain occurs in roughly 20% of mastectomy patients, and phantom sensations in close to half. Originally thought to be rare, phantom limb pain is now recognized to occur in between 60% and 80% of limb amputees. Phantom limb pain must be distinguished from phantom sensations, which occur in over 90% of patients. Vascular conditions account for over 80% of limb amputations in the United States. However, trauma is responsible for approximately 75% of upper extremity amputations. Most researchers have found a statistically significant association between phantom limb pain and persistent stump pain. Although earlier studies found a correlation between preamputation pain and phantom limb pain, more recent studies have not confirmed this relationship. It is widely held that phantom pain diminishes with time and eventually fades away. Though described, phantom pain associated with congenital absence of a limb is rare. Phantom pain is generally worse in the distal part of a limb. Most phantoms shrink with time, with the most distal aspect of a limb being the last to disappear. This is known as “telescoping,” and occurs in approximately half of all limb amputees. Archaeological records demonstrate that purposeful amputations have been practiced since Neolithic times. The concept of “phantom pain” has been recognized for hundreds, if not thousands, of years. In the 16th century, the French military surgeon Ambrose Paré outlined clear distinctions between phantom limb pain, phantom sensation, and stump pain. The term “phantom pain” was coined by Weir Mitchell in the American Civil War. A few years earlier, Mitchell used the word “causalgia” to describe the characteristic autonomic changes found in the extremities of soldiers who suffered major nerve damage.

Answer 2

277. (A) Palmar sweating and reduced transcutaneous oxygen concentration are indicative of, though not specific for, acute pain. In a young child, crying and increased vital signs (eg. heart rate, respiratory rate, and blood pressure) are associated with distress, which includes but is not limited to pain. Other factors that may cause these signs include separation anxiety, hunger, and fear. Unlike acute pain, chronic pain is usually not associated with elevated vital signs. The FACES scale and Charleston Pain Pictures are designed to provide assessments of pain in school aged, not preschool children. The FACS and COMFORT scale are used to assess pain in infants and young children. The FACS is a comprehensive coding system based on a wide range of facial actions. The COMFORT scale is an eight-item scale designed to measure distress (including pain) that includes alertness, calmness, respiratory response, physical movement, blood pressure, muscle tone, and facial tension. Pain scales used in adults such as verbal pain scores, numerical rating scales, and visual analogue scales provide accurate assessments of pain in most adolescents.

Answer 3

278. (B) The most common way to diagnose AHZ is clinically. In a small percentage of patients, AHZ may occur without a rash, a condition known as “zoster sine herpete” (zoster without rash). The PCR is often used to aid in the diagnosis of this condition. In descending order, the most common sites for AHZ are the midthoracic dermatomes, the ophthalmic division of the trigeminal nerve, and the cervical region. The incidence of both AHZ and postherpetic neuralgia increases with age. Other risk factors for AHZ include HIV infection and transplant surgery, which is likely because of the resultant immunosuppression. There is no standard time period after which persistent pain from AHZ is diagnoses as postherpetic neuralgia. Postherpetic neuralgia has been variably defined as the persistence of sensory symptoms 1 month, 6 weeks, 2 months, 3 months, and 6 months after herpes zoster. AHZ affects the lumbosacral dermatomes in between 5% and 15% of patients. Lumbosacral AHZ may be misdiagnosed as a herniated disc

Answer 4

279. (B) EMG provides a wealth of information about the integrity, function, and innervation of motor units and (using special techniques) individual muscle fibers. Serial EMG examinations permit monitoring of recovery or disease progression. A normal EMG indicates the absence of motor unit involvement. In neuropathies characterized by Wallerian degeneration, nerve conduction velocities range from low normal to mildly slow. In contrast, demyelinating neuropathies of the acute and chronic inflammatory types produce segmental demyelination, which markedly slows conduction velocities. The H wave is the electrical representation of the tendon reflex circuit. In adults, it is only obtainable in the lower reflexes. It is most prominent during stimulation of the tibial nerve, being particularly helpful in the diagnosis of S1 radiculopathy and predominantly sensory polyneuropathies. The F wave is a late response that is evoked by supramaximal stimulation of a motor nerve. It occurs when a small percentage of the stimulated motor neurons “rebound.” The initial response to stimulation of a motor nerve is the M wave. Unlike H waves, F waves are not true reflexes.

Answer 5

280. (C) Large, myelinated nerves are more vulnerable to injury than small neurons. The function of large, myelinated A-β function can be measured using both vibratory thresholds and von Frey filaments. QST is used to evaluate the function of individual nerve fibers. It is not useful in determining which nerve is injured and where along its path the injury lies. Both cold and hot thermal sensations are used to measure the function of small myelinated (A-δ) and unmyelinated C fibers. QST cannot be used to assess B (preganglionic autonomic) and A-γ (muscle spindle efferent) function. Adownside of QST is that its accuracy is dependent on the cooperation and reliability of the patient.

Answer 6

281. (C) Lumbar radiculopathy most often results from disc herniation. Depending on the level of herniated discs radiculopathy may affect specific nerve roots. Disc herniation at L4-5 and L5-S1 is most likely caused by mobility of the segment. A herniated disc may compromise the nerve root at the same level if displaced laterally in the recess or in the foramen (L4-5 disc affecting L4 nerve root), or it may effect the traversing nerve root to the level below (L4-5 disc affecting L5 nerve root). L5 radiculopathy results in pain, sensory, and motor changes in L5 dermatomal distribution. Pain is usually described as shooting or occasionally aching and burning sensation on the outside of leg radiating to the dorsum of foot. Sensory testing may also reveal a decrease in light-touch and pinprick sensation in the same distribution. L5 radiculopathy also may result in weakness in the extensor hallucis longus and thus heel walking. Deep tendon reflexes may be spared in the lower extremity.

