Review Question - QID 221262

The patient with a CD4+ count < 100 cells/mm^3 who presents with fever, headache, multiple enhancing lesions on brain imaging, and organisms on lumbar puncture most likely has cryptococcus meningitis. This infection should be treated initially with amphotericin B and flucytosine.

Cryptococcus neoformans is an encapsulated yeast that can be inhaled and disseminated to the brain through the bloodstream. Risk factors for this opportunistic infection include hematologic malignancies, HIV/AIDS (particularly with CD4+ counts < 100 cells/mm^3), and organ transplant recipients. Symptoms include fever, headache, malaise, and altered mental status. Brain imaging may reveal hydrocephalus, "soap bubble" lesions, or variably enhancing lesions. A lumbar puncture can confirm the diagnosis. India ink stain reveals yeast with clear halos, while mucicarmine staining shows yeast with red inner capsules. Initial treatment for cryptococcal meningitis consists of amphotericin B and flucytosine, followed by lifelong prophylaxis with fluconazole post-treatment or until the CD4 count exceeds 100 cells/mm^3.

Fisher et al. review the management and diagnosis of cryptococcal meningitis. They found that patients with presumed infection should be treated empirically for bacterial, fungal, and viral meningitis. They recommend that antiretroviral therapy should not be initiated or reinitiated acutely due to the risk of immune reconstitution inflammatory syndrome, which could exacerbate neuroinflammation.

Figure/Illustration A is a lumbar puncture stain showing an encapsulated yeast (blue circle). This appearance is consistent with a diagnosis of Cryptococcus neoformans.

Incorrect Answers
Answer 1: Albendazole is the preferred treatment for Taenia solium-caused neurocysticercosis, typically seen in individuals who have traveled to or come from Mexico. Symptoms include headaches, seizures, and focal calcifications on brain imaging.

Answer 2: Caspofungin, a systemic antifungal agent, is not the first-line treatment for cryptococcus meningitis. It may be used for aspergillus infections, which rarely disseminate to the brain and present with hyphae rather than narrow budding. Aspergillus can also form a fungal ball in the lung, which would present with symptoms like dyspnea and a large fungal mass on imaging.

Answer 3: Dapsone and pyrimethamine are suitable for prophylaxis against Pneumocystis jirovecii pneumonia (PJP) when the CD4+ count is < 200 cells/mm^3. PJP presents with fever, dry cough, bat-wing opacity on chest radiograph, and potential hypoxia. While this regimen is an option for prophylaxis, it would not treat the patient's acute cryptococcal infection.

Answer 4: Fluconazole should be used as a maintenance therapy for cryptococcal meningitis. Fluconazole is continued for at least 12 months and then for life or until the patient’s CD4+ count is > 100 cells/mm^3. It would not treat the patient’s acute infection.

Bullet Summary:
Cryptococcal meningitis should be treated initially with amphotericin B and flucytosine followed by lifelong fluconazole for prophylaxis.