TABLE XI-42 Initial Symptoms of MS

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XI-43. The answer is D.(Chap. 380) The four clinical types of multiple sclerosis (MS) include relapsing/remitting, secondary progressive, primary progressive, and progressive relapsing. Relapsing/remitting MS (RRMS) accounts for 85% of MS cases at onset and is characterized by discrete attacks that generally evolve over days to weeks (rarely over hours). There is often complete recovery over the ensuing weeks to months. However, when ambulation is severely impaired during an attack, approximately half will fail to improve. Between attacks, patients are neurologically stable. Secondary progressive MS (SPMS) always begins as RRMS. At some point, however, the clinical course changes so that the patient experiences a steady deterioration in function unassociated with acute attacks (which may continue or cease during the progressive phase). SPMS produces a greater amount of fixed neurologic disability than RRMS. For a patient with RRMS, the risk of developing SPMS is approximately 2% each year, meaning that the great majority of RRMS ultimately evolves into SPMS. SPMS appears to represent a late stage of the same underlying illness as RRMS. Primary progressive MS (PPMS) accounts for approximately 15% of cases. These patients do not experience attacks but only a steady functional decline from disease onset. Compared to RRMS, the sex distribution is more even, the disease begins later in life (mean age approximately 40 years), and disability develops faster (at least relative to the onset of the first clinical symptom). Despite these differences, PPMS appears to represent the same underlying illness as RRMS. Progressive/relapsing MS (PRMS) overlaps PPMS and SPMS and accounts for about 5% of MS patients. Like patients with PPMS, these patients

experience a steady deterioration in their condition from disease onset. However, like SPMS patients, they experience occasional attacks superimposed upon their progressive course. Autoimmune autonomic neuropathy is a distinct clinical syndrome not related to MS. It presents with the subacute development of autonomic disturbances with orthostatic hypotension, enteric neuropathy (gastroparesis, ileus, constipation/diarrhea), and cholinergic failure; the latter consists of loss of sweating, sicca complex, and a tonic pupil. Autoantibodies against the ganglionic ACh receptor (A₃ AChR) are present

in the serum of many patients and are now considered to be diagnostic of this syndrome.

XI-44. The answer is D.(Chap. 381) In a patient with suspected bacterial meningitis empirical therapy should be administered promptly to reduce mortality and morbidity. The decision to obtain an imaging study prior to lumbar puncture (LP) is based on the concern of precipitating herniation in a patient with elevated intracranial pressure or focal CNS lesions. Therefore, patients with the presence of papilledema on physical examination, history of recent head trauma, known or suspected intracranial lesions (immunosuppressed, known malignancy), focal neurologic findings, or depressed level of consciousness should have a head CT or MRI prior to LP. In an immunocompetent patient with no known history of recent head trauma, a normal level of consciousness, and no evidence of papilledema or focal neurologic deficits, it is considered safe to perform LP without prior neuroimaging studies. Kernig's sign is elicited in a supine patient by flexing the thigh and knee. A positive sign occurs when the patient has head/neck pain when passively straightening the knee. The sensitivity and specificity of this sign (also Brudzinski's) for bacterial meningitis are unknown, but they imply meningeal irritation, not an intracranial lesion or elevated intracranial pressure. While cerebrospinal fluid cultures may be impacted by administration of antibiotics prior to LP, stains, antigen tests, and polymerase chain reaction tests will not be affected.

XI-45. The answer is B.(Chap. 381) The release of bacterial cell wall components after killing by antibiotics may evoke a marked inflammatory cytokine response in the subarachnoid space. This inflammation may lead to increased damage of the blood-brain barrier and central nervous system damage. Glucocorticoids can blunt this response by inhibiting tumor necrosis factor and interleukin-1. They work best if administered before antibiotics. Clinical trials have demonstrated that dexamethasone, 10 mg IV administered 20 minutes before antibiotics, reduced unfavorable outcomes, including death. The dexamethasone was continued for 4 days. The benefits were most striking in pneumococcal meningitis. Because this is the most common cause of meningitis in the elderly, empirical coverage should include this intervention as well. The efficacy of dexamethasone therapy in preventing neurologic sequelae is different between high- and low-income countries. Randomized trials in low-income countries (sub-Saharan Africa, Southeast Asia) failed to show benefit in subgroups of patients. The lack of efficacy of dexamethasone in these trials has been attributed to late presentation to the hospital with more advanced disease, antibiotic pretreatment, malnutrition, infection with HIV, and treatment of patients with probable, but not microbiologically proven, bacterial meningitis. The results of these clinical trials suggest that patients in sub-Saharan Africa and those in low-income countries with negative CSF Gram stain and culture should not be treated with dexamethasone. Empirical antibiotics in this case should include a third-generation cephalosporin, vancomycin, and ampicillin. However, dexamethasone may decrease vancomycin penetration into the CSF, so its use should be considered carefully in cases where the most likely organism requires vancomycin coverage. Acyclovir or valacyclovir may be used as initial empiric treatment in cases of suspected herpes CNS infection. However, in this case the LP is highly suggestive of acute bacterial infection. Intravenous gamma