Answer 7

282. (A) Fibromyalgia syndrome is a common pain condition, estimated to occur in 2.4% of the general population. The syndrome is characterized by widespread musculoskeletal pain, sleep disturbance, psychologic distress, and comorbidity with other pain syndromes [eg, irritable bowel syndrome (IBS), interstitial cystitis, and the female urethral syndrome], which have considerable impact on the everyday life of patients. Fibromyalgia syndrome occurs predominantly in women and demonstrates familial aggregation. Since 1990, the diagnosis of fibromyalgia syndrome has been based on criteria of the American College of Rheumatology (ACR). A key dimension of the ACR criteria is the concept of tender points, 18 specific points on the body surface at which digital palpation elicits pain (11/18 “positive” tender points fulfills an fibromyalgia criteria). It is not uncommon for patients to have other pain pathologies in addition to fibromyalgia. However a complete clinical picture should be viewed before consideration of treatment options especially if it involves interventional procedures. Patient describes above most likely has fibromyalgia as evidenced by the presence of tender points. A negative physical examination except for tender points and hypersensitivity argues against other listed options.

Answer 8

283. (A) Following is the diagnostic criteria for CRPS I: 1. The presence of an initiating noxious event or a cause of immobilization. 2. Continuing pain, allodynia, or hyperalgesia with which the pain is disproportionate to any inciting event. 3. Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of the pain. 4. This diagnosis is excluded by the existence of condition that otherwise would account for the degree of pain and dysfunction. The patient in the question meets all the criteria for diagnosis of CRPS I (RSD). CRPS II (causalgia) by definition has a known injury to a major nerve. Vascular etiology though possible after trauma, is unlikely to give symptoms of allodynia as well as sudomotor changes. Median neuralgia would result in a similar clinical pain picture but only hand discomfort would be expected to be confined only to the distribution of median nerve.

Answer 9

284. (C) Spinal cord injury may result in various types of pain. To provide the most effective treatment—understanding the mechanism of pain is very important. Taxonomy of spinal cord injury pain may be divided into neuropathic or nociceptive pain. The patient in question appears to have most likely nerve root impingement at T4-5, level of his spinal cord injury, resulting in severe T4 neuralgic pain radiating towards the front of chest wall.

Answer 10

285. (B) Myofascial pain may result after a sudden acceleration-deceleration insult. Neck muscles may reflexly go into spasm. It may also result in straightening of cervical lordosis secondary to spasm of posterior supporting neck muscles. Myofascial pain from cervical neck muscle may radiate between shoulder blades as well into the upper extremity. Negative imaging studies are essential to rule out traumatic disc herniation or fracture. Treatment includes nonsteroidals, muscle relaxants, and physical therapy. In a small percentage of patients, if pain doesn’t resolve trigger point injections or cervical medial branch blocks may provide help with continuing physical therapy.

Answer 11

286. (C) In type 1 diabetes mellitus, distal polyneuropathy typically occurs after many years of chronic prolonged hyperglycemia. Conversely, in type 2, it may present after only a few years of poor glycemic control. Occasionally, in type 2, diabetic neuropathy is found at the time of diagnosis (or even predating diagnosis). Diabetic neuropathy can manifest with a wide variety of sensory, motor, and autonomic symptoms. Sensory symptoms may be negative or positive, diffuse or focal. Negative sensory symptoms include numbness; “deadness”; feeling of wearing gloves or walking on stilts; loss of balance, especially with the eyes closed; and painless injuries. Positive symptoms include burning, pricking pain, electric shocklike feelings, tightness, and hypersensitivity to touch. Motor symptoms can cause distal, proximal, or focal weakness. Autonomic symptoms may be sudomotor, pupillary, cardiovascular, urinary, GI, and sexual. A generally accepted classification of diabetic neuropathies divides them broadly into symmetric and asymmetric neuropathies. Symmetric polyneuropathies involve multiple nerves diffusely and symmetrically and are the most common form. The patient in question appears to have symmetrical small and large fiber neuropathy resulting in pain in both legs and feet, and decreased light-touch sensation as well as allodynia.

Answer 12

287. (C) Glossopharyngeal neuralgia is a disorder characterized by intense pain in the tonsils, middle ear, and back of the tongue. The pain can be intermittent or relatively persistent. Swallowing, chewing, talking, sneezing, or eating spicy foods may trigger the disorder. It is often the result of compression of the 9th nerve (glossopharyngeal) or 10th nerve (vagus), but in some cases, no cause is evident. Skull base surgery or surgeries in the infratemporal region may result in damage or irritation of glossopharyngeal nerve. Conservative treatment includes using anticonvulsants. In refractory cases glossopharyngeal nerve block may be helpful. Radiofrequency lesioning or neurolytic treatment should be reserved for resistant cases or ones associated with head and neck cancer. Surgical decompression should be reserved for nonresponders and resistant cases.

Answer 13

288. (D) Lumbar radiculopathy most often results from disc herniation. Depending on the level and “direction” of herniated discs a resultant radiculopathy may affect specific nerve roots. Disc herniation at L5-S1 is most likely a result of mobility of the segment. A herniated disc may compromise the nerve root at the same level if displaced laterally in the recess or in the foramen (L5-S1 disc affecting L5 nerve root), or it may affect the traversing nerve root to the level below (L5-S1 disc affecting S1 nerve root). S1 radiculopathy results in pain, sensory, and motor changes in S1 dermatomal distribution. Pain is usually described as shooting or occasionally as an aching and burning sensation on the back of thigh radiating to the plantar aspect (sole) of foot. Sensory testing may also reveal a decrease in light-touch and pinprick sensation in the same distribution. S1 radiculopathy also may result in weakness in Plantar flexion and thus toe walking. Most often with significant S1 nerve root compression, ankle reflex is diminished. Examination also may reveal positive straight leg raise and cross straight leg raise test (reproduction of radiating pain in lower extremity by raising the opposite extremity).

