Life Long Learning in Neurology - part 4 docx

Her blood pressure is not high enough to cause hypertensive encephalopathy; her examination and EEG show no features suggestive of hepatic encephalopathy; her spinal fluid, head CT, and

30 A 48-year-old woman with a history of hypertension, alcoholic cirrhosis, esophageal varices, and several

remote episodes of head trauma was brought to the emergency department because of confusion She had been

normal earlier in the day, but during supper she had started to make bizarre and irrelevant comments, and her

family said she "just seemed out of it." She was afebrile Her blood pressure was 150/90 mm Hg, and her heart rate

was 92/min Her speech was fluent, but tangential At times, she was able to answer complex questions and do

two-digit subtraction in her head, but at other times she acted as if she hadn't even heard the question Her cranial

nerves, motor examination, deep tendon reflexes, and sensation were normal A head CT scan showed a region of

encephalomalacia in the right temporal lobe; a lumbar puncture was normal except for a mildly elevated protein

level, and an EEG showed repetitive sharp-and-slow wave complexes at a frequency of 5/s in the right temporal

lobe Which of the following is the most likely diagnosis?

A Hepatic encephalopathy

B Herpes simplex virus encephalitis

C Hypertensive encephalopathy

D Nonconvulsive status epilepticus

E Subdural hematoma

Correct Answer: The correct answer is D The EEG features meet criteria for nonconvulsive status epilepticus Her

blood pressure is not high enough to cause hypertensive encephalopathy; her examination and EEG show no

features suggestive of hepatic encephalopathy; her spinal fluid, head CT, and EEG show no features suggestive of

herpes simplex virus encephalitis; and her head CT shows no evidence of subdural hematoma

31 Plateau waves (A waves) on an intracranial pressure tracing represent which of the following?

A Decreased intracranial pressure

B Increased cerebral blood flow

C Increased cerebral blood volume

D Increased cerebral perfusion pressure

E Increased intracranial compliance

Correct Answer: The correct answer is C Plateau waves (A waves) represent vasodilation in response to a decrease

in cerebral perfusion pressure, causing a simultaneous reduction in cerebral blood flow and increase in cerebral

blood volume The vasodilation results in an increase in intracranial pressure and reduced intracranial compliance

32 A 74-year-old hypertensive man with past history of atrial fibrillation, hypertension, hyperlipidemia, and a

small embolic right parietal infarct 1 year ago presents with a right hemiparesis and aphasia His medications

include warfarin, atorvastatin, and lisinopril; his wife reports that he has been taking significant amounts of

over-the-counter cimetidine recently due to heartburn His cranial CT shows a large lobar hemorrhage in the left frontal

lobe His international normalized ratio (INR) is 4.8 Of the following sets of interventions, which is most

appropriate for this man?

A Subcutaneous vitamin K and fresh frozen plasma

B Intramuscular vitamin K and prothrombin complex concentrate

C Intravenous vitamin K and fresh frozen plasma

D Recombinant activated factor VII alone

E Do not reverse his INR, as atrial fibrillation puts him at risk for an embolic stroke

Correct Answer: The correct answer is C Expert opinion endorses rapid reversal of anticoagulant effect following

intracerebral hemorrhage, despite theoretical concerns of increased risk of thromboembolism Intravenous vitamin

K is preferable because of variable absorption via the subcutaneous and intramuscular routes Most experts

recommend fresh frozen plasma or prothrombin complex concentration (PCC) In this case, there is no known

history of congestive heart failure so the volume load of fresh frozen plasma will likely be tolerated PCC may be

associated with thromboembolic complications Recombinant activated factor VII has not yet been tested in

controlled trials in patients with warfarin-associated intracerebral hemorrhage, but its use has been reported in case

series

33.Hypertensive encephalopathy preferentially affects which of the following arterial distributions?

A Anterior cerebral

B Anterior choroidal

C Middle cerebral

D Ophthalmic

E Vertebrobasilar

Correct Answer: The correct answer is E Hypertensive encephalopathy has a predilection for involvement of the

vertebrobasilar circulation with the occipital lobes and posterior parietal lobes being preferentially involved

34 A 47-year-old woman experiences a cardiac arrest after a run of ventricular tachycardia Emergency

resuscitation requires 25 minutes of acute efforts before stabilization One of the physicians involved in the

resuscitation performs a neurological examination after the code and records absence of pupillary response in either eye On morning rounds, the intern reports that he has read at least one study in which the absence of pupillary responses was almost uniformly predictive of severe deficit or worse neurological outcome What do more recent studies report as the percentage of patients who never awaken if pupillary light responses are not present immediately after resuscitation?

