Infections

Question 2

121. The most striking neurologic complication of von Economo’s encephalitis(encephalitis lethargica), a type of encephalitis that occurred in epidemicproportions along with viral influenza between 1917 and 1928, was
     a. Blindness
     b. Hearing loss
     c. Paraplegia
     d. Parkinsonism
     e. Incontinence

Answer 2

121. The answer is d. (Victor, p 813.) At the onset of encephalitis lethargica,patients often develop transient fevers, lethargy, and headache. Disturbedeye movements are the most common sign of neurologic diseaseduring the acute illness. A variety of movement disorders, including chorea,athetosis, dystonia, and myoclonus, develop with the disease. About one infour affected persons dies. The most common sequela of the disease is severe,unremitting parkinsonism with signs and symptoms similar to those exhibitedwith idiopathic parkinsonism (paralysis agitans). One rather unique featureis the occurrence of oculogyric crises, or episodes in which the eyesdeviate to one side or upward, associated with other forms of dystonia andautonomic symptoms, sometimes occurring with great regularity.

Question 3

122. A 37-year-old woman is noted to have lymphadenopathy on routine physical exam. Following an extensive evaluation, she is diagnosed with sarcoid. She has been entirely normal neurologically.
123. The cranial nerve most likely to be injured in this patient is
     a. II
     b. III
     c. V
     d. VII
     e. VIII

Answer 3

122. The answer is d. ( Rowland, p 621.) Facial paresis is the neurologicinjury most likely to develop with sarcoidosis. Almost half of patients withsarcoidosis and neurologic disease have a neurologic sign or symptom asthe first obvious complication of the sarcoidosis. These patients report progressive weakness of one side of the face with no substantial loss of sensationover 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 cranial nerves especially susceptible to injury in persons with sarcoidosisinclude II, III, IV, VI, and VIII.

Question 4

123. A 17-year-old female presents initially with fever and progressive weakness. An extensive neurological evaluation including EMG/NCS suggests a motor neuron disease. The motor neuron disease most certainly traced to a virus is
     a. Poliomyelitis
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Subacute HIV encephalomyelitis
     e. Kuru

Answer 4

123. The answer is a. ( Rowland, pp 136–137.) SSPE, PML, kuru, and HIVencephalomyelitis are all viral diseases affecting the CNS, but poliomyelitisis the only one that causes a purely motor neuron disease. Poliomyelitisvirus attacks the anterior horn cells in the spinal cord. It is most likely to beconfused with Guillain-Barré syndrome if the typical CSF picture of a viralmeningoencephalitis is not found with the progressive motor neuronimpairment. With poliomyelitis, the CSF will usually exhibit an elevatedprotein and white cell count. During the initial stages of the infection, thepatient will usually have fever.

Question 5

124. A 35-year-old woman who has received a liver transplant develops meningeal signs and fever. Cerebrospinal fluid testing reveals a fungal infection.The most common cause of fungal meningitis is
     a. Aspergillus
     b. Candida
     c. Mucor
     d. Cryptococcus
     e. Rhizopus

Answer 5

124. The answer is d. ( Bradley, pp 1377–1378.) Cryptococcosis is usuallyacquired 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 itsidentification. Fungal infections most often occur in the CNS in persons withdefects in their immune systems. These defects may be secondary to a viralinfection, as with AIDS, or they may be a consequence of immunosuppressivedrug exposure. Patients on immunosuppressive treatment after organtransplants and those with lymphoproliferative disorders, such as lymphocytic leukemia, were the most common victims of CNS fungal infectionsbefore 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.

Question 6

125. A 28-year-old man who has recently immigrated from Brazil presents with 3 months of fluctuating but slowly progressive bilateral lower extremityweakness, a little worse on the left than the right. After a complete evaluation,Schistosoma mansoni is diagnosed as the etiology. S. mansoni ova usually damage the nervous system at the level of the
     a. Cerebrum
     b. Cerebellum
     c. Basal ganglia
     d. Spinal cord
     e. Peripheral nerves

Answer 6

125. The answer is d. (Bradley, pp 1402–1403.) S. mansoni is endemic inPuerto Rico and may produce a subacutely evolving paraparesis. The flukeitself does not invade the spinal cord, but it deposits eggs in the valvelessveins 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.

Question 7

126. A 12-year-old boy has left body weakness. An MRI scan reveals a polycystic lesion. The parasitic brain lesion most likely to have a large cyst containing numerous daughter cysts is that associated with
     a. Taenia solium
     b. Schistosoma haematobium
     c. Taenia echinococcus
     d. Diphyllobothrium latum
     e. Schistosoma japonicum

Answer 7

126. The answer is c. (Bradley, pp 1396–1397.) Echinococcosis is usuallyacquired by eating tissue from infected sheep. Children are more likely todevelop cerebral lesions than adults, but people at any age may develop thisencephalic hydatidosis, which entails the development of a major cyst withmultiple compartments in which smaller cysts are evident. This hydatid cystof the brain behaves like a tumor and may become massive enough to causefocal deficits.