Answer 14

289. (C) The spinal cord is organized into a series of tracts or neuropathways that carry motor (descending) and sensory (ascending) information. These tracts are organized anatomically within the spinal cord. The corticospinal tracts are descending motor pathways located anteriorly within the spinal cord. Axons extend from the cerebral cortex in the brain as far as the corresponding segment, where they form synapses with motor neurons in the anterior (ventral) horn. They decussate (cross over) in the medulla prior to entering the spinal cord. The dorsal columns are ascending sensory tracts that transmit light-touch, proprioception, and vibration information to the sensory cortex. They do not decussate until they reach the medulla. The lateral spinothalamic tracts transmit pain and temperature sensation. These tracts usually decussate within three segments of their origin as they ascend. The anterior spinothalamic tract transmits light touch. Autonomic function traverses within the anterior anteromedial tract. Sympathetic nervous system fibers exit the spinal cord between C7 and L1, while parasympathetic system pathways exit between S2 and S4. Injury to the corticospinal tract or dorsal columns, respectively, results in ipsilateral paralysis or loss of sensation of light touch, proprioception, and vibration. Unlike injuries of the other tracts, injury to the lateral spinothalamic tract causes contralateral loss of pain and temperature sensation two to three segments below the level of injury. Because the anterior spinothalamic tract also transmits light-touch information, injury to the dorsal columns may result in complete loss of vibration sensation and proprioception but only partial loss of light-touch sensation. Anterior cord injury causes paralysis and incomplete loss of light-touch sensation.

Answer 15

290. (B) Patients with a C6 radiculopathy should have pain in the neck, shoulder, lateral arm, radial forearm, dorsum of hand, and tips of thumb, index, and long finger. Distribution of pain is less extensive and more proximal, whereas paresthesias predominate distally. In some individuals, a C6 lesion will manifest as a depressed or absent biceps reflex; in others, an abnormal brachioradialis or wrist extensor reflex can be found. Elbow flexion will be weak, and the patient will be unable to supinate the forearm against resistance with the elbow held in extension. Conservative treatment includes physical therapy, traction, and analgesics. If pain persists, cervical epidural steroid injection may provide relief from pain and aid in physical therapy. However, if symptoms persist or weakness/numbness doesn’t improve surgical decompression with or without anterior fusion may be considered

Answer 16

291. (B) Celiac plexus block is both a diagnostic and therapeutic tool to help in managing upper abdominal pain arising from viscera. Pancreatic cancer is the leading diagnosis for neurolytic celiac plexus block; other conditions may include visceral pain arising from malignancies of liver or GI tract. The procedure is performed either under fluoroscopic guidance or CT scan, though blind approaches have also been described. Both single transaortic as well bilateral needle approaches have been described. The fluoroscopic image in question demonstrates a single needle transaortic celiac plexus block. Complications include diarrhea, hypotension, genitofemoral neuralgia, infection, bleeding, damage to surrounding structures and rarely paralysis. All complications mentioned above may occur except hypertension

Answer 17

292. (A)Aproper diagnostic test requires a preblock patient evaluation (with special attention to the ipsilateral lower extremity pain, temperature, and condition), a local anesthetic injection using appropriate volume to avoid spread to adjacent nerves and a postblock evaluation of subjective improvement in pain score as well an objective increase in the temperature of the involved extremity is crucial. Significant improvement in pain scores with increase in temperature of the involved extremity points toward a positive diagnosis of sympathetically mediated pain. Discography is performed for diagnosis of lumbar discogenic pain. Whereas diabetic neuropathy may result in sympathetically mediated pain, it is a mixed somatic polyneuropathy and diagnosis is a clinical one. Lumbar selective nerve root block and facet joint injections may aid in the diagnosis of lumbar radiculopathy and facet arthritis resulting in pain.

Answer 18

293. (C) Cervical selective nerve root injection may be indicated for diagnosis and treatment of cervical radiculopathy. Complication other than infection, bleeding, and nerve damage, include intravascular uptake into vertebral artery or radicular arteries resulting in seizure, stroke, or paraplegia. Intraspinal spread into epidural or intrathecal spread is also possible resulting in high spinal anesthetic. Damage to spinal cord has also been reported with injection into the spinal cord. Considering the life-threatening complications, cervical selective nerve root block should only be performed by physicians well versed in this technique.

Answer 19

294. (A) Medial branches of the dorsal ramus provide innervations to the respective facet joint as well to the joint below. A diagnostic medial branch block with local anesthetic performed at appropriate levels (eg, L3 and L4 for L4-5 facet joint) may provide diagnostic and prognostic information to help with pain associated with facet arthritis. If pain is considerably albeit transiently improved after diagnostic medial branch blocks, a radiofrequency ablative procedure may be considered to provide longer lasting pain relief.

