Lumbar puncture in spontaneous subarachnoid haemorrhage.

Seventy-four patients with proved spontaneous subarachnoid haemorrhage were studied. Sixty-four underwent computed tomography and 55 underwent lumbar puncture. Seven cases deteriorated dramatically after lumbar puncture, six of these showing evidence of cerebral dislocation on further investigation. Four of the seven had not undergone computed tomography and three underwent computed tomography after lumbar puncture. Computed tomography of the brain could determine patients at risk of coning. It is suggested that computed tomography is the investigation of choice after spontaneous subarachnoid haemorrhage and that lumbar puncture, if still then necessary, should be avoided until computed tomography has been undertaken.