Cryptococcal meningitis: a fungal infection of the brain lining

The NHS describes meningitis as an infection of the protective layers that cover the brain and spinal cord, which can be very serious and even life-threatening if not treated quickly. Cryptococcal meningitis is one of the rarer causes, in which the infection is caused by a yeast-like fungus rather than bacteria or viruses.

Patient's clinical reference explains that the infection is caused by Cryptococcus, an encapsulated budding yeast found worldwide, with Cryptococcus neoformans abundant in soil contaminated by pigeon droppings. It occurs largely as an opportunistic infection in people with defective T-cell immunity.

Cryptococcus can affect several organs, but the reference says most patients present with meningitis or meningoencephalitis, and the lungs may also be involved.

Meningitis Now says that fungal meningitis usually occurs in people whose immune systems have been affected by other disease, for example HIV infection, or by drug therapy such as cancer treatment. It is very rare in people with healthy immune systems.

Patient's reference lists HIV and solid organ transplant recipients as the main risk groups, and other risk factors including diabetes mellitus, liver cirrhosis, blood cancers, corticosteroid therapy, sarcoidosis, connective tissue disorders and newer immunosuppressive antibody therapies such as infliximab.

It notes that Cryptococcus gattii, a related species, can infect people with normal immunity and is associated with certain trees, mainly in tropical regions.

Meningitis Now says the symptoms may develop over several weeks, and fungal meningitis often develops slowly with vague symptoms such as tiredness and a persistent headache which can last for some time before more specific symptoms appear.

• Headache, which may be persistent.

• Fever.

• Nausea and vomiting.

• Dislike of bright lights.

• Altered mental state, confusion, drowsiness, and in severe cases seizures or coma, as listed by Patient's reference.

• Cough, chest pain or breathlessness if the lungs are involved; the reference says lung involvement is often without symptoms.

The NHS says you need medical help immediately if you think you or your child might have meningitis, and to call 999 or go to A&E if there are symptoms such as a severe headache that is getting worse, stiff neck, vomiting, seizures, confusion, being very sleepy or difficult to wake, or a rash that does not fade when pressed with a glass.

The NHS notes that some early symptoms of meningitis can be similar to flu, a stomach bug or a hangover. For someone with a weakened immune system, a persistent headache with fever or confusion should not be put down to something minor, and the person should seek urgent advice.

People who know they are immunosuppressed, for example on high-dose steroids or biological therapy, should tell their care team promptly about new headaches or confusion.

Patient's reference describes diagnosis by testing cerebrospinal fluid, blood and urine, with cryptococcal antigen titres in the CSF or serum being a better indicator of fungal burden and outcome. Blood tests assess other illnesses and monitor medicine side effects, and brain imaging, generally MRI, is used in meningitis.

Cerebrospinal fluid is obtained by lumbar puncture in hospital. Because cryptococcal meningitis can be slow and non-specific in onset, it is usually found when a person with risk factors is investigated for persistent headache or confusion.

Meningitis Now says fungal meningitis is treated with long courses of high-dose antifungal drugs, usually given intravenously in hospital, and that the length of treatment depends on the patient's immune system and the type of fungus. For people with immune systems that do not work well because of conditions such as HIV infection, diabetes or cancer, treatment is often longer.

Patient's reference lists hydrocephalus and long-term impairment of mental function as complications. For HIV-associated cryptococcal meningitis, it says acute mortality is unchanged, although long-term outcomes are improved provided the patient becomes established on antiretroviral therapy.

It states that higher mortality is associated with failure of the fungus to clear at two weeks, dissemination of disease at the start, a high cryptococcal antigen titre, lack of flucytosine during initial therapy and abnormal mental function. Meningitis Now notes that some people will need life-long maintenance treatment to help prevent it recurring.

Cryptococcal meningitis is managed in hospital by infectious diseases or HIV and neurology specialists, with intravenous antifungal treatment, lumbar punctures and monitoring. It is an NHS emergency pathway, and private hospital care is rarely a planned choice for this condition.

Anyone with an immune-suppressing condition who is worried about persistent headache or confusion should speak to their specialist team early, and contact 111 or go to A&E if symptoms are severe.