Meningitis

Meningitis is a serious infection of the meninges, the membranes that cover the brain and spinal cord. This disease has a variety of causes, manifests a variety of symptoms, and may or may not be contagious. Most cases of meningitis are bacterial or viral, the former being much more severe. Bacterial meningitis can be caused by either meningococcus or pneumococcus bacteria. Fortunately, there are now vaccines available for both.

Causes of Meningitis

Meningitis can be caused by a large number of pathogens and transmitted in a number of different ways. There are three primary types of meningitis.

Bacterial Meningitis

Bacterial meningitis requires emergency medical care since without treatment is can lead to death within hours or, if the patient survives, can result in permanent brain or neurological damage. Bacterial meningitis is spread through airborne particles. It may also result from a bacterial illness elsewhere in the body that travels through the bloodstream to the brain.

Viral Meningitis

More common than bacterial meningitis, viral meningitis is usually less serious. Sometimes contagious, it is often precipitated by enteroviruses, the ones that originate in the intestinal tract where they cause diarrhea. It can also be caused by the herpes virus, the viruses that cause mumps and HIV. When it is caused by the West Nile virus which is transmitted by mosquitoes, it is not contagious person-to-person..

Non-Infectious Meningitis

There are several varieties of non-infectious meningitis. Though rare, some can be fatal.

Fungal meningitis

Fungal meningitis is not nearly as common as bacterial or virus meningitis. It is rarely contracted by healthy individuals, but patients with underlying immune disorders, may be susceptible. People are more at risk for the disease if they:

  • Are premature infants
  • Have compromised immune systems
  • Make contact with bird or bat droppings
  • Are African American or Filipino
  • Are pregnant women in their third trimester

Fungal meningitis is not a contagious disease.

Parasitic meningitis

Parasitic meningitis is extremely rare and usually deadly. The parasite causing the illness, a microscopic amoeba, enters the body through the nose. It cannot be contracted by drinking contaminated water. Parasitic meningitis is transmitted through contaminated fresh water, particularly warm water. Individuals may make contact with such water in:

  • Lakes and rivers
  • Hot springs
  • Water discharged by industrial plants
  • Poorly maintained swimming pools
  • Water heaters
  • Soil

The amoeba responsible for parasitic meningitis is not found in the ocean.

Other non-infectious meningitis

There are other several causes of non-infectious meningitis, including:

  • Certain cancers or inflammatory diseases
  • Lupus, an autoimmune condition
  • Particular medications, chemicals or allergies
  • Head injury
  • Brain surgery

Medications given for autoimmune diseases and those administered to keep patients from rejecting organ transplants may make individuals susceptible to non-infectious meningitis.

Risk Factors for Infectious Meningitis

While anyone can contract meningitis, the disease is most common in children under 5 years of age, young people between the ages of 16 and 25, and adults over 55 years old. Individuals with compromised immune systems, due to chronic disease or missing organs, such as a spleen, kidney or lung, are more at risk.

Since certain pathogens that cause meningitis are extremely contagious, those living in close quarters are more susceptible to meningitis. This include individuals living in dormitories, barracks, or communal shelters. Travelers to parts of the world where meningitis is more common, such as sections of Africa, are also at increased risk.

Symptoms of Meningitis

It is not the symptoms of meningitis that differentiate the type, so any patients with symptoms of meningitis should be immediately taken to a hospital emergency room for evaluation. Symptoms of meningitis may include:

  • Fever and chills
  • Tachycardia
  • Nausea and vomiting
  • Bulging fontanelle in infants
  • Sensitivity to light
  • Severe headache
  • Severe stiff neck
  • Decreased mental function
  • Arching back of the head and neck

Diagnosis of Meningitis

Because physical examination is not sufficient to make a definitive diagnosis, the following tests may be taken:

  • Blood cultures to check for bacteria
  • X-rays and CT scans to check for inflammation
  • Lumbar puncture (spinal tap)

If viral meningitis is suspected, a DNA test may be performed.

Treatment of Meningitis

Treatment varies according to which type of meningitis the patient has. If the infection has started elsewhere in the body, it may be necessary to treat the original site of the infection as well as the systemic illness. Bacterial meningitis is treated with intravenous antibiotics and cortisone to prevent seizures. Viral meningitis is most often treated with supportive therapy, although sometimes antiviral medication is also administered. Fungal meningitis is treated with antifungal medication.

Other types of meningitis may be treated with corticosteroids to reduce inflammation. If a cancerous tumor is causative, surgery may be necessary. If the cause of the illness is as yet unknown, antibiotic and antiviral medication may be prescribed while awaiting test results.

Additional Resources