Fungal Meningitis, What You Should Know
The rare fungal meningitis that has been linked to spinal injections of a steroid called methylprednisolone acetate has resulted in at least seven deaths and more than 90 illnesses across the United States, and there may be more to come. Yet many people are not familiar with fungal meningitis, which has a variety of causes and can affect individuals of any age. Here's what you should know.
What is fungal meningitis?
Fungal meningitis is a condition characterized by inflammation of the lining (meninges) that surrounds the brain and spinal cord and can be lethal. It is one of four main types of meningitis, and the names of each are related to their causes. They are listed here in descending order of prevalence.
- Viral meningitis: The most common type of meningitis, it is usually less serious than bacterial meningitis. Causes of viral meningitis include coxsackievirus, enterovirus, and infections such as measles, chickenpox, polio, or mumps
- Bacterial meningitis: This type of meningitis can be caused by a number of different bacteria, including Pneumococcus or Streptococcus pneumoniae (pneumococcal meningitis), Haemophilus influenzae type B (Hib meningitis), Bacillus tubercle (tuberculosis meningitis), meningococcal bacteria (meningococcal, meningococcal septicemia), and Escherichia coli and B streptococcal bacteria (neonatal meningitis)
- Fungal meningitis: This form of meningitis is caused by various types of fungus usually--but not always--found in soil, including Cryptococcus, Histoplasma, Blastomyces, and Coccidioides. (Candida usually infects individuals in hospitals.) The latest cases of fungal meningitis have been associated with two different fungi, both of which are in the environment: Aspergillus, which can be found in soil, grains, decaying leaves, heating ducts, and household dust; and Exserohilum, which is common in rotting wood, grass, and leaves.
- Amoebic meningitis: This very rare form of meningitis is caused by amoeba that live in stagnant fresh water at 86°F or in geothermal pools.
Who gets fungal meningitis?
Fungal meningitis is usually contracted by inhaling the offending fungi from the air, although it also can be acquired when a fungus is introduced via an injection or an infected body site near the central nervous system (e.g., spinal cord, brain). It is not contagious.
Although anyone can get fungal meningitis, it is most likely to develop in exposed individuals who have a compromised immune system, such as people with cancer, AIDS/HIV, diabetes, an organ transplant, or those being treated with certain medications for autoimmune conditions such as rheumatoid arthritis. According to the Meningitis Foundation of America, 85% of cases of fungal meningitis occur in people who are HIV positive.
A person's risk of getting fungal meningitis can depend on where he or she lives. For example, Coccidioides can be found in soil in the Southwestern United States as well as in Central and South America, while Blastomyces is especially prevalent in soil in the midwestern United States. A hospital can be home for premature infants with very low birth weights, and they are the ones at higher risk of developing a Candida infection that could lead to fungal meningitis.
The methylprednisolone that is the subject of the current scare was prepared by the New England Compounding Center in Framingham, Massachusetts. The medication is given as a spinal steroid injection for individuals with low back pain.
How to recognize fungal meningitis
The signs and symptoms of fungal meningitis are similar to those of other forms of meningitis. They include
- Stiff neck
- Nausea and vomiting
- Mental confusion, hallucinations
- Hypersensitivity to light
Anyone with these symptoms should seek medical help immediately. Fungal meningitis can be diagnosed by evaluating samples of cerebrospinal fluid obtained via a lumbar puncture (spinal tap) or a blood test. Identifying and confirming the causative fungus is important for helping physicians choose the most effective treatment.
How to treat and prevent fungal meningitis
Intravenous (IV) treatment with the antifungal medication amphotericin B is the most common approach for fungal meningitis, and treatment can last weeks. Amphotericin B can cause serious side effects, including but not limited to blurry vision, chills, dizziness, fainting, fever, headache, and rapid breathing.
People who don't respond to IV therapy may be given intrathecal medication (through the spinal cord). An oral medication called fluconazole can be beneficial when given at high doses, and it also is associated with serious side effects. A new study appearing in Current HIV Research reported that another antifungal medication, posaconazole, was effective in patients with HIV and fungal meningitis caused by Cryptococcus neoformans.
Even when people with fungal meningitis receive treatment, they are still at risk of hearing loss, learning disabilities, brain damage, problems with speech, seizures, paralysis, and death.
Preventing fungal meningitis is a matter of knowing the risks and avoiding them, as there is no vaccine for this disease. Individuals who have a compromised immune system should avoid exposure to soils, decaying leaves and wood, bird and bat feces, and other environments that may contain fungi that could place a person at risk of developing fungal meningitis.
Centers for Disease Control and Prevention
Gaona-Flores V et al. Meningitis due to Cryptococcus neoformans: treatment with posaconazole. Current HIV Research 2012 Aug 7
Meningitis Foundation of America
US National Library of Medicine
Image: Wikimedia Commons