How to differentiate bacterial from viral meningitis

Excerpt

Bacterial meningitis is a rapidly progressive infection whose prognosis depends on prompt initiation of adequate antimicrobial therapy [1, 2]. In case of suspicion of bacterial meningitis blood cultures are needed. Since diagnosis of meningitis depends on signs of inflammation in the cerebrospinal fluid, early lumbar puncture is crucial [3]. However, if there is suspicion of increased intracranial pressure, brain computed tomography must be performed to recognize those patients in whom lumbar puncture is contraindicated [2]. In these cases antibiotic therapy should be initiated prior to CT in order not to loose time until definite diagnosis, since delay in initial administration of antibiotic therapy deteriorates prognosis [3, 4]. In view of this emergency situation antibiotics are frequently given even in patients with suspected viral meningitis. In general this does not harm the individual patient with viral disease. However, it may have an impact on the local frequency of antibiotic resistance, which depends significantly on the amount of antibiotic consumption [5]. Thus, it is not only important to recognize patients who immediately need antibiotics but also those who do not need antimicrobial therapy at all. …