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

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.