A 40-year old alcoholic male is being treated for TB, but he has not been regular with his medications. He complains of increasing weakness and fatigue. He appears to have lost weight and his BP is 80/50. There is increased pigmentation over the elbows. Cardiac exam is normal. The next step in evaluation should be

This patient's symptoms of weakness, fatigue, and weight loss in combination with signs of hypotension and extensor hyperpigmentation are all consistent with Addison's disease. Tuberculosis can involve the adrenal glands and result in adrenal insufficiency. Measurement of serum coisol baseline and then stimulation with ACTH will confirm the clinical suspicion. The ACTH stimulation test is used to determine the adrenal reserve capacity for steroid production. Coisol response is measured 60 mm after cosyntropin is given intramuscularly or intravenously.