A 95%

B 90%

C 85%

D 80%

E 75%

Correct Answer: The correct answer is E In one study (Edgren et al, 1994) of 89 patients with absence of pupillary light reflexes after cardiac arrest, 21 of 89 (24%) awoke (11 with slight, 5 with moderate, and 5 with severe neurological deficits) Levy and colleagues (1985) may have observed a higher positive predictive value for severe neurological deficits from the finding of absence of the pupillary light reflex in their 1985 paper because the timing

of the initial examination varied from immediately to up to 24 hours postarrest

Correct Answer: Edgren E, Hedstrand U, Kelsey S, et al Assessment of neurological prognosis in comatose survivors of cardiac arrest BRCT I Study Group Lancet 1994;343:1055-1059

Correct Answer: Levy DE, Caronna JJ, Singer BH, et al Predicting outcome from hypoxic-ischemic coma JAMA 1985;253:1420-1426

35 Treatment for status epilepticus should be initiated whenever a generalized convulsive seizure persists for more than:

A 1 to 2 minutes

B 5 to 10 minutes

C 20 to 30 minutes

D 45 to 60 minutes

E 90 to 120 minutes

Correct Answer: The correct answer is B The definition of status epilepticus continues to evolve Because typical seizures last 1 to 2 minutes, and because the likelihood of irreversible neuronal injury increases as a function of seizure duration, the American Academy of Neurology and the American Epilepsy Society consider any seizure event lasting longer than 5 to 10 minutes to be status epilepticus

36 Which of the following, by itself, is sufficient justification for intracranial pressure monitoring in a patient with

an abnormal head CT scan after head trauma?

A Age 30 years or less

B Decorticate posturing

C Glasgow Coma Scale score of 8 or less

D Hemiparesis

E Systolic blood pressure 160 mm Hg or greater

Correct Answer: The correct answer is C The clearest indication for placing an intracranial pressure monitor is severe head injury (Glasgow Coma Scale score of 8 or less) with an abnormal head CT scan Even if the head CT scan is normal, there is a strong indication for placing an intracranial pressure monitor in patients with severe head injury if two of the following are present: age 40 years or more, motor posturing, or systolic blood pressure 90 mm

Hg or less

37 Which of the following clinical presentations represents the strongest immediate indication for surgical intervention for intracranial hemorrhage?

A Cerebellar hemorrhage of 4.5 cm diameter

B Parietal lobe hemorrhage of 2 cm

C Thalamic hemorrhage with extension of blood into third ventricle

D Large frontal lobe hemorrhage with slight effacement of lateral ventricle

E Pontine hemorrhage

Correct Answer: The correct answer is A Patients with cerebellar hemorrhages of 3-cm diameter or greater are generally offered surgical intervention Other patients with intracerebral hemorrhage who may benefit from surgical intervention include those with elevated intracranial pressure, deteriorating neurological function, significant mass effect, or hydrocephalus

38 The predilection of hypertensive encephalopathy for certain regions of the brain is thought to be due to regional variation in which of the following?

A Concentration of glutamate receptors

B Extent of collateral supply

C Extent of myelination

D Pattern of sympathetic innervation

E Pattern of venous drainage

Correct Answer: The correct answer is D The sympathetic innervation of the arteries in the vertebrobasilar system

is less robust than the sympathetic innervation of arteries in the anterior circulation This is thought to underlie the

vulnerability of territory supplied by the vertebrobasilar system to injury from severe hypertension

39 A 29-year-old man suffers a cardiopulmonary arrest in the setting of an opiate overdose After 48 hours, he has

not regained pupillary light reflexes or motor response to pain Cerebrospinal fluid is collected from a lumbar

puncture and sent for a cerebrospinal fluid creatine kinase-BB level Which is the lowest of the following levels

that would yield a 95% probability of never awakening according to the logistic regression analysis derived from

data from the study of Tirschwell and colleagues (1997)?

A 50 U/L

B 100 U/L

C 150 U/L

D 200 U/L

E 250 U/L

Correct Answer: The correct answer is C In Tirschwell and colleagues' study, a cerebrospinal fluid creatine

kinase-BB level of 150 U/L gave an estimated 95% probability that the patient would not awaken from cardiac arrest

None of the patients with levels greater than 50 U/L regained independence in activities of daily living

Correct Answer: Tirschwell DL, Longstreth WT Jr, Rauch-Matthews ME, et al Cerebrospinal fluid creatine kinase

BB isoenzyme activity and neurologic prognosis after cardiac arrest Neurology 1997;48:352-357

40 Which of the following is the primary end point in determining pentobarbital dosing for treatment of status

epilepticus by induction of pharmacological coma?

A Absence of pupillary light reflex

B Burst-suppression pattern on EEG

C Disappearance of brain stem auditory evoked response

D Infusion rate of 0.5 mg/kg per hour

E Serum pentobarbital level of 10 µg/mL to 20 µg/mL

Correct Answer: The correct answer is B Target pentobarbital levels and infusion rates serve as guidelines, but the

goal of therapy when treating status epilepticus by inducing pharmacological coma is a burst-suppression record,

with the suppression periods lasting 5 to 30 seconds In this condition, the neurological examination resembles that

of brain death, but a sluggish pupillary light reflex is occasionally preserved Evoked potentials may continue to

demonstrate peripheral and central signals

INFECTIOUS DISEASES April 2006

TYPE A QUESTIONS (ONE BEST ANSWER)

1 A 55-year-old man presents in the emergency department because of headache, fever, and somnolence

developing over the past 8 hours Examination reveals a temperature of 39.4°C, pain on flexion of the neck, and

stupor Which of the following is the most appropriate approach?

