A syndrome clinically resembling amyotrophic lateral sclerosis following chronic mercurialism

Abstract

In this paper, 11 cases of chronic mercurialism with a neurologic picture akin to amyotrophic lateral sclerosis are reported. All these patients consumed bread prepared from wheat treated with a seed fungicide called Granosan M (Dupont). The active ingredient is 7.7% ethyl mercury p-toluene sulfonanilide. The period of consumption was about two to three months. The physical examination was essentially normal, except for the presence of gingival swelling and a blue line at the gum margins in 7 patients and an erythematous rash in 2. Neurologic examination disclosed motor weakness of the extremities and wasting of the limb and trunk musculature, with widespread fasciculations in the atrophic areas in all the patients. In this group, 6 patients had hyperreflexia, and there was a definite Babinski sign in 4 and an equivocal sign in 2. The remaining 5 patients had no pathologic pyramidal signs. The underlying etiology was chronic mercurialism in all the patients. This was confirmed by detection of mercury in samples of hair and nails. Because of the presence of pathologic pyramidal signs, 6 of the cases in this group would have been diagnosed as amyotrophic lateral sclerosis. The remaining 5 would have been labeled progressive muscular atrophy because of limitation of the lesions to the lower motor neurons. Since the same causative factor was operative in all these cases, it would appear that amyotrophic lateral sclerosis and progressive muscular atrophy are probably nosologically identical. Amyotrophic lateral sclerosis should not be considered a disease entity but rather a syndrome of variable etiology. Chronic mercurialism is a possible etiologic factor in amyotrophic lateral sclerosis.