Haemophilus influenzae meningitis is a bacterial infection of the membranes covering the brain and spinal cord (meninges).
H. influenzae meningitis; H. flu meningitis
H. influenzae meningitis is caused by Haemophilus influenzae bacteria. These bacteria should not be confused with the disease influenza, an upper respiratory infection caused by the influenza virus.
Before the Hib vaccine became available, H. influenzae was the leading cause of bacterial meningitis in children under age 5. Since the introduction of the vaccine in the U.S., H. influenzae meningitis occurs in less than 2 in 100,000 children. It still causes 5% - 10% of bacterial meningitis cases in adults.
H. influenzae meningitis may occur after an upper respiratory infection. The infection usually spreads from the respiratory tract to the bloodstream, and then to the meninges. At the meninges, the bacteria produce infection and inflammation, causing serious illness and sometimes death.
Risk factors include:
Symptoms usually come on quickly, and may include:
Other symptoms that can occur with this disease:
Physical examination will usually show:
For a patient who is suspected of having meningitis, it is important to perform a lumbar puncture ("spinal tap"), in which spinal fluid (known as cerebrospinal fluid, or CSF) is collected for testing.
Tests that may be done include:
Treatment with antibiotics should be started as soon as possible. Ceftriaxone is one of the most commonly used antibiotics.
If the antibiotic is not working and the health care provider suspects antibiotic resistance, chloramphenicol with ampicillin may be used. Sometimes corticosteroids may be used, especially in children.
Unvaccinated people who are in close contact with someone who has H. influenzae meningitis should be given antibiotics to prevent infection. Such people include:
Early treatment improves the outcome. However, 3 - 5% of patients do not survive. Young children and adults over 50 have the highest risk of death.
Call the local emergency number (such as 911) or go to an emergency room if you suspect meningitis in a young child who has the following symptoms:
Call the local emergency number if you develop any of the serious symptoms listed above. Meningitis can quickly become a life-threatening illness.
To protect infants and young children:
All unvaccinated family members and close contacts (especially in health care or school settings) of people with this type of meningitis should begin antibiotic treatment as soon as possible to prevent spread of the infection. Ask your health care provider about this during the first visit.
Close contacts in the same household, school, or day care center should be watched for early signs of the disease as soon as the first case is diagnosed. If two cases occur in a day care center, preventive antibiotics should be considered. Always use good hygiene habits, such as washing hands before and after changing a diaper, and after using the bathroom.
Swartz MN. Meningitis: bacterial, viral, and other. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 437.