[Acute adrenal insufficiency: an entity that should not be missed].

Acute adrenal insufficiency is a rare pathology which can be life threatening if not diagnosed and treated adequately. Clinical presentation is aspecific. Etiologies are classified as central or adrenal origins. Diagnosis of adrenal insufficiency is based on dosage of morning cortisol combined with a Synacthen test. When acute adrenal insufficiency is suspected, 100 mg of hydrocortisone should be administered as soon as possible, even before biological confirmation. This article, illustrated by a clinical case, will review the clinical presentation, diagnostic approach, and treatment of adrenal insufficiency.