A Computed tomography (CT) scan of the head prior to lumbar puncture, followed by empiric antibiotic and

adjunctive therapy

B Lumbar puncture and blood culture prior to CT scan of the head, followed by empiric antibiotic and adjunctive

therapy

C Blood culture and empiric antibiotic and adjunctive therapy prior to CT scan of the head and lumbar puncture

D CT scan of the head and blood culture, followed by empiric antibiotic and adjunctive therapy and lumbar

puncture

E Empiric antibiotic and adjunctive therapy, followed by lumbar puncture and blood culture

Correct Answer: The correct answer is C The clinical features are strongly suggestive of bacterial meningitis The

initial step in management is to obtain blood cultures and initiate empiric antimicrobial therapy after receiving an

initial dose of dexamethasone After this initial step, the patient should have a CT scan of the head prior to the

lumbar puncture, as he has a depressed level of consciousness

2 A 55-year-old previously healthy businessman is evaluated for headache, neck stiffness, and progressive

somnolence over the past 2 weeks Two days ago, he developed gait difficulties and double vision He returned

from a summer vacation in Arizona 3 weeks ago Examination reveals a temperature of 38.5°C He is somnolent,

has mild nuchal rigidity, and has a left sixth nerve palsy He has a nodular lesion in the right thigh A head MRI

with gadolinium reveals diffuse meningeal enhancement, particularly of the basal meninges, and mild

hydrocephalus Cerebrospinal fluid (CSF) examination reveals 500/mm3 white blood cells (20% neutrophils, 30%

eosinophils, 50% mononuclear), glucose concentration of 40 mg/dL (CSF-plasma glucose ratio 0.3), and protein of

100 mg/dL Gram's stain is negative Which of the following CSF studies is most likely to provide the diagnosis in this patient?

A Polymerase chain reaction (PCR) assay for Borrelia burgdorferi DNA

B Complement-fixing antibody against Coccidioides immitis

C Latex agglutination for Cryptococcus neoformans antigen

D Acid-fast stain for Mycobacterium tuberculosis

E Enzyme immune assay for Histoplasma capsulatum antigen

Correct Answer: The correct answer is B In a patient with severe chronic meningitis, the history of recent travel to

an endemic area (southwest United States), the presence of a cutaneous nodule, and the CSF eosinophilia are highly suggestive of coccidioidal meningitis This can be confirmed by detection of CSF antibodies and identification of typical spherules on the biopsy of the skin nodule CSF cultures are positive in only 50%

3 Three days after visiting his grandson at a summer camp, a 72-year-old man developed fever, headache, confusion, and leg weakness Neurological examination 1 day later revealed decreased level of arousal, mild nuchal rigidity, facial weakness, and weakness and areflexia in the left arm and right leg Bilateral arm tremor with occasional myoclonus was observed A CT scan of the head without contrast was essentially normal CSF examination revealed an opening pressure of 200-mm H2O, 200/mm3 white cells (70% polymorphonuclear), a glucose concentration of 60 mg/dL (CSF-plasma ratio of 0.8), and a protein concentration of 100 mg/dL Which of the following is the most likely cause of his symptoms?

A Varicella-zoster virus

B Coxsackie B virus

C Herpes simplex virus 2 (HSV-2)

D West Nile virus

E Epstein-Barr virus (EBV)

Correct Answer: The correct answer is D The clinical picture is that of a viral meningoencephalitis The presentation in summer suggests a mosquito-or tick-borne disease In this clinical setting, the presence of weakness with lack of muscle stretch reflexes, tremor, myoclonus, and polymorphonuclear predominant pleocytosis with normal glucose concentration in the CSF is highly suggestive of West Nile virus encephalitis Although varicella-zoster virus may cause meningoencephalitis and radiculopathy, these tend to occur primarily in immunosuppressed patients HSV-2 causes recurrent meningitis and radiculopathy but rarely encephalitis EBV may trigger Guillain-Barré syndrome, which may resemble the acute anterior horn involvement by West Nile virus However, encephalitis would be an unusual association in that setting

4 A 55-year-old man undergoes bone marrow transplantation for treatment of chronic myelogenous leukemia In the posttransplant period, he receives cyclosporine and prednisone His posttransplant course has been complicated

by graft versus host disease and candidal esophagitis Six months following transplant, he develops a subacute progressive right hemiparesis He has recently traveled to Mexico and then the midwestern United States, where he went camping and had multiple mosquito bites He has three cats at home, and his house recently underwent repairs for damage related to black mold Magnetic resonance imaging (MRI) demonstrates multiple areas of abnormal T2 signal in the white matter, the largest of which is in the left frontal lobe There is minimal mass effect and no contrast enhancement CSF examination is remarkable for positive PCR for JC virus Which of the following features in this patient's history is the most significant risk factor for progressive multifocal leukoencephalopathy?

A Cat exposure

B Mosquito bites

C Graft versus host disease

D Travel to Mexico

E Candidal esophagitis

Correct Answer: The correct answer is C Progressive multifocal leukoencephalopathy (PML) is a demyelinating disorder due to infection with the JC virus The increased immunosuppression required for treatment of graft versus host disease placed the patient at increased risk for PML due to impairment of cell-mediated immunity The JC virus is ubiquitous in the environment; therefore, travel history and mosquito and cat exposure do not increase his risk of PML No direct association exists between candidal infection and PML

5 A 35-year-old man with a history of human immunodeficiency virus (HIV) infection presents with a 4-day history of headache, malaise, and low-grade fever He recently had been on a camping trip, and he has two cats in his home He has a previous history of Pneumocystis pneumonia His medications include trimethoprim-sulfamethoxazole; he is not receiving highly active antiretroviral therapy (HAART) His temperature is 38°C No meningismus is noted, and the neurological examination is normal His CD4 count is 20 cells/µL Serum anti-Toxoplasma serum immunoglobulin G (IgG) is negative Which of the following is the most significant risk factor for opportunistic central nervous system (CNS) infection in this patient?