Question 8

An 82-year-old previously healthy woman with a recent upper respiratory infection presents with generalized weakness, headache, and blurry vision. For the past 2 weeks she has had upper respiratory symptoms that started with a sore throat, nasal congestion, and excessive coughing. She went to her primary care doctor 4 days ago and was diagnosed with sinusitis. She was given a prescription for an antibiotic and took it for 2 days, then stopped. She thereafter had chills, lightheadedness, vomiting, blurry vision, general achiness, and a headache that started abruptly and has not gotten better since. Other than blurry vision, she has not had any other visual symptoms. Theblurry vision remains when she closes either eye. She also has eye tendernesswith movement and mild photosensitivity. She has no drug allergies. Examfindings include temperature of 102.5°F, nuchal rigidity, and sleepiness.127. The next most appropriate action in this case is which of the following?

a. Get a brain MRI, then perform a lumbar puncture
b. Give the patient a prescription for oral azithromycin and let her go home
c. Immediately give intravenous ceftriaxone plus ampicillin
d. Immediately start intravenous acyclovir
e. Obtain cerebrospinal fluid and blood cultures and observe the patient until the results come back

Answer 8

127. The answer is c. ( Bradley, pp 1319–1323.) The immediate concern isthat the patient has bacterial meningitis, and she should be treated. A lumbarpuncture and blood draw to obtain cultures should be done; however, it cantake a few days for the results to come back, and it may be too late for thepatient by then. Oral azithromycin is not the proper treatment for bacterialmeningitis. Intravenous acyclovir would be used to treat herpes encephalitis.

Question 9

An 82-year-old previously healthy woman with a recent upper respiratory infection presents with generalized weakness, headache, and blurry vision. For the past 2 weeks she has had upper respiratory symptoms that started with a sore throat, nasal congestion, and excessive coughing. She went to her primary care doctor 4 days ago and was diagnosed with sinusitis. She was given a prescription for an antibiotic and took it for 2 days, then stopped. She thereafter had chills, lightheadedness, vomiting, blurry vision, general achiness, and a headache that started abruptly and has not gotten better since. Other than blurry vision, she has not had any other visual symptoms. Theblurry vision remains when she closes either eye. She also has eye tendernesswith movement and mild photosensitivity. She has no drug allergies. Examfindings include temperature of 102.5°F, nuchal rigidity, and sleepiness.128. The next day the patient’s spinal fluid cultures begin growing Listeriamonocytogenes. The drug of choice in this case now is

a. Penicillin G
b. Ampicillin plus gentamicin
c. Tetracycline
d. Ceftriaxone
e. Rifampin

Answer 9

128. The answer is b. ( Bradley, pp 1323–1324.) L. monocytogenes meningitisdevelops 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 ampicillinand gentamicin are recommended therapy. Neither ampicillin nor penicillinalone is bactericidal.

Question 10

129. A 17-year-old right-handed boy has had infectious meningitis 8 times over the past 3 years. He has otherwise been generally healthy and developed normally. Recurrent meningitis often develops in persons with
     a. Otitis media
     b. Epilepsy
     c. Multiple sclerosis
     d. Whipple’s disease
     e. Cerebrospinal fluid (CSF) leaks

Answer 10

129. The answer is e. (Victor, pp 788–790.) 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.

Question 11

130. An 82-year-old man with a history of pulmonary tuberculosis in 1947 presents with left body weakness and neglect. Imaging and subsequent biopsy reveal that recurrent tuberculosis was the cause. Mass lesions in the brain of the patient with tuberculosis may develop as a reaction to the tubercle bacillus and consist of
     a. Dysplastic central nervous system (CNS) tissue
     b. Caseating granulomas
     c. Heterotopias
     d. Colobomas
     e. Mesial sclerosis

Answer 11

130. The answer is b. (Victor, p 759.) Rupture of a large caseating granulomainto 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.

Question 12

A 31-year-old homosexual man has had headache, sleepiness, and poor balance that have worsened over the past week. The patient is known to be HIV-seropositive, but has done well in the past and has not seen a doctor inover 1 year. On examination, his responses are slow and he has some difficulty sustaining attention. He has a right hemiparesis with increased reflexeson the right. Routine cell counts and chemistries are normal.131. Of the following, which is the most appropriate thing to do next?

a. Get a head CT with contrast
b. Get a noncontrast head CT
c. Perform a lumbar puncture
d. Start antiretroviral therapy
e. Start intravenous heparin

Answer 12

131. The answer is a. (Victor, pp 12–19.) The differential diagnosis is rather broad at this point. You 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 only be done 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.