globulin is used as adjunctive therapy in children with known immunoglobulin deficiency who are at risk of viral meningitis/encephalitis.

XI-46. The answer is D.(Chap. 381) Listeria has become an increasingly important cause of bacterial meningitis in neonates (<1 month of age), pregnant women, individuals more than 60 years old, and immunocompromised individuals. Infection is acquired by eating contaminated foods such as unpasteurized dairy products, coleslaw, milk, soft cheeses, delicatessen meats, and uncooked hot dogs. Ampicillin is the agent most often added to the initial empirical regimen to cover L. monocytogenes.

XI-47. The answer is D.(Chap. 382) Ibuprofen, isoniazid, ciprofloxacin, tolmetin, sulfa-containing medicines, and phenazopyridine have been implicated in drug hypersensitivity leading to meningitis. The cerebrospinal fluid (CSF) will typically show neutrophils, but mononuclear cells or eosinophils are occasionally present. Most causes of chronic (not recurrent) meningitis cause a predominance of mononuclear cells. The differential for chronic meningitis is broad and a diagnosis is often difficult to make. The treating physician needs to consider a diverse array of viral, fungal, bacterial, mycobacterial, helminthic, and protozoal pathogens, both common and exotic, and therefore should obtain a detailed social history and consult an expert in the field. Recurrent meningitis is often due to herpes simplex virus type 2 infection and this should be ruled out, particularly if active genital ulcers develop concurrently. Malignancy, sarcoidosis, and vasculitis are all potential causes, and history, physical examination, and appropriate further testing should dictate the degree to which these possibilities are explored. Medications are often overlooked as a cause of chronic meningitis and should always be carefully considered. When CSF neutrophils predominate after 3 weeks of illness, Nocardia, Actinomyces, Brucella, tuberculosis (<10% of cases), and fungal and noninfectious causes of chronic meningitis should be considered.

XI-48. The answer is E.(Chap. 383) Prions are infectious particles that cause central nervous system degeneration. The human prion diseases described to date include Creutzfeldt-Jacob disease (CJD), kuru, Gerstmann-Straussler-Scheinker disease, and fatal insomnia. The most common prion disease is sporadic CJD (sCJD), which occurs in a seemingly random pattern in adults in their fifth and sixth decades of life. sCJD accounts for about 85% of cases of CJD and occurs in approximately 1 per 1 million population. Variant CJD (vCJD) results from infection from bovine exposure to tainted beef from cattle with bovine spongiform encephalopathy (BSE). There has been a steady decline of cases of vCJD in Europe over the past decade. Infectious CJD (iCJD) has resulted from injection of tainted human growth hormone, as well as transplant of infected dura mater grafts into humans. Familial CJD (fCJD) is due to germ-line mutations that follow an autosomal dominant inheritance. Kuru is due to infection through ritualistic cannibalism. Gerstmann-Straussler-Scheinker disease and familial fatal insomnia (FFI) occur as dominantly inherited prion diseases. Sporadic cases of fatal insomnia (sFI) have been described.