A HAART

B Cat exposure

C Negative serum Toxoplasma IgG

D CD4 count

E History of Pneumocystis pneumonia

Correct Answer: The correct answer is D The strongest risk factor for opportunistic CNS infection in this patient is

the CD4 count below 200 cells/µL Patients with previous Pneumocystis pneumonia who have low CD4 counts

receive trimethoprim-sulfamethoxazole (TMP-SMX) for pneumocystis prophylaxis This treatment also lowers the

risk of Toxoplasma encephalitis The absence of serum Toxoplasma IgG makes the possibility of Toxoplasma

encephalitis less likely Most patients develop Toxoplasma encephalitis as reactivation of latent disease, not by new

exposure to infected cats

6 A 40-year-old woman presents with a 3-day history of fever, headache, and confusion She returned from a

vacation in southern India 10 days ago She spent 3 weeks in India, largely in rural areas Her husband reports that

she had no illness while on vacation other than a mild diarrheal illness On examination her temperature is 39°C

She is drowsy but able to follow one-step commands with all extremities She has a bilateral internuclear

ophthalmoplegia and bilateral facial weakness There is no papilledema Limb strength appears normal, but there is

generalized rigidity The deep tendon reflexes are brisk symmetrically, and bilateral Babinski signs are present

Mild meningismus is present CSF examination reveals a protein of 150 mg/dL, glucose 80 mg/dL, WBCs

200/mm3 (100%) lymphocytes An MRI of the brain reveals increased T2 signal bilaterally in the globus pallidus,

thalami, and in the pons and midbrain Serum enzyme-linked immunoabsorbent assay (ELISA) for Japanese

encephalitis virus immunoglobulin M (IgM) is positive Which of the following activities or exposures during her

trip has placed the patient at highest risk for developing her current illness?

A Mosquito exposure

B Consumption of undercooked pork

C Exposure to live poultry

D Snorkeling in the Bay of Bengal

E Eating unwashed vegetables

Correct Answer: The correct answer is A This patient most likely has encephalitis caused by Japanese encephalitis

virus Japanese encephalitis virus typically affects the basal ganglia, thalami, cerebellum, and brain stem as well as

the cerebral cortex It is the leading cause of viral encephalitis in Asia with 30,000 to 50,000 reported cases each

year The virus is transmitted by the Culex mosquito, which typically breeds in rice paddies Most cases occur

between June and September, and the incubation period is 5 to 14 days No treatment for the encephalitis is known,

other than supportive care A vaccine is available, although it is not usually recommended for travelers due to the

rarity of infection in this population and the risk of hypersensitivity reactions The best protection against Japanese

encephalitis virus is avoidance of mosquito bites The other activities listed in the option set would not put the

patient at risk for the development of encephalitis

7 A 65-year-old woman with a history of rheumatoid arthritis on chronic corticosteroid therapy presents in the

emergency department because of headache, fever, and confusion developing over the past 12 hours Examination

reveals temperature of 38.9°C, pain on flexion of the neck, and decreased level of arousal She has a right focal

motor seizure with secondary generalization during the examination Which of the following is the most

appropriate initial empiric antibiotic combination in this case?

A Cefepime, vancomycin, and acyclovir

B Cefepime, vancomycin, and ampicillin

C Penicillin, vancomycin, gentamicin, and doxycycline

D Cefepime, ampicillin, gentamicin, and acyclovir

E Cefepime, vancomycin, ampicillin, and acyclovir

Correct Answer: The correct answer is E The clinical picture is consistent with either bacterial meningitis or

herpes simplex encephalitis Prior to obtaining cerebrospinal fluid, the empiric antibiotic combination should

include a third- or fourth-generation cephalosporin plus vancomycin, based on the assumption that the cause may

be a penicillin- and cephalosporin-resistant strain of Streptococcus pneumoniae, as well as ampicillin due to the

possibility of Listeria monocytogenes in the setting of immunosuppression (corticosteroid therapy) and acyclovir

(until the results of the CSF exclude the possibility of herpes simplex encephalitis)

8 A 67-year-old farmer from Ohio with a history of rheumatoid arthritis treated with corticosteroids for several

years developed fever, chest pain, and cough approximately 3 weeks ago Two weeks ago, he started experiencing

headache, neck pain, and increased somnolence Two days ago he developed eye pain, floaters, and decreased

vision He had the acute onset of right arm weakness and diplopia 12 hours ago Examination reveals a temperature

of 39.5°C He is somnolent but arousable to loud voice and has mild nuchal rigidity He also has conjunctival

injection, decreased visual acuity, a right sixth nerve palsy, and right hemiparesis Funduscopy reveals multiple white foci consistent with retinochoroiditis A head MRI with gadolinium reveals diffuse meningeal enhancement, particularly of the basal meninges, and an area of acute infarction in the left frontal lobe A magnetic resonance angiogram reveals multisegmental narrowing of the middle cerebral artery CSF examination reveals an opening pressure of 300 cm H2O, white blood cells 200/mm3 (50% neutrophils), glucose concentration of 40 mg/dL (CSF-plasma glucose ratio 0.3), and protein of 100 mg/dL Gram's stain is negative A chest x-ray shows parenchymal granulomas and hilar adenopathy Which of the following is the most likely cause of this patient's condition?

