Methyl iodide poisoning: report of two cases.

Two workers were poisoned following exposure to methyl iodide with inadequate protective devices. Their cases are presented together with a review of literature. Both patients developed symptoms and signs of cerebellar lesions and damage of the third, fourth, or sixth cranial nerve pathways. Spinal cord lesions producing motor and sensory disturbances were present in one. Late psychiatric disorders were observed in both patients. Although these symptoms were very similar to those reported in the nine published cases of methyl iodide poisoning, the toxicological diagnosis was delayed in one case: as repeated overexposure produced recurrent attacks of multifocal neurological dysfunction, multiple sclerosis was initially diagnosed, although several of the features observed are unusual in this disease. The manifestations of methyl iodide poisoning are similar to those of intoxication with other monohalomethanes. All these compounds probably share the same mechanisms of action. This mechanism and its therapeutic consequences are discussed.