Discrepancies between brain CT imaging and severely raised intracranial pressure proven by ventriculostomy in adults with pneumococcal meningitis

Objectives: Computed tomography (CT) of the brain is recommended for assessment of intracranial pressure (ICP) of patients with acute bacterial meningitis who are comatose or show focal neurological deficits. The aim of this report is to draw attention to the possibility of a discrepancy between CT findings and ICP values in some patients with pneumococcal meningitis. Methods: We describe three adult patients with pneumococcal meningitis who had both successive CT examinations and ICP measurements at the time of clinically evident cerebral herniation (n = 2) and/or prolonged coma (n = 2). Results: Although measurements with a ventriculostomy catheter indicated that all three patients had severely raised ICP values of 90, 44, and 45 mmHg, repeated cranial CT greatly underestimated true ICP values. Despite clinical evidence of acute cerebral herniation, it was not detected in the contemporary CT findings of two patients. Continuous ICP monitoring in the ICU helped to guide treatment for increased ICP; nevertheless, two patients died. Conclusions: The clinician must be aware that cranial CT may fail to rule out the possibility of severely raised ICP or cerebral herniation in a patient with pneumococcal meningitis. Therefore, ICP monitoring of patients with bacterial (especially pneumococcal) meningitis who are in prolonged coma should be considered early and regardless of the cranial CT appearances.