128. The answer is d. (Ropper, pp 736-737.) At the onset of encephalitis lethargica, patients often develop transient fevers, lethargy, and headache. Disturbed eye movements are the most common sign of neurological disease during the acute illness. A variety of movement disorders, including chorea, athetosis, dystonia, and myoclonus, develop with the disease. About one in four affected persons die. The most common sequela of the disease is severe, unremitting parkinsonism with signs and symptoms similar to those exhibited with idiopathic parkinsonism. One rather unique feature is the occurrence of oculogyric crises, or episodes in which the eyes deviate to one side or upward, associated with other forms of dystonia and autonomic symptoms, sometimes occurring with great regularity.
129. The answer is d. (Ropper, pp 690-692.) Facial paresis is the neurological injury most likely to develop with sarcoidosis. Almost half of patients with sarcoidosis and neurological disease have a neurological sign or symptom as the first obvious complication of the sarcoidosis. These patients report progressive weakness of one side of the face with no substantial loss of sensation over the paretic side. They may feel that there is decreased sensitivity to touch on the weak side, but this is more commonly from a loss of tone in the facial muscles than from an injury to the trigeminal nerve. Other CNs especially susceptible to injury in persons with sarcoidosis include II, III, IV, VI, and VIII.
130. The answer is a. (Ropper, p 712.) SSPE, PML, kuru, and HIV encephalomyelitis are all viral diseases affecting the CNS, but poliomyelitis is the only one that causes a purely motor neuron disease. Poliomyelitis virus attacks the anterior horn cells in the spinal cord. It is most likely to be confused with Guillain-Barré syndrome if the typical CSF picture of a viral meningoencephalitis is not found with the progressive motor neuron impairment. With poliomyelitis, the CSF will usually exhibit an elevated protein and white cell count. During the initial stages of the infection, the patient will usually have fever.
131. The answer is d. (Ropper, pp 700-701.) Cryptococcosis is usually acquired through the lungs and spreads to the CNS through the bloodstream. In the CNS, it may produce either a meningitis or a meningoencephalitis. The organism has a characteristic capsule, which simplifies its identification. Fungal infections most often occur in the CNS in persons with defects in their immune systems. These defects may be secondary to a viral infection, as with AIDS, or they may be a consequence of immunosuppressive drug exposure. Patients on immunosuppressive treatment after organ transplants and those with lymphoproliferative disorders, such as lymphocytic leukemia, were the most common victims of CNS fungal infections before the start of the AIDS epidemic. Aspergillus, Candida, Mucor, and Rhizopuscan also cause CNS fungal infections, but rarely meningitis. Aspergillus tends to cause abscesses in immunocompromised individuals, and Mucor affects mostly diabetics.
132. The answer is d. (Ropper, p 1196.) Schistosoma mansoni is endemic in the tropics and may produce a subacutely evolving paraparesis. The fluke itself does not invade the spinal cord, but it deposits eggs in the valveless veins of Batson, which drain the intestines and communicate with the drainage from the lumbosacral spinal cord. The patient develops granulomas around the ova that lodge in the spinal cord, and these granulomatous lesions crush the cord.
133. The answer is c. (Ropper, p 706.) Echinococcosis is usually acquired by ingesting material contaminated with fecal matter from sheep or dogs. Children are more likely to develop cerebral lesions than adults, but people at any age may develop this encephalic hydatidosis, which entails the development of a major cyst with multiple compartments in which smaller cysts are evident. This hydatid cyst of the brain behaves like a tumor and may become massive enough to cause focal deficits.
134. The answer is c. (Ropper, pp 668-678.) The immediate concern is that the patient has bacterial meningitis, and she should be treated. A lumbar puncture and blood drawn to obtain cultures should be done; however, it can take a few days for the results to come back, and it may be too late for the patient by then. Oral azithromycin is not the proper treatment for bacterial meningitis. Intravenous acyclovir would be used to treat herpes encephalitis.