Question 13

A 31-year-old homosexual man has had headache, sleepiness, and poor balance that have worsened over the past week. The patient is known to be HIV-seropositive, but has done well in the past and has not seen a doctor inover 1 year. On examination, his responses are slow and he has some difficulty sustaining attention. He has a right hemiparesis with increased reflexeson the right. Routine cell counts and chemistries are normal.132. A CT scan reveals several rim-enhancing lesions with minimal masseffect. An appropriate investigation at this point would be to

a. Get a cerebral angiogram
b. Order a ventricular cerebrospinal fluid (CSF) aspiration
c. Perform a lumbar puncture and include cerebrospinal fluid for Epstein-Barr virus (EBV) PCR in tests ordered
d. Stop all antiretroviral therapy
e. Treat with intravenous acyclovir

Answer 13

132. The answer is choice c. ( Rowland, p 172.) The most common etiologiesof rim-enhancing brain lesions in AIDS patients are primary CNS lymphoma (PCNSL) 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 PCNSL. Since there is no mass effect, it is safe to do a lumbar puncture, so a ventricular cerebrospinal fluid (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. Thereis no reason to stop all antiretroviral therapy. Intravenous acyclovir is usedto treat herpes encephalitis, which is unlikely in this case.

Question 14

133. The patient turns out to have CNS Toxoplasma gondii. Which of thefollowing is the best treatment?
     a. Intravenous acyclovir
     b. Neurosurgical removal of the lesions
     c. Oral fluconazole
     d. Sulfadiazine and pyrimethamine
     e. Thiabendazole

Answer 14

133. The answer is d. ( Rowland, p 198.) 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. Thiabendazoleis used to treat helminth infections.

Question 15

134. A 35-year-old female has progressive numbness of the right arm and difficulty seeing objects in the left visual field. She is known to be HIVpositive, but has not consistently taken medications in the past. On examination, she appears healthy, but has a right homonymous hemianopsia and decreased sensory perception in her left upper extremity and face. Her CD4 count is 75 cells per ìL, and her MRI is consistent with a demylinatinglesion of the left parietooccipital area. CSF PCR for JC virus is positive. Which of the following is the most appropriate treatment in this case?
     a. Amphotericin B
     b. Cranial radiation
     c. Highly active antiretroviral therapy (HAART)
     d. Intravenous acyclovir
     e. Intravenous ceftriaxone

Answer 15

134. The answer is c. (Rowland, p 156.) The patient has progressivemultifocal leukoencephalopathy. It is caused by the JC virus, which is adouble-stranded DNA virus. The prognosis is poor, but HAART has beenknown to be effective in improving survival. JC virus is ubiquitous andmay be transmitted through respiratory secretions. Cranial radiation isused to treat malignancies. Amphotericin B is used to treat fungal infections.Intravenous acyclovir is not effective against JC virus, but is usedto treat herpes simplex virus encephalitis. Intravenous ceftriaxone is usedto treat bacterial meningitis.

Question 16

A 72-year-old right-handed woman has 2 days of headache and fever, followed by worsening confusion. She is taken to the hospital after having a generalized seizure. A head CT is consistent with left temporal hemorrhage and swelling.135. Localization of an encephalitis to the medial temporal or orbitalfrontal regions of the brain is most consistent with

a. Treponema pallidum
b. Varicella zoster virus
c. Herpes simplex virus
d. Cryptococcus neoformans
e. Toxoplasma gondii

Answer 16

135. The answer is c. (Victor, pp 793–795.) Herpes simplex type 1 is thestrain usually responsible for a herpetic encephalitis. Type 2 may occur innewborns who have been exposed during passage through the birth canal ofa woman with genital herpes. Persons with AIDS are also at risk for either type1 or type 2. Temporal lobe involvement in the immunocompetent patientmay produce unilateral swelling and hemorrhage into the temporal lobe.

Question 17

136. Neuroimaging of the brain before attempting a lumbar puncture is advisable in cases of acute encephalitis because
     a. The diagnosis may be evident on the basis of magnetic resonance imaging (MRI)alone
     b. Massive edema in the temporal lobe may make herniation imminent
     c. The computed tomography (CT) picture may determine whether a brain biopsyshould be obtained
     d. Shunting of the ventricles is usually indicated, and the imaging studies areneeded to direct the placement of the shunt
     e. It may establish what pathology is responsible

Answer 17

136. The answer is b. (Victor, pp 793–795.) Although there is some controversy regarding whether lumbar puncture can precipitate herniation witha herpes encephalitis, most authorities believe it is best to assess the risk ofherniation before doing a lumbar puncture. Cerebrospinal fluid examination is vital in establishing the diagnosis. A variety of infections may mimic herpesin both course and anatomic distribution. The CSF cultures and analysisof CSF constituents help to establish the probable cause of the encephalitisand to direct therapy.

Question 18

137. CSF testing establishes this case as being the commonest form of acute encephalitis. The CSF changes late in the course of this disease typically include
     a. An increased number of lymphocytes
     b. A glucose content of less than two-thirds the serum level
     c. A protein content of less than 45 mg/dL
     d. A normal opening pressure
     e. A predominance of polymorphonuclear white blood cells

Answer 18

137. The answer is a. (Victor, pp 793–795.) The increased number oflymphocytes in the CSF of the patient with herpes encephalitis ranges frommore than 12 to several hundred cells per cubic millimeter of fluid. Redblood cells may be apparent in the CSF late in the course of the disease, buttheir absence does not eliminate the possibility of herpes encephalitis.Cerebrospinal fluid pressure is usually increased, and the glucose contentis usually normal or only slightly depressed.

