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H influenzae meningitis

H. influenzae meningitis; H. flu meningitis; Haemophilus influenzae type b meningitis

Meningitis is an infection of the membranes covering the brain and spinal cord. This covering is called the meninges.

Bacteria are one type of germ that can cause meningitis. Haemophilus influenzae type b is one kind of bacteria that causes meningitis.

Causes

H influenzae meningitis is caused by Haemophilus influenzae type b bacteria. This illness is not the same as the flu (influenza), which is caused by a virus.

Before the Hib vaccine, H influenzae was the leading cause of bacterial meningitis in children under age 5. Since the vaccine became available in the United States, this type of meningitis occurs much less often in children in the United States.

H influenzae meningitis may occur after an upper respiratory infection. The infection usually spreads from the lungs and airways to the blood, then to the brain area.

Risk factors include:

  • Attending day care
  • Cancer
  • Ear infection (otitis media) with H influenzae infection
  • Family member with an H influenzae infection
  • Native American race
  • Pregnancy
  • Older age
  • Sinus infection (sinusitis)
  • Sore throat (pharyngitis)
  • Upper respiratory infection
  • Weakened immune system

Symptoms

Symptoms usually come on quickly, and may include:

Other symptoms that can occur include:

Exams and Tests

The health care provider will perform a physical exam. Questions will focus on symptoms and possible exposure to someone who might have the same symptoms, such as a stiff neck and fever.

If the doctor thinks meningitis is possible, a lumbar puncture (spinal tap) is done to take a sample of spinal fluid for testing.

Other tests that may be done include:

Treatment

Antibiotics will be given as soon as possible. Ceftriaxone is one of the most commonly used antibiotics. Ampicillin may sometimes be used.

Corticosteroids may be used to fight inflammation.

Unvaccinated people who are in close contact with someone who has H influenzae meningitis should be given antibiotics to prevent infection. Such people include:

  • Household members
  • Roommates in dormitories
  • Those who come into close contact with an infected person

Outlook (Prognosis)

Meningitis is a dangerous infection and it can be deadly. The sooner it is treated, the better the chance for recovery. Young children and adults over age 50 have the highest risk for death.

Possible Complications

Long-term complications may include:

When to Contact a Medical Professional

Call 911 or the local emergency number or go to an emergency room if you suspect meningitis in a young child who has the following symptoms:

  • Feeding problems
  • High-pitched cry
  • Irritability
  • Persistent, unexplained fever

Meningitis can quickly become a life-threatening illness.

Prevention

Infants and young children can be protected with the Hib vaccine.

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 person is diagnosed. All unvaccinated family members and close contacts of this person should begin antibiotic treatment as soon as possible to prevent spread of the infection. Ask your provider about antibiotics during the first visit.

Always use good hygiene habits, such as washing hands before and after changing a diaper, and after using the bathroom.

Open References

References

Centers for Disease Control and Prevention website. Meningitis. About bacterial meningitis. www.cdc.gov/meningitis/about/bacterial-meningitis.html. Updated January 9, 2024. Accessed June 17, 2024.

Nath A. Meningitis: bacterial, viral, and other. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 384.

Hasbun R, Van de Beek D, Brouwer MC, Tunkel AR. Acute meningitis. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 87.

  • Meninges of the brain

    Meninges of the brain - illustration

    The organs of the central nervous system (brain and spinal cord) are covered by connective tissue layers collectively called the meninges. Consisting of the pia mater (closest to the CNS structures), the arachnoid and the dura mater (farthest from the CNS), the meninges also support blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.

    Meninges of the brain

    illustration

  • Meninges of the spine

    Meninges of the spine - illustration

    The organs of the central nervous system (brain and spinal cord) are covered by 3 connective tissue layers collectively called the meninges. Consisting of the pia mater (closest to the CNS structures), the arachnoid and the dura mater (farthest from the CNS), the meninges also support blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.

    Meninges of the spine

    illustration

  • Central nervous system and peripheral nervous system

    Central nervous system and peripheral nervous system - illustration

    The central nervous system comprises the brain and spinal cord. The peripheral nervous system includes nerves outside the brain and spinal cord.

