ACTH deficiency: problems in recognition and diagnosis.

Corticotrophin (ACTH) deficiency is an important cause of a potentially lethal form of adrenocortical failure. Difficulties can arise in making the diagnosis, especially when secretion of other pituitary trophic hormones is normal. Presenting features of seven patients with ACTH deficiency, in whom the diagnosis was difficult for a variety of reasons, are reported and discussed. Two patients had a normal cortisol response to synthetic ACTH. The possibility of ACTH deficiency should be considered in any patient presenting with weight loss, vomiting, muscular fatigue and stiffness, hyponatraemia or hypoglycaemia.