OTOGENIC BRAIN ABSCESS

AN AUDIT OF TWENTY ONE CONSECUTIVE CASES

Abstract

Otogenic brain abscesses imply accumulation of pus in the brain originating from inflammatory process in the middle ear cavity. OBJECTIVES: The aim of the study was to investigate mechanisms of development, diagnostic methods and treatment of otogenic brain abscesses. Twenty one patients suffering from otogenic brain abscesses. SETTING: Nishtar Hospital Multan in the department of Otorhinolaryngology and Neurosurgery. PERIOD: From June 1996 to December 1999. PATIENTS & METHODS: Detailed history and physical examination were followed by CT scan with contrast enhancement. Burr hole aspiration, craniectomy and craniotomy are the procedures employed according to individual needs. After aspiration, the pus was subjected to microscopy for AFB and culture and sensitivity. Histopathology of the abscess was performed whenever available. RESULTS: Sixteen of the twenty one patients were males and five females. Mean age at presentation was 20.7 years [ranging from 7 to 60]. Headache (100%), vomiting 100% and ear discharge 100% were the commonest symptoms while fever 95%, drowsiness 48% and papilloedema 29% were the commonest signs. Temporal lobe abscesses were diagnosed in thirteen 62% and an abscess in posterior fossa was present in eight patients 38%.. Aspiration of pus through a brain cannula after making a burr hole was tried in all the patients but eight patients underwent craniotomy/craniectomy for excision of abscess wall after repeated aspirations failed to lead to complete resolution on follow up scans. Bacteriology was positive in twelve of twenty one (57%) patients. Staph aureus was detected in three (14%), E coli in three (14%), pseudomonas in two (9.5%), streptococci in two (9.5%), B. Proteus in one patient (5%) and aspergillus fumigatus in one (5%) patient. After improvement in their clinical status, seventeen patients were referred to the department of ENT for mastoidectomy. One patient suffering from cerebellar abscess died on third post operative day and one with a temporal extradural abscess did not improve after repeated aspirations and died within thirty days of operation. Both of these patients were comatosed (GCS below 7) at the time of admission. The mortality in this study was 9.5%. Level of consciousness at the time of admission was the most significant factor affecting the outcome. CONCLUSIONS: Advances in the microbial isolation methods, specificity of antimicrobial agents and earlier diagnosis by CT scan have contributed to an improved outcome for this dreaded disease.