What is Haemophilus influenzae type b (Hib) meningitis?

Updated: Jul 09, 2018
  • Author: Prateek Lohia, MD, MHA; Chief Editor: Niranjan N Singh, MBBS, MD, DM, FAHS, FAANEM  more...
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Answer

Throughout the modern era of bacteriology, Haemophilus influenzae type b (Hib) has been identified as 1 of the 3 most common causes of bacterial meningitis in adolescents. The other 2 are Neisseria meningitidis and Streptococcus pneumoniae. Before the development of effective immunizations, these 3 bacteria accounted for more than 80% of all cases of meningitis in industrialized nations. (See Pathophysiology and Etiology.)

Initial manifestations of meningitis, seen in more than half of all cases of Hib meningitis, include altered cry, change in mentation, nausea or vomiting, fever, headache, photophobia, meningismus, irritability, anorexia, and seizures. The possibility of Hib meningitis is suggested by the presence of risk factors (eg, time of year, patient age, vaccination status), as well as clinical features. (See Clinical Presentation and Diagnosis.)

Lumbar puncture is critical in the evaluation of patients with suspected meningitis and should be performed unless some specific contraindication exists. In the absence of focal neurologic findings, the risk of herniation in cases of Hib meningitis is low and one can safely proceed to lumbar puncture without imaging. Brain imaging is also helpful in certain cases. (See Workup.)

The most critical aspect of initial treatment is prompt initiation of antimicrobial therapy, because any delay in treatment is associated with increased morbidity and mortality. Either cefotaxime or ceftriaxone should be initially provided to children who present with meningitis and who are older than 6 weeks and younger than 6 years. Adjunctive anti-inflammatory therapy continues to be controversial. (See Treatment and Management.)

In countries where effective immunization against Hib has been provided to children, the incidence of Hib meningitis—as well as other serious Hib-related diseases, such as pneumonia or sepsis—has diminished by as much as 87-90% or more. Unfortunately, the important goal of global immunization of children against Hib has not yet been realized. (See Prevention of Haemophilus Meningitis.)

Go to Meningitis, Meningococcal Meningitis, Staphylococcal Meningitis, Tuberculous Meningitis, Viral Meningitis, and Aseptic Meningitis for more complete information on these topics.


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