What other endocrinopathies have been seen with ICPIs?
Primary adrenal insufficiency, type 1 diabetes mellitus, and hypoparathyroidism have been occasionally seen with use of ICPIs. Primary adrenal insufficiency should be suspected in the setting of typical symptoms of adrenal insufficiency (fatigue, light headedness, weight loss, abdominal pain, nausea, vomiting), with an elevated plasma adrenocorticotropic hormone (ACTH) level and a low serum cortisol level (especially < 3 mcg/dL) or a failure to stimulate cortisol to 18 mcg/dL or greater during a cosyntropin stimulation test. Patients with primary adrenal insufficiency need both glucocorticoid and mineralocorticoid supplementation, whereas those with central adrenal insufficiency only require glucocorticoid replacement. Type 1 diabetes can be suspected in patients with sudden-onset diabetes, especially if they present with diabetic ketoacidosis. Antibodies for type 1 diabetes along with C-peptide and insulin levels can help differentiate type 1 diabetes from type 2 diabetes. Hypoparathyroidism presents with symptoms of hypocalcemia (numbness, tingling, tetany), low serum calcium and high serum phosphorus levels, and low or low-normal serum parathyroid hormone (PTH) levels. This condition can be treated with a combination of calcium, calcitriol, and, as necessary, a thiazide diuretic and PTH (Natpara) replacement. Knowledge of the natural history of these disorders is limited because of their rare occurrences at this time.