Secondary adrenal insufficiency caused by adult development of pituitary stalk transection

We report the case of a 38-year-old man with secondary adrenal insufficiency due to pituitary stalk transection that may have been caused by birth injury. He was admitted to our hospital with epigastalgia and severe hyponatremia (120 mEq/L). His past history showed fetal distress due to an abnormal delivery, and he received growth hormone replacement therapy for growth hormone-deficient short stature. Magnetic resonance imaging of the brain revealed an atrophic anterior lobe, a pseudo-posterior lobe of the pituitary gland, and a transection of the pituitary stalk. Endocrinological examination revealed secondary adrenal insufficiency due to a suprapituitary lesion, with concomitant impaired secretion of growth hormone, gonadotropins, and thyroid-stimulating hormone. Hyponatremia was improved immediately after administration of hydrocortisone. This is a case of adult development of pituitary stalk transection syndrome, involving the sequential impairment of the secretion of several pituitary hormones, and finally presenting severe hyponatremia caused by secondary adrenal insufficiency.