Endocrinology & Diabetes Practice Questions

Q: A 46-year-old man presents with recurrent episodes of severe flushing and diarrhea. CT shows liver metastases and a pancreatic mass. Chromogranin A is markedly elevated. What is the most likely primary tumor?

Pancreatic neuroendocrine tumor. ***Pancreatic neuroendocrine tumor*** - The classic presentation of recurrent **flushing** and **diarrhea**, combined with a **pancreatic mass** and **liver metastases**, is highly characteristic of a functional **neuroendocrine tumor (NET)**, specifically a **carcinoid syndrome**. - Markedly elevated **Chromogranin A** is a widely used and sensitive biochemical marker for **neuroendocrine tumors**, confirming this diagnosis. *Pancreatic adenocarcinoma* - This tumor typically presents with symptoms such as **jaundice**, **weight loss**, and **abdominal pain**, not **flushing** and **diarrhea**. - **Chromogranin A** is not elevated in pancreatic adenocarcinoma; **CA 19-9** is a more common tumor marker. *Hepatocellular carcinoma* - While **liver metastases** are mentioned, the primary tumor is a **pancreatic mass**, not a primary liver tumor. - It does not typically cause **flushing** and **diarrhea**, nor is **Chromogranin A** a marker for hepatocellular carcinoma. *Cholangiocarcinoma* - This is a cancer of the **bile ducts** and usually presents with **jaundice**, **pruritus**, and **dark urine**, not **flushing** and **diarrhea**. - The primary mass is in the **pancreas**, not the bile ducts, and **Chromogranin A** is not elevated in cholangiocarcinoma. *Gastrinoma* - A **gastrinoma** is a type of pancreatic neuroendocrine tumor that primarily causes **Zollinger-Ellison syndrome**, characterized by severe **peptic ulcer disease** and **diarrhea** due to excessive gastrin. - While it's a NET, the prominent **flushing** is not a typical feature of gastrinoma; this symptom strongly points towards a tumor producing other vasoactive substances (e.g., serotonin, VIP) consistent with a broader **carcinoid syndrome** presentation.

Q: A 43-year-old man presents with recurrent episodes of severe sweating, palpitations, and headache. His BP during episodes is 240/130 mmHg. What is the most appropriate preoperative management?

Alpha-blockers then beta-blockers. ***Alpha-blockers then beta-blockers***- The clinical presentation (paroxysmal **hypertension**, headache, palpitations, and sweating) is highly suggestive of a **pheochromocytoma**.- Preoperative stabilization requires adequate **alpha-adrenergic blockade** first (e.g., phenoxybenzamine or doxazosin) to control blood pressure and allow for volume expansion, followed by **beta-blockade** to manage tachycardia or arrhythmias.*Beta-blockers only*- Using beta-blockers alone is contraindicated as it causes **unopposed alpha-adrenergic stimulation**, leading to severe **vasoconstriction** and potentially a fatal hypertensive crisis or pulmonary edema.- Beta-blockers are only instituted *after* achieving complete alpha-blockade and adequate blood pressure control, typically to manage persistent tachycardia.*Alpha-blockers only*- While alpha-blockade is the essential first step, it is usually insufficient for full preoperative management, as patients often require subsequent **beta-blockade** to control catecholamine-induced tachycardia and arrhythmias.- Complete preparation requires both classes of medication to fully mitigate cardiovascular risk before surgery.*ACE inhibitors*- These medications target the **renin-angiotensin-aldosterone system** and are ineffective at blocking the direct severe vasoconstrictive effects of excessive circulating catecholamines.- They may also increase the risk of severe **hypotension** after tumor removal if the patient is relatively volume-depleted from prolonged vasoconstriction.*Calcium channel blockers*- While some CCBs (like nicardipine) can be used as **adjuncts** for blood pressure control, they cannot replace the mandatory initial step of **alpha-adrenergic blockade** and volume repletion.- They do not address the need for full adrenergic receptor blockade necessary to prevent cardiovascular catastrophe during surgical manipulation of the tumor.

Q: A 44-year-old woman presents with fatigue, muscle weakness, and weight loss. She has hyperpigmentation of palmar creases. Blood tests show Na+ 128 mmol/L, K+ 5.6 mmol/L. What is the most appropriate diagnostic test?

Synacthen stimulation test. ***Synacthen stimulation test*** - Also known as the **ACTH stimulation test**, this is the **gold standard** for diagnosing adrenal insufficiency, as the clinical signs (hyperpigmentation, hyponatremia, hyperkalemia) strongly suggest **Primary Adrenal Insufficiency** (Addison's disease). - The test assesses the adrenal gland's reserve capacity to produce cortisol; an insufficient rise in cortisol following the injection of synthetic **ACTH (Synacthen)** confirms the diagnosis. *Dexamethasone suppression test* - This test is primarily used to confirm or exclude **Cushing syndrome** (hypercortisolism) by checking if cortisol production can be suppressed by exogenous steroids. - It is inappropriate for suspected adrenal insufficiency, as it does not evaluate the maximum functional capacity of the adrenal glands. *24-hour urine cortisol* - This test measures the total amount of free cortisol excreted over a day and is typically used as a screening tool for **Cushing syndrome**. - While very low values might suggest adrenal failure, it is less sensitive and specific for diagnosing adrenal insufficiency compared to the **Synacthen test**. *Adrenal antibodies* - Detecting adrenal antibodies (e.g., against **21-hydroxylase**) is crucial for determining the **autoimmune etiology** of primary adrenal insufficiency. - However, measuring antibodies is a step in determining the *cause* of the disease, not the definitive *diagnostic test* for glandular failure. *ACTH levels* - Plasma **ACTH** measurement is essential for distinguishing between primary (high ACTH) and secondary (low ACTH) insufficiency *after* the diagnosis is confirmed by the Synacthen test. - It serves as a differentiation tool, but cannot confirm the initial diagnosis of adrenal insufficiency, which requires assessing the cortisol response to stimulation.

