Severe Hypokalaemia, Hypertension, and Intestinal Perforation in Ectopic Adrenocorticotropic Hormone Syndrome.

Ectopic adrenocorticotropic hormone (ACTH) syndrome is a rare cause of the Cushing's syndrome. The occurrence of the ectopic ACTH syndrome presenting with severe hypokalaemia, metabolic alkalosis, and hypertension has been highlighted in case reports. However, presentation with lower gastrointestinal perforation is not known. We report the case of a 70-year-old male patient with severe hypokalaemia, metabolic alkalosis, hypertension, and colonic perforation as manifestations of an ACTH-secreting small cell lung carcinoma. Ectopic ACTH syndrome should be kept in mind as a cause of hypokalaemia, hypertension, and intestinal perforation in patients with lung carcinoma.