[Addison's disease, primary adrenal insufficiency in adults]

Adrenal insufficiency is a rare but fatal disease if left unrecognized. Symptoms often mimic more prevalent diseases. We discuss three patients with primary adrenal insufficiency. These cases illustrate that presenting symptoms such as syncope, nausea, vomiting, weight loss and hypoglycemia are often non-specific and, therefore, often not immediately recognized. When an adrenal crisis is suspected, glucocorticoids should be given promptly. The symptoms are caused by insufficient production of adrenal hormones due to destruction of the adrenal glands by auto-immune adrenalitis. An ACTH stimulation test should confirm the diagnosis when primary adrenal insufficiency is suspected. Treatment consists of glucocorticoid and mineralocorticoid replacement. Primary adrenal insufficiency is a 'master of disguise'. Unexplained syncope, vomiting, weight loss or hypoglycemia should prompt suspicion of this disease.