Fungal Meningitis: Rare, Serious and Hard to Diagnose

Fungal meningitis is a very rare but life-threatening infection that inflames the meninges, the membranes around the brain and spinal cord. It mostly affects people whose immune systems are weakened, and it usually begins with fungi breathed in from the environment.

Image from CDC's page on fungal meningitis.

How it starts

In someone with a weakened immune system, a fungal infection can begin elsewhere in the body and spread to the tissues around the brain and spinal cord. Breathing in spores, for example, can cause a lung infection that later spreads.

Fungi that can cause infections leading to meningitis include:

• Blastomyces
• Candida
• Coccidioides
• Cryptococcus
• Histoplasma

In 2023 an outbreak of fungal meningitis was linked to procedures performed under epidural anesthesia in Mexico.

Image from CDC's page on fungal meningitis.

Fungal meningitis does not spread from person to person.

Symptoms

Symptoms may start mild and then become the typical signs of meningitis:

• fever
• headache
• stiff neck
• nausea and vomiting
• sensitivity to light
• confusion

Anyone with meningitis symptoms should see a healthcare provider right away to find out whether it is meningitis, what is causing it, and how to treat it.

Who is at risk

Anyone can get it, but it is usually limited to people with weakened immune systems. Conditions such as advanced HIV disease and cancer, some surgical procedures and some medicines can weaken immunity. Those medicines include:

• steroids, such as prednisone;
• drugs given after an organ transplant;
• anti-tumor necrosis factor (anti-TNF) drugs, sometimes used for rheumatoid arthritis and other autoimmune conditions.

Other groups at higher risk:

• Premature babies with very low birth weight are more likely to get Candida bloodstream infections, which can reach the brain.
• People living in certain parts of the United States face a higher risk of fungal lung infections, which can spread to the brain or spinal cord.
• People having surgery can get fungal meningitis, though very rarely.

Lowering the risk

People with weak immune systems can protect themselves, especially where these fungi are found:

• Avoid dust and dirt. Stay away from dusty places such as construction or excavation sites, or wear an N95 respirator if you must be there. Stay indoors with windows shut during dust storms, and avoid activities that put you in close contact with soil or dust.
• Look after wounds. Wash skin injuries thoroughly with soap and water, especially if dirt or dust got in.
• Take care with healthcare abroad. Check that facilities and providers meet safety and quality standards, consider travel insurance that covers medical costs, and look up any vaccines or health precautions recommended for your destination.
• Filter indoor air, and take preventive antifungal medicine if it is prescribed.

Diagnosis and treatment

Fungal meningitis is difficult to diagnose. Testing may include a spinal tap, in which a long needle draws fluid from around the spine so a lab can look for signs of infection such as specific proteins or pieces of fungi. Doctors may also check the blood for beta-D-glucan (BDG), a substance that can appear during a fungal infection. The same testing and treatment options apply wherever the exposure happened.

Treatment starts with high-dose antifungal medicines, often through an IV, followed by antifungal pills. How long it lasts depends on the person's immune system and the fungus involved; people with weak immune systems often need longer treatment, possibly for life.

Image from CDC's page on fungal meningitis.

Sources

Based on "About Fungal Meningitis," Centers for Disease Control and Prevention; a work of the United States government in the public domain.