Wednesday, October 8, 2008

136 - infectious diseases mcqs - 1

Match the clinical description with the most likely etiologic agent.

a. Candida albicans
b. Aspergillus flavus
c. Coccidioides immitis
d. Herpes simplex type 1
e. Herpes simplex type 2
f. Hantavirus
g. Tropheryma whippelii
h. Coxsackievirus B
i. Histoplasma capsulatum
j. Human parvovirus
k. Cryptococcus neoformans

55. An HIV-positive patient develops fever and dysphagia; endoscopic
biopsy shows yeast and hyphae.

56. A 50-year-old develops sudden onset of bizarre behavior. CSF shows
80 lymphocytes; magnetic resonance imaging shows temporal lobe abnormalities.

57. A patient with a previous history of tuberculosis now complains of
hemoptysis. There is an upper lobe mass with a cavity and a crescentshaped
air-fluid level.

58. A Filipino patient develops a pulmonary nodule after travel through
the American Southwest.

59. A 35-year-old male who had a fever, cough, and sore throat develops
chest pain after several days, with diffuse ST segment elevations on ECG.

60. Overwhelming pneumonia with adult respiratory distress syndrome
occurs on an Indian reservation in the Southwest following exposure to
deer mice.

The answers are 55-a, 56-d, 57-b, 58-c, 59-h, 60-f.

(Kasper,

pp 1038, 1055–1056, 1144–1146, 1172, 1180–1181, 1186–1187, 1188, 1413,
2480–2483.)

There are several causes for dysphagia in the HIV-positive

patient, including C. albicans, herpes simplex, and cytomegalovirus. The
biopsy result in this patient confirms Candida infection with the typical picture
of both yeast and hyphae seen on smear.

Herpes simplex encephalitis can occur in patients of any age—usually
in immunocompetent patients. Most adults with HSV encephalitis have
previous infection with mucocutaneous HSV-1. The bizarre behavior
includes personality aberrations, hypersexuality, or sensory hallucinations.
CSF shows lymphocytes with a close-to-normal sugar and protein. Focal
abnormalities are seen in the temporal lobe by CT scan, MRI, or EEG.

The patient who has had a previous history of tuberculosis and now
complains of hemoptysis would be reevaluated for active tuberculosis.
However, the chest x-ray described is characteristic of a fungus ball—
almost always the result of an aspergilloma.

The Filipino patient who has developed a pulmonary nodule after
travel through the Southwest would be suspected of having developed coccidioidomycosis.Individuals from the Philippines have a higher incidence
of the disease and are more likely to have complications of dissemination.

The 35-year-old with cough, sore throat, and fever went on to develop

symptoms of myopericarditis with typical ECG findings. Coxsackievirus B
infection is the most likely cause of URI symptoms that evolve into a picture
of myocarditis. Myocarditis may be asymptomatic or can present with
chest pain, both pleuritic and ischemic-like. Enteroviruses rarely if ever
attack the pericardium alone without involving the subepicardial
myocardium.

Hantavirus pulmonary syndrome begins with a prodromal illness of
cough, fever, and myalgias that is difficult to distinguish from other viral
illnesses such as influenza. However, the illness progresses to increased
dyspnea, hypoxia, and hypotension. The picture resembles adult respiratory
distress syndrome (ARDS), and most patients require mechanical ventilation.
The infection should be suspected when a previously healthy adult
develops unexplained pulmonary edema or ARDS without known causes.
Thrombocytopenia is also a useful clue. Transmission of hantavirus usually
occurs through aerosolization of urine from infected rodents or through the
bite of an infected rodent

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