Key Concepts
Introduction
Cryptococcus neoformans is an encapsulated yeast acquired through inhalation of spores from contaminated soil (particularly pigeon droppings). The polysaccharide capsule is the primary virulence factor, inhibiting phagocytosis and suppressing T-cell responses. In immunocompetent hosts, cell-mediated immunity typically contains the infection as granulomas. In immunocompromised patients (especially those with CD4 counts < 200 cells/mcL), the organism proliferates unchecked in alveolar macrophages, causing pneumonia with a propensity for hematogenous dissemination to the central nervous system (cryptococcal meningitis). On the exam, writers often pair stable-sounding options with unstable dataโnotice the mismatch before you commit. If the stem names a license or role, reread that line; scope errors are classic trap answers even when the clinical topic is familiar. Run a 60-second scan: breathing work and oxygenation, perfusion and end organs, neuro baseline, likely infection sources, and devices that can fail quietly. When two answers feel partly right, pick the one that reduces imminent harm and matches orders for the role you were given. Train yourself to state the primary risk in one short phrase before you read the options so distractors do not...