Computed tomography before lumbar puncture in acute meningitis: a review of the risks and benefits.

OBJECTIVE

To determine the indications, if any, for routine computed tomography (CT) of the brain before lumbar puncture in the management of acute meningitis.

DATA SOURCES

Original research papers, reviews and editorials published in English from 1965 to 1991 were retrieved from MEDLINE. The bibliographies of these articles and of numerous standard texts were examined for pertinent references. A survey of local neurologists was conducted, and legal opinion was sought from the Canadian Medical Protective Association.

DATA EXTRACTION

There were no studies directly assessing the risks of lumbar puncture in meningitis; however, all sources were culled for other pertinent information.

RESULTS

No cases could be found of patients with acute meningitis deteriorating as a result of lumbar puncture. The neurologic consensus refuted the need for CT in typical acute meningitis. All sources stressed speedy lumbar puncture and the early institution of appropriate antibiotic therapy to minimize the severity of the illness and the risk of death.

CONCLUSIONS

(a) There is no evidence to recommend CT of the brain before lumbar puncture in acute meningitis unless the patient shows atypical features, (b) for patients with papilledema the risks associated with lumbar puncture are 10 to 20 times lower than the risks associated with acute bacterial meningitis alone, (c) CT may be necessary if there is no prompt response to therapy for meningitis or if complications are suspected, (d) the inability to visualize the optic fundi because of cataracts or senile miosis is not an indication for CT and (e) there are no Canadian legal precedents suggesting liability if physicians fail to perform CT in cases of meningitis.