A Listeria monocytogenes

B Histoplasma capsulatum

C Cytomegalovirus

D Treponema pallidum

E HSV-2

Correct Answer: The correct answer is B The patient has anterior and posterior uveitis and severe chronic meningitis resulting in cranial nerve palsy and vasculitis The endemic area of origin, history of immunosuppression, chorioretinitis, and neutrophil predominant CSF pleocytosis, together with pulmonary lesions, strongly suggest H capsulatum as a probable cause Cytomegalovirus may produce retinitis and CSF polymorphonuclear pleocytosis, but this typically occurs in the setting of polyradiculopathy in patients with HIV infection Neurosyphilis can produce chorioretinitis, vasculitis, and chronic meningitis, but in general CSF mononuclear pleocytosis and hypoglycorrhachia are less common or milder, and pulmonary lesions are not a feature HSV-2 is typically associated with recurrent aseptic meningitis

9 Approximately 2 weeks after Christmas, a 28-year-old neuroscience graduate student comes to the emergency department complaining of fever, headache, photophobia, and myalgias over the past 12 hours He has been studying the neuroprotective effects of hypothermia in a hamster model of stroke Prior to the onset of the current symptoms, he had a mild fever that subsided spontaneously and was attributed to a "flu." Neurological examination reveals nuchal rigidity but is otherwise normal He has a mild erythematous rash and mild generalized lymphadenopathy CSF examination shows an opening pressure of 280-mm H20, white blood cells 1000/mm3 (98% mononuclear), a glucose concentration of 30 mg/dL (CSF-plasma glucose ratio of 0.3), and a protein concentration

of 60 mg/dL Laboratory tests show mild leukopenia and thrombocytopenia Human immunodeficiency virus type

1 (HIV-1) serology is negative Which of the following is the most likely etiological agent?

A Varicella-zoster virus

B Herpes simplex virus 1 (HSV-1)

C West Nile virus

D Lymphocytic choriomeningitis virus

E Cytomegalovirus

Correct Answer: The correct answer is D Lymphocytic choriomeningitis virus should be considered in patients with aseptic meningitis and history of exposure to rodents, including hamsters, particularly in the fall and winter The presence of a mild erythematous rash, lymphadenopathy, and marked CSF mononuclear pleocytosis and hypoglycorrhachia are consistent with this diagnosis Varicella-zoster virus may cause encephalitis, meningitis, myelitis, or radiculitis, particularly in an immunocompromised patient HSV-1 produces focal encephalitis more commonly than aseptic meningitis West Nile virus is a mosquito-borne agent that commonly causes aseptic meningitis in summer and early fall Cytomegalovirus would be an unusual cause of aseptic meningitis in an immunocompetent host

10 A 55-year-old woman develops progressive headache 6 months following bone marrow transplantation for acute myelogenous leukemia She has a temperature of 38°C and scores 25/30 on the Mental Status Examination She has mild papilledema, and the remainder of her neurological examination is unremarkable An MRI of the brain demonstrates multiple ring-enhancing lesions Noncontrast head CT demonstrates mild hemorrhage associated with 1 lesion Chest x-ray shows a 3-cm nodular lesion in the right lower lobe Bronchoalveolar lavage

is performed, and galactomannan index is noted to be greater than 0.5 in both the serum and bronchoalveolar lavage fluid Which of the following medications is most appropriate to treat this patient's condition?

A Pyrimethamine

B Trimethoprim-sulfamethoxazole

C Isoniazid

D Amphotericin B

E Ganciclovir

Correct Answer: The correct answer is D This patient most likely has infection with Aspergillus, the most common cause of CNS focal infection in patients with organ or bone marrow transplantation Concurrent pulmonary infection is common in Aspergillus, Mycobacterium tuberculosis, Toxoplasma gondii, and nocardiosis The

presence of an elevated galactomannan in the serum and bronchoalveolar lavage fluid is highly suggestive of

Aspergillus, since galactomannan is a polysaccharide marker on the surface of the Aspergillus cell wall

Amphotericin is an appropriate treatment for Aspergillus

11 A 44-year-old Laotian man with a history of HIV infection presents to the emergency department with a

1-week history of headache and neck pain, fever, diplopia, and right-sided facial weakness He has a history of

candidal esophagitis for which he has taken fluconazole for the last 6 months His neurological examination reveals

mild meningismus, bilateral sixth nerve palsies, and a right seventh nerve palsy His CD4 count is 40 cells/µL A

noncontrast CT of the head is negative CSF examination reveals an opening pressure of 230-mm H2O, protein 140,

glucose 40 mg/dL, and white blood cell count 150/mm3 (100% lymphocytes) CSF acid-fast bacillus stain, india ink

stain, and cryptococcal antigen are negative Which of the following is the most likely responsible organism for this

patient's infection?