XI-49. The answer is B.(Chap. 383) Startle myoclonus is a worrisome sign but is neither sensitive nor specific for CJD, though it is more worrisome if it occurs during sleep. The constellation of dementia, myoclonus, and periodic electrical bursts in an afebrile 60-year-old patient generally indicates CJD. Clinical abnormalities in CJD are confined to the CNS. Lewy body dementia, Alzheimer's disease, central nervous system infections, and myoclonic epilepsy can all cause myoclonus. Both EEG and MRI can help differentiate CJD from these disorders. The MRI finding of cortical ribboning and intensity in the basal ganglia on fluid-attenuated inversion recovery sequences is characteristic of CJD. EEG is

useful if stereotypical periodic bursts every 1-2 seconds are present, but this is seen in only 60% of cases, and other findings may be less specific. Demonstration of specific immunoassays for proteolytic products of disease-causing prion proteins (PrP^Sc) at brain biopsy may be necessary to confirm diagnosis in some cases. However, these proteins are not uniformly distributed throughout the brain and false-negative biopsies occur. Both surgeons and pathologists must be warned to use standard precautions under these circumstances. These proteins cannot be measured from cerebrospinal fluid (CSF). CSF in CJD is usually normal except for a minimally elevated protein. Many patients with CJD have elevated CSF stress protein 14-3-3. This test alone is neither sensitive nor specific, as patients with herpes simplex virus encephalitis, multi-infarct dementia, and stroke may have similar elevations.

XI-50. The answer is A.(Chap. 384) Charcot-Marie-Tooth (CMT) syndrome is the most common type of hereditary neuropathy. CMT is comprised of several similar but genetically distinct conditions with different associated mutations. CMT1 is the most common and is an inherited demyelinating sensorimotor neuropathy. CMT1 affects patients in the first to third decades of life with distal leg weakness, i.e., footdrop. Although patients generally do not complain of sensory symptoms, these can often be elicited on physical examination. Muscle stretch reflexes are unobtainable or reduced throughout and calves are often atrophied, which makes legs appear to have a so-called inverted champagne bottle appearance. Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant disorder characterized by recurrent attacks of pain, weakness, and sensory loss in the distribution of the brachial plexus that often begins in childhood. Hereditary sensory and autonomic neuropathy (HSAN) is a very rare group of hereditary neuropathies in which sensory and autonomic dysfunction predominates over muscle weakness. This would not fit the clinical pattern described here. Guillain-Barre syndrome presents generally acutely with involvement of both proximal and distal weakness and sensory loss. The prolonged symptom period and distribution described here is not typical for Guillain-Barre syndrome. Fabry disease is an X-linked disorder in which men are more commonly affected than women. Patients have angiokeratomas, which are reddish-purple lesions usually found around the umbilicus, scrotum, and inguinal region. Burning pain in the hands and feet often is found in late childhood or early adult life. Patients also have premature atheroscloerosis from the underlying mutation in the alpha-galactosidase gene with accumulation of ceramide in nerves and blood vessels.

XI-51. The answer is F.(Chap. 384) One of the most common side effects of isoniazid treatment is peripheral neuropathy. The elderly, malnourished, and "slow acetylators" are at increased risk for developing the neuropathy. INH inhibits pyridoxal phosphokinase, resulting in pyridoxine (vitamin B₆)

deficiency and the neuropathy. Prophylactic administration of pyridoxine can prevent the neuropathy from developing. Symptoms are generally dysesthesias and sensory ataxia. Impaired large-fiber sensory modalities are found on examination. Cobalamin (B₁₂) is not reduced in this condition and is unaffected

by isoniazid. Neurontin and pregabalin may alleviate symptoms but will not reverse the neuropathy. There is no indication that hypothyroidism is present.

XI-52. The answer is C.(Chap. 384) Diabetes mellitus (DM) is the most common cause of peripheral neuropathy in developed countries and is associated with several different types of polyneuropathy including distal symmetric sensory or sensorimotor polyneuropathy, autonomic neuropathy, diabetic neuropathic cachexia, polyradiculoneuropathies, cranial neuropathies, and other mononeuropathies. Risk factors for the development of neuropathy include long-standing and poorly controlled diabetes and the presence of retinopathy or nephropathy. The patient here appears to have diabetic distal

symmetric sensory and sensorimotor polyneuropathy (DSPN), which is the most common form of diabetic neuropathy and presents with sensory loss beginning in the toes and gradually progresses over time up the legs and into the fingers and arms. Symptoms also may include tingling, burning, and deep, aching pains. Nerve biopsy, though rarely indicated, often shows axonal degeneration, endothelial hyperplasia, and occasionally perivascular inflammation. Tight glucose control prevents the development of disease but does not reverse established disease. Diabetic autonomic neuropathy is often seen in combination with DSPN and manifests by abnormal sweating, dysfunctional thermoregulation, dry eyes and mouth, postural hypotension, gastrointestinal abnormalities including gastroparesis, and genitourinary dysfunction.