Answer 20

295. (B) SI joint injection is performed for both diagnostic and therapeutic reasons in patient complaining of SI joint pain. After a therapeutic injection with 5 to 10 mL of local anesthetic; it is possible that the local anesthetic may spill inferiorly and anteriorly and anesthetize sciatic nerve resulting in leg weakness. Patients may be warned about this, if observed afterward, and should be accompanied by a reasonable adult to avoid any falls and resultant injuries

Answer 21

296. (E) Vertebroplasty is an advanced procedure that is performed to stabilize recently fractured vertebral bodies resulting in excruciating back pain. Performed properly and by trained physicians, vertebroplasty is a safe procedure. However, complications, though rare, are possible and uncompromising. These may include infection; bleeding; pulmonary embolus; damage to pedicles, spinal cord, or surrounding structures; allergic reactions to injectate; and cement leak into soft tissue or in spinal canal resulting in spinal cord compression.

Answer 22

297. (A) Spinal stenosis may result from narrowing of the spinal canal secondary to hypertrophy of ligamentum flavum, articular processes and anteriorly from degenerative bulging discs. Stenosis may result in a classical presentation of neurogenic claudication with pain in lower legs or feelings of “charley horse” that come with walking an unpredictable distance and is relieved by resting or sitting down. In contrast to vascular claudication, the patient may report some back pain as well. In addition, pain is not predictably elicited after a certain walking distance because it is relative extension of the lumbar segments that results in worsening stenosis and neurogenic claudication rather than ischemia. Pain is relieved in neurogenic claudication by assuming a flexion posture (bending forward). Treatment includes posture education, education and improvement of body mechanics, and physical therapy. Epidural steroid injection series may provide pain relief in some patients. If pain or significant limitation in activity persists a decompressive laminectomy may be considered.

Answer 23

298. (B) The piriformis is a sausage-shaped muscle which originates from the anterior surface of the lateral sacrum and attaches to the greater trochanter. In most individuals the sciatic nerve lies anterior to the muscle belly. Spasm of the muscle may result in irritation of the sciatic nerve and resultant sciatica. The patient may report localized tenderness in the lower part of the buttock. In addition, if patients have irritation of sciatic nerve, they may also report symptoms suggestive of sciatica which may easily be confused with lumbar radiculopathy. However, flexion, adduction, and internal rotation of the thigh results in tightening of piriformis muscle which may reproduce pain symptoms. MRI should be carefully evaluated to rule out any radicular component. Treatments include muscle relaxants and physical therapy to break muscle spasm. If pain persists or if the patient is unable to continue with physical therapy, piriformis muscle injection may aid in treatment.

Answer 24

299. (C) There can be physical and psychologic symptoms of malingering and factitious disorder. In these conditions the patient willfully produces or feigns symptoms of illness or injury. In the factitious disorder the goal of the behavior is the patient’s need to be in sick role—a need not understood by the patient. Placing blood into urine and pretending to have posttraumatic stress disorder are examples. There is no apparent external goal such as to obtain money or drugs. It is always a psychiatric illness. This contrast with malingering, in which there is a clearly defined external goal. Malingering is not a psychiatric illness. Diagnosis of hypochondriasis require atleast 6 month of preoccupation with the fear or belief that one has a serious disease, based on the interpretation of physical signs or sensations as evidence of illness. Somatization disorder is characterized by an extensive history of multiple somatic symptoms that are psychologic in nature. In addition to many physical complaints or a belief that one is sickly, the criteria require at least 13 symptoms from a list of 41. The symptom list includes 6 GI symptoms, 7 pain symptoms, 4 cardiopulmonary symptoms, 12 conversion/pseudoneurologic symptoms, 4 sexual symptoms, and 4 female reproductive symptoms. Conversion disorders are patients presenting with physical symptoms without any anatomic or pathophysiologic basis (pseudoneurologic symptoms; pseudoparalysis, pseudoseizure etc).

Answer 25

300. (A) Ilioinguinal neuralgia may develop after any surgery in inguinal area resulting in damage to the ilioinguinal nerve. Pain may start immediately after the surgery or may start after a reasonable period of healing has passed. Wound infection, recurrent hernia, and mesh infection should be ruled out to avoid any correctable causes of ilioinguinal pain. Pain is usually described as sharp, electrical sensation or sometimes as constant burning sensations in the groin area with occasional radiation into the testicles. Pain is exacerbated by light touch or rubbing of clothes. Treatment includes anticonvulsants and other adjuvant medications. If pain persists, local anesthetic diagnostic and therapeutic block as well as other treatment approaches may be warranted. Radiofrequency ablation, peripheral nerve stimulation, neurectomy, and repeat surgery should be reserved for resistant cases.

Answer 26

301. (A) A. Hypotension from sympathetic blockade is the most common complication. It is important to optimally prehydrate these patients prior to the onset of the block. B. Seizure results from intravascular injection of large volume of local anesthetic stressing the need to confirm negative aspiration prior to injecting the solution. C. Diarrhea ensues as a result of sympathetic blockade and unopposed parasympathetic tone. D. Retroperitoneal hematoma is a rare complication of celiac plexus block. E. Subarachnoid injection is the most serious and very rare complication celiac block.

Answer 27

302. (D) A. Increase in the intrathecal morphine dose is warranted in some situations when a patient demonstrates signs and symptoms consistent with withdrawal or has inadequate analgesia. In that case it is important to carefully evaluate the equianalgesic dose accounting for change in route or incomplete cross tolerance with change of drugs. In this case, considering the oral to intrathecal conversion is 300 to 1, the patient has been escalated to 10 mg of intrathecal morphine a day; it seems unlikely that his symptoms would be because of opioid withdrawal provided his catheter is in the correct position as had been confirmed under fluoroscopy in this case. B. CT scan can be done to confirm the correct placement of the catheter if necessary; however it is highly unlikely that the catheter would move in a short time in a sedentary postsurgical patient. C. Removal of catheter followed by reimplantation is a possibility if indeed catheter is determined to be malpositioned. It seems rather premature to pursue such option at this time. D. Urine toxicology seems like a more viable option considering this patient’s association with a half way home and the time of onset of his symptoms approximately 12 hours after the hospitalization. Also, the symptoms experienced although nonspecific, point toward possible withdrawal from a substance of abuse. It is reasonable to order a urine/serum toxicology screen as an initial step at this point while instituting conservative treatment with nonopioid analgesics and antinausea preparations. E. Spine surgeon consultation does not seem necessary at this point since the symptoms experienced are not truly suggestive of spinal hematoma, infection, or neurologic deficits warranting acute surgical intervention.

