Infections Flashcards
- The most striking neurologic complication of von Economo’s encephalitis (encephalitis lethargica), a type of encephalitis that occurred in epidemic proportions along with viral influenza between 1917 and 1928, was
a. Blindness
b. Hearing loss
c. Paraplegia
d. Parkinsonism
e. Incontinence
D
(Victor, p 813.) At the onset of encephalitis lethargica, patients often develop transient fevers, lethargy, and headache. Disturbed eye movements are the most common sign of neurologic disease during the acute illness. A variety of movement disorders, including chorea, athetosis, dystonia, and myoclonus, develop with the disease. About one in four affected persons dies. The most common sequela of the disease is severe, unremitting parkinsonism with signs and symptoms similar to those exhibited with idiopathic parkinsonism (paralysis agitans). One rather unique feature is the occurrence of oculogyric crises, or episodes in which the eyes deviate to one side or upward, associated with other forms of dystonia and
autonomic symptoms, sometimes occurring with great regularity.
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.
- The cranial nerve most likely to be injured in this patient is
a. II
b. III
c. V
d. VII
e. VIII
D
(Rowland, p 621.) Facial paresis is the neurologic injury most likely to develop with sarcoidosis. Almost half of patients with sarcoidosis and neurologic disease have a neurologic sign or symptom as the first obvious complication of the sarcoidosis. These patients report progressive weakness of one side of the face with no substantial loss of sensation over the paretic side. They may feel that there is decreased sensitivity to touch on the weak side, but this is more commonly from a loss of tone in the facial muscles than from an injury to the trigeminal nerve. Other cranial nerves especially susceptible to injury in persons with sarcoidosis
include II, III, IV, VI, and VIII.
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.
- 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
A
(Rowland, pp 136–137.) SSPE, PML, kuru, and HIV encephalomyelitis are all viral diseases affecting the CNS, but poliomyelitis is the only one that causes a purely motor neuron disease. Poliomyelitis virus attacks the anterior horn cells in the spinal cord. It is most likely to be confused with Guillain-Barré syndrome if the typical CSF picture of a viral meningoencephalitis is not found with the progressive motor neuron impairment. With poliomyelitis, the CSF will usually exhibit an elevated
protein and white cell count. During the initial stages of the infection, the patient will usually have fever.
- 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
D
(Bradley, pp 1377–1378.) Cryptococcosis is usually acquired through the lungs and spreads to the CNS through the bloodstream. In the CNS, it may produce either a meningitis or a meningoencephalitis. The organism has a characteristic capsule, which simplifies its identification. Fungal infections most often occur in the CNS in persons with defects in their immune systems. These defects may be secondary to a viral infection, as with AIDS, or they may be a consequence of immunosuppressive drug exposure. Patients on immunosuppressive treatment after organ transplants and those with lymphoproliferative disorders, such as lymphocytic leukemia, were the most common victims of CNS fungal infections
before the start of the AIDS epidemic. Aspergillus, Candida, Mucor, and Rhizopus can also cause CNS fungal infections, but rarely meningitis. Aspergillus
tends to cause abscesses in immunocompromised individuals, and Mucor affects mostly diabetics.
- A 28-year-old man who has recently immigrated from Brazil presents with 3 months of fluctuating but slowly progressive bilateral lower extremity weakness, 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
D
(Bradley, pp 1402–1403.) S. mansoni is endemic in Puerto Rico and may produce a subacutely evolving paraparesis. The fluke itself does not invade the spinal cord, but it deposits eggs in the valveless veins of Batson, which drain the intestines and communicate with the drainage from the lumbosacral spinal cord. The patient develops granulomas around the ova that lodge in the spinal cord, and these granulomatous lesions crush the cord.
- A 12-year-old boy has left body weakness. An MRI scan reveals a poly-cystic 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
C
(Bradley, pp 1396–1397.) Echinococcosis is usually acquired by eating tissue from infected sheep. Children are more likely to develop cerebral lesions than adults, but people at any age may develop his encephalic hydatidosis, which entails the development of a major cyst with multiple compartments in which smaller cysts are evident. This hydatid cyst of the brain behaves like a tumor and may become massive enough to cause focal deficits.
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. The blurry vision remains when she closes either eye. She also has eye tenderness with movement and mild photosensitivity. She has no drug allergies. Exam findings include temperature of 102.5°F, nuchal rigidity, and sleepiness.
- 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
C
(Bradley, pp 1319–1323.) The immediate concern is that the patient has bacterial meningitis, and she should be treated. A lumbar puncture and blood draw to obtain cultures should be done; however, it can take a few days for the results to come back, and it may be too late for the
patient by then. Oral azithromycin is not the proper treatment for bacterial meningitis. Intravenous acyclovir would be used to treat herpes encephalitis.
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. The blurry vision remains when she closes either eye. She also has eye tenderness with movement and mild photosensitivity. She has no drug allergies. Exam findings include temperature of 102.5°F, nuchal rigidity, and sleepiness.
