Medscape Questions Flashcards
A 50-year-old man presents to your clinic complaining of ringing in his right ear and of feeling as if the room is spinning around him. The latter symptom lasts for hours at a time. His wife points out that he is also losing his hearing. You suspect that he is suffering from Meniere syndrome.
Which of the following statements about Meniere syndrome is false?
❑ A. Meniere syndrome is characterized by tinnitus, vertigo, and hearing
loss
❑ B. Patients suffering from Meniere syndrome can have sudden attacks,
during which they fall to the ground
❑ C. Episodes of vertigo and deafness in Meniere syndrome can last for
hours to a day
❑ D. The deafness associated with Meniere syndrome begins with an inability
to hear low-frequency sounds and later progresses to involve higher
frequency sounds
C
- Although episodes of vertigo associated with Meniere syndrome usually last from hours to a day - deafness is constant after it develops
- The deafness is characterised initially by a compromised ability to hear low frequency sounds
- Meniere syndrome is the result of excessive production and decreased absorption of inner ear endolymphatic fluid, resulting in endolymphatic hydrops
- Patients usually complain of unilateral attacks of tinnitus (some have bilateral attacks), vertigo and fullness in an ear
- Deafness develops over time.
- Tumarkin otholithic crisis can be associated with a sudden spell of falling to the ground associated with Meniere syndrome
- Can be associated with nausea and vomiting.
A 52-year-old patient is diagnosed with Meniere syndrome. She has experienced several episodes of vertigo and now has right ear deafness. She has responded well to oral meclizine for the vertigo and to antiemetics for the associated vomiting. She wants to know if there are ways to avoid having similar attacks in the future, as this last one was particularly disabling.
Which of the following is not a long-term treatment for Meniere syndrome?
❑ A. Salt restriction
❑ B. The Epley maneuver
❑ C. Diuretics
❑ D. Weight loss
B
- Meniere syndrome is the result of increased levels of endolymphatic fluid.
- Treatments include:
- Salt restriction
- Diuretics
- Weight loss
- During attacks, vestibular suppressants and antiemetics can be useful for symptom relief
- Refractory cases can be treated with surgical endolymphatic shunting, labyrinthectomy and vestibular neurectomy
- The Epley maneuver is intended to dislodge otoconia from the semicircular canal system and is therefore useful in the treatment of benign paroxysmal positioning vertigo (BPPV)
A 66-year-old man presents to the emergency department complaining of nausea, vomiting, dizziness, and unsteadiness on his feet. The onset of these symptoms was acute. He states he has had a few similar episodes during the past month; each episode lasted a few hours. His medical history is notable for hypertension, hyperlipidemia, and coronary artery disease. He continues to smoke cigarettes despite his difficulties with heart disease.
The treatment of this patient should include which of the following measures?
❑ A. Performance of the Epley maneuver
❑ B. Administration of vestibular suppressants
❑ C. Reassurance and the prescription of a salt-restricted diet
❑ D. A thorough neurologic examination and consideration of neurovascular
imaging
D
- Episodes of vertigo in middle aged patients should prompt consideration of verebrobasilar insufficiency as a cause
- The vertigo can represent transient ischaemic attacks, which are warning signs of possible vertobrobasilar occlusion - a life-threatening condition.
- One should have even more concern about this condition in those with known risk factors for vascular disease or those with established vascular disease
- Diagnosis often requires MRI or conventional angiogram or both
- The patient’s episodes are very much a cause of concern, given his medical history and the recent onset of multiple attacks
- Positive findings on neurologic examination would be even more compelling.
A 30-year-old woman presents to the emergency department complaining of the room “moving all around her,” nausea, and one episode of emesis. She states she was well until the week before, when she had a cold. Nasal congestion, a nonproductive cough, and a runny nose characterized the latter. She has no previous medical problems. Examination is notable only for torsional-horizontal nystagmus and difficulty with balance. You suspect she has vestibular neuritis. Which of the following statements regarding vestibular neuritis is false?
❑ A. It is commonly associated with upper respiratory tract infection
❑ B. It is rare
❑ C. It usually lasts from days to weeks
❑ D. It can be treated with vestibular suppressants during the first few days
of the illness
B
- Vestibular neuritis is quite common, second only to BPPV as a cause of vertigo in most dizziness clinics.