135. The answer is a. (Ropper, pp 737-741.) The spinal fluid examination in a patient with spongiform encephalopathy, or Creutzfeldt-Jakob disease, is typically normal. On occasion, the protein level may be mildly elevated, and, in up to 20% of cases, there may be an increase in the ratio of immunoglobulin G to total protein, occasionally with oligoclonal bands. In many, but not all patients, a somewhat specific protein (14-3-3 proteinase inhibitor) may be present.
136. The answer is e. (Ropper, p 674.) A CSF leak indicates a communication between the subarachnoid space and the surface of the body. This leak most often occurs through the nose as rhinorrhea or through the ear as otorrhea. The CSF may be distinguished from other fluid discharged from the nose or ear by its relatively obvious glucose content. The most common basis for a CSF leak is head trauma.
137. The answer is b. (Fauci, pp 1008-1009.) Rupture of a large caseating granuloma into the ventricles or the subarachnoid space may produce an abrupt and often lethal deterioration. If the mass becomes large enough before it ruptures, it may in all respects imitate a brain tumor. Such lesions may respond to antituberculous medications even when they are quite large, and the patient may be spared surgical intervention.
138. The answer is a. (Ropper, pp 726-730.) The differential diagnosis is rather broad at this point. One should look for an infectious or malignant mass with a contrast-enhanced CT or MRI. A noncontrast head CT is less sensitive for abscess or tumor. A lumbar puncture should be done only after you are sure that there is not significant mass effect. This patient has an acute problem, which should be addressed now. Antiretroviral therapy will help him in the long term, but does not need to be initiated in the emergency room. Intravenous heparin is a treatment for embolic stroke. Embolic stroke is unlikely in this case, and further evaluation is needed before treatment with intravenous heparin is considered.
139. The answer is c. (Ropper, pp 726-730.) The most common etiologies of rim-enhancing brain lesions in AIDS patients are primary CNS lymphoma and Toxoplasma gondii infection. Other etiologies such as bacterial or fungal abscess are also possible. CSF EBV PCR test is highly sensitive and specific for primary CNS lymphoma. Because there is no mass effect, it is safe to do a lumbar puncture, so a ventricular CSF aspiration is not necessary. A cerebral angiogram should be done if you suspect an aneurysm or vascular malformation. These are unlikely in this case. There is no reason to stop all antiretroviral therapy. Intravenous acyclovir is used to treat herpes encephalitis, which is unlikely in this case.
140. The answer is d. (Ropper, pp 726-730.) The combination of sulfadiazine and pyrimethamine is proper treatment for T gondii infection. Neurosurgical removal of the lesions is not indicated. Oral fluconazole is a treatment for fungal infections. Intravenous acyclovir is used to treat herpes encephalitis. Thiabendazole is used to treat helminth infections. Other possible causes of ring-enhancing lesions on CT scan include bacterial abscess or malignancy.
141. The answer is c. (Ropper, p 712.) The patient has PML. It is caused by the JC virus, which is a double-stranded DNA virus. The prognosis is poor, but HAART has been known to be effective in improving survival. JC virus is ubiquitous and may be transmitted through respiratory secretions. Cranial radiation is used to treat malignancies. Amphotericin B is used to treat fungal infections. Intravenous acyclovir is not effective against JC virus, but is used to treat herpes simplex virus encephalitis. Intravenous ceftriaxone is used to treat bacterial meningitis.
142. The answer is c. (Ropper, pp 719-721.) Herpes simplex type 1 is the strain usually responsible for a herpetic encephalitis. Type 2 may occur in newborns who have been exposed during passage through the birth canal of a woman with genital herpes. Persons with AIDS are also at risk for either type 1 or type 2. Temporal lobe involvement in the immunocompetent patient may produce unilateral swelling and hemorrhage into the temporal lobe.