Answer 28

303. (B) The mechanism by which ovarian hormones influence migraines remain to be determined, but an abrupt decrease in serum estrogen concentrations before the onset of an attack appears to be a critical factor. Sometimes the use of percutaneous estrogen gel applied just before and through the menstrual cycle may reduce the frequency of headaches. However, in some other cases use of low-dose estrogen oral contraceptive formulation are associated with a haphazard occurrence of attacks during the cycle, probably because of fluctuating estrogen levels. Therefore, it seems prudent to have the treatment strategies aimed toward preventing either a decrease or substantial fluctuation in the levels of estrogen.

Answer 29

304. (A) A. Considering the acute onset of bladder dysfunction and neurologic deficits on physical examination along with the anterolisthesis of L5 on S1, urgent evaluation by a spine surgeon seems to be the best immediate option of all. This patient needs further workup and possibly even urgent intervention by the spine surgeon at this time. B. While intravenous opioids can be used to control acute pain, they by no means should be considered adequate in managing this situation that demands urgent surgical attention. C. Physical therapy may be considered in future for this patient for physical rehabilitation once surgical evaluation and/or intervention has been completed. Physical therapy for acute pain management is inappropriate for this case considering the risk of neurologic deficits that may ensue from further movement of an unstable spine. D. This condition could be a surgical emergency and so this patient should be actively managed in an in-patient setting. E. Oral steroids may sometimes be beneficial in such setting to decrease the pain and inflammation associated with acute spine pain, but the surgical evaluation should take precedence over all conservative treatment options that may delay resolution of the spinal pathology.

Answer 30

305. (E) Celiac plexus or ganglia, these terms often used interchangeably, are a dense network of pre- and postganglionic fibers. The three splanchnic nerves; greater, lesser, and least synapse at the celiac ganglia. A. Retrocrural approach is the most commonly utilized by anesthesiologists and considered the most traditional. The landmarks include iliac crests, 12th rib, dorsal midline, vertebral bodies (T12-L2), and lateral border of the paraspinal (sacrospinalis) muscles. B. Transcrural approach involves placement of needle tips anterior and caudal to the diaphragmatic crura. Advocates of this approach believe that this approach maximizes spread of injected solutions anterior to the aorta where the celiac plexus is most concentrated and this minimizes the somatic nerve block. C. Transaortic approach to celiac plexus has been described under both fluoroscopic and CT guidance. It is considered safe by many because of the use of single fine needle compared to two-needle posterior approach. This approach has three distinct advantages over the classic two-needle approach. First, it avoids the risk of neurologic complications related to posterior retrocrural spread of drugs. Secondly, the aorta provides a definitive landmark for needle placement when radiographic guidance is not available and thirdly, much smaller volumes of local anesthetic and neurolytic solutions are required to achieve efficacy equal to or greater than that of classic retrocrural approach. D. Intercrural approach is a term that can technically be applied to transaortic approach since the needle tips are placed in front of the diaphragmatic crura in this approach, but more commonly this term is used to refer to the classic anterior approach to celiac plexus under CT or ultrasound guidance. E. Lateral approach has not been described in literature.

Answer 31

306. (A) A. The trial of oral opioids, steroids, and urgent consultation with a spine surgeon are the most appropriate initial steps in management of what seems to be a case of acute radiculopathy secondary to acute disc herniation. Because these substantial neurologic deficits may be reversed with appropriate and timely decompression the surgical evaluation and course of steroids are top priorities here. B. Cervical epidural steroid injections can be considered to decrease the inflammation, but does not qualify to be “most appropriate initial treatment.” C. Physical therapy can be instituted further down the road for rehabilitation. D. SCS may be beneficial to decrease neuropathic pain of chronic nature, but it has no role in an acute setting of this nature. E. Pain psychologist can prove to be very useful in patients suffering from chronic pain, but again has little role in acute pain management in this setting.

Answer 32

307. (A) Hoffmann sign is indicative of UMNL. In fact, it is the upper extremity equivalent of Babinski reflex. The examiner holds the patient’s middle finger and briskly flicks the distal phalanx. A positive sign is noted if the interphalageal joint of thumb of the same hand flexes.

