Endocrinology

Topics in this chapter

• Pituitary Disorders
• Thyroid Disorders
• Adrenal Disorders
• Diabetes Mellitus
• Parathyroid and Calcium Disorders
• Endocrine Pharmacotherapy
• Endocrine Syndromes and Pregnancy

Practice questions

1. Question 1Q-18484A

   A 34-year-old woman presents with palpitations, weight loss, heat intolerance, and a tremor. Laboratory investigations reveal a suppressed TSH of <0.01 mIU/L, elevated free T4, and significantly elevated radioactive iodine uptake diffusely throughout the gland. She is diagnosed with Graves disease. Which of the following antibodies is the primary pathogenic driver of this condition?

   1. A.Anti-thyroid peroxidase (anti-TPO) antibodies
   2. B.Thyroid-stimulating hormone receptor antibodies (TRAb)
   3. C.Anti-thyroglobulin antibodies
   4. D.Thyroid-stimulating immunoglobulin G Fc-receptor antibodies
   See the answer and solution
2. Question 2Q-448255

   A 45-year-old man is evaluated for recurrent kidney stones, bone pain, and generalized fatigue. Serum calcium is 11.8 mg/dL (normal 8.5-10.2), serum phosphate is 2.1 mg/dL (normal 2.5-4.5), and intact PTH is markedly elevated at 145 pg/mL (normal 10-65). 24-hour urinary calcium excretion is elevated. Which of the following is the most common cause of primary hyperparathyroidism?

   1. A.Parathyroid carcinoma
   2. B.Single parathyroid adenoma
   3. C.Four-gland parathyroid hyperplasia
   4. D.Ectopic PTH secretion by a neuroendocrine tumor
   See the answer and solution
3. Question 3Q-C32A83

   A 28-year-old pregnant woman in her first trimester is evaluated for mild tachycardia and fatigue. Thyroid function tests show a TSH of 0.05 mIU/L (low) and free T4 within the normal reference range. She has no palpable goiter, ophthalmopathy, or prior history of thyroid disease. What is the most appropriate next step in management?

   1. A.Start propylthiouracil immediately
   2. B.Check free T3 and thyroid-stimulating immunoglobulins (TSI)
   3. C.Perform a radioactive iodine uptake scan
   4. D.Reassure and monitor thyroid function tests in 4 weeks
   See the answer and solution
4. Question 4Q-455B17

   A 52-year-old man presents with progressive fatigue, skin hyperpigmentation, orthostatic hypotension, and weight loss. Laboratory workup reveals hyponatremia, hyperkalemia, and a low morning serum cortisol level. An ACTH stimulation test shows a baseline cortisol of 3 mcg/dL and a 60-minute post-cosyntropin cortisol of 5 mcg/dL. Which of the following additional findings is most characteristic of primary adrenal insufficiency compared to secondary adrenal insufficiency?

   1. A.Severe hypoglycemia
   2. B.Hyperpigmentation and hyperkalemia
   3. C.Metabolic alkalosis
   4. D.Elevated thyroid-stimulating hormone
   See the answer and solution
5. Question 5Q-60B442

   A 60-year-old obese man with type 2 diabetes mellitus presents for routine checkup. His HbA1c is 8.2% despite maximal doses of metformin. He has a history of congestive heart failure (NYHA Class III) and stage 3 chronic kidney disease. Which of the following classes of glucose-lowering agents should be added with demonstrated benefit for both heart failure and renal protection?

   1. A.Sulfonylureas
   2. B.Thiazolidinediones
   3. C.Sodium-glucose cotransporter-2 (SGLT2) inhibitors
   4. D.Dipeptidyl peptidase-4 (DPP-4) inhibitors
   See the answer and solution