Scorpion envenomation as a risk factor for development of dilated cardiomyopathy.

OBJECTIVES: Though scorpion envenomation is known to lead to acute myocarditis and a reversible decrease in left ventricular function, it has not been implicated as an etiological factor in idiopathic dilated cardiomyopathy. We studied the association of idiopathic dilated cardiomyopathy with a history of scorpion sting as well as with socio-economic status, history of smoking and alcoholism, rural habitation, and history of snake bites.

METHODS: Consecutive cases of idiopathic dilated cardiomyopathy were recruited for this study: The association with putative risk factors was studied using a case-control study design with two sets of controls. One set of controls were age and sex matched inpatients selected at random, the other set of controls were spouse, or if not available, a close relative, ordinarily resident with the patient.

RESULTS: On analysis, none of the factors except scorpion envenomation had a significant association. A past history of scorpion envenomation had an adjusted odds ratio of 8.01 (3.55-18.06) when compared to one set of controls and an odds ratio of 8.33 (6.55-10.59) when compared to the second group of controls.

CONCLUSIONS: Our study indicates that a history of scorpion envenomation acts as a risk factor for the subsequent development of idiopathic dilated cardiomyopathy. Despite an apparently complete recovery from a scorpion sting, many patients probably retain sub-clinical deficits that predispose to the development of cardiomyopathy later in life, when other factors get added on. The known association of cardiomyopathy with catecholamine excess in experimental situations in animal studies, and in other disease states in humans, supports this hypothesis.