- The next day the patient’s spinal fluid cultures begin growing Listeria monocytogenes. The drug of choice in this case now is
a. Penicillin G
b. Ampicillin plus gentamicin
c. Tetracycline
d. Ceftriaxone
e. Rifampin
B
(Bradley, pp 1323–1324.) L. monocytogenes meningitis develops in renal transplant recipients, patients with chronic renal disease, immunosuppressed persons, and occasionally in otherwise unimpaired persons. It may also affect neonates. This type of meningitis is not usually seen in older children. It may on occasion lead to intracerebral abscess formation. Third-generation cephalosporins are inactive against Listeria, and ampicillin and gentamicin are recommended therapy. Neither ampicillin nor penicillin alone is bactericidal.
- 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
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.
- 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
B
(Victor, p 759.) Rupture of a large caseating granuloma into the ventricles or the subarachnoid space may produce an abrupt and often lethal deterioration. If the mass becomes large enough before it ruptures, it may in all respects imitate a brain tumor. Such lesions may respond to antituberculous medications even when they are quite large, and the patient may be spared surgical intervention.
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 in over 1 year. On examination, his responses are slow and he has some difficulty sustaining attention. He has a right hemiparesis with increased reflexes on the right. Routine cell counts and chemistries are normal.
- 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
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.
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 in over 1 year. On examination, his responses are slow and he has some difficulty sustaining attention. He has a right hemiparesis with increased reflexes on the right. Routine cell counts and chemistries are normal.
- A CT scan reveals several rim-enhancing lesions with minimal mass effect. 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
C
(Rowland, p 172.) The most common etiologies of 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
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 in over 1 year. On examination, his responses are slow and he has some difficulty sustaining attention. He has a right hemiparesis with increased reflexes on the right. Routine cell counts and chemistries are normal.
- The patient turns out to have CNS Toxoplasma gondii. Which of the following is the best treatment?
a. Intravenous acyclovir
b. Neurosurgical removal of the lesions
c. Oral fluconazole
d. Sulfadiazine and pyrimethamine
e. Thiabendazole
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. Thiabendazole is used to treat helminth infections.
- 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 HIV-positive, but has not consistently taken medications in the past. On exam¬ination, 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 µL, and her MRI is consistent with a demylinating lesion 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
C
(Rowland, p 156.) The patient has progressive multifocal leukoencephalopathy. It is caused by the JC virus, which is a double-stranded DNA virus. The prognosis is poor, but HAART has been known to be effective in improving survival. JC virus is ubiquitous and may be transmitted through respiratory secretions. Cranial radiation is used to treat malignancies. Amphotericin B is used to treat fungal infections. Intravenous acyclovir is not effective against JC virus, but is used to treat herpes simplex virus encephalitis. Intravenous ceftriaxone is used to treat bacterial meningitis.
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.
- Localization of an encephalitis to the medial temporal or orbital frontal 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
C
(Victor, pp 793–795.) Herpes simplex type 1 is the strain usually responsible for a herpetic encephalitis. Type 2 may occur in newborns who have been exposed during passage through the birth canal of a woman with genital herpes. Persons with AIDS are also at risk for either type
1 or type 2. Temporal lobe involvement in the immunocompetent patient may produce unilateral swelling and hemorrhage into the temporal lobe.
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.
- 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 biopsy should be obtained
d. Shunting of the ventricles is usually indicated, and the imaging studies are needed to direct the placement of the shunt
e. It may establish what pathology is responsible
B
(Victor, pp 793–795.) Although there is some controversy regarding whether lumbar puncture can precipitate herniation with a herpes encephalitis, most authorities believe it is best to assess the risk of herniation before doing a lumbar puncture. Cerebrospinal fluid examination is vital in establishing the diagnosis. A variety of infections may mimic herpes in both course and anatomic distribution. The CSF cultures and analysis of CSF constituents help to establish the probable cause of the encephalitis and to direct therapy.
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.
- 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
A
(Victor, pp 793–795.) The increased number of lymphocytes in the CSF of the patient with herpes encephalitis ranges from more than 12 to several hundred cells per cubic millimeter of fluid. Red blood cells may be apparent in the CSF late in the course of the disease, but their absence does not eliminate the possibility of herpes encephalitis. Cerebrospinal fluid pressure is usually increased, and the glucose content
is usually normal or only slightly depressed.
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.
- With this disease, EEG may exhibit
a. α activity over the frontal regions
b. β activity over the temporal regions
c. Three-per-second spike-and-wave discharges
d. Bilateral, periodic epileptiform discharges
e. Unilateral δ activity over the frontal region
D
(Victor, pp 793–795.) The periodic discharges seen with herpes encephalitis typically occur over the temporal regions. Slow waves, rather than sharp waves, may be evident over the temporal lobes in many persons with severe disease. Seizures commonly occur early in the
course of herpes encephalitis, and so the EEG may be severely disturbed generally.
- 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
B
(Bradley, pp 1932–1933.) This specimen is a transverse section through the brainstem and cerebellum. There is a large area of discoloration and disturbed anatomy in the left cerebellar hemisphere that is producing little mass effect. Because this is the only lesion postulated for this patient, there is no reason to suspect seizure activity, because that phenomenon would be unlikely in the absence of a cerebrocortical (or at least cerebral) lesion. The other findings listed would similarly not be expected in a patient with cerebellar damage.
- 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
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.