Answer 33

308. (D) A. Plantar fascitis is an inflammation of the tendons and the fascia of the foot as they insert into the calcaneal periosteum. It is typically seen in the people who stand on hardwood floors for a prolonged period of time. Pain is elicited with plantar compression over the anterior calcaneus and also may radiate along plantar fascia. B. Metatarsalgia is characterized by pain in the plantar surface of the metatarsal heads caused by prolonged weight-bearing. It can also be replicated with manual compression over the metatarsal heads. Pain is most commonly increased in combined pronation and eversion. C. The etiology and diagnosis of tarsal tunnel syndrome is somewhat controversial. This syndrome involves compression or inflammation of the posterior tibial nerve that provides sensory innervation to medial aspect of the calcaneus, motor supply to small lateral musculature of the foot and to the medial and lateral plantar branches. The symptoms are usually vague with activity related problems. Pain along with paresthesia, cramping, and burning is seen in the distribution. Palpation reveals sensitivity in the area. EMG testing can be utilized in diagnosis of tarsal tunnel syndrome but is controversial. D. Morton neuroma (interdigital neuroma) is the compression of the interdigital nerves in between the metatarsal heads and deep transverse metatarsal ligaments. The third interspace between third and fourth metatarsal is most frequently involved, it is believed to be so because lateral plantar nerve sends a branch to the medial plantar nerve to form a larger third common digital nerve making it less mobile. The condition is usually unilateral and affects females more commonly than men, usually in their 50s. The most common symptom is plantar pain that is increased by walking or by palpation between the third and fourth metatarsal heads. E. Painful calcaneal spur is often seen in morbidly obese people or those who stand or walk excessively. Pain is increased in the morning or after a prolonged rest and similar to plantar fascitis except that it is more predominant in the posterior aspect of the plantar calcaneus.

Answer 34

309. (A) Interscalene block of brachial plexus is especially effective for surgery of the shoulder or upper arm, as the roots of the brachial plexus are most easily blocked with this technique. Ulnar nerve is most frequently spared since it is derived from the eighth cervical nerve and the block is placed at a more cephalic site with this approach. This block is ideal for reduction of a dislocated shoulder or any other type of surgery on shoulder or upper arm.

Answer 35

310. (D) A. A baker (popliteal) cyst represents ballooning of the synovium-lined joint capsule, usually on the posteromedial aspect of the knee. It is usually a secondary manifestation of underlying condition that causes chronic inflammation of the knee, such as meniscal tear, knee synovitis or intra-articular loose body. The diagnosis of the popliteal cyst can be made by direct palpation of the mass. Arthrography or an MRI can verify the diagnosis and demonstrate its communication with the joint cavity. The cyst usually resolves with correction of the underlying pathology. B. Anterior cruciate ligament is the most commonly injured knee ligament in athletes. Injury to this ligament will result in a bloody knee effusion that is very indicative of this particular kind of injury. Three tests used to diagnose anterior cruciate ligament injury are anterior drawer test, Lachman test, and pivot shift test. C. Posterior cruciate ligament is usually damaged in violent, usually high–kinetic energy injuries. These usually occur in combination with fractures, specifically to the patella and hip or with other knee ligament injuries. Injury to popliteal artery should be evaluated in this injury with palpation or even arteriography. The test used to diagnose posterior cruciate ligament injury is posterior drawer test. D. In stance more than 60% of the body’s weight is carried on the peripheral aspect of the tibial plateau by meniscal fibrocartilages. In younger persons, the meniscal injuries usually accompany other ligament injuries whereas in elderly, these usually occur in isolation. When a meniscal tear is extensive it can result in block to terminal knee flexion or extension, commonly described by patients as “locking of the knee”. A torn meniscus can cause knee swelling and pain as it irritates the joint surface or synovium. Chronic meniscal injuries can result in arthritic joint surface. Joint line tenderness is found in about 50% of these injuries. McMurray test is used to detect tear of the meniscus that can be displaced. It is performed by flexing and extending the knee between 90° and 140° of flexion. One of the examiner’s hands rotates the tibia at the ankle while the other hand is placed in front of the joint line. This is followed by the extension of knee in the rotated position. A palpable click indicates an unstable tear of the meniscus. The Apley grind test can help distinguish between tear in the anterior or posterior portion of the meniscus. MRI or arthroscopy can also be used as diagnostic tools to identify a meniscal lesion. E. Pes anserine bursa lies between the medial hamstring tendons (sartorius, gracilis, and semitendinosus) and proximal medial tibia. It is inferior to the joint line which helps distinguish from the medial joint line tenderness secondary to meniscal injury.

Answer 36

311. (E) A. Brachial plexitis is an acute disorder of that almost always begins with unilateral diffuse pain in the shoulder followed by weakness in the proximal muscles. Sensory disturbances are less pronounced than motor deficits. The pain usually subsides after the acute phase. Electrodiagnostic studies can help to establish the diagnosis. B. Cervical degenerative disc disease can result in diffuse axial pain in the neck or radicular pain along a particular dermatome corresponding to the nerve root involved if associated with a herniated nucleus pulposus. C. Whiplash injury typically follows a highimpact motor vehicle accident that results in axial neck pain. It has a musculoskeletal component to it and is frequently associated with facet joint involvement. D. Pancoast tumor is the tumor of the apex of the lung that typically involves the brachial plexus. Pain is a common presenting symptom usually involving the lower cervical nerve roots or trunks. CT scan or MRI can sometimes offer valuable diagnostic information. E. Thoracic outlet syndrome usually involves impingement of subclavian vessels and lower trunk of brachial plexus resulting in various degrees of vascular or neurologic compromise or both with local supraclavicular pain. The most common etiologies are cervical rib, hypertrophy of scalenus anticus, costoclavicular abnormalities, but nevertheless can result from an acute trauma. The pain and sensory changes are usually aggravated by any activity that extends the brachial plexus, including carrying heavy objects, abducting arms over the head or with repetitive movements of the arm. Motor weakness is seen in intrinsic muscles of the hand. The obliteration of radial pulse with arm extension or abduction or traction can be present and is called Adson or Allen test.

