Internal Medicine Endocrinology and Metabolism Questions and Answers

Question 1

A 58-year-old male with type 2 diabetes, hypertension, and a history of heart failure with reduced ejection fraction (HFrEF) presents for a medication review. His A1c is 7.8% on metformin and glipizide. His eGFR is 50 mL/min/1.73m². Which of the following medications should be added to his regimen to improve glycemic control and provide a mortality benefit?

Accepted Answer

Empagliflozin

Answer

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, such as empagliflozin, have demonstrated significant cardiovascular benefits in patients with type 2 diabetes and established cardiovascular disease. Clinical trials like EMPA-REG OUTCOME have shown that empagliflozin reduces the risk of cardiovascular death, all-cause mortality, and hospitalization for heart failure. Pioglitazone is contraindicated in patients with heart failure as it can cause fluid retention and exacerbate the condition. Sitagliptin (a DPP-4 inhibitor) is considered cardiovascularly neutral. Insulin glargine effectively lowers glucose but does not provide the same cardiovascular mortality benefit seen with SGLT2 inhibitors in this patient population.

Question 2

A 45-year-old female is evaluated for a 1.5 cm thyroid nodule found incidentally. Her TSH is normal. A fine-needle aspiration (FNA) returns as 'Bethesda category III: Atypia of Undetermined Significance (AUS)'. What is the most appropriate next step in management?

Accepted Answer

Perform molecular testing on the FNA sample

Answer

For thyroid nodules with indeterminate cytology, such as Bethesda category III (Atypia of Undetermined Significance or AUS), molecular testing is recommended to further stratify the risk of malignancy. Tests like Afirma Gene Expression Classifier or ThyroSeq can help differentiate benign from potentially malignant nodules, guiding the decision between observation and diagnostic surgery. Repeating the FNA is an alternative but offers less definitive risk stratification. Immediate thyroidectomy is overly aggressive for a Bethesda III nodule, and suppressive levothyroxine therapy is not indicated for euthyroid patients with benign or indeterminate nodules.

Question 3

A 34-year-old woman presents with central obesity, facial plethora, proximal muscle weakness, and new-onset hypertension. An overnight 1-mg dexamethasone suppression test fails to suppress serum cortisol. Her plasma ACTH level is <5 pg/mL (suppressed). What is the most likely source of her condition?

Accepted Answer

Adrenal adenoma

Answer

The clinical presentation and non-suppressed cortisol after dexamethasone confirm Cushing's syndrome. The key diagnostic finding is the suppressed plasma ACTH level. This indicates an ACTH-independent cause, meaning the adrenal gland is autonomously producing cortisol and suppressing the pituitary via negative feedback. The most common cause of ACTH-independent Cushing's syndrome is a cortisol-producing adrenal adenoma. In contrast, Cushing's disease (pituitary source) and ectopic ACTH-producing tumors would present with normal or elevated ACTH levels. Iatrogenic use would also cause a suppressed ACTH but is a diagnosis of exclusion based on history.

Question 4

Which of the following is the most significant contraindication to the use of teriparatide for the treatment of severe osteoporosis?

Accepted Answer

Prior radiation therapy to the skeleton

Answer

Teriparatide carries a warning regarding an increased risk of osteosarcoma, based on findings in rat studies. Therefore, it is contraindicated in patients with an increased baseline risk for osteosarcoma. This includes individuals with Paget's disease of the bone, unexplained elevations of alkaline phosphatase, and, significantly, a history of prior radiation therapy to the skeleton. While caution is advised in patients with renal impairment or a history of kidney stones, and vitamin D should be repleted before starting therapy, these are not absolute contraindications like prior skeletal radiation.

Question 5

A 72-year-old male admitted for pneumonia is found to have a serum sodium of 118 mEq/L. Further labs show serum osmolality of 255 mOsm/kg, urine osmolality of 450 mOsm/kg, and urine sodium of 50 mEq/L. He is clinically euvolemic. What is the most appropriate initial treatment for his hyponatremia?

Accepted Answer

Fluid restriction to <1 L/day

Answer

The patient's presentation of euvolemic hypotonic hyponatremia with inappropriately concentrated urine is classic for the Syndrome of Inappropriate Antidiuretic Hormone (SIADH), which is often precipitated by pulmonary infections. For mild to moderate asymptomatic or mildly symptomatic hyponatremia from SIADH, the cornerstone of initial management is free water restriction. Administering normal saline can worsen hyponatremia in SIADH. Desmopressin is used to treat central diabetes insipidus. Hypertonic saline is reserved for severe, symptomatic hyponatremia (e.g., seizures, coma).

Internal Medicine Exam Practice Test

Internal Medicine Exam Practice Test

Internal Medicine Endocrinology and Metabolism Questions and Answers