What is viral meningitis?

Definition

The brain and spinal cord are encased by layers of tissue called the
meninges. Certain viruses can cause an infection in these
layers. This infection is called viral meningitis. Some types of viral meningitis
can be less serious than bacterial meningitis.

Causes

A number of viruses can cause viral meningitis, including enteroviruses, herpesviruses, mumps,
varicella virus (chickenpox), measles, rubella viruses, and
West Nile
virus. Most of these viruses can also cause encephalitis,
an inflammation of the brain tissue. It is a much more serious
condition.

Viruses that cause meningitis can be spread in numerous ways. Enteroviruses are spread through direct contact with respiratory secretions of an infected person, and through feces. Other viruses (mumps, herpes, chickenpox) are spread through close personal contact or through the air. Some viruses (such as West Nile) that cause encephalitis are spread by insects.

Risk Factors

Risk factors for viral meningitis include conditions that weaken the
immune
system, such as human immunodeficiency virus infection
(which itself can lead to meningitis and encephalitis); immunosuppressive
treatments; crowded, unsanitary conditions; and the months of summer and early
fall.

Symptoms

Classic symptoms of viral meningitis include high fever, headache, stiff, sore neck, nausea, vomiting, sensitivity to bright lights, and sleepiness. In newborns and infants, symptoms include inactivity, high fever (especially unexplained high fever), irritability, vomiting, feeding poorly or refusing to eat, tautness or bulging of soft spots between skull bones, and difficulty awakening.

Screening and Diagnosis

A doctor will ask about symptoms and medical history and will perform a
physical exam. The doctor will focus on the nervous
system. To help rule out other causes of the inflammation,
such as a tumor, the doctor may order a magnetic resonance imaging (MRI) scan
(a scan that uses radio waves and a powerful magnet to produce detailed computer
images) or a computed tomography (CT) scan (a detailed X-ray picture that
identifies abnormalities of fine tissue structure).

To rule out bacterial meningitis, the doctor may order a lumbar
puncture (spinal tap), which removes fluid from the lower
spinal column to be tested for bacteria (bacterial cultures), or the doctor may
order other cultures, such as blood, urine, mucus, and pus from skin
infections.

Treatment and Therapy

Treatment includes rest and fluids, nonsteroidal anti-inflammatory drugs, and
aspirin. Aspirin, however, is not recommended for children with a current or
recent viral infection. Antibiotics may be given for two to
three days while waiting for bacterial cultures to be reported as negative. If
encephalitis is present, the doctor may prescribe IV antiviral drugs and other medications.

Prevention and Outcomes

To help prevent infection, one should wash his or her hands often if in close contact with an infected person, after changing the diaper of an infected infant, or if working in a child-care setting; and should regularly wash objects and surfaces touched by children using a diluted bleach solution. Persons who have not had measles, mumps, rubella, or chickenpox should consider being vaccinated.

Some forms of viral meningitis are spread by mosquito bites. One should follow public health recommendations for reducing mosquitoes near one’s home and should take steps to avoid being bitten by mosquitoes.

If thinking about pregnancy, one should ensure protection (such as a chickenpox vaccine) from common diseases. Also, one should avoid all contact with rodents during pregnancy because lymphocytic choriomeningitis virus can be acquired from pet hamsters, mice, or other rodents. Pregnant women who have a pet rodent should consider finding another home for the rodent for the duration of the pregnancy.

Bibliography

Ferreiros, C. Emerging Strategies in the Fight Against Meningitis. New York: Garland Science, 2002.

Logan, Sarah A. E., and Eithne MacMahon. “Viral Meningitis.” British Medical Journal 336 (January 5, 2008): 36-40.

National Institute of Neurological Disorders and Stroke. “Meningitis and Encephalitis Fact Sheet.” Available at http://www.ninds.nih.gov.

Shmaefsky, Brian. Meningitis. Rev. ed. Philadelphia: Chelsea House, 2010.

Strauss, James, and Ellen Strauss. Viruses and Human Disease. 2d ed. Boston: Academic Press/Elsevier, 2008.

Wagner, Edward K., and Martinez J. Hewlett. Basic Virology. 3d ed. Malden, Mass.: Blackwell Science, 2008.