Cryptococcal meningitis is caused by the fungus Cryptococcus infecting the brain and spinal cord. It commonly affects people with weakened immune systems. Symptoms include headache, fever, neck stiffness, nausea and altered mental status. Diagnosis involves examining cerebrospinal fluid for cryptococcal antigen or viewing yeast cells with India ink stain. Treatment involves antifungal medications like amphotericin B and fluconazole given over several weeks to months depending on severity and patient's immune status.