Fungal meningitis refers to

meningitis Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...

caused by a

fungal infection Fungal infection, also known as mycosis, is disease caused by fungi. Different types are traditionally divided according to the part of the body affected; superficial, subcutaneous, and systemic. Superficial fungal infections include common ti ...

Signs and symptoms

Symptoms of fungal meningitis are generally similar to those of other types of meningitis, and include: a fever, stiff neck, severe headache, photophobia (sensitivity to light), nausea and vomiting, and altered mental status (drowsiness or confusion).

Causes

Fungal meningitis may be caused by the following (and also other) types of fungi: * ''Candida'' - ''C. albicans'' is the most common ''Candida'' species that causes infections of the central nervous system. * ''Coccidioides'' - it is endemic to southwestern United States and Mexico. A third of patients presenting with disseminated coccidioidomycosis have developed meningitis. * ''Histoplasma'' - occurs in bird and bat droppings and is endemic to parts of the United States, South, and Central America. Involvement of the central nervous system occurs in about 10-20% of cases of disseminated histoplasmosis. * ''Blastomyces'' - occurs in soil rich in decaying organic matter in the Midwest United States. Meningitis is an unusual manifestation of blastomycosis and can be very difficult to diagnose. * ''Cryptococcus'' (

Cryptococcal meningitis Cryptococcosis is a potentially fatal fungal infection of mainly the lungs, presenting as a pneumonia, and brain, where it appears as a meningitis. Cough, difficulty breathing, chest pain and fever are seen when the lungs are infected. When th ...

) - it is thought to be acquired through inhalation of soil contaminated with bird droppings. ''C. neoformans'' is the most common pathogen to cause fungal meningitis. * ''Aspergillus'' - ''Aspergillus'' infections account for 5% of fungal infections involving the central nervous system.

Risk factors

Individuals with a weak

immune system The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinte ...

are most at risk. This includes individuals taking immunosuppressive medication, cancer patients, HIV patients, premature babies with very low birth weight, the elderly, etc. People who are at an increased risk of acquiring particular fungal infections in general may also be at an increased risk of developing fungal meningitis, as the infection may in some cases spread to the central nervous system. People residing in the Midwestern United States, and Southwestern United States and Mexico are at an increased risk of infection with ''Histoplasma'' and ''Coccidioides'', respectively.

Diagnosis

If suspected, fungal meningitis is diagnosed by testing blood and cerebrospinal fluid for pathogens. Identifying the specific pathogen is necessary to determine the proper course of treatment and the prognosis. Measurement of opening pressure, cell count with differential, glucose and protein concentrations, Gram's stain, India ink, and culture tests should be performed on cerebrospinal fluid when fungal meningitis is suspected.

Treatment

Fungal meningitis is treated with long courses of high dose antifungal medications. The duration of treatment is dependent upon the causal pathogen and the patient's ability to stave off the infection; for patients with a weaker immune system or diabetes, treatment will often take longer.

Prognosis

Prognosis depends on the pathogen responsible for the infection and risk group. Overall mortality for ''Candida'' meningitis is 10-20%, 31% for patients with HIV, and 11% in neurosurgical cases (when treated). Prognosis for ''Aspergillus'' and coccidioidal infections is poor.

Outbreaks

As of November 5, 2012, the CDC reported that 409 patients had laboratory-confirmed fungal meningitis caused by injections with contaminated medication. There had been 30 fatalities. A black mold, ''

Exserohilum rostratum ''Setosphaeria rostrata'' is a heat tolerant fungus with an asexual reproductive form (anamorph) known as '' Exserohilum rostratum''. This fungus is a common plant pathogen, causing leaf spots as well as crown rot and root rot in grasses. It is ...

'', was found in 45 of these cases. ''

Aspergillus fumigatus ''Aspergillus fumigatus'' is a species of fungus in the genus '' Aspergillus'', and is one of the most common ''Aspergillus'' species to cause disease in individuals with an immunodeficiency. ''Aspergillus fumigatus'', a saprotroph widespread i ...

'' was found in one case, and a ''

Cladosporium ''Cladosporium'' is a genus of fungi including some of the most common indoor and outdoor molds. Species produce olive-green to brown or black colonies, and have dark-pigmented conidia that are formed in simple or branching chains. Many specie ...

'' species was found in one case. ''Aspergillus'' has been very rarely associated with meningitis while cases caused explicitly by ''Exserohilum'' in otherwise healthy individuals have not been previously reported.

References

External links

{{Diseases of meninges Disorders causing seizures Medical emergencies Meningitis Animal fungal diseases