Haemophilus Influenzae Infections
What is Haemophilus influenzae?
Haemophilus influenzae, or H. influenzae, represents a group of bacteria that may cause different types of infections in infants and children. H. influenzae most commonly causes ear, eye, or sinus infections, and pneumonia. A more serious strain of the bacteria called H. influenzae type b has been nearly abolished in the United States due to the development of an effective vaccine, which has been available since 1988. The more serious strain was responsible for causing many cases of meningitis (infection of the membranes that surround the brain) and a life-threatening infection called epiglottitis (infection of the area of the throat that covers and protects the voice box and trachea during swallowing). Both meningitis and epiglottitis can be caused by other bacteria, however. In rare cases, children may still develop H. influenzae type b infections. This can occur in a child who has not completed his or her series of immunizations or in older children who did not receive the vaccine as an infant.
How is H. influenzae transmitted?
The H. influenzae bacteria live in the upper respiratory tract and are usually transmitted by close contact with an infected individual. Droplets in the air from a sneeze or cough can be inhaled and may also cause infection.
What are the symptoms of H. influenzae?
The following are the most common symptoms of H. influenzae infections. However, each child may experience symptoms differently. Symptoms may include:
Otitis media (middle ear infection). May develop after a child has a common cold caused by a virus. Symptoms may include:
Difficulty sleeping or staying asleep
Tugging or pulling at one or both ears
Fluid draining from ear(s)
Loss of balance
Nausea and vomiting
Conjunctivitis. An inflammation of the conjunctiva of the eye. The conjunctiva is the membrane that lines the inside of the eyelid and also a thin membrane that covers the actual eye. Symptoms may include:
Sinusitis. Infection in the sinuses. Symptoms may include:
Runny nose that lasts longer than 10 days. The discharge is usually thick green or yellow, but it can be clear.
Occasional daytime cough
Swelling around the eyes
Usually do not complain of headaches if less than 5 years of age
Runny nose or cold symptoms that last longer than 10 days
Post nasal drip (nasal drainage that travels down the back of the throat)
Facial discomfort (usually over the cheek bones or over the eyes which worsens when bending over)
Swelling around the eye (tends to be worse in the morning)
Epiglottitis. Due to the H. influenzae type b vaccine, epiglottitis is very rare in children and infants. Epiglottitis is an infection of the area of the throat that covers and protects the voice box and trachea (or windpipe) during swallowing. It can be fatal if not treated rapidly.
Some children begin with an upper respiratory infection, such as a cold. Symptoms may include:
As the infection worsens, the following symptoms may appear:
Meningitis. Due to the H. influenzae type b vaccine, meningitis (due to this bacteria) is very rare in children and infants. Meningitis is an infection of the membranes that surround the brain and spinal cord. Symptoms may include:
The symptoms of H. influenzae infection may resemble other medical conditions. Always consult your child's doctor for a diagnosis.
How is H. influenzae diagnosed?
Your child's doctor may diagnose the illness based on clinical examination and a medical history. Specific tests will depend on the location of the infection. In some cases, your doctor may take a culture of fluid from the eye, ear, blood, or spinal fluid. In other situations, this may be not be possible and a diagnosis will be made based on your child's specific symptoms. Other diagnostic tests may include:
What is the treatment for H. influenzae infections?
Treatment for H. influenzae greatly depends on which area of the body is infected. Specific treatment for H. influenzae will be determined by your child's doctor based on:
Your child's age, overall health, and medical history
Extent of the disease
Your child's tolerance for specific medications, procedures, or therapies
Expectations for the course of the disease
Your opinion or preference
Regardless of the location, antibiotics may be used to treat infections caused by H. influenzae. The length of treatment varies depending on the location and severity of the infection. Other therapy will be supportive (aimed at treating the symptoms present).
How can H. influenzae be prevented?
Immunization against type b, which is the most invasive strain of H. influenzae, is routinely administered in a three- or four-part series. The vaccine is often referred to as "Hib" vaccine. Primary doses are given at 2 and 4 months of age or at 2, 4, and 6 months of age, based on the brand used by the doctor's office. A booster is then given between 12 and 15 months of age. If a child did not receive the vaccine and is older than 5 years, it may not be necessary for him/her to be immunized. Other populations that should be encouraged to receive the vaccine include the following:
Adults and children with sickle cell disease
Individuals without a spleen
Adults and children with weakened immune systems
Individuals who are HIV positive