- It is frequently associated with an upper tract respiratory infection and usually lasts from days to weeks
- In most patients, symptoms improve within 1-2 days, and resolution occurs within 6 weeks of onset
- The characteristic physical finding is torsional and horizontal nystagmus with the slow component being toward the affected side.
- During the early phase of the illness, vestibular suppressants such as meclizine and diazepam can be useful in treating symptoms of vertigo
- However, these agents should not be used for prolonged periods, because they may hinder the development of central compensation
- Vertigo should be considered in the diagnosis of patients presenting with symptoms and signs consistent with vestibular neuritis especially in the setting of diabetes or hypertension
- Hearing is uniformly preserved.
A 38-year-old white man presents to clinic with a complaint of sharp, “lightning-like” pain in both feet. He has had no recent trauma. His problem has been slowly progressing, and he is very concerned that this disorder will lead to disability. You suspect a peripheral neuropathy. Which of the following statements regarding peripheral neuropathy is false?
❑ A. A peripheral nerve disease can manifest as a dysfunction of motor, sensory, or autonomic systems
❑ B. Nerve conduction studies can provide support for a diagnosis of neuropathy and are a relatively objective way to follow the course of the
disease
❑ C. Complete pain relief should be the goal when using medications to
treat neuropathic pain
❑ D. Drugs used to treat neuropathic pain include tricyclics, carbamazepine,
and gabapentin
C
- Peripheral nervous system disorders produce combinations of motor, sensory and autonomic symptoms
- These symptoms primarily determined by class of nerve fibers affected (e.g. motor or sensory fibers) and by the location of the lesions rather than by the etiology of the process
- Neurophysiologic testing (especially nerve conduction studies) can be considered a routine part of evaluation of any patient with polyneuropathy
- Nerve biopsy is best reserved for patients with disabling neurologic symptoms and signs
- Nerve conduction studies can provide support for a diagnosis of neuropathy and are a relatively objective way to follow the course of the disease
- These studies may also allow a clinician to infer whether a disease is affecting primarily axons or their myelin sheaths - an important distinction in the differential diagnosis of polyneuropathy
- Needle electromyography is a complementary investigation that is usually performed at the same time as nerve conduction studies
- In a patient with peripheral neuropathy, electromyography is helpful in detecting small degrees of axon loss that may go undetected by nerve condution studies.
- The symptoms of neuropathy may be treatable even if the cause of the neuropathy is untreatable or unknown
- With simple measures, many patients can have meaningful relief of symptoms.
- Medications can be useful in the management of neuropathic pain, but the goals of therapy should be realistic
- Complete pain relief is unlikely
- Therefore, the aim of therapy should be to make the pain more tolerable without adding intolerable side effects of medication
- Of the many drugs that can be tried for neuropathic pain, tricyclics (especially amitriptyline) and carbamazepine are still most frequently used, although gabapentin is increasingly used as a first line agent.
Which of the following statements regarding GBS is true?
❑ A. Another name for GBS is chronic inflammatory demyelinating
polyneuropathy
❑ B. The fundamental pathologic event in GBS is the stripping of myelin
from axons by macrophages, which occurs in a patchy fashion
throughout the peripheral nervous system
❑ C. Several studies have proved that there is a link between a preceding
Shigella dysentery infection and GBS
❑ D. A cardinal feature of GBS is the asymmetrical pattern of involvement
B
- GBS or acute inflammatory demyelinating polyradiculoneuropathy is the most common cause of acute generalised paralysis in the Western world
- Chronic inflammatory demyelinating polyradiculoneuropathy is an immune mediated neuropathy whose onset is insidious with symptoms and signs developing over weeks to months.
- In contrast, the initial course of GBS is rapid.
- Most often, the first symptom of GBS is prickling paresthesia, beginning in the feet and spreading proximally hour by hour.
- Weakness is noticed some hours to a few days later
- Some patients have only motor symptoms without sensory symptoms.
- Classically, symptoms begin symmetrically in the distal limbs and proceed proximally (so called ascending paralysis)
- Nerve conduction studies provide evidence of demyelinating process affecting the spinal roots and peripheral nerves (a demyelinating polyradioculoneuropathy)
- The fundamental pathologic event in GBS is the stripping of myelin from axons by macrophages, which occurs in a patchy fashion throughout the peripheral nervous system.
