Haemophilus influenzae meningitis: the spectrum of disease in adults.

Fifteen cases of Haemophilus influenzae (HI) meningitis in adults occurring of Cleveland during the last 11 years are presented. The majority of patients had factors predisposing to infection such as otitis, pneumonia, diabetes or alcoholism. In addition, 7 of the 15 patients developed meningitis at various intervals following head trauma and neurosurgery, and 3 patients required dural repairs for CSF rhinorrhea. The diagnosis of meningitis may be difficult to establish resulting in delay in appropriate therapy in some cases. Nuchal rigidity was absent frequently; CSF lymphocytosis can be seen initially. The CSF Gram stain may be negative or the pleomorphic nature of the organism on Gram-stain may make distinction from other gram-negative organisms difficult. The majority of patients had meningitis due to non-Type B HI in contrast to previous reports of this illness in children and adults. One of our patients had beta-lactamase producing HI isolated from CSF. We believe that chloramphenicol should be included in the initial empiric therapy for adults with meningitis and gram-negative coccobacillary rods on Gram-stain or negative CSF Gram-stains.