MD - Doctor of Medicine Endocrine and Metabolic Disorders Questions and Answers

Question 1

A 24-year-old female with a known history of type 1 diabetes presents to the emergency department with nausea, vomiting, abdominal pain, and deep, rapid breathing.
Her blood glucose is 550 mg/dL, arterial pH is 7.15, and serum ketones are strongly positive.
After confirming the diagnosis of Diabetic Ketoacidosis (DKA), what is the most critical initial step in management?

Accepted Answer

Start aggressive intravenous fluid resuscitation with normal saline.

Answer

Administer a subcutaneous dose of long-acting insulin.

Answer

Begin intravenous regular insulin infusion.

Answer

Administer intravenous sodium bicarbonate to correct acidosis.

Question 2

A 42-year-old female presents with central obesity, purple striae, hypertension, and easy bruising. You suspect Cushing's syndrome. Which of the following is considered a first-line screening test to confirm hypercortisolism?

Accepted Answer

24-hour urinary free cortisol measurement.

Answer

Plasma ACTH level.

Answer

High-dose dexamethasone suppression test.

Answer

Abdominal MRI.

Question 3

A 68-year-old male with small cell lung cancer is admitted with confusion and lethargy. His laboratory results are significant for a serum sodium of 118 mEq/L. Which of the following laboratory patterns is most consistent with the Syndrome of Inappropriate Antidiuretic Hormone (SIADH)?

Accepted Answer

Euvolemic hyponatremia, high urine osmolality (>100 mOsm/kg), high urine sodium (>40 mEq/L).

Answer

Hypervolemic hyponatremia, low urine osmolality (<100 mOsm/kg), low urine sodium (<20 mEq/L).

Answer

Hypovolemic hyponatremia, high urine osmolality (>450 mOsm/kg), low urine sodium (<20 mEq/L).

Answer

Euvolemic hyponatremia, low urine osmolality (<100 mOsm/kg), high urine sodium (>40 mEq/L).

Question 4

A 35-year-old patient reports episodic headaches, palpitations, and profuse sweating, often accompanied by severe hypertension. A pheochromocytoma is suspected. What is the most appropriate initial biochemical test to establish the diagnosis?

Accepted Answer

Plasma free metanephrines.

Answer

Serum epinephrine and norepinephrine levels.

Answer

24-hour urine for vanillylmandelic acid (VMA).

Answer

Clonidine suppression test.

Question 5

A patient with Graves' disease is started on methimazole. Which of the following best describes the primary mechanism of action of this thionamide medication?

Accepted Answer

It inhibits the thyroid peroxidase enzyme, blocking the organification of iodine.

Answer

It blocks the peripheral conversion of T4 to T3.

Answer

It competitively blocks the TSH receptor on thyroid follicular cells.

Answer

It destroys thyroid follicular cells through radioactive emission.

Question 6

A 60-year-old woman is found to have an elevated serum calcium level of 11.5 mg/dL on routine labs. A subsequent workup confirms primary hyperparathyroidism. Which of the following sets of laboratory findings is most characteristic of this condition?

Accepted Answer

High serum calcium, low serum phosphate, high or inappropriately normal parathyroid hormone (PTH).

Answer

High serum calcium, high serum phosphate, low parathyroid hormone (PTH).

Answer

Low serum calcium, high serum phosphate, high parathyroid hormone (PTH).

Answer

High serum calcium, low serum phosphate, low parathyroid hormone (PTH).