- A cascade of events involving cell mediated and humoral immune mechanisms is assumed to be activated and lymphocytic inflammatory infiltrates are often foundin nerves and nerve root biopsy or autopsy
- Studies of the pathogenesis of GBS have focused on the potential roles of antecdent C.jejuni infection and production of antiganglioside autoantibodies both of which occur in a large number of patients with GBS
A 68-year-old African-American patient with type 2 diabetes mellitus presents to clinic for a 6-month follow- up visit. His daily capillary blood glucose level has been ranging from 160 to 190 mg/dl, and he has not been adhering to his diet. His major complaint today is a burning pain in both feet. On foot examination, you discover a 1 cm ulcer on the plantar surface of the left foot and a loss of light touch sensation in both feet. You make a diagnosis of diabetic polyneuropathy. Which of the following statements regarding diabetic polyneuropathy is false?
❑ A. There is a strong correlation between the presence of diabetic polyneuropathy, retinopathy, and nephropathy
❑ B. Autonomic diabetic neuropathy can occur and cause orthostatic
hypotension, impaired gastrointestinal motility, or blunting of the sympathetic response to hypoglycemia
❑ C. The classic distribution for diabetic polyneuropathy is the glove-andstocking distribution
❑ D. The severity of the polyneuropathy correlates more closely with the
duration of diabetes than the degree of hyperglycemia (mean glycosylated
hemoglobin)
D
- Peripheral neuropathy is common in patients with diabetes mellitus.
- Of various types of diabetic neuropathy by far the most common is distal, symmetrical sensorimotor neuropathy commonly referred to as diabetic polyneuropathy.
- In one prospective, population-based study of Americans of mainly northern European ancestry, diabetic polyneuropathy was foundin 54% of patients with type 1 diabetes and in 45% of patients with type 2 diabetes mellitus
- However, symptomatic polyneuropathy occurred in only 15% of the cohort, and none of the patients have disabling neurologic deficits.
- The severity of the polyneuropathy correlated more closely with the degree of hyperglycaemia (mean glycosated haemoglobin) than with duration of the diabetes.
- In this study and other large studies, the prevalence of diabetic neuropathy increased with the duration of diabetes, and a strong correlation existed between the presence of diabetic neuropathy, retinopathy and nephropathy.
- An important practical corollary of these observations is that a diagnosis of diabetic polyneuropathy in a patient with newly diagnosed diabetes but without other diabetic complications is likely to be incorrect
- Diabetic polyneuropathy has the classic so-called glove-and-stocking distribution of symptoms usually a combination of sensory loss and an unpleasent feeling of numbness or burning.
- Sensory loss in the feet and fingers and mild weakness in the feet and ankles are typical.
- Diabetic polyneuropathy can be expected to worsen slowly over the years.
- The other varieites of diabetic neuropathy usually occur on a background of diabetic polyneuropathy.
- Some degree of diabetic autonomic neuropathy is found in most patients with diabetic polyneuropathy although in some patients the autonomic symptoms and signs predominate.
- Orthostatic hypotension, impaired gastrointestinal motility (including gastroparesis) and blunting of the sympathetically mediated warning symptoms of hypoglycaemia are important management problems.
A 49-year-old man presents to the emergency department with abrupt onset of right facial weakness. He experienced a respiratory infection 2 weeks ago and has had a dull ache behind the right ear for 2 days. This morning while shaving, he noticed a drooping of the right side of his face. Neurologic examination reveals a neuropathy of cranial nerve VII, with complete paralysis of the right upper face and forehead. Hearing, taste, and sensation are normal, and the other cranial nerves are functioning normally. No rash
or shingles lesions are noted. Which of the following clinical features seen in this patient suggests a poorer prognosis and would prompt more aggressive medical treatment (e.g., prednisone and acyclovir)?
❑ A. Age younger than 60 years
❑ B. Normal hearing
❑ C. Normal taste
❑ D. Complete paralysis
❑ E. Abrupt onset of symptoms
D
- This patient has acute, idiopathic, facial neuropathy (Bell palsy).
- The abrupt onset of unilateral facial weakness with lower motor neurone (forehead) involvement preceded by pain behind the ear is classic.
