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.
Fungal infections of the central nervous system are not particularly common, but when such infections occur, the results can be devastating.
The following is not a complete list of all fungal infection, but a review of the most common ones.
SIMON FRASER/NEWCASTLE HOSPITALS NHS TRUST / SCIENCE PHOTO LIBRARY / Getty Images
Aspergillus
Aspergillusspecies are numerous in nature as a common mold. Despite frequent exposure, human infection withAspergillusis relatively uncommon, unless the immune system has been suppressed. Risk factors for a suppressed immune system include diabetes, steroid treatment,organ transplants, cancers, trauma, malnutrition, andAIDS, among others.
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.
Meningitis
Candida Albicans
Almost everyone is already harboringCandidain the body; it’s part of the normal flora of the gastrointestinal and genitourinary tracts. Sometimes an event happens that causesCandidato outgrow its normal boundaries, which can cause avaginal yeast infection.Candidais also well known for causingthrush, a whitish coating of the mouth and throat.
How Candida Can Cause Infection
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.
If not treated, approximately 95% of patients with coccidial meningitis will die within two years, according to the National Institutes of Health.
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.
Symptoms include asevere headache, as well as other symptoms that may not be present until late in the course of the disease.
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.
What Is Coccidiodomycosis (Valley Fever)?
Cryptococcus Neoformans
Cryptococcususually causes an aseptic meningoencephalitis (inflammation of the brain and surrounding tissues), with a headache, fever, and often astiff neckand vomiting. Theencephalitiscomponent causes associated memory changes and other cognitive deficits.
An MRI frequently shows no changes, though sometimes a mass may be present. A blood test can also be done in patients for a cryptococcal antigen that can be useful in making this diagnosis.
Cryptococcal Meningitis: A Guide to Infection
Histoplasmosa
Histoplasmais a fungus that may be found in normal, healthy people—but it also occasionally causes serious illness termedhistoplasmosis. In the United States, it’s 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.
The organism does not seem to grow easily in a laboratory. Half of the time, cultures of CSF do not grow the organism, even if there is an infection. 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. About 60% to 80% of patients respond to treatment initially, but about half of these may relapse in later years. In the case of relapse, some patients may require long-term—or even life-long—anti-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.
An Overview of Ocular Histoplasmosis
Mucormycosis
As soon as the diagnosis of mucormycosis is made, a surgeon is required in order to cut away all dead tissue. This surgery can be disfiguring, as the nasal cartilage, the orbit of the eye, and the palate may all have to be removed.
The fungi that cause these infections, mucomycetes are actually commonly found in nature and all humans are regularly exposed. 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.
A mucormycosis infection of the brain usually starts in the nasal sinuses, where the disease initially mimics sinusitis with a headache, congestion, and fever. The fungus kills invaded tissues quickly and can spread from the sinuses directly into the eyes and brain.
Rarely, the fungus can reach the brain through other routes, such as after being injected into the bloodstream with intravenous drugs.
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.
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Wheat LJ, Musial CE, Jenny-Avital E.Diagnosis and management of central nervous system histoplasmosis.Clinical Infectious Diseases. 2005 Mar 15;40(6):844-52.
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