Answer 37

312. (C) A. H wave responses, in adults can be obtained in lower extremities. H wave response is an electric equivalent of the ankle deep tendon reflex, when the tibial nerve is stimulated. B. The tibial nerve behind the knee in the popliteal fossa is stimulated and the impulse travels via afferent fibers to the spinal cord at the S1 level. After synapse in the cord, anterior horn cells produce a motor response that can be recorded in gastrocnemius and soleus muscles. C. H waves are true reflexes, F wave is not. Because the H wave has to travel to the level of cord in order to produce a response, the latency is longer compared to F wave. D. This is correct as explained in (B). E. Since the impulses are conducted through S1 nerve, H reflex is typically prolonged in S1 radiculopathy but may be normal in L5 radiculopathy.

Answer 38

313. (B) The spinal cord receives its blood supply from three longitudinal arteries: a single anterior spinal artery and two posterior spinal arteries. The diameter of anterior spinal artery is greatest at the cervical and lower thoracic levels and narrowest at the midthoracic levels from T3-T9. This region of the cord is considered to be the “vulnerable zone” with respect to circulation. The anterior spinal artery is reinforced at a number of segmental levels by feeder arterial branches called anterior medullary feeder arteries. At the thoracic level, there are a total of eight of these feeder arteries, largest of which is called artery of Adamkiewicz or great anterior medullary artery. This artery typically enters the cord on the left side anywhere from T7 to L4, but most commonly at T9-T12.

Answer 39

314. (C) A. The involvement of deep radial nerve is called posterior interosseous nerve entrapment. The symptoms are similar to radial tunnel syndrome including pain over the proximal dorsal forearm, with maximum tenderness at the site of radial tunnel that is 4 cm distal to the lateral epicondyle over the posterior interosseous nerve. The pain is typically elicited by attempting to resist extension of long finger. B. Medial epicondylitis or golfer’s elbow results in pain and exquisite tenderness over medial epicondyle that is further aggravated by flexion and pronation of the forearm and the wrist. C. Lateral epicondylitis or tennis elbow involves the extensor-supinator muscle mass, including extensor carpi radialis brevis, extensor digitorum communis, extensor carpi radialis longus, extensor carpi ulnaris, and supinator. The extensor carpi radialis is most commonly involved, mostly from repetitive movement of the wrist involving wrist flexion, elbow extension, and forearm pronation. Provocative test involves grasping or extending the wrist against resistance or supinating the forearm when sudden and severe pain is experienced in the area of lateral epicondyle. The patient’s being an “avid golfer” is a distractor here. D. de Quervain disease or tenosynovitis of the tendon sheath of extensor pollicis brevis and adductor pollicis longus causes swelling and tenderness of anatomic snuff box. E. Brachioradialis tendonitis results in pain in the lateral forearm, that is, region of brachioradialis tendon, the provocative tests described above typically do not elicit characteristic symptoms.

Answer 40

315. (C) Patients with cervical rheumatoid arthritis develop neck pain exacerbated by movement, with atlantoaxial disease producing pain in upper cervical spine and subaxial involvement producing pain in lower neck and clavicular areas. Neurologic involvement is seen in more advanced cases of spinal cord or nerve root compromise related to deformity and soft tissue hypertrophy. Plain radiography is useful in showing structural abnormalities and dynamic studies including flexion extension, oblique and open mouth frontal projections in identifying instability. Anterior subluxation of atlantoaxial joint is the most common form of cervical spine derangement followed by subaxial subluxation (between C3 and C7), lateral subluxation, cranial settling (vertical subluxation), and posterior subluxation. Also, the autoimmune inflammatory changes affect the synovium of zygapophyseal joints resulting in laxity and subsequent instability.

Answer 41

316. (B) A. Trauma to L2 nerve root may cause ipsilateral groin pain, but is not the most likely cause. B. The most likely cause of the symptoms mentioned in the question is trauma to genitofemoral nerve. In fact, it is the most common complication associated with lumbar sympatholysis, particularly by the lateral approach. The incidence has been reported to be as high as 15%, but may be as low as 4% with a single-needle technique. Most cases are transient and resolve with conservative measures but others may last as long as 6 weeks. Repeat local anesthetic lumbar sympathetic block, TENS (transcutaneous electrical nerve stimulator) unit and intravenous lidocaine have all been described as options for remission of genitofemoral neuralgia. C. Psoas spasm is also sometimes seen but it typically produces discomfort in ipsilateral low back. (D) and (E) do not present as groin pain.

Answer 42

317. (D) Painful symptoms of Charcot-Marie-Tooth (CMT) disease have been described in the hypertrophic or demyelinating form (CMT-1). Pain may be described shooting, sharp, or burning in their toes, feet, ankles, and knees. Common presentation is in the first or second decade with difficulties walking or running.

Answer 43

318. (C) Morton neuroma may be considered in the spectrum of interdigital neuritis (compression neuropathy). It is usually between the third and fourth toes or less often between the fourth and fifth toes. The pain tends to be experienced more with walking and weight bearing while wearing shoes. The pain is generally alleviated with rest and removal of shoes. The pain may be reproduced by exerting pressure between the two toes implicated. Interdigital injection of local anesthetic relieves the pain.

Answer 44

319. (B) MRI, especially with T2-weighted images (though generally more time consuming to obtain) is useful in imaging conditions such as osteomyelitis, discitis, spinal cord compression, and malignancy. T1-weighted images provide reasonably good anatomic detail in imaging of end-plate reactive changes as well as postoperative scarring, but gadolinium-DTPA contrast should be used in postoperative patients to differentiate scarring from intervertebral discs.

Answer 45

320. (E) The H reflex is examined utilizing a modified motor nerve conduction study technique. The H reflex is generally present in the soleus muscle and at time forearm flexor muscles. It may be more widespread in hyperreflexic conditions (eg, myelopathy) and pediatrics. Delayed or absence of the tibial H wave may reflect S1 radiculopathy or other neuropathic processes.