XI-53. The answer is B.(Chap. 384) Peripheral neuropathy is a general term indicating peripheral nerve disorders of any cause. The causes are legion, but peripheral neuropathy can be classified by a number of means: axonal versus demyelinating, mononeuropathy versus polyneuropathy versus mononeuritis multiplex, sensory versus motor, and by the tempo of the onset of symptoms. Mononeuropathy typically results from local compression, trauma, or entrapment of a nerve. Polyneuropathy often results from a more systemic process. The distinction between axonal and demyelinating can often be made only with nerve conduction studies. HIV infection causes a common, distal, symmetric, mainly sensory polyneuropathy. Vitamin B₁₂ deficiency typically causes a sensory neuropathy that predominantly

involves the dorsal columns. Hypothyroidism and acromegaly may both cause compression and swelling of nerve fibers, resulting first in sensory symptoms and later in disease with motor symptoms. Critical illness polyneuropathy is predominantly motor in presentation. Patients typically present with weakness that can be profound. These patients may recover over the course of weeks to months. The etiology is unknown, but an association may exist with prolonged immobilization, severity of illness, neuromuscular blockade, and corticosteroids.

XI-54. The answer is B.(Chap. 384) Carpal tunnel syndrome is caused by the entrapment of the median nerve at the wrist. Symptoms begin with paresthesias in the median nerve distribution. With worsening, atrophy and weakness may develop. This condition is most commonly caused by excessive use of the wrist and situations involving repetitive motion. Most cases are idiopathic other than those related to occupational or environmental associations. Less commonly, systemic disease may result in carpal tunnel syndrome related to nerve compression or infiltrative disease. This may be suspected when bilateral disease is apparent. Tenosynovitis with arthritis, as in the case of rheumatoid arthritis, and thickening of the connective tissue, as in the case of amyloid or acromegaly, may cause carpal tunnel syndrome. Other systemic diseases, such as hypothyroidism and diabetes mellitus, are also possible etiologies. Acute or chronic leukemia is not typically associated with carpal tunnel syndrome.

XI-55. The answer is B.(Chap. 385) Guillain-Barre syndrome (GBS) is an acute, severe polyradiculoneuropathy that is autoimmune in nature. GBS manifests as rapidly evolving, areflexic motor paralysis with or without sensory disturbance, usually with ascending paralysis developing over several days. Approximately 70% of GBS cases occur 1-3 weeks after an acute infectious process, usually respiratory or gastrointestinal. Twenty to thirty percent of cases in North America, Europe, and Australia are preceded by infection or reinfection with Campylobacter jejuni. Other implicated infections include Epstein-Barr virus, CMV, and Mycoplasma pneumoniae. T. whippelii is the etiologic agent of Whipple's disease and B. henselae is implicated in cat-scratch fever.

XI-56. The answer is E.(Chap. 386) Myasthenia gravis (MG) is a neuromuscular disorder characterized by weakness and fatigability of skeletal muscles. The primary defect is a decrease in the number of acetylcholine receptors at the neuromuscular junction secondary to autoimmune antibodies. MG is not rare, affecting at least 1 in 7500 individuals. Women are affected more frequently than men. Women typically present in the second and third decades of life, and men present in the fifth and sixth decades. The key features of MG are weakness and fatigability. Clinical features include weakness of the cranial muscles, particularly the eyelids and extraocular muscles. Diplopia and ptosis are common initial complaints. Weakness in chewing is noticeable after prolonged effort. Speech may be affected secondary to weakness of the palate or tongue. Swallowing may result from weakness of the palate, tongue, or pharynx. In the majority of patients the weakness becomes generalized. The diagnosis is suspected after the appearance of the characteristic symptoms and signs. Edrophonium is an acetylcholinesterase inhibitor that allows ACh to interact repeatedly with the limited number of AChRs, producing improvement in the strength of myasthenic muscles. False-positive tests may occur in patients with other neurologic diseases. Electrodiagnostic testing may show evidence of reduction in the amplitude of the evoked muscle action potentials with repeated stimulation. Testing for the specific antibodies to AChR are diagnostic. In addition to anti-AChR antibodies, antibodies to MuSK have been found in some patients with clinical MG. Antibodies to voltage-gated calcium channels are found in patients with the Lambert-Eaton syndrome.