A Toxoplasma gondii

B Cryptococcus neoformans

C Borrelia burgdorferi

D West Nile virus

E Mycobacterium tuberculosis

Correct Answer: The correct answer is E The cranial nerve abnormalities suggest that the patient has basal

meningitis In patients infected with HIV, the most likely etiologies for meningitis are C neoformans, M

tuberculosis, and Treponema pallidum Toxoplasma usually produces parenchymal lesions and not meningitis This

patient would not be at higher risk for Lyme meningitis because he is immunocompromised West Nile virus may

produce a meningoencephalitis in immunocompromised patients but should not produce a low CSF glucose The

fact that the patient is on fluconazole prophylaxis for Candida esophagitis would lower the risk for Cryptococcus

infection Moreover, the patient comes from Laos, a developing country with a high likelihood of exposure to M

tuberculosis

12 A 35-year-old man is brought to the emergency department for evaluation of fever, somnolence, and a single

seizure He is originally from a rural community in the Sudan but immigrated to the United States 5 days ago

Three days ago he developed high fever and chills with nausea and vomiting This morning he was unarousable and

had a 2-minute generalized tonic-clonic seizure He was previously healthy and takes no medication Vital signs are

temperature 40°C, heart rate 110 regular, blood pressure 105/70 mm Hg, respiratory rate 18/min An airway is

placed, and he is given supplemental oxygen A finger-stick glucose is 80 mg/dL His examination is significant for

retinal hemorrhages without evidence of papilledema His examination is nonfocal A noncontrast CT of the head is

normal CSF examination reveals an opening pressure of 190-mm H2O, protein 60 mg/dL, glucose 70 mg/dL,

WBCs 5/mm3 (100% lymphocytes), red blood cell count 0 Gram's stain, acid-fast bacilli, and india ink stain are

negative What additional testing would be most likely to yield a diagnosis in this patient?

A Giemsa stain of the peripheral blood

B Cerebral angiogram

C Brain biopsy

D Single-photon emission computed tomography scan

E Japanese encephalitis virus IgM antibody in the CSF

Correct Answer: The correct answer is A In a patient from sub-Saharan Africa who presents with fever,

encephalopathy, and seizures, a diagnosis of cerebral malaria should always be considered Cerebral malaria is

usually caused by infection with Plasmodium falciparum or less likely Plasmodium vivax The parasite-infected red

blood cells become adherent to brain capillaries and venules, causing microvascular obstruction This in turn

produces diffuse encephalopathy, focal neurological deficits, and seizures The best way to detect the parasite is

with a thick-and-thin peripheral blood smear with Giemsa staining Serological tests are available but less reliable

This patient is not from an area endemic for Japanese encephalitis virus

13 A 65-year-old previously healthy man presents in the emergency department because of headache, fever, and

neck stiffness over the past 12 hours Examination reveals temperature of 40°C, pain on flexion of the neck, and an

apical systolic murmur A chest x-ray reveals a left lower lobe pneumonia Which of the following is the most

appropriate statement regarding dexamethasone treatment in this patient?

A Dexamethasone is contraindicated, given the presence of presumed bacterial meningitis, endocarditis, and

pneumonia

B Dexamethasone should be administered if the patient's mental status deteriorates despite appropriate empiric

antimicrobial therapy

C A 10-mg dose of dexamethasone should be given prophylactically against brain edema after 24 hours of

antimicrobial therapy if blood cultures are negative

D A 10-mg intravenous (IV) dose of dexamethasone should be given prior to initiation of antimicrobial therapy and continued every 6 hours for 4 days

E Dexamethasone, 10 mg intravenously every 8 hours for 2 days, should be initiated after the first dose of antimicrobial therapy

Correct Answer: The correct answer is D This patient probably has bacterial meningitis, which, in the setting of pneumonia and endocarditis, is likely due to Streptococcus pneumoniae There is evidence that corticosteroids may reduce the potential detrimental effects of cytokines released during the acute inflammatory reaction and presumably prevent further cytokine release triggered by antimicrobial-induced bacterial lysis Dexamethasone is administered at a dose of 10 mg intravenously prior to initiation of antimicrobial therapy and continued at the same dose every 6 hours for 4 days

14 A 28-year-old man is evaluated for fever, headache, neck stiffness, irritability, and impaired memory over the past 6 days Two days ago, he developed weakness in the right arm, diplopia, and imbalance He has experienced 2 episodes of eye pain and blurred vision, diagnosed as anterior uveitis, over the past 3 years He has also experienced recurrent episodes of arthralgia associated with painful subcutaneous nodules in the pretibial areas Examination reveals impaired attention, neck stiffness, papilledema, right oculomotor palsy, gait ataxia, and upper motor weakness in the right upper limb He has several painless ulcers in the mouth and the penis Head MRI reveals several T1-hypointense and T2-hyperintense lesions in the pons and midbrain, cerebellum, and internal capsule Some lesions enhance with gadolinium A magnetic resonance venogram reveals a partial occlusion of the superior sagittal sinus CSF examination reveals an opening pressure of 400 cm H2O, white blood cells 400/mm3 (80% mononuclear), glucose of 60 mg/dL, and a protein of 200 mg/dL HIV-1 serology is negative Two days after admission, he suffers one episode of hemoptysis, and a CT angiogram of the chest reveals an aneurysm in the left pulmonary artery What is the most likely diagnosis?

