[A case of metrizamide encephalopathy with triphasic waves on EEG].

Metrizamide (Amipaque), a water soluble nonionic contrast medium has less toxic effect in comparison with other contrast media, and it is now widely used for myelography, cisternography, ventriculography and cerebrospinal fluid dynamic imaging. However, as the number of cases in which this medium has been utilized has gradually increased, incidents of toxic manifestations have been reported. Among these, there are a considerable number of case reports referring to metrizamide encephalopathy, but only a few authors reported the appearance of triphasic waves on EEG when they occurred. The authors experienced one case of metrizamide encephalopathy accompanied by frequent appearance of triphasic waves on EEG. A 31-year old male was admitted to our hospital with the complaint of right homonymous hemianopsia. At that time he was fully conscious and mentally alert. On CT, 39 mm X 45 mm partially enhanced isodense mass was revealed on the enlarged sella turcica. Laboratory findings showed high titer of prolactin (10200 ng/ml). Premedication of 100 mg phenobarbital i.m. was followed by the tomography of the sella turcica, using 8 ml of 250 mgI/ml metrizamide injected into L 3-L 4 subarachnoid space. Several hours after the examination, he complained of slight nausea and was kept in bed with his head placed in an elevated position. The next morning, he was found to be in a drowsy state. He was disoriented and could not respond adequately to questions asked. His naming of daily necessities was also poor, although he knew how to use them.(ABSTRACT TRUNCATED AT 250 WORDS)