XI-57. The answer is C.(Chap. 386) Except for lumbar puncture, all of the options listed are indicated at this time. Thymic abnormalities are present in 75% of patients with myasthenia gravis. A CT or MRI of the mediastinum may show enlargement or neoplastic changes in the thyrnus and is recommended upon diagnosis. Hyperthyroidism occurs in 3-8% of patients with myasthenia gravis and may aggravate weakness. Testing for rheumatoid factor and antinuclear antibodies should also be obtained because of the association of myasthenia gravis to other autoimmune diseases. Due to side effects of immunosuppressive therapy, a thorough evaluation should be undertaken to rule out latent or chronic infections such as tuberculosis. Measurements of ventilatory function are valuable as a baseline because of the frequency and seriousness of respiratory impairment in myasthenic patients, and they can be used as an objective measure of response to therapy.

XI-58. The answer is E.(Chap. 387) All classes of lipid-lowering agents have been implicated in muscle toxicity including fibrates, HMG-CoA reductase inhibitors, niacin, and ezetimibe. Myalgia, malaise, and muscle tenderness are the most common manifestations, and muscle pain may be exacerbated by exercise. Proximal weakness may be found on examination. In severe cases, rhabdomyolysis and myoglobinuria may occur, though most cases are mild. Concomitant use of statins with fibrates and cyclosporine are more likely to cause adverse muscle reactions. Elevated serum CK is often identified, and muscle weakness is evidenced by myopathic EMG studies and myonecrosis on muscle biopsy. Severe myalgias, muscle weakness, and significant elevations in CK (>3 x upper limit of normal) and myoglobinuria are indications for stopping. After cessation, improvement generally occurs after several weeks.

XI-59. The answer is E.(Chap. 387) A number of endocrinologic conditions are associated with myopathy. Both hypo- and hyperthyroidism are associated with proximal muscle weakness. Hypothyroidism is frequently associated with an elevated CK, even with minimal clinical evidence of muscle disease. Thyrotoxic patients may have fasciculations in addition to proximal myopathy, but in

contrast to hypothyroid patients, CK is not generally elevated. Hyperparathyroidism is associated with muscle weakness that is generally proximal. Muscle wasting and brisk reflexes are also generally present. Serum CK levels may be normal or slightly elevated. Serum calcium and phosphate levels show no correlation with clinical weakness. Hypoparathyroid patients also often have myopathy due to hypocalcemia. Patients with acromegaly usually have mild proximal weakness without atrophy. The duration of acromegaly, not the serum growth hormone levels, correlate with the degree of myopathy. Diabetes mellitus is a very rare cause of myopathy, generally due to ischemic infarction of muscle and not a primary myopathy. Finally, vitamin D deficiency is associated with muscle weakness, as are glucocorticoid excess states, e.g., Cushing's disease.

XI-60. The answer is D.(Chap. 387) There are two recognized clinical forms of myotonic dystrophy, both of which are characterized by autosomal dominant inheritance. Myotonic dystrophy 1 (DM1) is the most common form and the most likely disorder in this patient. Characteristic clinical features of this disorder include a "hatchet-faced" appearance, due to wasting of the facial muscles, and weakness of the neck muscles. In contrast to the muscular dystrophies (Becker and Duchenne), distal limb muscle weakness is more common in DM1. Palatal, pharyngeal, and tongue involvement are also common and produce the dysarthric voice that is frequently heard. The failure of relaxation after a forced hand-grip is characteristic of myotonia. Percussion of the thenar eminence can also elicit myotonia. In most individuals, myotonia is present by age 5, but clinical symptoms of weakness that lead to diagnosis may not be present until adulthood. Cardiac conduction abnormalities and heart failure are also common in myotonic dystrophy. Diagnosis can often be made from clinical features alone in an individual with classic symptoms and a positive family history. An electromyogram would confirm myotonia. Genetic testing for DM1 would show a characteristic trinucleotide repeat on chromosome 19. Genetic anticipation occurs with an increasing number of repeats and worsening clinical disease over successive generations. Myotonic dystrophy 2 (DM2) causes primarily proximal muscle weakness and is also known by the name proximal myotonic myopathy (PROMM). Other features of the disease overlap with DM1. Acid maltase deficiency (glucosidase deficiency, or Pompe's disease) has three recognized forms, only one of which has onset in adulthood. In the adult-onset form, respiratory muscle weakness is prominent and often is the presenting symptom. As stated previously, Becker and Duchenne muscular dystrophies present with primarily proximal muscle weakness and are X-linked recessive disorders. Becker muscular dystrophy presents at a later age than Duchenne muscular dystrophy and has a more prolonged course. Otherwise, their features are similar. Nemaline myopathy is a heterogeneous disorder marked by the threadlike appearance of muscle fibers on biopsy. Nemaline myopathy usually presents in childhood and includes a striking facial appearance similar to that in myotonic dystrophy with a long, narrow face. This disease is inherited in an autosomal dominant fashion.

