Meningitis is an infection affecting the membranes that line the skull and spinal cord. Cryptococcal meningitis is a type of meningitis caused by a fungus called Cryptococcus.
This type of meningitis mainly affects people with weakened immune systems due to another illness. If not treated, cryptococcal meningitis can have lasting consequences and can even be fatal.
Cryptococcus is a common fungus that is often found in soil and bird droppings. Cryptococcal meningitis is a serious infection of the lining of the brain and spinal cord caused by this fungus.
It is rare for a healthy person to develop cryptococcal meningitis. Most people who develop cryptococcal meningitis have a weakened immune system caused by an underlying illness, for example, HIV or cirrhosis of the liver.
Symptoms of cryptococcal meningitis often develop gradually, within a few days to weeks of exposure to the fungus.
A person with cryptococcal meningitis may develop the following symptoms:
- nausea and vomiting
- confusion or hallucinations
- personality changes
- sensitivity to light
- stiff neck
- blurred vision
It may be difficult for someone to tell if they have symptoms of cryptococcal meningitis. Many of the symptoms may be similar to the side effects of a medication they may be taking to treat an underlying condition.
If left untreated, cryptococcal meningitis can lead to more serious symptoms, including:
Cryptococcal meningitis can be fatal if not treated quickly, especially in people with HIV or AIDS.
Two types of Cryptococcus fungi cause cryptococcal meningitis.
The fungus C. neoformans causes most cases of cryptococcal meningitis. This species is commonly found in soil and is spread via bird droppings.
The second fungus that causes cryptococcal meningitis is C. gatti. This variety is not found in the soil but is associated with several trees, including eucalyptus.
Not as many cases of cryptococcal meningitis are caused by C. gatti as by C. neoformans. However, C. gatti is more likely to cause cryptococcal meningitis in individuals who are healthy.
Cryptococcal meningitis is a relatively rare illness, and most healthy people are not at risk of developing cryptococcal meningitis. It is most common in people who have a weakened immune system.
People more at risk for developing cryptococcal meningitis will often have one of the following underlying conditions:
Cryptococcal meningitis is most likely to occur in people who have a low CD4 count. CD4 cells, also known as T cells, are a type of white blood cell and vital to the immune system.
People with HIV and AIDS often have low CD4 counts, so they are much more likely than others to develop cryptococcal meningitis.
Fungal meningitis is not spread from person to person. Instead, an individual acquires cryptococcal meningitis when they inhale soil particles contaminated by bird droppings.
The fungus first infects the body, and then the infection spreads to the central nervous system, resulting in cryptococcal meningitis.
A doctor will diagnose cryptococcal meningitis by assessing someone's symptoms and medical history. If a doctor suspects a person has cryptococcal meningitis, they will order a spinal tap to confirm the diagnosis.
During a spinal tap, a doctor will insert a needle into the person's spinal column, just above their hips, to extract spinal fluid.
The fluid will be examined for signs of infection and to see if cryptococcus is the cause of the infection.
A doctor may order blood tests in addition to doing a spinal tap.
Doctors use antifungal drugs to treat cryptococcal meningitis. Common antifungal medications used to treat it include:
- amphotericin B
Doctors often use a combination of amphotericin B and fluconazole. These drugs may be administered intravenously, usually for a long time.
A person will be carefully monitored during treatment, as both of these drugs can have serious side effects, including kidney damage.
Once a person's spinal fluid shows no signs of cryptococcal meningitis, a doctor will likely adjust their medications and stop using amphotericin B, to reduce the risk of kidney problems.
In some people with cryptococcal meningitis, a doctor may also recommend draining some of the spinal fluid. Doing this reduces the pressure on the brain.
It is possible for a person to have complications from cryptococcal meningitis, as well as from the treatment they receive.
Complications from cryptococcal meningitis may include:
- repeat cryptococcal infections
- hearing loss
- brain damage
- excessive fluid in the brain
Complications from treatment with amphotericin B may include:
- kidney damage
- muscle and joint pain
- nausea and vomiting
Most people who develop cryptococcal meningitis have an underlying condition that weakens their immune system, most often HIV or AIDs.
Cases of cryptococcal meningitis among people with AIDS has decreased by 90 percent in the United States since the introduction of antiretroviral therapy or ART.
Cryptococcal meningitis is now uncommon in the U.S., though it remains prevalent in countries with higher rates of HIV and AIDS where ART is less available.
Cryptococcal meningitis infections tend to recur after treatment. Because of this, many people who have had the illness will take antifungal medications to prevent a recurrence.