Clinical and echocardiographic findings in patients with myocardial toxicity due to scorpion sting.

ABSTRACT

BACKGROUND: Myocardial toxicity following a sting by the Indian red scorpion (Mesobuthus tamulus) is a life-threatening medical emergency. A perusal of the published literature suggests that this problem has seldom been studied systematically. METHODS: We retrospectively studied the clinical presentation and echocardiographic findings in 24 patients (mean [SD] age 23.2 [11.7] years; 19 males) with myocardial toxicity caused by the sting of an Indian red scorpion (Mesobuthus tamulus). They were treated with inotropic support and diuretics depending on the requirement. At admission, oral L-carnitine was administered in a dose of 1980 mg/day in three divided doses till the left ventricular (LV) function normalized. None of the patients received digitalis, prazosin, hydrocortisone or antivenin. RESULTS: Extreme anxiety and severe pain at the site of sting were present in all the patients. Hypotension (n = 19), pulmonary oedema (n= 15) and acute renal failure (n=8) were the other presenting features. Chest X-ray revealed cardiomegaly in 8 and pulmonary oedema in 13 patients. Serum creatinine phosphokinase levels were elevated more than two times the upper limit of normal (200 IU/L) in 22 patients (92%). The mean duration of hospitalization was 5 days (range 3- 11 days). L-carnitine treatment resulted in significant reduction in the LV diameter (mm) in diastole (47.6 [6.2] v. 42 [6.1], p < 0.01) and systole (42 [7.1] v. 28.2 [4], p<0.001); end-diastolic volume (ml) (108.7 [31.9] v. 81 [26.7], p <0.01) and end-systolic volume (ml) (81.3 [30.9] v. 31.1 [10.7], p < 0.001); and significant improvement in the stroke volume (ml) 27.8 [13.2] v. 61.7 [6.2], p<0.001) and ejection fraction (%) (25.5 [12.8] v. 61.2 [6.5], p<0.001). All the patients responded well to treatment and none died. CONCLUSION: Our initial observations suggest a potential benefit with additional oral L-carnitine treatment in patients with myocardial toxicity caused by scorpion sting presenting with hypotension and severe LV dysfunction. These findings merit further study.