XI-61. The answer is B.(Chap. 388) When patients present with proximal muscle weakness and myositis, whether polymyositis, dermatomyositis, or inclusion body myositis, the diagnosis is confirmed by analysis of serum muscle enzymes, EMG findings, and muscle biopsy. The most sensitive serum enzyme is creatinine kinase (CK), which can be elevated as much as 50-fold in active disease. CK levels usually parallel disease activity, but can be normal in some patients with inclusion body myositis or dermatomyositis. CK is always elevated in active polymyositis and thus is considered most sensitive. Other enzymes may be elevated as well including glutamic-oxaloacetic transaminase, glutamate pyruvate transaminase, lactate dehydrogenase, and aldolase.

XI-62. The answer is B.(Chap. 388) Various autoantibodies against nuclear antigens, e.g., ANAs, and cytoplasmic antigens are found in up to 20% of patients with inflammatory myopathies. The antibodies to cytoplasmic antigens are directed against ribonucleoproteins involved in protein synthesis (antisynthetases) or translational transport (anti-signal-recognition particles). The antibody directed against the histidyl-transfer RNA synthetase, called anti-Jo-1, accounts for 75% of all the antisynthetases and is clinically useful because up to 80% of patients with this autoantibody will have interstitial lung disease. Patients with anti-Jo-1 may also have Raynaud's phenomenon, nonerosive arthritis, and the MHC molecules DR3 and DRw52. Interstitial lung disease associated with anti-Jo-1 is often rapidly progressive and fatal, even if treated aggressively with cyclophosphamide or other immunosuppressants.

XI-63. The answer is A.(Chap. 388) Dermatomyositis is associated with malignancy in up to 15% of cases, thus age-appropriate cancer screening is indicated when this diagnosis is made. Exhaustive cancer searches are not recommended, however. Dermatomyositis may be associated occasionally with scleroderma and mixed connective tissue disease, but less frequently with systemic lupus erythematosus, rheumatoid arthritis, or Sjogren's syndrome, which are more closely associated with polymyositis or inclusion body myositis (IBM). Viruses may be associated with IBM and polymyositis, but are not proven to be associated with dermatomyositis. Parasites and bacteria such as cestodes and nematodes are associated with polymyositis, but not other forms of inflammatory myopathy. Finally, thyroid-stimulating immunoglobulins are not known to be associated with dermatomyositis.

XI-64. The answer is A.(Chap. 388) A common mistake in the management of patients with inflammatory myopathy is to "chase the CK" instead of adjusting therapy based on the clinical response. The goal of therapy is to improve strength. If that goal is being achieved, no augmentation of therapy is necessary. In this case, the plan to switch to long-term maintenance with steroid-sparing immunosuppressants should still be pursued. There have been no controlled studies comparing mycophenolate to methotrexate for long-term use in polymyositis, and in the absence of an adverse reaction to mycophenolate, therapy should not be changed. Despite an elevated CK, patients with polymyositis who are responding to therapy do not need a repeat muscle biopsy.