143. The answer is b. (Ropper, pp 719-721.) Although there is some controversy regarding whether lumbar puncture can precipitate herniation with a herpes encephalitis, most authorities believe it is best to assess the risk of herniation before doing a lumbar puncture. CSF examination is vital in establishing the diagnosis. A variety of infections may mimic herpes in both course and anatomic distribution. The CSF cultures and analysis of CSF constituents help to establish the probable cause of the encephalitis and to direct therapy.
144. The answer is a. (Ropper, pp 719-721.) The increased number of lymphocytes in the CSF of the patient with herpes encephalitis ranges from more than 12 to several hundred cells per cubic millimeter of fluid. Red blood cells may be apparent in the CSF late in the course of the disease, but their absence does not eliminate the possibility of herpes encephalitis. CSF pressure is usually increased, and the glucose content is usually normal or only slightly depressed.
145. The answer is c. (Ropper, pp 697-699.) Facial weakness may be the only neurological sign of Lyme disease. The neurological deficits usually appear weeks after the initial rash. Untreated neurological disease may persist for months. The facial palsy or optic neuritis that develops with CNS disease is characteristically associated with meningitis.
146. The answer is b. (Ropper, pp 113-114.) This specimen is a transverse section through the brainstem and cerebellum. There is a large area of discoloration and disturbed anatomy in the left cerebellar hemisphere that is producing little mass effect. Because this is the only lesion postulated for this patient, there is no reason to suspect seizure activity, because that phenomenon would be unlikely in the absence of a cerebrocortical (or at least cerebral) lesion. The other findings listed would similarly not be expected in a patient with cerebellar damage.
147. The answer is a. (Ropper, pp 703-704.) Primary amebic meningoencephalitis is usually caused by organisms from the genera Hartmanella or Acanthamoeba. The parasites enter the nervous system through the cribriform plate at the perforations for the olfactory nerves. An especially lethal form of this meningoencephalitis may develop with Naegleria spp. Other parasites, such as S mansoni, may be acquired through swimming in contaminated freshwater, but it is unlikely that other parasites reach the nervous system through direct invasion across the cribriform plate. Schistosomiasis is acquired when the cercarial phase of the organism penetrates the swimmer’s skin and finds its way into the blood.
148. The answer is e. (Ropper, p 729.) The microglial nodules occurring with HIV are associated with syncytial cells in the brain and spinal cord, a cell type not typically seen with cytomegalovirus (CMV) encephalitis. Cytomegalovirus is a common CNS opportunistic agent in patients with AIDS. With HIV infection, the microglial nodules are distributed around blood vessels throughout the brain. With CMV, the nodules are more characteristically subpial and subependymal.
149. The answer is d. (Ropper, pp 697-699.) B burgdorferi is the agent responsible for Lyme disease. It is a spirochete usually transmitted to humans through tick bites. Multiple organ systems are attacked by the spirochete; the nervous system is especially susceptible. Erythema chronicum migrans is an expanding reddish discoloration of the skin that spreads away from the site of the bite as an expanding ring of erythema. It usually evolves over 3-to-4 weeks. This ring of erythema clears spontaneously within about 1 month and is usually associated with some headache and neck stiffness. Some patients with Lyme disease fail to exhibit the rash.
150. The answer is d. (Ropper, p 720.) The periodic discharges seen with herpes encephalitis typically occur over the temporal regions. Slow waves may be evident over the temporal lobes in many persons with severe disease. Seizures commonly occur early in the course of herpes encephalitis, so the EEG may be severely disturbed generally.
151. The answer is b. (Ropper, p 699.) If there is meningeal involvement, high-dose penicillin or ceftriaxone must be given intravenously for 10-to-14 days. Tetracycline qid for 30 days should be used for patients who are allergic to the intravenous treatments.
152. The answer is a. (Ropper, pp 683-686.) There are many bases for abscess formation in the brain, but the most frequent causes are blood-borne infections from sources in the lung, heart, sinuses, and ears. Extension of infection from a chronic otitis or mastoiditis was much more common before the introduction of antibiotics. Facial or dental infections may spread to the brain through valveless veins draining about the muscles of mastication and communicating with the venous drainage of the brain.