A Granulomatous angiitis

B Neurosarcoidosis

C Behçet's disease

D Meningovascular neurosyphilis

E Varicella-zoster meningoencephalitis

Correct Answer: The correct answer is C The history of recurrent anterior uveitis and the presence of oral and genital ulcers are characteristic of Behçet's disease This disorder may manifest with an uveomeningeal syndrome and multifocal cerebral lesions, particularly in the brain stem, and is typically associated with predisposition to venous thrombosis The presence of aneurysms in visceral vessels is typical of the disease Sarcoidosis can also produce uveitis and meningoencephalitis but is not typically associated with oral or genital ulcers or pulmonary artery aneurysm Granulomatous angiitis of the central nervous system and systemic lupus erythematosus may also manifest with meningeal and brain lesions but are not typically associated with uveitis or oral and genital ulcers Meningovascular syphilis and varicella-zoster meningoencephalitis may be associated with uveitis However, the oral and genital ulcers are distinct from the maculopapular rash or vesicles associated with syphilis and herpes zoster, respectively

15 In the fall, a 5-year-old girl presents to the emergency department with headache, neck pain, and vomiting starting approximately 8 hours prior to evaluation Examination reveals fever (38.9°C), nuchal rigidity, tender papules and vesicles in the palms and soles, and ulcers in the gingiva and soft palate She is somnolent but has no focal neurological deficits CSF examination reveals an opening pressure of 260-mm H2O, white blood cells 200/mm3 (50% polymorphonuclear and 50% mononuclear), glucose concentration of 65 mg/dL (CSF-glucose ratio 0.7), and protein concentration of 70 mg/dL Which of the following CSF studies is most likely to provide a definite diagnosis?

A IgM for EBV viral capsid antigen

B Reverse transcriptase polymerase chain reaction (RT-PCR) for enterovirus

C PCR for HSV-2

D Latex agglutination study for Neisseria meningitidis

E Venereal Disease Research Laboratory (VDRL) testing

Correct Answer: The correct answer is B Enteroviruses are responsible for approximately 80% of aseptic meningitis cases, particularly in the fall The presence of exanthem and enanthem (hand-foot-and-mouth syndrome)

is supportive of enteroviral aseptic meningitis As in this case, the CSF may show pleocytosis with polymorphonuclear predominance in the first 48 hours, with subsequent shift to mononuclear cells EBV is a relatively infrequent cause of aseptic meningitis, and the rash present in this patient would be atypical for EBV HSV-2 is a common cause of aseptic meningitis but produces focal encephalitis more commonly than aseptic meningitis, and the rash, characterized by grouped vesicles in the genitalia, occurs in sexually active adults Despite the polymorphonuclear pleocytosis in the CSF, the clinical picture and the normal CSF glucose suggest a viral

rather than bacterial meningitis caused by meningococcus, and the rash produced by N meningitidis is purpuric

Secondary neurosyphilis may cause a maculopapular rash affecting the palms but would be a much less likely

cause of aseptic meningitis in this age group

16 Prophylactic use of trimethoprim-sulfamethoxazole (TMP-SMX) in transplant recipients is effective in

preventing which of the following CNS infections posttransplant?

A Scedosporium apiospermum

B Listeria monocytogenes

C Mycobacterium avium-intracellulare

D Pseudomonas aeruginosa

E Cryptococcus neoformans

Correct Answer: The correct answer is B TMP-SMX is an effective drug in primary prophylaxis for L

monocytogenes, Toxoplasma gondii, and Nocardia asteroides This drug would have no efficacy in preventing the

other infections listed

17 A 42-year-old woman with HIV infection presents to the physician with a 2-week history of right visual field

loss and progressive right-sided weakness She has a previous history of Pneumocystis pneumonia Her current

medication is trimethoprim-sulfamethoxazole Findings from neurological examination reveal a right homonymous

hemianopia and mild pyramidal distribution weakness in the right face, arm, and leg with right hyperreflexia and

right Babinski sign Her CD4 count is 30/µL An MRI of the head with contrast reveals multiple areas of abnormal

T2 signal in the white matter, sparing the U fibers The largest lesion is in the left frontoparietal region No mass

effect or enhancement is associated with the lesions CSF examination shows a protein of 70 mg/dL, glucose 80

mg/dL, white blood cell count 6/mm3, and positive PCR for JC virus Which of the following is the most effective

treatment for this patient's neurological condition?

A HAART

B Interferon alpha

C AraC

D Amphotericin B

E Pyrimethamine

Correct Answer: The correct answer is A HAART is the only proven treatment for HIV-associated PML Even

with treatment, the neurological deficits may not completely resolve Without HAART, HIV-associated PML is

almost always fatal Amphotericin B is an antifungal agent used to treat cryptococcal infection Pyrimethamine is

used to treat toxoplasmosis Neither interferon alpha nor AraC has any proven effectiveness in the treatment of

HIV-associated PML

18 A 29-year-old woman presents with fever, headache, and facial weakness 4 days after returning from a 3-week

vacation in Thailand She had felt well during her trip She used no malaria prophylaxis Two days ago she

developed retro-orbital headache, myalgias, fever, and generalized rash Today she noted bilaterally facial

weakness with difficulty closing her eyes On examination, her temperature is 40°C She has bilateral facial

weakness but an otherwise normal neurological examination, including normal mental status A generalized

macular rash spares the palms and soles An MRI of the head is normal Lumbar puncture reveals a protein of 90

mg/dL, glucose of 80 mg/dL, WBCs 30/mm3 (100% lymphocytes) CSF cultures are negative PCR for Lyme and

herpes simplex in the CSF is negative Which of the following tests would be most helpful in making a diagnosis?

