Subclinical organic psychosyndromes on intrathecal injection of metrizamide for lumbar myelography.

Eighteen patients with symptoms and signs of possible lumbar disc herniation, who had no evidence of a preexisting organic psychosyndrome were included in the study. An organic psychosyndrome was found in six of them 10 h after lumbar myelography with metrizamide. The psychosyndrome, which was characterized by impaired memory and depression, could be demonstrated only by psychometric methods. In these patients metrizamide could be demonstrated within the basal cisterns by computed tomography 8 h after lumbar injection of the contrast medium. The organic psychosyndrome was completely reversible; five days after myelography it could not be detected any more by psychometric means. The development of an organic psychosyndrome in six of the 18 patients suggests a neurotoxic effect of metrizamide. This assumption is supported by hypo- and areflexia in four patients after intrathecal metrizamide as well as by EEG changes seen in three patients after myelography. There was no correlation between the EEG changes or reflex abnormalities and the organic psychosyndrome.