Postmeningitis subdural fluid collection in infants: changing pattern and indications for surgery

Abstract

Object: Postmeningitis subdural fluid collection (PMSFC) is a classic complication of bacterial meningitis in infants. When the diagnosis was based solely on subdural puncture (SDP), its incidence was estimated to be as high as one half of the cases of meningitis, with Haemophilus influenzae as the most common causative bacterium. Knowledge concerning the diagnostic and bacteriological characteristics of PMSFC has expanded greatly since the introduction of computerized imaging and the use of the anti-H. influenzae vaccine; however, in no recent study have the authors reappraised this clinical entity with regard to diagnosis, bacteriology, and indications for surgery.

Methods: The authors reviewed their cases of PMSFC in infants in which a diagnosis was made based on computerized tomography findings and confirmed with SDP. They treated PMSFC using placement of a subdural drain whenever the collection was either clinically eloquent or exerted a mass effect on the brain. In the 26 years preceding the study, the authors had treated 29 patients younger than 16 months of age for PMSFC. Eight patients required SDP only, 20 underwent surgical drainage, and five required craniotomy. In six cases, the fluid was grossly purulent; in the others, it was clear, xanthochromatic, or hemorrhagic. Cultures were positive for Streptococcus pneumoniae in only two cases. Although H. influenzae was the most common bacterium at the beginning of the series, Neisseria meningitidis has become more prevalent since vaccination against the former became widespread. Based on their data the authors estimate that 5% of N. meningitidis infections in infants are complicated by a significant PMSFC.

Conclusions: At present, PMSFCs are most often caused by N. meningitidis. Temporary surgical drain placement is advised for all cases in which a significant mass effect is apparent on imaging.