XI-65. The answer is B.(Chap. e47) The FLAIR MRI shows increased signal bilaterally in the occipital lobes predominantly involving the white matter. This pattern is typical of a hyperperfusion state, in this case secondary to calcineurin-inhibitor toxicity. This clinical-radiographic abnormality was previously described as reversible posterior leukoencephalopathy. However, this characterization is no longer utilized because the syndrome may not be reversible, the territory may not be confined posteriorly, and gray matter may be involved. Hyperperfusion syndrome may be due to a hydrostatic elevation in cerebral capillary pressure or disorders with endothelial dysfunction and capillary leakage. Hydrostatic causes include hypertensive encephalopathy, post-carotid endarterectomy syndrome, (pre)eclampsia, and high-altitude cerebral edema. Endothelial dysfunction causes include calcineurin-inhibitor toxicity, other chemotherapeutic agent toxicity, HELLP syndrome, TTP, SLE, or Wegener's granulomatosis. The diagnosis is clinical and radiographic. CSF findings are nonspecific. In the case of cyclosporine the syndrome may occur with therapeutic serum levels and sporadically after years of treatment. Acoustic neuroma would present on MRI with a discrete mass. The radiologic and clinical appearance is not consistent with pituitary apoplexy. Post-liver transplant patients are at risk of acute (streptococcal) and chronic (tuberculous) meningitis, but the clinical and radiologic findings in this

case would not be typical.

XI-66. The answer is B.(Chap. e47) Acute neurologic events, such as encephalopathy or stroke (often related to intraoperative hypotension or embolism), are common after open heart surgery or coronary artery bypass graft (CABG). Additionally, a chronic syndrome of cognitive impairment is now increasingly recognized after surgery. Small or microemboli during surgery are thought to be the etiology of a hyper- or hypoactive confusional state in the postoperative period. A smaller burden of microemboli may be responsible for the more subtle post-cardiac surgery syndrome characterized by confusion and depressive symptoms as described in this case. Cardiac surgery may also unmask the early manifestations of vascular dementia or Alzheimer's disease. Off-pump CABG patients have a shorter length of hospital stay and fewer perioperative complications. Recent studies do not confirm the hypothesis that off-pump surgery results in less cognitive impairment than on-pump surgery. Ongoing studies are testing the efficacy of microfilters to capture emboli and reduce CNS complications. Given the temporal relation to CABG surgery and the lack of temporal variability, multiple sclerosis is not likely in this case. Similarly, in the absence of meningitis or encephalitis signs or symptoms, streptococcal or West Nile virus disease is unlikely. vCJD is associated with ingestion of prion-contaminated product. It is characterized by rapidly developing delirium and dementia, often associated with myoclonic jerks.

XI-67. The answer is E.(Chap. e47) The peroneal nerve winds around the head of the fibula below the lateral aspect of the knee. This superficial location makes it vulnerable to trauma. Poorly applied leg braces, fibular fracture, tight-fitting stockings, or casts may cause peroneal nerve injury and neuropathy. Patients may present with footdrop (dorsiflexion defect) with weakness of foot eversion. Intact foot inversion at the ankle distinguishes peroneal nerve injury from L5 radiculopathy, which involves the muscles innervated by the tibial nerve. Sensory loss due to peroneal nerve injury involves the lateral aspect of the leg below the knee and the dorsum of the foot. Cauda equina syndrome is caused by compression of the spinal nerve roots of the lumbar plexus usually due to tumor, trauma, or spinal stenosis. It typically presents with weakness of the muscles innervated by the involved nerves, incontinence, and decreased anal sphincter tone. Cauda equina syndrome is usually a medical emergency to avoid permanent functional loss. The femoral nerve branches into anterior and posterior portions in the leg. Injury of the anterior branches may lead to sensory findings in the thigh and muscular findings in the sartorius and the quadriceps. L4 radiculopathy causes symptoms in the anterior thigh and knee extensors (including the patellar reflex).

XI-68. The answer is A.(Chap. 389) Chronic fatigue syndrome (CFS) is a disorder characterized by persistent and unexplained fatigue resulting in severe impairment in daily functioning. Besides intense fatigue, most patients with CFS report concomitant symptoms such as pain, cognitive dysfunction, and unrefreshing sleep. Additional symptoms can include headache, sore throat, tender lymph nodes, muscle aches, joint aches, feverishness, difficulty sleeping, psychiatric problems, allergies, and abdominal cramps. Criteria for the diagnosis of CFS have been developed by the U.S. Centers for Disease Control and Prevention (see Table XI-68). CFS is seen worldwide, with adult prevalence rates varying between 0.2% and 0.4%. In the United States, the prevalence is higher in women, members of minority groups (African and Native Americans), and individuals with lower levels of education and occupational status. Approximately 75% of all CFS patients are women. The mean age of onset is between 29 and 35 years. It is probable that many patients go undiagnosed and/or do not seek help.

Date: 2016-04-22; view: 773