- Over 80% of patients eventually recover fully.
- A course of corticosteroids and acyclovir may hasten recovery and is appropriate for patients with clinical features portending a poorer prognosis.
- Such features include severe (complete) paralysis, older age, hyperacusis, altered taste and electromyographic evidence of axonal degeneration.
- Recent evidence implicates HSV type I infection in many patients and trials of facial nerve decompression - have not demonstrated efficacy.
A 68-year-old diabetic man presents to the office for evaluation of double vision and right retro-orbital headache. Neurologic examination reveals right ptosis. The eye is deviated laterally and inferiorly. The right pupil is not dilated and reacts normally to light and accommodation. The patient has decreased
sensation in his feet to pin and light touch, but the rest of the examination results are normal. Which of the following is indicated for this patient at this time?
❑ A. Cranial CT
❑ B. Magnetic resonance angiography
❑ C. Cerebral angiography
❑ D. Neurosurgical consultation
❑ E. Reassurance and no further evaluation at this time
E
- This diabetic patient has developed an isolated third nerve palsy.
- The presenting symptoms are typical:
- The sudden development of ptosis with a ‘down and out eye’ and a retro-orbital headache
- The major consideration in the differntial diagnosis is a mass lesion along the course of the third cranial nerve - particularly an aneurysm in the circle of Willis. - most likely a posterior communicating artery aneurysm
- The absence of pupillary paralysis (pupil sparing third nerve palsy) seen in elderly, hypertensive and especially diabetic patients points to a putative microvascular lesion of the third cranial nerve.
- The findings of pupillary sparing can be distinguished at the bedside and can obviate the need for expensive neuroradiologic imaging in most cases, though such investigations is still advised in young patients who are without hypertension or diabetes.
A 72-year-old man has experienced numbness of his hands and feet for at least 5 years. Several times recently, he has tripped over the right foot. There is no history of diabetes, alcoholism, or other medical illness. He takes no medications or vitamin preparations. Examination reveals reduced pinprick and light-touch sensation in a stocking-and-glove distribution, which is worse in the feet than the hands. He has bilateral pes cavus and bilateral footdrop, which is worse on the right side. Chest x-ray, hematology group, chemistry panel, sedimentation rate, hemoglobin A1c level, antinuclear antibody assay, and protein electrophoresis results are all normal or negative.
Electromyography (EMG) shows primarily axonal degeneration of motor and sensory nerves of the lower and upper extremities. Which of the following is most likely to identify the cause of this patient’s neuropathy?
❑ A. Family history and examination of suspect family members
❑ B. Screening of the urine for heavy metal
❑ C. Nerve biopsy
❑ D. Assessment of vitamin B12 levels
❑ E. Liver function tests, including GGT
A
- Middle aged or older patients with mild, nondisabling slowly progressive polyneuropathy frequently have no identifiable etiology on routine examination or laboratory testing.
- In the absence of diabetes, alcohol abuse, medications or other systemic illness, more extensive studies (e.g. screening of urine for heavy metals, fat aspiration for amyloid, sural nerve biopsy) rarely reveal an etiology.
- Many of these patients in fact suffer from inherited polyneuropathy.
- They frequently are asymptomatic for years, then develop numbness (prickling or pins and needles sensation suggests an acquired cause)
- The routine family history is negative.
- However, specific questioning about relatives with foot deformities or who need special shoes, braces or gait assist devices may be revealing.
- Neurologic evaluation of first degree relatives who might be affected is more cost-effective than additional laboratory tests
A 34-year-old woman presents to the emergency department complaining of a “pins-and-needles” sensation in her feet and legs, which began yesterday. Initially, this sensation involved only her feet, but it has gradually moved up to involve her ankles, calves, and thighs. She has had difficulty walking for the
past few hours. She recalls a recent episode of bloody diarrhea, but otherwise she has been in good health. On examination, there is weakness of the foot and leg muscles in a symmetrical distribution. Deep tendon reflexes are absent at the knees and ankles. Plantar reflex is flexor. Fasciculations are not
seen. Inconsistent results are obtained on sensory exam. Cranial nerves are intact. The rest of the physical exam is normal. CSF examination is normal except for an elevated protein level.
Which of the following is the most likely diagnosis for this patient?