Question 19

138. With this disease, EEG may exhibit
     a. á activity over the frontal regions
     b. â activity over the temporal regions
     c. Three-per-second spike-and-wave discharges
     d. Bilateral, periodic epileptiform discharges
     e. Unilateral ä activity over the frontal region

Answer 19

138. The answer is d. (Victor, pp 793–795.) The periodic discharges seenwith herpes encephalitis typically occur over the temporal regions. Slowwaves, rather than sharp waves, may be evident over the temporal lobes inmany persons with severe disease. Seizures commonly occur early in thecourse of herpes encephalitis, and so the EEG may be severely disturbedgenerally.

Question 20

139. The pathologic specimen above shows the only intracranial lesion found in this patient. This patient would be expected to have exhibited which of the following symptoms?
     a. Seizures
     b. Gait ataxia
     c. Hemiparesis
     d. Visual loss
     e. Hallucinations

Answer 20

139. The answer is b. (Bradley, pp 1932–1933.) This specimen is a transversesection through the brainstem and cerebellum. There is a large area ofdiscoloration and disturbed anatomy in the left cerebellar hemisphere thatis producing little mass effect. Because this is the only lesion postulated forthis patient, there is no reason to suspect seizure activity, because that phenomenonwould be unlikely in the absence of a cerebrocortical (or at leastcerebral) lesion. The other findings listed would similarly not be expectedin a patient with cerebellar damage.

Question 21

140. If this patient had coincidental findings of oral moniliasis, diffuse lymphadenopathy, recent weight loss, and lymphopenia, the most probable cause of the lesion would be
     a. Ependymoma
     b. Medulloblastoma
     c. Granuloma
     d. Hemorrhage
     e. Infarction

Answer 21

140. The answer is c. (Bradley, p 1410.) The clinical picture presented suggests immunosuppression and in the current environment must be considered HIV-related disease (AIDS) until proved otherwise. The most likely cause of intracranial granuloma in an AIDS patient in the United States is Toxoplasma gondii. That this is a granuloma is supported by the limited mass effect that is evident. Tumors, such as ependymoma or medulloblastoma, might extend from the midline into a cerebellar hemisphere but would not be expected to produce so little distortion of surrounding tissues. Toxoplasma granulomas and abscesses are the most common causes of focal brain lesions in patients with AIDS.

Question 22

141. A 13-year-old boy is brought into the emergency room lethargic with a stiff neck and fever. Despite aggressive therapy, the child dies. Postmortem evaluation reveals that the child had primary amebic meningoencephalitis.This condition is usually acquired through
     a. Freshwater swimming
     b. Eating contaminated meat
     c. Eating calves’ brains
     d. Anal intercourse
     e. Animal bites

Answer 22

141. The answer is a. ( Bradley, pp 1389–1390.) Primary amebic meningoencephalitis is usually caused by organisms from the genera Hartmanella or Acanthamoeba. The parasites enter the nervous system through the cribriformplate 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.

Question 23

142. Both HIV and cytomegalovirus infections in the brain characteristically produce
     a. Senile plaques
     b. Intraneuronal amyloid
     c. Intranuclear inclusions
     d. Intracytoplasmic inclusions
     e. Microglial nodules

Answer 23

142. The answer is e. (Bradley, pp 1360–1361, 1415.) The microglial nodulesoccurring with HIV are associated with syncytial cells in the brain andspinal cord, a cell type not typically seen with cytomegalovirus (CMV)encephalitis. Cytomegalovirus is a common CNS opportunistic agent inpatients with AIDS. With HIV infection, the microglial nodules are distributedaround blood vessels throughout the brain. With CMV, the nodulesare more characteristically subpial and subependymal.

Question 24

Following several days of low-grade fever and mild neck and head pain, a 10-year-old boy develops bilateral face drooping and difficulty fully closing his eyes. Serum is positive for Borrelia burgdorferi IgM. CSF PCR is also positive for this organism’s DNA.143. After B. burgdorferi is introduced by the tick that carries it, the skinaround the bite develops

a. An exfoliative dermatitis
b. Purpura
c. Localized edema
d. Erythema chronicum migrans
e. Vesicular lesions

Answer 24

143. The answer is d. (Victor, pp 768–770.) B. burgdorferi is the agentresponsible for Lyme disease. It is a spirochete usually transmitted to humansthrough tick bites. Multiple organ systems are attacked by the spirochete; thenervous system is especially susceptible. Erythema chronicum migrans is anexpanding 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.

Question 25

144. The cranial neuropathy most commonly found with Lyme disease isthat associated with damage to cranial nerve
     a. III
     b. V
     c. VII
     d. IX
     e. XII

Answer 25

144. The answer is c. (Victor, pp 768–770.) Facial weakness may be theonly neurologic sign of Lyme disease. The neurologic deficits usually appearweeks after the initial rash. Untreated neurologic disease may persist formonths. The facial palsy or optic neuritis that develops with CNS disease ischaracteristically associated with meningitis.

