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no i m remembering it from medical school
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and seems like i have seen this slide.
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The correct answer is C.
Patients with HIV infection are prone to a variety of opportunistic infections, and pneumocystis carinii pneumonia represents one of the most common initial presentations. This organism is a ubiquitous fungus that may cause an acute, life-threatening acute interstitial pneumonia in immunocompromised patients. P. carinii appears as a 5 µm cyst-like organism with a characteristic cup shape, which has been likened to a "crushed tennis ball." Silver staining allows its identification in bronchoalveolar lavage. A frothy exudate
filling the alveolar cavities is a characteristic finding in patients with PCP.
Cryptococcus neoformans (choice A) is a fungus that appears as encapsulated yeast on tissue sections. It causes meningoencephalitis in immunocompromised patients. The characteristic mucopolysaccharide capsule of C. neoformans can be demonstrated by mucicarmine or PAS staining.
Histoplasma capsulatum (choice B) is a fungus acquired by inhalation of spores in dust contaminated by bird and bat droppings. Histoplasma infection is endemic in the Ohio and Mississippi River valleys. Disseminated histoplasmosis develops in immunocompromised patients. Histoplasma organisms can be visualized by silver staining but are mainly seen within the cytoplasm of histiocytes.
Staphylococcus aureus (choice D) is a frequent pathogen causing infections in AIDS patients,
especially acute pneumonia. However, this gram-positive coccus can not be confused with P. carinii in a bronchoalveolar lavage.
Toxoplasma gondii (choice E) is a protozoon transmitted to humans by cats. It causes infection in fetuses and immunodepressed patients. In the latter, Toxoplasma infection is virtually always limited to the central nervous system. Intracerebral Toxoplasma abscesses (which appear as ring-enhancing lesions on MRI or CT scans) are among the most frequent opportunistic infections of AIDS patients.