❑ A. Botulism
❑ B. Motor neuron disease
❑ C. GBS
❑ D. Poliomyelitis
❑ E. Acute HIV infection
C
Inflammatory demyelinating polyradiculoneuropathy is the most common variant of the GBS.
The disease incidence is approximately 1 case per million population per month.
Antecedent infections with viruses, mycoplasmas, or Campylobacter jejuni occur in one half to two thirds of patients. Patients typically present with paresthesias in the feet, which progress proximally. Pain is common early in the course of illness.
An areflexic motor paralysis and an acellular increase in total protein levels in the CSF develop in most patients within 1 week.
Paralysis can progress rapidly; early diagnosis facilitates early hospitalization
for appropriate nursing and medical care. Up to one third of patients require ventilatory support. Complete or near-complete recovery is the rule in 85% of patients. Early in the course of disease, many patients are misdiagnosed as having anxiety disorder, as malingering, or as having other psychiatric illness.
Careful neurologic examination and early neurologic
consultation in suspect cases are advised. Early cranial nerve involvement would suggest botulism, myasthenia gravis, or the Miller-Fisher variant of GBS. Muscle cramps, normal sensation, fasciculations, and preserved or hyperactive deep tendon reflexes characterize motor neuron disease (e.g., ALS).
Poliomyelitis was the major consideration in the differential diagnosis before the development of the polio vaccine, but it is now rare. A GBS-like syndrome with CSF pleocytosis can occur early in acute HIV infection.
A 46-year-old man presents with difficulties of gait and weakness of the face, neck, and hands. On examination, the patient has a “hatchet-face” appearance, with obvious wasting of the temporalis and masseter muscles. Bilateral eyelid ptosis without extraocular weakness is noted. There is prominent neck flexion but not extension, weakness, and atrophy. Interosseous atrophy and a bilateral footdrop are noted.
The patient has prominent frontal baldness and testicular atrophy. When asked to grip the examiner’s hand, the patient has difficulty relaxing the grip quickly. Percussion of the thenar eminence leads to slow
relaxation. The serum creatine phosphokinse (CPK) level is normal.
Which of the following is the most likely diagnosis for this patient?
❑ A. Becker muscular dystrophy
❑ B. Duchenne muscular dystrophy
❑ C. Autosomal recessive sarcoglycanopathy
❑ D. Autosomal dominant fascioscapulohumeral dystrophy
❑ E. Myotonic dystrophy (MD)
E
- Most likely has MD - most common muscular dystrophy in adults. MD is an autosomal dominant disorder; patients present with a unique constellation of clinical features:
- Ptosis
- Temporal and masseter atrophy
- Atrophy of the sternocleidomastoid muscles
- With sparing of the other posterior neck muscles
- Atrophy of the distal musculature, dysarthria and dysphagia
- Myotonia (the inability to quickly relax a firm hand grip) should be specifically sought - its presence is characteristic
- Most patients have disorders of the cardiac conduction system
- Other features include:
- Frontal baldness
- Testicular atrophy
- Cataracts
- Mild mental dysfunction
- GI motility disorders
- Hypersomnia
- CPK level is normal or mildly increased - EMG is diagnostic, revealing myotonic discharges
A 60-year-old woman is referred to you for a preanesthetic medical evaluation before elective total knee arthroplasty. Her degenerative joint disease of the knees has led to severe pain at rest and while walking, and conservative treatment measures have failed. Otherwise, she has been in good health and takes no medications. The patient has been told that no one in her family should undergo anesthesia with halothane, because her father developed a high fever and died during a cholecystectomy. What is the most appropriate step to take next in the care of this patient?
❑ A. Proceed with surgery; no additional precautions are needed
❑ B. Proceed with surgery but alert the anesthesiologist to avoid halothane
anesthetics
❑ C. Proceed with surgery; administer I.V. dantrolene if fever develops
❑ D. Cancel surgery and refer for caffeine-halothane contraction test
❑ E. Cancel surgery and advise against any elective surgical procedure
D
- Malignant hyperthermia is an autosomal dominant disorder caused by a defect on chromosome 19q13, leading to a mutation of the ryanodine receptor (RyR) gene.
- Mutations of RyR cause accelerated calcium release from the sarcoplasmic reticulum during general anesthesia with compounds such as halothane either and succinylcholine.
