What to know about noninfectious meningitis

Meningitis causes life threatening inflammation of the protective membranes surrounding the brain and spinal cord called the meninges. Bacteria and viruses usually cause the condition.

Doctors classify meningitis as infectious or noninfectious. Infectious meningitis occurs when a pathogen invades the meninges and causes an infection, while noninfectious meningitis can develop due to a disease or injury.

Various types of noninfectious meningitis may develop due to causes other than infections.

Chemical meningitis

Some substances or medications can cause chemical meningitis. Drugs that cause chemical meningitis include certain cancer medications and contrast dyes that healthcare professionals use during X-ray tests.

If a person’s benign brain tumor ruptures, fat droplets can potentially leak into the space between the skull and brain and cause chemical meningitis.

Doctors characterize chemical meningitis as sterile because there are no pathogens in a person’s cerebrospinal fluid.

People may not require treatment to resolve this condition. However, they may require steroid therapy to reduce inflammation and surgery to remove any tumors.

Malignant or carcinomatous meningitis

Cancer causes malignant or carcinomatous meningitis. It is rare and affects less than 5% of people with cancer who have solid tumors, such as breast or lung cancer.

If the cancer spreads to the central nervous system, it may cause malignant meningitis. Doctors treat this form of noninfectious meningitis by addressing the underlying cancer with chemotherapy.

Underlying conditions

Noninfectious meningitis may develop if a person has an underlying inflammatory disorder, including:

• systemic lupus erythematosus or lupus
• Sjögren’s syndrome
• primary central nervous system angiitis
• sarcoidosis
• Behçet’s disease

A head injury or prior brain surgery could also cause noninfectious meningitis.

The symptoms of noninfectious meningitis often resemble those of other types of meningitis, including:

• headache
• fever
• stiff neck
• light sensitivity
• nausea and vomiting
• confusion

Doctors treat noninfectious meningitis by treating or removing the underlying cause. For example, if doctors suspect a person has developed meningitis because of a reaction to certain medications, they should prescribe an alternative.

Likewise, if a person has a brain tumor that triggers noninfectious meningitis, a surgeon may remove the tumor or treat it with chemotherapy.

Managing meningitis generally focuses on supportive care that:

• allows a person to breathe
• provides intravenous fluids
• reduces fever

Doctors may also prescribe antibiotics until they rule out bacterial meningitis.

Noninfectious meningitis is challenging to prevent because infectious germs are not the underlying cause. Unlike infectious meningitis, there is no vaccine for this condition.

Additionally, maintaining good personal hygiene and avoiding contact with people with the condition will not decrease a person’s chances of developing noninfectious meningitis.

The causes of noninfectious meningitis may not be avoidable. Therefore, if individuals are at risk of noninfectious meningitis, understanding the symptoms and seeking prompt medical attention may lead to positive outcomes.

The primary difference between infectious and noninfectious meningitis is the underlying cause.

Bacteria, fungi, and viruses are the most common cause of infectious meningitis. However, in rare cases, a type of ameba that lives in soil and warm freshwater can cause the infection.

Although infectious and noninfectious meningitis symptoms are similar, the treatment differs. In the case of bacterial meningitis, antibiotics are a critical part of therapy. Vaccines are also the most effective way to protect against certain types of bacterial meningitis.

For viral meningitis, doctors have no specific treatment. In mild cases, people often recover within 7–10 days without treatment. However, there are no vaccines to protect against viral meningitis.

With noninfectious meningitis, doctors must find and treat the underlying cause.

In all cases of meningitis, people who are severely ill or at risk of becoming so require supportive care in the hospital.

Noninfectious meningitis is a potentially serious illness. Therefore, anyone experiencing symptoms of headache, stiff neck, light sensitivity, and fever should seek urgent medical attention.

Doctors typically rule out infectious causes of meningitis then address the underlying cause of noninfectious meningitis. They will also provide supportive care, including assisting with breathing and administering intravenous fluids and medications to reduce fever.

Seeking early treatment means a person has the best chance of a positive outlook.