A 23 year old woman complains of excessive weakness and fatigue for the last two months. She also complains of nausea, vomiting, anxiety and lightheadedness on standing. She had no similar attacks on the past. Her medical, surgical and family history are unremarkable. On examination, her blood pressure is 100/64 on sitting and 90/60 on standing. Darkening of the skin especially palm creases and around the nipples. Her laboratory tests show hypocalcemia, hypoglycemia, hyponatremia and hyperkalemia. She is referred for ACTH stimulation test. http://medical-usmle.com/repeated-usmle-questions-52
