Addison's Disease: A Diagnosis Easy to Overlook

Addison's disease is a rare and potentially life-threatening clinical condition that often presents with an insidious onset of nonspecific symptoms and signs, frequently resulting in a significant delay in diagnosis. Clinical presentation usually includes fatigue and electrolyte imbalance disorders such as hyponatremia. However, specific diagnostic features, such as hyperpigmentation, should raise clinical suspicion. This case report describes a 43-year-old Caucasian male who presented with general malaise, fatigue, anorexia, and weight loss (7 Kg in four weeks). On physical examination, he was found to have severe hyperpigmentation of the skin and mucosal surfaces as well as hypotension. Laboratory tests revealed hypoosmolar hyponatremia and serum potassium levels in the upper limit of normal. Findings of high serum adrenocorticotropic hormone (ACTH) and renin, as well as low cortisol and aldosterone levels, helped establish a diagnosis of Addison's disease. After the initiation of treatment, the patient experienced full recovery of symptoms, normalization of hyponatremia, and improvement of hyperpigmentation. Patients with Addison's disease have the potential to resume normal daily activities with a highly functional status. However, this condition requires lifelong follow-up and surveillance.