ITE Endocrinology and Metabolism Questions and Answers — Questions and Answers
Question 1: A 62-year-old male with a 10-year history of type 2 diabetes mellitus and a prior myocardial infarction has an HbA1c of 7.8% on metformin monotherapy. His eGFR is 65 mL/min/1.73m². According to the most recent American Diabetes Association (ADA) guidelines, which of the following medications would be the most appropriate addition to his regimen?
- Glipizide
- Empagliflozin (Correct answer)
- Sitagliptin
- Pioglitazone
Correct answer: Empagliflozin
For patients with type 2 diabetes and established atherosclerotic cardiovascular disease (ASCVD), guidelines strongly recommend adding an agent with proven cardiovascular benefit. Empagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, has demonstrated a significant reduction in major adverse cardiovascular events, cardiovascular mortality, and hospitalization for heart failure in this patient population. Glipizide (a sulfonylurea) increases insulin secretion but carries a risk of hypoglycemia and is cardiovascular neutral. Sitagliptin (a DPP-4 inhibitor) is also weight and cardiovascular neutral. Pioglitazone (a thiazolidinedione) can cause weight gain and fluid retention, and should be used with caution in patients at risk for heart failure.
Question 2: A 48-year-old woman is found to have a 1.8 cm thyroid nodule incidentally on a carotid ultrasound. Her TSH level is normal. A dedicated thyroid ultrasound is performed and describes the nodule as solid, markedly hypoechoic, with a taller-than-wide shape and microcalcifications. Based on these high-risk features, which of the following is the most appropriate next step in management?
- Reassurance and repeat ultrasound in 12 months
- Fine-needle aspiration (FNA) biopsy (Correct answer)
- Trial of levothyroxine suppression therapy
- Measurement of serum thyroglobulin
Correct answer: Fine-needle aspiration (FNA) biopsy
According to the American Thyroid Association (ATA) and ACR TI-RADS guidelines, a nodule >1 cm with high-suspicion sonographic features warrants a fine-needle aspiration (FNA) biopsy. The features described (solid, markedly hypoechoic, taller-than-wide, microcalcifications) place this nodule in the highest risk category for malignancy (TI-RADS 5). Reassurance would be inappropriate. Levothyroxine suppression is not recommended for the management of thyroid nodules. Serum thyroglobulin is primarily used as a tumor marker for surveillance after thyroidectomy, not for the initial diagnosis of a nodule.
Question 3: A 42-year-old woman presents with several months of progressive fatigue, weight loss, nausea, and orthostatic dizziness. On examination, her blood pressure is 90/60 mmHg, and she has hyperpigmentation of her palmar creases. Laboratory studies reveal hyponatremia and hyperkalemia. A baseline 8 AM serum cortisol level is 2.8 µg/dL (low). Which of the following tests is the most appropriate next step to confirm the diagnosis of primary adrenal insufficiency?
- CRH stimulation test
- 24-hour urine free cortisol measurement
- High-dose (250 mcg) ACTH (cosyntropin) stimulation test (Correct answer)
- Metyrapone test
Correct answer: High-dose (250 mcg) ACTH (cosyntropin) stimulation test
The clinical presentation and initial laboratory findings are highly suggestive of primary adrenal insufficiency (Addison's disease). The standard and most definitive diagnostic test is the high-dose (250 mcg) ACTH stimulation test. A failure of serum cortisol to rise to an adequate level (typically >18-20 µg/dL) after cosyntropin administration confirms the diagnosis. A 24-hour urine free cortisol is used to screen for cortisol excess (Cushing's syndrome). The CRH stimulation test is used to differentiate between secondary (pituitary) and tertiary (hypothalamic) adrenal insufficiency. The metyrapone test is rarely used.
Question 4: A 72-year-old woman sustains a hip fracture after a fall from standing height. A subsequent DEXA scan reveals a T-score of -2.8 at the femoral neck. She has no contraindications to oral medications and her renal function is normal. Which of the following is the most appropriate initial long-term pharmacologic therapy?
- Raloxifene
- Teriparatide
- Denosumab
- Oral alendronate (Correct answer)
Correct answer: Oral alendronate
This patient has established, severe osteoporosis, defined by the presence of a fragility fracture. According to major clinical guidelines (AACE/ACE), oral bisphosphonates such as alendronate are the recommended first-line therapy for most postmenopausal women with osteoporosis. They are effective at reducing both vertebral and hip fractures, are cost-effective, and have an extensive safety record. Denosumab is also a first-line option but is often used in those who cannot tolerate oral bisphosphonates. Teriparatide, an anabolic agent, is typically reserved for very high-risk patients or those who fail bisphosphonate therapy. Raloxifene is less potent and is not proven to reduce the risk of hip fractures.
Question 5: A 32-year-old woman presents with a 9-month history of amenorrhea and milky breast discharge. Her serum prolactin level is 150 ng/mL (normal <25 ng/mL). An MRI of the pituitary reveals a 7 mm microadenoma. Visual field testing is normal. What is the most appropriate initial treatment for this condition?
- Cabergoline (Correct answer)
- Transsphenoidal surgery
- Observation with serial MRIs
- Stereotactic radiosurgery
Correct answer: Cabergoline
The patient has a symptomatic prolactin-secreting microadenoma (prolactinoma). The first-line treatment for virtually all prolactinomas, regardless of size, is medical therapy with a dopamine agonist. Cabergoline is generally preferred over bromocriptine due to its higher efficacy and better side-effect profile. Dopamine agonists are highly effective at normalizing prolactin levels, restoring gonadal function (and thus menses), and shrinking the tumor. Surgery is considered second-line for patients who are intolerant of or resistant to medical therapy. Observation is not appropriate for a symptomatic patient. Radiation is a third-line option for aggressive or refractory tumors.
Question 6: A 65-year-old asymptomatic woman is found to have a serum calcium of 11.4 mg/dL (normal range 8.6-10.3 mg/dL) on routine labs. A repeat level confirms hypercalcemia. Subsequent workup reveals an elevated intact PTH of 110 pg/mL (normal 15-65 pg/mL) and a 24-hour urine calcium of 350 mg. Her eGFR is 75 mL/min, and a DEXA scan shows a T-score of -1.8 at the lumbar spine. According to the guidelines from the International Workshop on Asymptomatic Primary Hyperparathyroidism, which of the following is a clear indication for parathyroidectomy in this patient?
- Age of 65 years
- DEXA scan T-score of -1.8
- Serum calcium level >1.0 mg/dL above the upper limit of normal (Correct answer)
- 24-hour urine calcium of 350 mg/day
Correct answer: Serum calcium level >1.0 mg/dL above the upper limit of normal
The patient has asymptomatic primary hyperparathyroidism. The current guidelines for recommending parathyroidectomy include several criteria. One major criterion is a serum calcium level 1.0 mg/dL or more above the upper limit of the normal range. In this case, the upper limit is 10.3 mg/dL, so a level ≥11.3 mg/dL is an indication for surgery. Her level of 11.4 mg/dL meets this criterion. The other options are incorrect: the age criterion is for patients <50 years old, the bone density criterion is a T-score of ≤ -2.5 (osteoporosis), and the hypercalciuria criterion is typically >400 mg/day.
ITE Endocrinology and Metabolism Questions and Answers
A 62-year-old male with a 10-year history of type 2 diabetes mellitus and a prior myocardial infarction has an HbA1c of 7.8% on metformin monotherapy.
His eGFR is 65 mL/min/1.73m².
According to the most recent American Diabetes Association (ADA) guidelines, which of the following medications would be the most appropriate addition to his regimen?