A 2-year-old boy with underlying congenital cyanotic heart disease presented with seizures and fever and was found to have bilateral parietal cerebral abscesses. Drainage of the pus from the abscesses was done in stages; on the day of admission, four days after admission and 3 weeks after admission. Although the pus from the first drainage did not grow any organisms, the pus from the second drainage on the fourth day of admission yielded a mixed growth of Eikenella corrodens and Streptococcus milleri. Following the second drainage of pus, the child was noted to have mild weakness (grade 3/5) and increased tone in the left upper limb. Three weeks after admission, due to recurring fever, further neurological signs and findings of an enlarging right cerebral abscess on a repeat CT scan, a third drainage was carried out. However no growth was obtained from this specimen. This patient was managed both surgically and with appropriate antibiotics. Over the next four months, serial CT scans revealed gradual resolution of the abscesses with disappearance of the surrounding oedema. The child showed gradual recovery of his left sided weakness with resolution of tone and reflexes to normal.
A prospective study was carried out to determine the aetiology of cerebral abscess in relation to the primary source of infections. Seventy-five patients with cerebral abscess were included in the study in the period January 1985 to December 1988. More than half of the patients studied had single lesions and the overall most common sites were in the frontal and parietal regions. Chronic suppurative otitis media, cyanotic congenital heart diseases and meningitis were among the important predisposing conditions in these patients. Approximately 25% of the patients with cerebral abscesses had no documented antecedent infections. Pure cultures were found to be predominant (66.7%) and sterile cultures were obtained from 10 (13.3%) patients. Streptococci were isolated from 23 (30.7%) patients, the commonest species being Streptococcus milleri. Proteus sp, Pseudomonas aeruginosa, Pseudomonas putrifaciens and Bacteroides sp were almost exclusively found in cerebral abscesses secondary to chronic suppurative otitis media; these organisms were found in mixed cultures. Streptococcus milleri, Bacteroides sp and Eikenella corrodens were found in pure cultures in patients with cyanotic congenital heart disease. In patients with ventriculoperitoneal shunts in-situ, Staphylococcus aureus, Staphylococcus epidermidis and diphtheroids were common. Anaerobes were found in 15 (20.0%) patients, the majority in mixed cultures. Culture, as well as gas-liquid chromatographic analysis of volatile fatty acids of cerebral pus, was carried out to enhance the detection of the anaerobes. Based on these findings, an antibiotic regimen consisting of penicillin, chloramphenicol and metronidazole is recommended as an initial therapy while awaiting culture and sensitivity results.