Question 26

145. The medication most appropriate in patients with CNS involvementby B. burgdorferi is
     a. Streptomycin
     b. Ceftriaxone
     c. Gentamicin
     d. Isoniazid
     e. Rifampin

Answer 26

145. The answer is b. (Victor, pp 768–770.) 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.

Question 27

146. Abscesses in the brain most often develop from
     a. Hematogenous spread of infection
     b. Penetrating head wounds
     c. Superinfection of neoplastic foci
     d. Dental trauma
     e. Neurosurgical intervention

Answer 27

146. The answer is a. (Victor, pp 752–756.) There are many bases forabscess formation in the brain, but the most frequent causes are blood-borneinfections from sources in the lung, heart, sinuses, and ears. Extension ofinfection 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 andcommunicating with the venous drainage of the brain.

Question 28

147. The most common site for abscess formation in the brain is the
     a. Putamen
     b. Thalamus
     c. Head of the caudate
     d. Gray-white junction
     e. Subthalamus

Answer 28

147. The answer is d. (Victor, pp 752–756.) Brain abscesses usually startfrom a microscopic focus of infection at the junction of gray matter and white matter. As the infection develops, a cerebritis appears, and subsequentlythis focus of infection becomes necrotic and liquefies. Around the enlarging abscess there is usually a large area of edema.

Question 29

148. Most of the organisms found in brain abscesses are
     a. Streptococcal
     b. Staphylococcal
     c. Bacteroides spp.
     d. Proteus spp

.e. Pseudomonas spp.

Answer 29

148. The answer is a. (Victor, pp 752–756.) Both aerobic and anaerobicstreptococcal bacteria occur in more than half of all brain abscesses. Staphylococcus aureus most often occurs in patients who have had penetratinghead wounds or have undergone neurosurgical procedures. Entericbacteria (e.g., Escherichia coli, Proteus, and Pseudomonas) account for twiceas many abscesses as S. aureus.

Question 30

149. The most common cause of brain abscess in patients with AIDS is
     a. Cryptococcus neoformans
     b. Toxoplasma gondii
     c. Tuberculosis
     d. Cytomegalovirus
     e. Herpes zoster

Answer 30

149. The answer is b. ( Bradley, pp 1410, 1415.) Fungal abscesses developwith unusual frequency in patients with AIDS, but T. gondii, an obligate intracellularparasite, is considerably more common than fungi as the cause of abscess formation. The fungi that do produce abscesses in persons with AIDSare most often Cryptococcus, Candida, Mucor, and Aspergillus. Mycobacteriaand atypical mycobacteria are also common causes of abscess formation insome populations.

Question 31

150. The most common complaint in patients with brain abscess is
     a. Nausea and vomiting
     b. Ataxia
     c. Headache
     d. Neck stiffness
     e. Seizures

Answer 31

150. The answer is c. (Victor, p 754.) Three-fourths of patients with brainabscess have headache. This usually develops within a few weeks of theappearance of the abscess. Only one-third of patients present with seizuresor focal neurologic 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.

Question 32

151. A 38-year-old man who is immunocompromised because of HIVpresents with 1 month of worsening right headache, ear pain, and fever. He is determined to have malignant external otitis and osteomyelitis of the base of the skull. The etiology is fungal. Fungal malignant external otitis and osteomyelitis of the base of the skull in HIV patients is most commonly caused by
     a. Nocardia
     b. Cryptococcus neoformans
     c. Actinomyces
     d. Aspergillus
     e. Candida

Answer 32

151. The answer is d. (Rowland, pp 127–128.) Patients with brainabscesses may exhibit focal signs, seizures, delirium, or less specific neurologic findings. These patients often have fever, but the CSF may not reflectthe infectious basis of the fever until the abscess ruptures into the ventriclesor subarachnoid space. Although Aspergillus is the most common cause offungal abscesses, it is a relatively uncommon cause of fungal meningitis ormeningoencephalitis. Nocardia is not classified as a fungus despite its resemblance to a fungus.

Question 33

A 55-year-old woman has a progressive dementia over the past year. Over the last 3 months she has also developed dysarthria, myoclonus, intention tremor, and hyperreflexia. CSF VDRL is positive.152. This patient’s symptoms are being caused by which of the following?

a. A response to penicillin treatment
b. An autoimmune reaction
c. An acute meningoencephalitis
d. A chronic meningoencephalitis
e. A chronic rhombencephalitis

Answer 33

152. The answer is d. (Bradley, pp 1334–1336.) General paresis is a slowlyevolving 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 bythis chronic infection. The meninges are thickened and opaque, and a granularependymitis characteristically develops. Degenerative changes occurthroughout the cerebral parenchyma. Penicillin is the treatment of choicefor this disease. The damage done to the brain is not mediated by autoimmuneor adverse drug reaction mechanisms. This infection produces widespreadinjury to the brain, rather than the restricted brainstem damage thattypically occurs with infections that attack structures arising from the embryonic rhombencephalon. With a rhombencephalitis, the pons and medulla oblongata are the principal targets of disease.