A Giemsa-stained peripheral blood smear

B Dengue-specific IgM in the serum

C Skin biopsy for rabies virus antigen

D CSF ELISA for Taenia solium

E IgM ELISA for Japanese encephalitis virus

Correct Answer: The correct answer is B The constellation of symptoms and signs in this patient suggests dengue

fever, a mosquito-borne flavivirus particularly common in Asia, although it can be found in most tropical areas

The illness has a 3- to 7-day incubation period, followed by high fever, myalgias, arthralgias, retro-orbital

headache, and generalized rash Neurological manifestations are uncommon but include encephalitis,

mononeuropathy or polyneuropathy, and transverse myelitis Confirmatory diagnosis is by detection of

dengue-specific IgM in the serum or identification of the virus in the CSF by PCR Cerebral malaria, rabies encephalitis,

cysticercosis, and Japanese encephalitis would be unlikely to present in this manner

19 A 35-year-old previously healthy man presents to the emergency department complaining of headache and neck

pain over the past 6 hours He has just returned from coaching his son's soccer team at a summer camp

Examination reveals temperature of 39.4°C, mild tachycardia, and normal blood pressure He is mildly somnolent,

has pain on flexion of the neck but no focal neurological deficits, and has an erythematous maculopapular rash on

his chest and forearms Which of the following antimicrobial agents should be added to the empirical regimen with cefepime and vancomycin until the CSF results are available?

A Ampicillin

B Gentamicin

C Rifampin

D Doxycycline

E Meropenem

Correct Answer: The correct answer is D The history and findings are suggestive of meningitis Since the patient has a maculopapular rash and his disease occurred in summer, the possibility of a tick-borne infection such as Rocky Mountain spotted fever or ehrlichiosis should be considered In these circumstances, doxycycline is added to the empirical regimen until the results of the CSF examination are available and support an alternative diagnosis Rifampin is used to treat patients with meningitis due to Neisseria meningitidis after they finish a course of IV antibiotic therapy to eradicate nasopharyngeal colonization Ampicillin is added if there is suspicion of Listeria monocytogenes meningitis, which would be unusual in a previously healthy and immunocompetent host Gentamicin is added to ampicillin in critically ill patients with Listeria meningitis Meropenem is the preferred antibiotic for Pseudomonas aeruginosa meningitis

20 A 38-year-old woman is evaluated for a 3-week history of progressive headache, blurred vision, and gait difficulties She developed double vision 12 hours ago She has a history of left Bell's palsy diagnosed 8 months ago with almost complete recovery Prior to this episode, she developed painful subcutaneous nodules in the pretibial areas, which also resolved Examination reveals nuchal rigidity, mild papilledema, a mild residual left facial palsy, and a new right sixth nerve palsy A head MRI with gadolinium reveals diffuse meningeal enhancement, particularly of the basal meninges, with mild hydrocephalus CSF examination reveals white blood cells 50/mm3 (80% mononuclear), glucose concentration of 40 mg/dL, and protein of 100 mg/dL Gram's stain is negative A chest x-ray reveals mediastinal adenopathies, and the patient has hypercalcemia Which of the following is the most likely diagnosis?

A Cryptococcal meningitis

B Tuberculous meningitis

C Carcinomatous meningitis

D Neurosarcoidosis

E Behçet's disease

Correct Answer: The correct answer is D The patient most likely has neurosarcoidosis, particularly given the history of a previous episode of facial palsy and erythema nodosum and the presence of hypercalcemia Hypercalcemia is not a typical feature of Behçet's disease Although it can occur in many granulomatous disorders

or as paraneoplastic manifestation, the spontaneous improvement of facial palsy would make the diagnosis of tuberculous, cryptococcal, or carcinomatous meningitis unlikely

21 A 22-year-old previously healthy student in Minnesota is evaluated for fever, headache, and neck pain over the past 18 hours He has become progressively more somnolent over the past 6 hours and had a right focal motor seizure with secondary generalization 30 minutes ago One week ago, on New Year's Eve, he complained of a sore throat He received ampicillin, but this had to be discontinued because he developed a diffuse maculopapular rash Examination reveals somnolence, neck stiffness, and mild right hemiparesis with a Babinski sign He has mild hepatomegaly A CT scan of the head is negative CSF examination shows an opening pressure of 290-mm H2O, total white blood cell count of 200/mm3 (90% mononuclear), glucose concentration of 60 mg/dL (CSF-plasma glucose ratio 0.6), and protein of 100 mg/dL Gram's stain is negative Which of the following CSF studies is most likely to determine the etiology of the patient's condition?

A RT-PCR for enterovirus RNA

B IgM antibody against EBV viral capsid antigen

C PCR for Cytomegalovirus DNA

D IgG antibody against varicella-zoster virus

E IgM antibody against West Nile virus

Correct Answer: The correct answer is B The history of maculopapular rash triggered by ampicillin is highly suggestive of EBV infection The patient's clinical picture is consistent with EBV meningoencephalitis Focal encephalitis, sometimes resembling HSV-1 encephalitis, complicates less than 1% of cases of infectious mononucleosis Acute EBV virus infection is confirmed by detection of antiviral capsid antigen-positive IgM antibodies in serum or CSF The history, time of the year of occurrence, and findings on physical examination are not consistent with enteroviral infection In the absence of immunosuppression, meningoencephalitis due to Cytomegalovirus or varicella-zoster virus is unlikely West Nile virus is a mosquito-borne pathogen and therefore

an unlikely cause of encephalitis during winter