Answer 46

321. (E) The elderly may seek medical attention for multiple problems with initial complaints of abdominal pain including: dissecting abdominal aortic aneurysm in diabetic ketoacidosis, pneumonia, pyelonephritis, inflammatory bowel disease, mesenteric ischemia, constipation, bowel obstruction, peritonitis, and druginduced GI mucosal irritation.

Answer 47

322. (A) The ulnar nerve may be compressed in the cubital tunnel (cubital tunnel syndrome) which may lead to atrophy of the first dorsal interosseous muscle, clawing of the small finger, weakness of small finger adduction (Wartenberg sign) and eventually in chronic ulnar nerve compromise—with weakness of grip and pinch.

Answer 48

323. (E) Tarsal tunnel syndrome is not a common source of foot discomfort and needs to be distinguished from multiple other causes of pain in the foot including: painful peripheral neuropathies, medial plantar nerve entrapment (which may occur in joggers), posterior tibial nerve entrapment symptoms tend to be located in medial plantar heel area, abductor digiti quinti nerve entrapment (usually with burning pain in heel pad area), and plantar fasciitis. Plantar fasciitis pain may be diffuse or migrate but with time is usually noted at the inferior aspect of the heel (around the medial calcaneal tuberosity) mainly, although typically severe with the first few steps in the morning, tends to diminish through the course of the day (unless intense or prolonged weight-bearing activity is under taken).

Answer 49

324. (E) Although, somewhat controversial and different from various proposed research criteria, the diagnosis of CRPS I, includes: 1. The presence of an initiating noxious event or a cause of immobilization. 2. Continuing pain, allodynia, or hyperalgesia with which the pain is disproportionate to any inciting event. 3. Evidence at some time of edema, changes in skin blood flow, or abnormal sudomotor activity in the region of the pain. 4. This diagnosis is excluded by the existence of condition that otherwise would account for the degree of pain and dysfunction.

Answer 50

325. (E) Paroxysmal hemicranias may be chronic (CPH) (eg, daily) or episodic (EPH) (eg, discrete headache period or separated by periods of remission) characterized by severe, excruciating, throbbing, boring, or pulsatile pain affecting the orbital, supraorbital, and temporal regions. The pain tends to be associated with at least one of the following signs or symptoms ipsilateral to the painful side: 1. Conjunctival injection 2. Nasal congestion 3. Lacrimation 4. Ptosis 5. Rhinorrhea 6. Eyelid edema Attacks may occur at any time—occasionally waking patients from sound sleep and tend to last for 2 to 25 minutes (although may linger a couple of hours). The patient generally has 1 to 40 attacks per day.

Answer 51

326. (E) 1. Although thoracic radiculopathy has been described to result from multiple etiologies including tumor, scoliosis, infection, spondylosis, and herniated disc, diabetes mellitus is described as the most common cause. 2. The lower cervical discs are most commonly affected by herniation. 3. The frequency of L4-5 herniation is 45% compared to 42% at the level of L5-S1. With L4-5 herniation, L5 nerve root is most commonly affected. 4. Lower cervical nerve roots of brachial plexus, that is, C8 and T1 nerve roots are most commonly affected in thoracic outlet syndrome.

Answer 52

327. (C) Epidural spinal cord compression is compression of spinal cord or cauda equina nerve roots from a lesion outside the dura mater. Epidural spinal cord or cauda equina compression is the second most common neurologic complication of cancer, occurring in up to 10% of patients. The most common tumors causing metastatic epidural compression are breast, lung, prostate, lymphoma, sarcoma, and kidney. Conus medullaris lesions typically cause a rapidly progressive symmetric perineal pain followed by early autonomic dysfunction, saddle sensory loss, and motor weakness. Limited straight leg raise test usually points to an epidural or intradural extramedullary lesion causing root compression, whereas segmental pain and sacral sparing suggest intramedullary disease.

Answer 53

328. (E) 1. The incidence of spinal cord pain has been estimated to be in the range of 6.4% to 94% of patients who experience spinal cord injury. 2. Patients may describe a variety of pain types; however, the three most common types are spontaneous steady, spontaneous neuralgic, and evoked pain including allodynia and hyperpathia. According to a study of 127 patients with spinal cord pain by Boureau and colleagues, 75% of patients reported burning pain. 3. Bowel and bladder dysfunction may be associated with spinal cord injury depending on the level and extent of injury. 4. Onset is typically within 1 to 6 months of the injury. When the onset was delayed beyond 1 year, 56% of the patients were found to suffer from a syrinx.

Answer 54

329. (A) Froment sign is positive when ulnar nerve dysfunction is present. Froment sign is tested by placing a piece of paper between patient’s thumb and index finger and checking the position of the thumb as the examiner tries to pull the paper away from the patient. Normally the distal joint of the thumb remains in extension but if there is ulnar nerve dysfunction the tip of the thumb flexes significantly to increased pressure in attempt to keep the paper from moving.

Answer 55

330. (E) Drug-induced painful neuropathies may include toxoids (especially with doses greater than 200 mg/m2), cisplatinum, vincristine, amiodarone, metronidazole, and pyridoxine (especially at doses greater than 200-300 mg/d).

Answer 56

331. (E) SCS has been utilized by clinicians for a variety of chronic pain issues. Although a large body of work has been published, precise mechanisms of action of SCS remain elusive. Animal studies suggest that SCS triggers release of serotonin, substance P, and γ-aminobutyric acid (GABA) within the spinal cord dorsal horn.