- This leads to a rapid increase in metabolism, dramatic elevations of body temperature, acidosis, muscle rigidity, myoglobinuria and death
- A careful family history may give clues to the diagnosis and should prompt referral for a muscle biopsy and in vitro caffeine-halothane contraction testing.
- Patients with malignant hyperthermia can usually safely undergo anesthesia with nitrous oxide, thiopental and nonpolarizing muscle relaxants.
- IV dantrolene is effective if administered early in the disease course, but patients who develop the syndrome still have 7% mortality.
A 24-year-old Asian man presents to the emergency department with an attack of profound weakness after a meal with friends. He reports that for several years he has had similar episodes after exercise and large meals.
Which of the following diagnostic tests should be performed immediately for this patient?
❑ A. Testing for acetylcholine receptor antibodies
❑ B. Assessment of serum potassium level
❑ C. Assessment of serum thyroxine level
❑ D. EMG
❑ E. Assessment of urinary aldosterone level
B
- Hyperkalemic and hypokalemic periodic paralysis are characteribsed by an abnormal serum potassium at the time of symptom occurrence.
- However, the potassium levels can be normal between attacks and thus measurement of serum potassium during the period in which symptoms occur is the most important step to take next in treating this patient.
- Hyperkalemic periodic paralysis is caused by a defect of the sodium channel, precipitated by rest following exercise, stress, potassium administration and ingesting of certain foods.
- Hypokalaemic periodic paralysis is caused by a defect in the calcium channel and is precipitated by the partaking of meals high in carbohydrates, rest following exercise and excitement.
- If the potassium level is found to be low during attaks, secondary causes of hypokalaemia:
- diuretics
- hyperaldosteronism
- laxatives
- thyrotoxicosis (asian descent especially)
- A serum potassium level that is elevated without apparent cause is suggestive of hyperkalemic periodic paralysis.
A 25-year-old woman presents for evaluation of progressive muscle weakness and fatigability for the past 9 months. She has otherwise been healthy and takes no medication except oral contraceptives. The
weakness involves her face, neck, and arms. The weakness is worse toward the end of the day and after repetitive activity. Her symptoms improve somewhat with sleep or rest. On examination, bilateral ptosis
and extraocular muscle weakness are noted, particularly on upward and lateral gaze. Attempts at forced smiling produce a snarling expression. She has prominent neck muscle weakness. Her speech has a nasal quality. Moderate weakness is evident on upper-extremity muscle testing. Deep tendon reflexes and plantar reflexes are normal. Routine laboratory examinations, including CBC, chemistry panel, and thyroid function testing, are normal. What is the most likely cause of this patient’s symptoms?
❑ A. Motor neuron disease
❑ B. Lambert-Eaton myasthenic syndrome
❑ C. Myasthenia gravis
❑ D. Congenital myasthenia
❑ E. Polymyositis
C
Primary care physicians should suspect myasthenia gravis in patients who have progressive skeletal muscle weakness and fatigability. The illness typically presents in young women or older men as weakness of the eyelids and extraocular muscles, which leads to ptosis and diplopia.
Patients develop weakness of the neck extensors and bulbar weakness
that leads to dysarthria and dysphagia. Proximal weakness may present as progressive weakness experienced when climbing stairs or rising from a chair.
Some patients complain of weakness combing their hair. Fluctuation of symptoms and fatigue with activity are characteristic. Deep tendon reflexes and the plantar reflex are normal. The presence of antibodies against the acetylcholine receptor and a positive EMG are diagnostic.
Lambert- Eaton myasthenic syndrome is frequently associated with small cell lung cancer; its symptoms are ptosis, diplopia, fatigability, and muscle weakness.
Features distinguishing it from myasthenia gravis include hyporeflexia, autonomic dysfunction, and an increase in muscle strength after several seconds of maximal effort. Congenital myasthenia presents in
infancy, childhood, or, occasionally, young adulthood. Motor neuron disease can present as muscle aches, weakness, and fatigue.
The first manifestation may be asymmetrical distal weakness, with progressive wasting and atrophy of muscles or difficulty with chewing, swallowing, and moving the face and tongue. Fasciculation, caused by spontaneous
twitching of motor units, is characteristic. With prominent corticospinal involvement, hyperactivity of the deep tendon reflexes is found.