Question 34

A 55-year-old woman has a progressive dementia over the past year. Over the last 3 months she has also developed dysarthria, myoclonus, intention tremor, and hyperreflexia. CSF VDRL is positive.153. This patient’s underlying disease may present a picture easily confusedwith brain tumor if

a. A reaction to penicillin treatment occurs
b. An intracranial gumma forms
c. Tabes dorsalis is the primary manifestation of the disease
d. Meningovascular syphilis develops
e. The patient is a newborn with congenital syphilis

Answer 34

153. The answer is b. (Bradley, pp 1334–1336.) A gumma is a largely orentirely avascular granuloma. It rarely develops intracranially, but when itdoes, it may grow to several centimeters across. The lesion starts as aninflammatory process but becomes fibrosed as it evolves. The term gummahas traditionally been reserved for granuloma-like lesions caused by spirochetal infection.

Question 35

A 35-year-old woman is bitten by a small doglike wild animal while camping. The animal immediately runs away. Her skin is barely broken, and, besides feeling a little frightened, she says that she is fine. Despite this, her friend convinces her to be evaluated in the nearest emergency room.154. Which of the following viruses, which typically invades the CNS byextending centripetally (i.e., inward away from the periphery) along peripheralnerves is the woman most at risk for?

a. Mumps
b. Measles
c. Varicella zoster
d. Polio
e. Rabies

Answer 35

154. The answer is e. (Victor, p 796.) 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.

Question 36

A 35-year-old woman is bitten by a small doglike wild animal while camping. The animal immediately runs away. Her skin is barely broken, and, besides feeling a little frightened, she says that she is fine. Despite this, her friend convinces her to be evaluated in the nearest emergency room.155. From the brain, this virus establishes itself for transmission to anotherhost by spreading to the

a. Intestines
b. Nasopharynx
c. Lungs
d. Bladder
e. Salivary glands

Answer 36

155. The answer is e. (Bradley, pp 1362–1363.) Rabies is usually spreadthrough the saliva of an infected animal. Introduction of saliva into a bitewound allows the virus to inoculate muscles or subcutaneous tissues. Afterintroduction 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 bymouth. Other complications of rabies include a paralytic form of the diseasethat progresses to quadriplegia (dumb rabies) in 20% of patients. With the classic form of the disease, the patient will also exhibit intermittent hyperactivity.

Question 37

A 35-year-old woman is bitten by a small doglike wild animal while camping. The animal immediately runs away. Her skin is barely broken, and, besides feeling a little frightened, she says that she is fine. Despite this, her friend convinces her to be evaluated in the nearest emergency room.156. The best therapy currently available for this disease is

a. Supportive therapy
b. Zidovudine
c. Cytarabine
d. Amantadine
e. Ganciclovir

Answer 37

156. The answer is a. ( Bradley, pp 1362–1363.) No antiviral therapy affectsthe course of rabies. Immunization against rabies after exposure has occurredis essential, though even this may not substantially improve the outlook ofthis almost invariably fatal disease. The infected patient must receive intensivecare with precautions taken to prevent spread of the virus through contactwith body fluids, such as saliva. Transmission of the virus through casualcontact does not seem to occur, but it may be transmitted through cornealtransplantation when the donor has been infected. Zidovudine (azidothymidine,AZT) is an antiretroviral drug useful in slowing the progression of HIV-1 infection. Ganciclovir has found increasing use in the management of cytomegalovirus (CMV) infection, especially when CMV involves the eye in a chorioretinitis. Amantadine was developed as an anti-influenzal agent, but it is used primarily to reduce the symptoms of Parkinson’s disease. The reason for its antiparkinsonian action is unknown.

Question 38

A 52-year-old woman develops progressive dementia, tremors, gait ataxia, and myoclonic jerks over the course of 6 months. Her speech is slow and slurred, and hand movements are clumsy. No members of her immediate family have a history of degenerative neurologic disease. Magnetic resonance imaging (MRI) of the head reveals a subtle increase in signalin the basal ganglia bilaterally. EEG reveals disorganized backgroundactivity with periodic sharp-wave discharges that occur repetitively at 1-sintervals and extend over both sides of the head. Arteriogram reveals no vascular abnormalities.157. The clinical picture is most consistent with

a. Multi-infarct dementia
b. Tabes dorsalis
c. Friedreich’s disease (Friedreich’s ataxia)
d. Subarachnoid hemorrhage
e. Spongiform encephalopathy

Answer 38

157. The answer is e. ( Bradley, pp 1424–1425.) This patient has a subacuteto chronic progressive disease characterized by a combination of dementia, tremor, ataxia, and myoclonus. The EEG and MRI findings are typical of aspongiform encephalopathy. Multi-infarct dementia and subarachnoid hemorrhagewould 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’s 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’s disease.

