Adrenal insufficiency is a potentially life-threatening condition when it occurs acutely, as in adrenal hemorrhage. Generally it is not reversible and requires chronic replacement therapy. Acute intermittent porphyria (AIP) is a rare genetic disease characterized by alterations in heme biosynthesis that result in accumulation of precursors in tissues. A crisis can be triggered by many conditions such as surgery and infections. Symptoms are similar to those of acute hypoadrenalism. Moreover, both conditions are characterized by hyponatremia. We describe the case of a postmenopausal woman known to be affected by AIP who developed after surgery a primary adrenal insufficiency associated with adrenal enlargement; the latter completely reverted in six months.