**2. Epidemiology**

## **2.1 Incidence**

Incidence of thyroid storm is not precisely known. Incidence in general population was reported as 0.57-0.76 per lac per year in USA and 0.20 per lac per year in Japan, whereas incidence in hospitalized patients was 4.8-5.6 per lac per year [4–6]. Hospital data suggest that it occurs in 1–2% of patients admitted for thyrotoxicosis [5]. It occurs more commonly in women and patients with Graves' disease [7]. Autonomous nodules are the culprit in elderly patients [8].

### **2.2 Mortality**

Seventy-five percent of patients hospitalized with thyroid storm die [9]. Overall mortality rate has been reported to be 10–20% [4, 10–12]. Multiple system dysfunction is the commonest cause of death, followed by heart failure [13], respiratory failure [13], and sepsis [3, 14].