Question 39

A 52-year-old woman develops progressive dementia, tremors, gait ataxia, and myoclonic jerks over the course of 6 months. Her speech is slow and slurred, and hand movements are clumsy. No members of her immediate family have a history of degenerative neurologic disease. Magnetic resonance imaging (MRI) of the head reveals a subtle increase in signalin the basal ganglia bilaterally. EEG reveals disorganized backgroundactivity with periodic sharp-wave discharges that occur repetitively at 1-sintervals and extend over both sides of the head. Arteriogram reveals no vascular abnormalities.158. Routine spinal fluid examination in this patient would be expected toshow

a. No abnormalities on routine studies
b. Elevated protein
c. More than 100 lymphocytes
d. More than 1000 red blood cells
e. Decreased glucose

Answer 39

158. The answer is a. (Bradley, p 1425.) 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 immunoglobulin G–to–total protein ratio, occasionally with oligoclonal bands. Studies have indicated that a protein highly sensitive and specific for prion disease, a 14-3-3 proteinase inhibitor protein released from neurons, may be found in patients with this illness.

Question 40

A 52-year-old woman develops progressive dementia, tremors, gait ataxia, and myoclonic jerks over the course of 6 months. Her speech is slow and slurred, and hand movements are clumsy. No members of her immediate family have a history of degenerative neurologic disease. Magnetic resonance imaging (MRI) of the head reveals a subtle increase in signalin the basal ganglia bilaterally. EEG reveals disorganized backgroundactivity with periodic sharp-wave discharges that occur repetitively at 1-sintervals and extend over both sides of the head. Arteriogram reveals no vascular abnormalities.159. The patient dies after a severe bout of aspiration pneumonia. Autopsy of her brain reveals extensive loss of granule cells in the cerebellum and other changes most obvious in the cerebellar cortex. Fine vacuoles give the brain a spongiform appearance. No senile plaques are evident. The patient could have acquired this progressive disease through

a. Sexual intercourse
b. A blood transfusion
c. Consumption of raw fish
d. An upper respiratory infection
e. Growth hormone treatment

Answer 40

159. The answer is e. (Bradley, p 1427.) The most likely cause of spongiformencephalopathy 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.

Question 41

160. A 27-year-old man develops recurrent episodes of involuntary movements.He abused intravenous drugs for several years and has had several admissions for recurrent infections, including subacute bacterial endocarditis.His involuntary movements are largely restricted to the right side of his body and are associated with hoarseness and difficulty swallowing.The patient has lost 40 lb over the past 4 months. Examination reveals diffuselymphadenopathy and right-sided hypertonia. His CSF is normal except for a slight increase in protein content. Computed tomography reveals a large area of decreased density on the left side of the cerebrum. EEG reveals diffuse slowing over the left side of the head. Biopsy of thislesion reveals oligodendrocytes with abnormally large nuclei that containdarkly staining inclusions. There is extensive demyelination and there aregiant astrocytes in the lesion. Over the course of 1 month, the man exhibitsincreasing ataxia. Within 2 months, he shows evidence of mild dementiaand seizures. Within 3 months of presentation, his dementia is profoundand he has bladder and bowel incontinence. Over the course of a few days, he becomes obtunded and dies. (SELECT 1 CONDITION)
     a. Subacute HIV encephalomyelitis (AIDS encephalopathy)
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Rabies encephalitis
     e. Guillain-Barré syndromef. Tabes dorsalisg. Neurocysticercosish. Bartonella henselae encephalitisi. HTLV-I infection

Answer 41

160. The answer is c. ( Bradley, pp 1413–1414.) This patient probably hadAIDS with PML as a complication of that disease. The inclusion bodies in theoligodendrocyte nuclei are JC virus, a papillomavirus. Primary infection withJC virus is universal and asymptomatic. Immunosuppression leads to reactivationof 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. Cerebrospinal fluid 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. Less 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 U.S. population has expanded greatly since the dissemination of HIV in the population.

Question 42

161. An 18-year-old man notices tingling about his ankles 2 weeks after an upper respiratory tract infection. Within 2 days, he has weakness in dorsiflexion of both feet, and within 1 week he develops problems with walking. He has no loss of bladder or bowel control. His weakness progresses rapidly over the ensuing week and necessitates his being placed ona ventilator to support his breathing. He is quadriplegic, but retains control of his eye movements. Cerebrospinal fluid studies reveal a protein content of greater than 1 g/dL with a normal white cell count. There are no red blood cells in the CSF. (SELECT 1 CONDITION)
     a. Subacute HIV encephalomyelitis (AIDS encephalopathy)
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Rabies encephalitis
     e. Guillain-Barré syndrome
     f. Tabes dorsalis
     g. Neurocysticercosis
     h. Bartonella henselae encephalitis
     i. HTLV-I infection

Answer 42

161. The answer is e. (Victor, pp 1380–1387.) The loss of strength associated with Guillain-Barré syndrome usually reaches a nadir within 2 weeks ofthe onset of symptoms. Sensation is usually preserved except for paresthesiasin the feet or lower legs. Weakness is usually symmetric and often followsan 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.