153. The answer is d. (Ropper, pp 683-686.) Brain abscesses usually start from a microscopic focus of infection at the junction of gray matter and white matter. As the infection develops, a cerebritis appears, and subsequently this focus of infection becomes necrotic and liquefies. Around the enlarging abscess, there is usually a large area of edema.
154. The answer is b. (Fauci, pp 1040-1042.) A gumma is a largely or entirely avascular granuloma. It rarely develops intracranially, but when it does, it may grow to several centimeters across. The lesion starts as an inflammatory process but becomes fibrosed as it evolves. The term gumma has traditionally been reserved for granuloma-like lesions caused by spirochetal infection.
155. The answer is e. (Ropper, pp 721-723.) Rabies is usually spread through the saliva of an infected animal. Introduction of saliva into a bite wound allows the virus to inoculate muscles or subcutaneous tissues. After introduction of the virus, the incubation period until fulminant infection appears extends from a few days to over 1 year, but usually ranges from 1-to-2 months. Bites of the head and face carry the greatest risk of causing fatal disease. Early after exposure, the patient will often complain of pain or paresthesias at the site of the animal bite. Animals transmitting the virus include dogs, bats, skunks, foxes, and raccoons. Dehydration as a complication of rabies is no longer likely because intravenous fluids can be given to completely replace what the hydrophobic patient cannot consume by mouth. Other complications of rabies include a paralytic form of the disease that progresses to quadriplegia (dumb rabies) in 20% of patients. With the classic form of the disease, the patient will also exhibit intermittent hyperactivity.
156. The answer is d. (Ropper, p 701.) Patients with brain abscesses may exhibit focal signs, seizures, delirium, or less specific neurological findings. These patients often have fever, but the CSF may not reflect the infectious basis of the fever until the abscess ruptures into the ventricles or subarachnoid space. Although Aspergillus is the most common cause of fungal abscesses, it is a relatively uncommon cause of fungal meningitis or meningoencephalitis. Nocardia is not classified as a fungus despite its resemblance to a fungus.
157. The answer is d. (Ropper, pp 692-697.) General paresis is a slowly evolving process that may require years to produce substantial disability. The early symptoms are a subtle dementia, characterized by memory loss and impaired reasoning, with later development of dysarthria, myoclonus, tremor, seizures, and upper motor neuron signs, leading to a bedridden state. Both the meninges and the parenchyma of the brain are involved in this chronic infection. The meninges are thickened and opaque, and a granular ependymitis characteristically develops. Degenerative changes occur throughout the cerebral parenchyma. Penicillin is the treatment of choice for this disease. The damage done to the brain is not mediated by autoimmune or adverse drug reaction mechanisms. This infection produces widespread injury to the brain rather than the restricted brainstem damage that typically occurs with infections that attack structures arising from the embryonic rhombencephalon. With a rhombencephalitis, the pons and medulla oblongata are the principal targets of this disease.
158. The answer is b. (Ropper, pp 702-703.) Fungal abscesses develop with unusual frequency in patients with AIDS, but T gondii, an obligate intracellular parasite, is considerably more common than fungi as the cause of abscess formation. The fungi that do produce abscesses in persons with AIDS are most often Cryptococcus, Candida, Mucor, and Aspergillus. Myco-bacteria and atypical mycobacteria are also common causes of abscess formation in some populations.
159. The answer is e. (Ropper, pp 721-723.) Mumps, measles, and varicella zoster infection appear to be acquired primarily by way of the respiratory tract. The poliovirus is an enterovirus, which means it enters primarily through the gastrointestinal tract. Rabies is transmitted by animal bites and reaches the CNS by migration in neuronal processes, presumably as it is swept along by retrograde axoplasmic flow. This is believed to be an unusual method of viral spread to the CNS. Most viruses that do produce CNS disease are carried to the CNS in the bloodstream rather than along neuronal processes with infected axoplasm.
