Neisseria meningitidis (meningococcus) is a bacteria that is commonly found in the nose and throat of healthy children without symptoms.  Rarely, Neisseria meningitidis may cause one or both of two severe illnesses, meningitis and meningococcemia.  Both illnesses are life-threatening and survivors may have permanent disability.  It is not completely clear why N. meningitidis is a seemingly harmless passenger in many individuals, and life-threatenting to others.  Meningococcal disease is diagnosed by identifying the bacteria in body fluids such as blood or spinal fluid.  Successful treatment requires rapid diagnosis and treatment with supportive care and antibiotics.

What is Neisseria meningitidis (meningococcus)?

Neisseria meningitidis (meningococcus) is a bacteria that may cause rapid-onset severe illness in otherwise healthy children.  Meningococcus is found in the nose and throat of 5-10% of healthy children.  It is spread from person-to-person via respiratory droplets.  About half of cases of meningoccal disease occur in children less than 2 years old.  There is also an increased incidence in children 15-19 years of age and college freshmen living in dormitories.  This has led to current recommendations of vaccination at 11-12 years of age.

What is meningococcemia?

Meningococcemia occurs when N. meningitidis bacteria enter the bloodstream.  The initial symptoms may look like a common viral illness.  Some cases progress rapidly to cause a systemic inflammatory response.  That is, the body's immune system goes into "overdrive," releasing a full attack with white blood cells and chemicals that cause inflammation.  This full-body inflammation may progress out-of-control, causing life-threatening organ failure, low blood pressure and blood clotting dysfunction.

What are the symptoms of meningococcemia?

Initially, symptoms are like a common viral illness...

• Fever
• Sore throat
• Malaise (feeling ill)
• Weakness
• Vomiting and diarrhea
• Muscle aches
• Headache

And if the illness progresses...

• Severe ill appearance
• Lethargy
• Confusion
• Full-body rash (small or large bruise-like lesions)
• and possibly, death

What is meningitis?

Meningitis is inflammation of the meninges, the covering of the the brain and spinal cord.   The spinal fluid is found between the meninges and the brain/spinal cord.  When meningitis occurs, this fluid may contain white blood cells, red blood cells and/or increased inflammatory proteins.  Meningitis may progress to encephalitis, inflammation of the brain.  If this occurs, seizures and brain swelling may develop.  Meningococcal meningitis develops when meningoccocal bacteria enter the spinal fluid, causing inflammation.

What are the symptoms of meningococcal meningitis?

• Headache
• Neck stiffness
• Seizures
• Severe ill appearance
• Lethargy or unusual behavior

How is meningococcal disease diagnosed?

A sample of blood or spinal fluid can be "cultured" to see if Neisseria meningitidis is present.  Severe illness may require treatment before making a definitive diagnosis.

A spinal tap is an important test when meningococcal disease is suspected.  A needle is placed in the lower back of the child and spinal fluid is removed.  This sample is checked for Neisseria meningitidis bacteria.  If present, antibiotic therapy is mandatory, and may need to be given in higher doses and for longer than would be be done for other infections.

What are the possible complications of meningococcal disease?

• Skin wounds
• Gangrene of extremities (sometimes requiring amputation)
• Hearing loss (5-10% of children after meningitis)
• Brain damage
• Arthritis (inflammation of joints)
• Death (in around 10% of cases in children)

What is the treatment of meningococcal disease?

Antibiotics such as cephalosporins are effective against Neisseria meningitidis.  Rapid supportive care (such as intravenous fluids) is often necessary.  Children may need to be placed in an intensive care unit.

Can meningococcal disease be prevented?

For individuals exposed to an infected individual in the past 7 days, antibiotics may be necessary to reduce the risk of disease.  Only individuals with close contact or an abnormal immune system need this special protection (ask your doctor if you qualify).

A vaccine is now recommended for all children between the ages of 11-12 years.  Older children who have not received the vaccine may also need immunization... especially children planning on living in close quarters with other individuals from multiple locations such as college freshmen or military recruits.  The vaccine provides only partial protection, since some strains of meningococcus are not covered.  Unfortunately, the vaccine is not effective for children younger than 2 years of age.