Severe iatrogenic ergotism: incidence and clinical importance.

Ergot's derivatives are widely used to treat and prevent migraine and, associated with heparin, for the prevention of deep vein thrombosis. During a five-year period, 7 patients have been admitted in our hospital for severe vasospasm of one or several extremities due to ergot's derivatives. All patients presented with acute severe ischemia of the lower limb requiring iv infusion of vasodilator drugs. Ergotamine tartrate was the responsible drug in four patients and dihydroergotamine(DHE)-heparin in three patients. Intravenous administration of sodium nitroprusside (n = 6) relieved vasospasm in all but one of the patients within hours to days and no amputation was required. Ankle or great toe to arm systolic pressure index was normalized in the majority of the patients after treatment. A sympathectomy was performed in two patients which did not improve the clinical course. Distal necrosis developed in two patients (DHE-heparin). It is concluded that incidence of severe ergotism is less than 0.5/100,000/year in Geneva. This contrasts with the high prevalence (15%) of subclinical ergotism reported by others. No amputation was required in this series in spite of severe and prolonged vasospasms. Subclinical ergotism most probably precedes for weeks the onset of severe vasospasm, which calls for close monitoring of patients taking ergot's derivatives.