    Central nervous system and peripheral nervous system

    illustration

  • CSF cell count

    CSF cell count - illustration

    CSF (cerebrospinal fluid) is a clear fluid that circulates in the space surrounding the spinal cord and brain. A CSF cell count is a test to measure the number of red and white blood cells that are in CSF.

    CSF cell count

    illustration

  • Haemophilus influenzae organism

    Haemophilus influenzae organism - illustration

    This is a Gram stain of spinal fluid from a person with meningitis. The rod-like organisms seen in the fluid are Haemophilus influenzae, one of the most common causes of childhood meningitis (prior to the widespread use of the H influenzae vaccine). The large red-colored objects are cells in the spinal fluid. A vaccine to prevent infection by Haemophilus influenzae (type B) is available as one of the routine childhood immunizations (Hib), typically given at 2, 4, and 12 months.

    Haemophilus influenzae organism

    illustration

  • Haemophilus influenza organism

    Haemophilus influenza organism - illustration

    This picture shows the organism Haemophilus influenza. Infections caused by Haemophilus influenza usually occur in children under 6 years old and are extremely serious. Haemophilus (type B) is responsible for meningitis, periorbital cellulitis, buccal cellulitis and epiglottitis, septic arthritis, osteomyelitis, pericarditis, and bacteremia. The small organisms live within cells (intracellular) as shown in this picture. (Image courtesy of the Centers for Disease Control and Prevention.)

    Haemophilus influenza organism

    illustration

  • Meninges of the brain

    Meninges of the brain - illustration

    The organs of the central nervous system (brain and spinal cord) are covered by connective tissue layers collectively called the meninges. Consisting of the pia mater (closest to the CNS structures), the arachnoid and the dura mater (farthest from the CNS), the meninges also support blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.

    Meninges of the brain

    illustration

  • Meninges of the spine

    Meninges of the spine - illustration

    The organs of the central nervous system (brain and spinal cord) are covered by 3 connective tissue layers collectively called the meninges. Consisting of the pia mater (closest to the CNS structures), the arachnoid and the dura mater (farthest from the CNS), the meninges also support blood vessels and contain cerebrospinal fluid. These are the structures involved in meningitis, an inflammation of the meninges, which, if severe, may become encephalitis, an inflammation of the brain.

    Meninges of the spine

    illustration

  • Central nervous system and peripheral nervous system

    Central nervous system and peripheral nervous system - illustration

    The central nervous system comprises the brain and spinal cord. The peripheral nervous system includes nerves outside the brain and spinal cord.

    Central nervous system and peripheral nervous system

    illustration

  • CSF cell count

    CSF cell count - illustration

    CSF (cerebrospinal fluid) is a clear fluid that circulates in the space surrounding the spinal cord and brain. A CSF cell count is a test to measure the number of red and white blood cells that are in CSF.

    CSF cell count

    illustration

  • Haemophilus influenzae organism

    Haemophilus influenzae organism - illustration

    This is a Gram stain of spinal fluid from a person with meningitis. The rod-like organisms seen in the fluid are Haemophilus influenzae, one of the most common causes of childhood meningitis (prior to the widespread use of the H influenzae vaccine). The large red-colored objects are cells in the spinal fluid. A vaccine to prevent infection by Haemophilus influenzae (type B) is available as one of the routine childhood immunizations (Hib), typically given at 2, 4, and 12 months.

    Haemophilus influenzae organism

    illustration

  • Haemophilus influenza organism

    Haemophilus influenza organism - illustration

    This picture shows the organism Haemophilus influenza. Infections caused by Haemophilus influenza usually occur in children under 6 years old and are extremely serious. Haemophilus (type B) is responsible for meningitis, periorbital cellulitis, buccal cellulitis and epiglottitis, septic arthritis, osteomyelitis, pericarditis, and bacteremia. The small organisms live within cells (intracellular) as shown in this picture. (Image courtesy of the Centers for Disease Control and Prevention.)

    Haemophilus influenza organism

    illustration

 

Review Date: 9/10/2022

Reviewed By: Jatin M. Vyas, MD, PhD, Associate Professor in Medicine, Harvard Medical School; Associate in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital, Boston, MA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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