Fungal Meningitis: Types, Symptoms, and Treatment

Though bacteria and viruses are often thought of as the causes of infections and illnesses, other microbes, such as fungi, can also cause disease.

Fungal infections can spread through the blood to the central nervous system, which is made up of the spinal cord and brain. When this occurs, it may cause fungal meningitis, which is an inflammation of the protective membrane surrounding the central nervous system.

Although it can be very serious, fungal meningitis is also very rare, and it is not contagious.

But like bacterial meningitis, it can cause outbreaks, such as the highly publicized one that occurred in 2012, when steroid injections contaminated with the fungus Exserohilum rostratum resulted in more than 50 deaths and approximately 700 illnesses across the country. (1,2)

The following fungi are the most common causes of fungal meningitis:

• Cryptococcus neoformans
• Histoplasma
• Coccidioides
• Blastomyces
• Candida

The overall prevalence of the disease is unclear, but certain forms are somewhat common among high-risk populations.

Groups most at risk for fungal meningitis include:

• Newborns
• Individuals with weakened immune systems through diseases such as cancer, diabetes, and HIV or AIDS
• Individuals on long courses of antibiotics
• Individuals taking certain steroids, chemotherapy drugs, or rheumatoid arthritis medication
• Patients with shunts or intravascular catheters
• Recent organ or bone marrow transplant recipients

There has also been some research linking fungal meningitis from Cryptococcus neoformans and Candida albicans to intravenous drug use, particularly in those with weakened immune systems. (3,4)

Yes. Candida albicans, the fungus that causes yeast infections, can also cause meningitis, generally in premature babies with very low birth weights. The fungus is usually acquired in hospital settings and is most often the result of infections caused by shunts used during neurosurgery (particularly in infants).

C. neoformans and C. albicans are the most common causes of fungal meningitis.

Cryptococcus neoformans is a fungus that is found naturally in the environment—often in soil and decaying wood—and in bird droppings.

You can become infected with the fungus if you inhale particles contaminated with the droppings, whether they’ve settled in soil or elsewhere.

But only in very rare cases will someone with a healthy immune system develop cryptococcal meningitis. (5)

Individuals with compromised immune systems, especially those living with HIV or AIDS, are most at risk. According to one study, the fungus causes an estimated 220,000 cases of cryptococcal meningitis among people with HIV or AIDS worldwide each year. (6)

But in the United States and other developed countries, the numbers of fungal infections and deaths among individuals with advanced forms of HIV or AIDS have significantly decreased, since HIV diagnosis and treatment helps prevent HIV from progressing to the point where the immune system is dangerously compromised. (5)

Histoplasma is a fungus that lives in the environment, usually in soil that has high concentrations of bird or bat droppings. Chicken coops, caves, parks and barns are breeding grounds.

In the United States, Histoplasma is predominantly found in central and eastern regions, such as the Ohio and Mississippi River valleys. So states occupying those areas (including Missouri, Ohio, and Tennessee) have the highest rates of histoplasmosis.

Histoplasma is usually harmless in people with normal immune systems. (7) But again, in those with compromised immune systems, the fungus can cause histoplasmosis, which, as happens with Cryptococcus neoformans infection, often starts off as a lung infection but can sometimes turn into meningitis.

Coccidioides is a fungus that can get into the body and cause meningitis when its spores are inhaled after the spores’ environment is disturbed.

Coccidioides is found in arid soil in the Southwestern United States and parts of Central and South America; it’s carried by wind and dust. The fungus can cause an infection known as valley fever, which affects the lungs and causes flu-like symptoms. Similar to other fungal infections, it usually starts as a respiratory infection. This infection can occasionally lead to meningitis.

Certain people have a higher risk of getting a Coccidioides infection, including:

• Black Americans
• Filipinos
• Pregnant women, especially those in their third trimester (8)
  
• People with weakened immune systems

Doctors don’t know exactly why Black Americans and Filipinos are particularly at risk. What is known is that in California, valley fever rates have been steadily on the rise since 1998. (9) Experts suspect that the increased rate may be due to wetter wet seasons and the dry spells that follow, as well as increased construction that’s literally kicking up dust. (10)

There’s no foolproof way to protect against this fungus. But you can try to reduce your exposure by: (11)

• Avoiding known areas in which the fungi may live
• Wearing N95 respirator masks
• Closing house and car windows
• Using recirculating air conditioners

These steps are especially important for people who have weakened immune systems.

Like Coccidioides, Blastomyces can (very rarely) cause meningitis when its spores are inhaled. This fungus is found in soil full of decaying organic matter in midwestern, south central, and southeastern states.

And like Histoplasma, Blastomyces can causes an infection — in this case blastomycosis — that can progress to meningitis.

People with fungal meningitis often experience similar symptoms to other forms of meningitis, including:

• Fever, headache, and stiff neck
• Nausea and vomiting
• Sensitivity to light
• Confusion

But in fungal meningitis these symptoms may be slower to appear than they would be in the viral or bacterial forms of the disease.

There are no vaccines that prevent fungal meningitis.

Treating fungal meningitis involves killing the underlying infection with a long course of antifungal medication (specific to the fungus) that is usually given intravenously in the hospital.

These drugs, which can be given orally and intravenously, include:

• amphotericin B (Fungizone)
• itraconazole (Sporanox)
• fluconazole (Diflucan)
• posaconazole (Noxafil)
• isavuconazole

Some of these drugs, especially amphotericin B, can be toxic to the kidneys.

Additional reporting by Carlene Bauer.