Question 43

162. Over the course of 6 months, a 50-year-old immigrant from EasternEurope develops problems with bladder control, an unsteady gait, and pain in his legs. On examination, it is determined that he has absent deep tendon reflexes in his legs, markedly impaired vibration sense in his feet, and a positive Romberg sign. Despite his complaint of unsteady gait, he has no problems with rapid alternating movement of the feet and no tremors areevident. He has normal leg strength. The pain in his legs is sharp, stabbing,and paroxysmal. His serum glucose and glycohemoglobin levels are normal.(SELECT 1 CONDITION)
     a. Subacute HIV encephalomyelitis (AIDS encephalopathy)
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Rabies encephalitis
     e. Guillain-Barré syndromef. Tabes dorsalis
     g. Neurocysticercosis
     h. Bartonella henselae encephalitis
     i. HTLV-I infection

Answer 43

162. The answer is f. (Victor, pp 766–767.) 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 degenerativechanges associated with this form of neurosyphilis. Tabes dorsalis is a formof neurosyphilis that usually becomes symptomatic decades after the initialtreponemal 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.

Question 44

163. A 10-year-old girl is referred to a physician because of rapidly deterioratingschool performance. Over the course of a few weeks, the child has lost interest in her schoolwork, appeared apathetic at home, and had frequent temper tantrums with little provocation. A psychiatric evaluation reveals that, in addition to emotional lability, the child has substantial intellectual deficits that appear to be new. Within 1 month of this evaluation, the child has a generalized tonic-clonic seizure. A neurologist examining the child discovers chorioretinitis, ataxia, hyperactive reflexes, and bilateral Babinski signs. Her EEG exhibits periodic bursts of high-voltage slowwaves, followed by recurrent low-voltage stretches (burst suppression pattern).The CSF is remarkable for an increase in the gamma globulin fraction. The child becomes increasingly lethargic and obtunded over the ensuing 2 months. She remains in a coma for several months before dying.(SELECT 1 CONDITION)
     a. Subacute HIV encephalomyelitis (AIDS encephalopathy)
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Rabies encephalitis
     e. Guillain-Barré syndrome
     f. Tabes dorsalis
     g. Neurocysticercosis
     h. Bartonella henselae encephalitis
     i. HTLV-I infection

Answer 44

163. The answer is b. (Victor, pp 810–811.) Subacute sclerosing panencephalitisusually 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 gamma globulin fraction and the presence of oligoclonal bands. The measles virus appears to be directly responsible for this demyelinating disease, and the oligoclonalbands that appear in the CSF include a substantial proportion of measlesspecificantibody. Eosinophilic inclusions are typically present in the cytoplasmand nuclei of neurons and glial cells.

Question 45

164. A 37-year-old female Navy officer presents with 3 days of confusionand seizures. Her colleagues report that she has been acting strangely for 3days. This is followed by generalized status epilepticus. The woman has previously been well. She has traveled to the Caribbean several times annually,and she has a new pet cat. General exam discloses epitrochlear lymphadenopathy.Neurologic exam shows the woman to be in status epilepticus. Cerebrospinal fluid is negative; MRI shows increased signal in the pulvinar bilaterally. (SELECT 1 CONDITION)
     a. Subacute HIV encephalomyelitis (AIDS encephalopathy)
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Rabies encephalitis
     e. Guillain-Barré syndrome
     f. Tabes dorsalis
     g. Neurocysticercosis
     h. Bartonella henselae encephalitis
     i. HTLV-I infection

Answer 45

164. The answer is h. (Bradley, p 1347.) Cat-scratch disease produces aregional adenitis, frequently involving epitrochlear nodes due to scratcheson the patient’s arm from an infected animal. The causative agent is B.henselae (rarely Afipia felis). In immunocompetent hosts, it may produce aself-limited aseptic meningitis. In HIV-infected individuals, it may producea more virulent encephalitis associated with status epilepticus. Typically,these patients have disseminated disease, including distinctive skin lesionscomposed of neovascular proliferation (bacillary angiomatosis). On rareoccasions, immunocompetent patients may have encephalitis as well. AnMRI may show a characteristic increased signal intensity in the pulvinar,suggesting a tropism of the organism or immune response to this particularstructure in the posterior thalamus.

Question 46

165. A 29-year-old immigrant from El Salvador is brought to the emergencyroom after a generalized seizure. After awakening, he relates that he has had two or three episodes of unexplained loss of consciousness in the past 2 years. He has otherwise been healthy. He served in the Salvadoran military for 3 years. His examination is normal. Computed tomography scan with contrast reveals two small hyperintense foci in the right frontallobe, as well as a 1-cm cystic lesion with a nodular focus within it in the left frontal region. The cyst wall of the latter lesion enhances with contrast. The two right frontal lesions do not enhance. (SELECT 1 CONDITION)
     a. Subacute HIV encephalomyelitis (AIDS encephalopathy)
     b. Subacute sclerosing panencephalitis (SSPE)
     c. Progressive multifocal leukoencephalopathy (PML)
     d. Rabies encephalitis
     e. Guillain-Barré syndrome
     f. Tabes dorsalis
     g. Neurocysticercosis
     h. Bartonella henselae encephalitis
     i. HTLV-I infection

Answer 46

165. The answer is g. (Bradley, pp 1394–1396.) Cysticercosis is producedby 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.