While no infection is welcome, fungal infections are uniquely dangerous and can be difficult to diagnose and treat.
This is particularly the case when the fungus invades the brain.
Aspergillus
Aspergillusspecies are numerous in nature as a common mold.
SIMON FRASER/NEWCASTLE HOSPITALS NHS TRUST / SCIENCE PHOTO LIBRARY / Getty Images
Despite frequent exposure, human infection withAspergillusis relatively uncommon, unless the immune system has been suppressed.
The organism enters the body after being inhaled into the lungs, where it enters the bloodstream.
Once in the blood,Aspergilluscan infect many different organs, including the brain.
Aspergillus that invades the brain can cause seizures or focal deficits, like numbness or weakness.
It can alsocause meningitis.Symptoms of meningitisinclude a headache, fever, and a rigid neck.
On imaging, anAspergillusinfection causes an abscess that looks like a cannonball in the brain.
Treatment is with an antifungal agent such as voriconazole or amphotericin.
Treatment can sometimes be given directly into the brain via a delivery technique called intrathecal access.
Even with treatment, the mortality of this infection is relatively high.
Coccidioides Immitis
Coccidioidesis found in the deserts of the Southwestern United States and Central and South America.
Infection withCoccidiosiscan cause numerous problems, ranging from the usually benign valley fever to lethal meningitis.
Approximately 150,000Coccidioidesinfections occur every year, and fewer than 100 progress to meningitis.
However, it may take months from the initial infection for meningitis to become obvious.
The diagnosis of coccidial meningitis is best done by examination of CSF, obtained by alumbar puncture.
Antibodies for the organism can be tested for using that CSF.
The preferred treatment forCoccidiosisinfections is oral fluconazole.
Some doctors will add amphotericin B.
If fluid buildup in the brain (hydrocephalus) is present, a shunt may be necessary as well.
It may take weeks before there is any obvious improvement.
Cryptococcus Neoformans
Cryptococcusenters the body through the lungs after someone breathes in a fungal spore.
From there, the fungus enters the bloodstream and spreads through the body, particularly to the brain.
Theencephalitiscomponent causes associated memory changes and other cognitive deficits.
Cryptococcal meningitis can be diagnosed by running appropriate tests on cerebrospinal fluid collected by a lumbar puncture.
If the pressure of the CSF is measured, it can be very high in these infections.
An MRI frequently shows no changes, though sometimes a mass may be present.
In the United States, its usually found in the Ohio and Mississippi River valleys in the midwestern states.
Outbreaks can occur in people who are exposed to large amounts of disturbed bird or bat droppings.
Histoplasmosis can cause fever, weight loss, and fatigue.
The organism does not seem to grow easily in a laboratory.
Sometimes, a brain or meningeal biopsy is the only way to make the diagnosis.
Histoplasmosathat enters the central nervous system can be very difficult to treat.
In the case of relapse, some patients may require long-termor even life-longanti-fungal treatment.
Amphotericin B is the recommended treatment for those patients sick enough to be hospitalized.
Those who are less severely ill may be better treated with itraconazole, another anti-fungal.
Mucormycosis
Also known as black fungus, Mucormycosis is one of the most feared neurological infections.
Like many fungal infections, almost all human cases of invasion occur when the patient is immunocompromised.
Early initiation of a strong anti-fungal agent such as amphotericin B is critical.
Even with aggressive treatment, survival of such invasive cerebral mucormycosis is low.
In combination with anti-fungals, early surgical intervention is required to remove as much infected tissue as possible.
Depending of the extent of the infection, surgery can be disfiguring.
The fungus kills invaded tissues quickly and can spread from the sinuses directly into the eyes and brain.
Early initiation of a strong anti-fungal agent such as amphotericin is also critical.
Even with aggressive treatment, survival of such invasive cerebral mucormycosis is rare.
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