Fungal Meningitis

Español: Meningitis micótica

Causes

Fungal meningitis is rare and usually caused by fungus spreading through blood to the spinal cord. Although anyone can get fungal meningitis, people with weakened immune systems, like those with an HIV infection or cancer, are at increased risk.

The most common cause of fungal meningitis for people with weak immune systems is Cryptococcus. This disease is one of the most common causes of adult meningitis in Africa.

How it Spreads

Fungal meningitis is not spread from person to person. Fungal meningitis can develop after a fungus spreads through the bloodstream from somewhere else in the body to the brain or spinal cord or from an infection next to the brain or spinal cord.

You may also get fungal meningitis after taking medications that weaken your immune system. Examples of these medications include steroids (such as prednisone), medications given after organ transplantation, or anti-TNF medications, sometimes given for treatment of rheumatoid arthritis or other autoimmune conditions.

Different types of fungus are transmitted in several ways.

• Cryptococcus is thought to be acquired through inhaling soil contaminated with bird droppings.
• Histoplasma is found in environments with heavy contamination of bird or bat droppings, particularly in the Midwest near the Ohio and Mississippi Rivers.
• Blastomyces is thought to exist in soil rich in decaying organic matter in the Midwest United States, particularly the northern Midwest.
• Coccidioides is found in the soil of endemic areas (Southwestern US and parts of Central and South America).

When these environments are disturbed, the fungal spores (small pieces of fungus) can be inhaled. Meningitis results from the fungal infection spreading from the lungs to the spinal cord. Unlike the fungi above, Candida, which can also cause meningitis, is usually acquired in a hospital setting.

Risk Factors

Certain diseases, medications, and surgical procedures may weaken the immune system and increase your risk of getting fungal infection, which can lead to fungal meningitis. Premature babies with very low birth weights are also at increased risk for getting Candida blood stream infection, which may spread to the brain.

Living in certain areas of the United States may increase your risk for fungal lung infections, which can also cause meningitis. For example, bird and bat droppings in the Midwestern United States may contain Histoplasma, and soil in the Southwestern United States may contain Coccidioides.

African Americans, Filipinos, pregnant women in the third trimester, and people with weakened immune systems are more likely to get Coccidiodes infection, which is also called valley fever.

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Signs and Symptoms

Signs and symptoms of fungal meningitis may include the following:

• Fever
• Headache
• Stiff neck
• Nausea and vomiting
• Photophobia (sensitivity to light)
• Altered mental status (confusion)

Diagnosis

If meningitis is suspected, samples of blood or cerebrospinal fluid (fluid surrounding the spinal cord) are collected and sent to a laboratory for testing. Knowing the specific cause of meningitis is important because the severity of illness and the treatment depend on the cause.

To confirm fungal meningitis, specific lab tests can be performed, depending on the type of fungus suspected.

Treatment

Fungal meningitis is treated with long courses of high dose antifungal medications, usually given through an IV in the hospital. The length of treatment depends on how strong the immune system is and the type of fungus that caused the infection. For people with weak immune systems, like those with AIDS, diabetes, or cancer, treatment is often longer.

Prevention

No specific activities are known to cause fungal meningitis. Avoid soil and other environments that are likely to contain fungus. People with weak immune systems, like those with HIV infection or cancer, should try to avoid bird droppings and avoid digging and dusty activities, particularly if they live in a geographic region where fungi like Histoplasma, Coccidioides, or Blastomyces exist. HIV-infected people cannot completely avoid exposure.

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