Hydrocephalus associated with subarachnoid hemorrhage: clinical study by computed tomography, radioisotope cisternography and constant infusion test.

Thirteen patients exhibited a communicating hydrocephalus following subarachnoid hemorrhage secondary to ruptured intracranial aneurysms and were treated with shunt procedures. The interval between subarachnoid hemorrhage and surgery averaged 9 weeks. Seven of the patients showed improvement. The prognostic value for surgical management was evaluated on the basis of three different diagnostic examinations (computed tomography(CT), cisternography and constant infusion test). A correct diagnosis was obtained in 78 per cent in cisternography, and 63 per cent in infusion test and CT. All patients responding to surgery showed a typical pattern in cisternography, consisting of ventricular retention of radiopharmaceutical tracer for 48 h or longer in association with no radioactivity over the cerebral hemispheres. The constant infusion test correlated well with typical cisternographic patterns. CT is useful in demonstrating pathophysiological changes in hydrocephalus. Periventricular hypodensity was visible in patients with normal or slightly elevated intracranial pressure, accompanied by fairly rapid deterioration. All of them responded well to shunting. In most cases which benefited from the shunt, the postoperative CT showed not only normal-sized ventricles but also marked regression of the hypodensity over a short period.