160. The answer is c. (Ropper, pp 683-686.) Three-fourths of patients with brain abscess have headache. This usually develops within a few weeks of the appearance of the abscess. Only one-third of patients present with seizures or focal neurological deficits. Only one-fourth exhibit papilledema. Brain abscesses may produce remarkably few changes in the CSF until the abscess penetrates into the subarachnoid or intraventricular space. Abscesses that have not yet communicated with the CSF will usually produce only a moderate elevation in the CSF protein content. If the abscess is unsuspected and untreated, it will usually extend to the ventricles. With perforation into the ventricle, the abscess usually proves fatal. The treatment of choice for brain abscess is surgical resection.
161. The answer is a. (Ropper, pp 683-686.) Both aerobic and anaerobic streptococcal bacteria occur in more than half of all brain abscesses. Staphylococcus aureus most often occurs in patients who have had penetrating head wounds or have undergone neurosurgical procedures. Enteric bacteria (eg, Escherichia coli, Proteus, and Pseudomonas) account for twice as many abscesses as S aureus.
162. The answer is e. (Ropper, pp 737-741.) This patient has a subacute to chronic progressive disease characterized by a combination of dementia, tremor, ataxia, and myoclonus. The EEG and MRI findings are typical of a spongiform encephalopathy. Multi-infarct dementia and subarachnoid hemorrhage would be expected to produce at least one very discrete event, and the imaging studies would be expected to show evidence of infarcts or other vascular abnormalities. Friedreich disease may produce some dementia, but it is not a prominent part of the clinical deterioration. This patient is also much older than would be consistent with Friedreich disease.
163. The answer is b. (Ropper, pp 678-679.) The presentation is highly suggestive of Listeria monocytogenes meningitis. This infection commonly develops in renal transplant recipients, patients with chronic renal disease, immunosuppressed persons, and occasionally in otherwise unimpaired persons. It may also affect neonates. This type of meningitis is not usually seen in older children. It may on occasion lead to intracerebral abscess formation. Third-generation cephalosporins are inactive against Listeria, and ampicillin and gentamicin are recommended therapy. Neither ampicillin nor penicillin alone is bactericidal.
164. The answer is e. (Ropper, pp 737-741.) The most likely cause of spongiform encephalopathy in this middle-aged woman is Creutzfeldt-Jakob disease. This is classified as a prion disease and can be transmitted via infected nervous system tissue, including dura mater grafts, and occasionally via growth hormone preparations acquired from cadaver pituitary glands. A similar disease (kuru) occurs in Fore Islanders of New Guinea and is presumed to spread through the ritual handling or eating of human brain tissue. As of 1999, 113 cases due to growth hormone preparations had been reported, with incubation periods ranging from 5-to-30 years.
165. The answer is c. (Ropper, p 711.) This patient probably had AIDS with PML as a complication of that disease. The inclusion bodies in the oligodendrocyte nuclei are JC virus. Primary infection with JC virus is universal and asymptomatic. Immunosuppression leads to reactivation of the virus. Diagnosis is typically made by MRI, which shows multiple focal well-defined white matter lesions that do not enhance or have mass effect. CSF PCR for JC virus is also available, obviating the need for brain biopsy in most cases. Treatment with cytarabine arabinoside has not been shown to be effective in clinical trials. Fewer than 10% of patients may experience spontaneous remission. PML may also develop with lymphomas, leukemias, or sarcoid, but the incidence of this disease in the US population has expanded greatly since the dissemination of HIV in the population.
166. The answer is e. (Ropper, pp 1261-1270.) The loss of strength associated with Guillain-Barré syndrome usually reaches a nadir within 2 weeks of the onset of symptoms. Sensation is usually preserved except for paresthesias in the feet or lower legs. Weakness is usually symmetric and often follows an ascending pattern of involvement. Tendon reflexes in the weak limbs are usually hypoactive or absent. Bladder and bowel control remain intact, but the patient usually exhibits some autonomic dysfunction, such as tachycardia and excessive sweating, which is rarely life-threatening. Eye muscles may be affected with Guillain-Barré syndrome, particularly in the condition called the Miller-Fisher variant. Before artificial ventilators were available, these patients often died from respiratory complications. The CSF with this disease typically reveals an elevated protein content with a relatively normal or only slightly abnormal white cell count and an invariably normal glucose content. This helps to distinguish it from poliomyelitis, a cause of paralysis that produces an alteration in both the protein and WBC content of the CSF consistent with a viral meningitis.
