A 40-year-old alcoholic man is being treated for tuberculosis, but he has no compliant with his medications. He complains of increasing weakness, fatigue, weight loss, and nausea over the preceding 3 weeks. He appears thin, and his blood pressure is 80/50 mm Hg. There is increased pigmentation over the elbows and in the palmar creases. Cardiac examination is normal. Which of the following is the best next step in evaluation?
A. CBC with iron and iron-binding capacityThis patient’s symptoms of weakness, fatigue, and weight loss in combination with hypotension and extensor hyperpigmentation are all consistent with Addison disease (adrenal insufficiency). Tuberculosis can involve the adrenal glands and result in adrenal insufficiency. Measurement of serum cortisol baseline and then stimulation with cosyntropin (a synthetic ACTH analogue) will confirm the clinical suspicion. The ACTH stimulation test is used to determine the adrenal reserve capacity for steroid production. Cortisol response is measured 30 and 60 minutes after cosyntropin is given intramuscularly or intravenously; a value of 18 μg/dL or above effectively excludes adrenal insufficiency. Hemochromatosis can cause hyperpigmentation but not the weight loss and hypotension. Bacteremia would not cause the gradually increasing symptoms or the hyperpigmentation. In some patients with weight loss and nausea, an EGD may be warranted; however, the clinical features of adrenal insufficiency in conjunction with poorly treated tuberculosis would first direct attention toward adrenal status.