Bacterial Meningitis

(Spinal Meningitis)

by Krisha McCoy, MS

Definition

The brain and spinal cord are encased by layers of tissue. These layers are called the meninges. Certain bacteria can cause an infection in these layers. This is called bacterial meningitis.

It is a serious infection that can cause death within hours. A quick diagnosis and treatment is vital.

Bacterial Meningitis

© 2009 Nucleus Medical Media, Inc.

Causes

Many times, the bacteria first cause an upper respiratory tract infection. Then it travels through the blood stream to the brain.

Worldwide, three types of bacteria cause the majority of cases of acute bacterial meningitis:

• Streptococcus pneumoniae (the bacteria that causes pneumonia)
• Neisseria meningitidis
• Haemophilus influenzae b (Hib)
  • In the US, widespread immunization has almost eliminated meningitis due to Hib

Other forms of bacterial meningitis include:

• Listeria monocytogenes meningitis
• Escherichia coli meningitis
• Mycobacterium tuberculosis meningitis
• Group B Streptococcus meningitis

Newborn babies and the elderly are more prone to get sick.

Some forms are spread by direct contact with fluid from the mouth or throat of an infected person. This can happen during a kiss or by sharing eating utensils. In general, meningitis is not spread by casual contact.

Risk Factors

If you have any of these risk factors for meningitis, tell your doctor:

• Age: infancy and early childhood; over 60 years of age
• People in close and prolonged contact with patients with meningitis due to Hib or Neisseria meningitidis
• A weakened immune system due to HIV infection or other conditions
• Alcoholism
• Smoking (for meningitis due to Neisseria meningitidis)
• Living in proximity to others, such as dormitories and military barracks (for meningitis due to Neisseria meningitidis)

Symptoms

Classic symptoms can develop over several hours, or may take 1 to 2 days:

• High fever
• Headache
• Very stiff, sore neck

Other symptoms may include:

• Red or purple skin rash
• Cyanosis (bluish skin color)
• Nausea
• Vomiting
• Photophobia (sensitivity to bright lights)
• Sleepiness
• Mental confusion

In newborns and infants, symptoms are hard to see. As a result infants under three months old with a fever are often checked for meningitis. Symptoms in newborns and infants may include:

• Inactivity
• Unexplained high fever or any form of temperature instability, including a low body temperature
• Irritability
• Vomiting
• Jaundice (yellow color to the skin)
• Feeding poorly or refusing to eat
• Tautness or bulging of soft spots between skull bones
• Difficulty awakening

As the illness progresses, seizures and/or hearing loss can occur. This can happen to patients of all ages.

Diagnosis

Your doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests may include the following:

• Spinal tap —removal of a small amount of cerebrospinal fluid to check for bacteria
• Other cultures—testing of samples of blood, urine, mucous, and/or pus from skin infections
• MRI scan —a test that uses magnetic waves to make pictures of structures inside the body (to be sure the inflammation is not from some other cause, such as a tumor)
• CT scan —a type of x-ray that uses a computer to make pictures of structures inside the body

Treatment

More than 90% of all people with this infection survive with immediate care including:

• Antibiotics and corticosteroids—often given together
• Fluids may also be given

Prevention

To help reduce your chances of getting bacterial meningitis, consider the following steps:

• Get the recommended vaccines for you and your child:
  • Hib vaccine (recommended for babies)
  • Pneumococcal vaccine (recommended for children under 2 years old, adults over 65, and others with certain medical conditions)
  • Meningococcal vaccine (recommended for children 11-12 years old and others at high risk; people in the high-risk group may need to be revaccinated every 5 years)
• If you are a healthcare worker or have close contact with someone who's infected, take preventative antibiotics.
• Buy pasteurized milk and milk products. This can prevent meningitis due to Listeria monocytogenes.
• If you are pregnant, your doctor will monitor you to make sure the infection is not passed to your baby.

Centers for Disease Control and Prevention
http://www.cdc.gov/

Meningitis Foundation of American
http://www.musa.org/

National Institute of Neurological Disorders and Stroke
http://www.ninds.nih.gov/

Health Canada
http://www.hc-sc.gc.ca/

Meningitis Research Foundation of Canada
http://www.meningitis.ca/

REFERENCES:

Beers MH, Berkow R. The Merck Manual of Diagnosis and Therapy . 17th ed. Hoboken, NJ: John Wiley & Sons;1999.

Diagnosis of acute meningitis in adult patients. American Family Physician website. Available at: http://www.aafp.org/afp/20000115/tips/9.html . Accessed June 24, 2008.

Meningitis and encephalitis fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.n... . Accessed June 24, 2005.

Meningococcal disease. Centers for Disease Control and Prevention website. Available at: http://www.cdc.gov... . Accessed November 27, 2005.

Meningococcal vaccine. EBSCO Health Library website. Available at: http://www.ebscohost.com/thisTopic.php?marketID=15topicID=81 . Updated January 2009. Accessed July 29, 2008.

¹10/2/2009 DynaMed's Systematic Literature Surveillance http://www.ebscohost.com/dynamed/what.php : Centers for Disease Control and Prevention. Updated recommendation from the Advisory Committee on Immunization Practices (ACIP) for revaccination of persons at prolonged increased risk for meningococcal disease. MMWR. 2009;58(37):1042-1043. Centers for Disease Control and Prevention, MMWR website. Available at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5837a4.htm . Published September 25, 2009. Accessed October 2, 2009.

Last reviewed October 2009 by David L. Horn, MD, FACP
Last Updated: 10/20/09