[Severe hyponatremia revealing Sheehan's syndrome]

We describe the case of a young woman admitted for severe hyponatremia due to hypopituitarism caused by a Sheehan's syndrome. Sheehan's syndrome is a rare disorder. It develops after obstetrical hemorrhage that causes ischemic necrosis of the pituitary gland. In most cases, illness appears progressively and diagnosis is made after variable delay. Acute syndrome may develop immediately after delivery in some rare cases. Hyponatremia is a frequent manifestation and may be severe. It is principally caused by secondary adrenal failure.