Adrenal insufficiency typically presents with non-specific symptoms, followed by shock secondary to a salt-wasting crisis and/or the vascular effects of glucocorticoid deficiency if it progresses to acute adrenal insufficiency. Rhabdomyolysis and cardiac dysfunction are rarely reported, particularly in children. We report a child with adrenal insufficiency, presenting with acute abdominal signs, probably secondary to rhabdomyolysis, and complicated by reversible cardiomyopathy. Acute adrenal insufficiency should be considered with this presentation. The possibility of impaired cardiac function during its treatment should also be considered.