167. The answer is f. (Ropper, pp 695-696.) Tabes dorsalis is caused by Treponema pallidum, the agent responsible for all types of neurosyphilis, but it is a disease entity distinct from general paresis, the form of neurosyphilis in which personality changes and dementia do occur. With tabes dorsalis, the patient develops a leptomeningitis. The posterior columns of the spinal cord and the dorsal root ganglia are hit especially hard by degenerative changes associated with this form of neurosyphilis. Tabes dorsalis is a form of neurosyphilis that usually becomes symptomatic decades after the initial treponemal infection. The gait ataxia and positive Romberg sign in this patient are manifestations of absent position sense. Bladder and bowel control may be profoundly disturbed, presumably on the basis of dorsal spinal root disease. The bladder is usually hypotonic (flaccid), and megacolon may develop. Patients with tabes dorsalis routinely exhibit abnormal (Argyll Robertson) pupils and optic atrophy. The glucose and glycohemoglobin should be checked to eliminate the more common cause of impaired position sense in the United States, diabetes mellitus. That this patient is from a part of the world that has relatively poor health care is relevant because this form of syphilis is rarely seen in persons who have spent most of their lives in countries with easy access to antibiotics.
168. The answer is b. (Ropper, p 734.) Subacute sclerosing panencephalitis (SSPE) usually develops in children and is rarely seen after the age of 18. Most affected children have had a bout of measles (rubeola) that occurred before they were 2 years old. SSPE may not appear for as long as 6-to-8 years after the episode of measles. Death usually occurs within 1-to-3 years after the onset of symptoms. SSPE produces a CSF pattern similar to that seen with multiple sclerosis, whose features include an increase in the γ-globulin fraction and the presence of oligoclonal bands. The measles virus appears to be directly responsible for this demyelinating disease, and the oligoclonal bands that appear in the CSF include a substantial proportion of measles-specific antibody. Eosinophilic inclusions are typically present in the cytoplasm and nuclei of neurons and glial cells.
169. The answer is h. (Fauci, p 990.) Cat-scratch disease produces a regional adenitis, frequently involving epitrochlear nodes caused by scratches on the patient’s arm from an infected animal. The causative agent is B henselae(rarely Afipia felis). In immunocompetent hosts, it may produce a self-limited aseptic meningitis. In HIV-infected individuals, it may produce a more virulent encephalitis associated with status epilepticus. Typically, these patients have disseminated disease, including distinctive skin lesions composed of neovascular proliferation (bacillary angiomatosis). On rare occasions, immunocompetent patients may have encephalitis as well. An MRI may show a characteristic increased signal intensity in the pulvinar, suggesting a tropism of the organism or immune response to this particular structure in the posterior thalamus.
170. The answer is g. (Ropper, p 706.) Cysticercosis is produced by the larval form (cysticercus) of the pork tapeworm, Taenia solium. This is the most common neurological infection throughout the world, occurring most commonly in South America, Southeast Asia, and Africa. It is transmitted by fecal-oral contact; tapeworm eggs hatch in the human GI tract, invade the bowel mucosa, and migrate throughout the body, particularly into CNS, muscle, eye, and subcutaneous tissues. Cysticercal infection of muscles produces a nonspecific myositis. Brain involvement may lead to seizures. The lesions in the brain may calcify and often appear as multiple small cysts spread throughout the cerebrum. Treatment of neurocysticercosis is controversial. The best effort should be made to find the carrier of the tapeworm (possibly the patient himself) and treat with antiparasitics.