Haemophilus meningitis

Haemophilus meningitis is a type of bacterial meningitis caused by the bacterium Haemophilus influenzae. This bacterium was once the leading cause of bacterial meningitis in children, but the incidence has significantly decreased due to the widespread use of the H. influenzae type b (Hib vaccine).

Etiology

Haemophilus influenzae is a small, Gram-negative bacterium that can cause a variety of infections, including pneumonia, otitis media, epiglottitis, and meningitis. There are six identifiable types of H. influenzae (a-f) and other non-identifiable types (nontypeable). The most virulent strain, type b, was responsible for most cases of Haemophilus meningitis prior to the introduction of the Hib vaccine.

Clinical Presentation

Patients with Haemophilus meningitis typically present with symptoms of meningitis, such as fever, headache, neck stiffness, and altered mental status. In infants, symptoms may be less specific and can include irritability, poor feeding, and lethargy.

Diagnosis

Diagnosis of Haemophilus meningitis is made by lumbar puncture and examination of the cerebrospinal fluid (CSF). The CSF in bacterial meningitis typically shows a high white blood cell count, high protein, and low glucose. H. influenzae can be identified by culture or by polymerase chain reaction (PCR) testing of the CSF.

Treatment

Treatment of Haemophilus meningitis involves antibiotic therapy to eradicate the bacteria. The choice of antibiotic is guided by susceptibility testing, but typically includes a third-generation cephalosporin such as ceftriaxone or cefotaxime. In addition, dexamethasone is often given to reduce inflammation and decrease the risk of neurological complications.

Prevention

Prevention of Haemophilus meningitis is primarily achieved through vaccination. The Hib vaccine is typically given as part of routine childhood immunizations and has been highly effective in reducing the incidence of disease.

See Also

• Meningitis
• Haemophilus influenzae
• Hib vaccine
• Bacterial meningitis