Haemophilus Influenzae Infection

Although Haemophilus influenzae can affect many or gan systems, it most frequently attacks the respiratory system. It's a common cause of epiglottitis, laryngotracheobronchitis, pneumonia, bronchiolitis, otitis media, and meningitis. Less often, it causes bacterial endocarditis, conjunctivitis, facial cellulitis, septic arthritis, and osteomyelitis.

H. influenzae type B (Hib) infection predominantly affects children, at a rate of 3% to 5%. This incidence was higher before vaccinations were used in day-care centers. The vaccine is administered at ages 2. 4. 6, and 15 months. The. incidence of meningitis in black children is higher due to Hib. In Native Americans, the incidence of the disease is 10 times higher, possibly due to exposure, socioeconomic conditions, and genetic differences in immune response.

Causes

A small, gram-negative, pleomorphic aerobic bacillus, H. InfIuenzae appears predominantly in coccobacillary exudates. It's usually found in the pharynx and less often in the conjunctiva and genitourinary tract. Transmission occurs by direct contact with secretions or by airborne droplets.

Signs and symptoms

Haemophilus influenzae is among the most common cause of ear infections and sinus infections. These bacteria can cause many other types of infections including septic arthritis , pneumonia , meningitis , and conjunctivitis .

Diagnostic tests

Isotation of the organism, usually with a blood culture, confirms H. injluenzae infection. Hib meningitis is detectable in cerebrospinal fluid cultures. A positive nasopharyngeal culture isn't diagnostic because this may be a normal finding in healthy people.

Treatment

H. influenzae type B infections may be rapidly fatal without prompt, effective treatment. Patients with meningitis due to Hib are treated with cefotaxime or ceftriaxone. As an alternative, doctors may prescribe a combination of chloramphenicol and ampicillin. Glucocorticoids can reduce neurologic sequelae. Airway maintenance is critical in epiglottitis.

Prevention

Immunization against type b, which is the most invasive strain of H. influenzae, is routinely administered in a three- or four-part series. The first vaccine is received at 2 months of age and the two subsequent doses are given at about 4 months and 6 months. 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 them 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