Cryptococcal meningitis is the most common form of fungal meningitis and occurs in immunocompromised hosts. It is characterized by the presence of Cryptococcus cells within the central nervous system (CNS) and by the production of various neurotoxic substances including polysaccharide capsules, proteinases, and cytokines. Symptoms of infection include fever, headache, lethargy, a stiff neck, confusion and blurred vision, and sensitivity to bright light. Papilledema (a build-up of fluid in the brain) may also be present. It is more commonly seen in people with AIDS but can occur in immunocompetent individuals as well. Most cases of cryptococcal meningitis are associated with impaired cell-mediated immunity such as those with HIV, lymphoreticular malignancies, sarcoidosis, organ or bone marrow transplantation, and chronic glucocorticoid therapy. The organism is capable of hematogenous dissemination from its primary sites of infection, and may reactivate in the CNS years after initial cellular immunity has been restored.
The fungus that causes cryptococcal meningitis is called Cryptococcus neoformans. It is usually found in the lungs of people with HIV but can also live in other parts of the body and enter the bloodstream, where it can cause disease in other tissues. It can then spread to the central nervous system (brain and spinal cord) or other parts of the body such as the kidneys and skin.
Infection with this fungus is usually not contagious. It can only be spread by breathing in air and dust containing the fungus, and most healthy people who breathe it in do not get sick. However, in those with weakened immune systems the infection can be life-threatening.
Symptoms of cryptococcal meningitis can be difficult to diagnose, especially when they come on slowly. They can be mistaken for other illnesses such as the flu, or they may not show up at all until the person is already very ill. The fungus can be detected with laboratory tests.
Treatment for this condition includes a combination of antifungal drugs. The most important drug is amphotericin B. This medication binds to the ergosterol in the cryptococcal cell membrane and alters its permeability. Another important drug is flucytosine. Several large randomized studies have shown that combining these two drugs can significantly improve survival.
Despite the effectiveness of these medications, there are still too many people who die from cryptococcal meningitis, mostly in low- and middle-income countries where access to the life-saving treatments is limited. That is why we have joined a broad network of partners to call for better access to the life-saving combination treatment and to end cryptococcal meningitis deaths by 2030. You can join this movement by signing the pledge below. We thank you for your support. Dr Marco Pescador Ruschel, Professor of Infectious Diseases and Infection, University of Bristol. Disclosure: Marco Pescador Ruschel declares no relevant financial relationships with ineligible companies.