Q: A 64-year-old woman presents with bone pain and fatigue. Blood tests show calcium 3.1 mmol/L, phosphate 0.7 mmol/L, and suppressed PTH. She has a history of sarcoidosis. What is the most likely cause of hypercalcemia?

Granulomatous disease. ***Granulomatous disease*** - Sarcoidosis, a common granulomatous disease, causes non-PTH mediated hypercalcemia due to the autonomous expression of **1-alpha-hydroxylase** by activated macrophages within the granulomas. - This enzyme overproduces **1,25-dihydroxyvitamin D (calcitriol)**, leading to increased intestinal calcium absorption and subsequent **suppression of PTH**. *Primary hyperparathyroidism* - This condition is characterized by an elevated or inappropriately normal **parathyroid hormone (PTH)** level in the setting of hypercalcemia, typically due to a parathyroid adenoma. - The patient's lab results show **suppressed PTH**, which effectively rules out primary hyperparathyroidism. *Malignancy* - Malignancy frequently causes hypercalcemia, often through osteolytic bone destruction or the secretion of **Parathyroid Hormone-related Protein (PTHrP)**, which also suppresses PTH. - Although PTH is suppressed, the strong history of **sarcoidosis** (a known non-malignant cause of calcitriol-mediated hypercalcemia) makes granulomatous disease the most probable specific diagnosis. *Vitamin D intoxication* - This typically results from massive exogenous intake of vitamin D, leading to extremely high levels of serum **25-hydroxyvitamin D** and subsequent elevation of serum calcium. - While it causes suppressed PTH and hypercalcemia, the known diagnosis of sarcoidosis provides a strong, intrinsic explanation that must be prioritized over exogenous intake. *Milk-alkali syndrome* - This syndrome is caused by the substantial intake of **calcium** and absorbable **alkali**, resulting in hypercalcemia, suppressed PTH, and often metabolic alkalosis. - The history provided emphasizes sarcoidosis rather than excessive antacid or calcium supplementation, making this diagnosis less likely.

Q: A 47-year-old woman presents with fatigue, muscle weakness, and depression. She has purple striae and central obesity. 24-hour urine cortisol is elevated. What is the next most appropriate test?

Dexamethasone suppression test. ***Dexamethasone suppression test*** - An elevated 24-hour urine cortisol confirms hypercortisolism; the next step is to determine the underlying cause, which the **dexamethasone suppression test** helps to differentiate. - This test assesses the feedback control of the **hypothalamic-pituitary-adrenal axis** to differentiate among pituitary Cushing's disease, ectopic ACTH production, and adrenal tumors. *MRI pituitary* - **MRI pituitary** is primarily used for **localization** of a pituitary adenoma after ACTH-dependent Cushing's syndrome has been established. - It is not the initial test to *determine the cause* of hypercortisolism after it has been confirmed. *ACTH levels* - **ACTH levels** are crucial to differentiate between **ACTH-dependent** (pituitary or ectopic) and **ACTH-independent** (adrenal) causes of Cushing's syndrome. - While important, a **dexamethasone suppression test** is often performed first or concurrently to provide functional insight into cortisol suppressibility. *Adrenal CT* - **Adrenal CT** is performed to **localize an adrenal adenoma** or hyperplasia once ACTH-independent Cushing's syndrome (low ACTH) has been identified. - It is a localization step, not the primary diagnostic test to determine the *type* of Cushing's syndrome after initial confirmation of hypercortisolism. *CRH stimulation test* - The **CRH stimulation test** is typically used to help differentiate between **pituitary Cushing's disease** and **ectopic ACTH production** in cases of ACTH-dependent Cushing's syndrome. - It is a more specialized test performed after initial confirmation and differentiation steps like the dexamethasone suppression test and ACTH levels.

Question 1

A 46-year-old man presents with recurrent episodes of severe flushing and diarrhea. CT shows liver metastases and a pancreatic mass. Chromogranin A is markedly elevated. What is the most likely primary tumor?

Accepted Answer

Pancreatic neuroendocrine tumor

Answer

Pancreatic adenocarcinoma

Answer

Hepatocellular carcinoma

Answer

Cholangiocarcinoma

Answer

Gastrinoma

Question 2

A 43-year-old man presents with recurrent episodes of severe sweating, palpitations, and headache. His BP during episodes is 240/130 mmHg. What is the most appropriate preoperative management?

Accepted Answer

Alpha-blockers then beta-blockers

Answer

Beta-blockers only

Answer

Alpha-blockers only

Answer

ACE inhibitors

Answer

Calcium channel blockers

Question 3

A 44-year-old woman presents with fatigue, muscle weakness, and weight loss. She has hyperpigmentation of palmar creases. Blood tests show Na+ 128 mmol/L, K+ 5.6 mmol/L. What is the most appropriate diagnostic test?

Accepted Answer

Synacthen stimulation test

Answer

Dexamethasone suppression test

Answer

24-hour urine cortisol

Answer

Adrenal antibodies

Answer

ACTH levels

Question 4

A 64-year-old woman presents with bone pain and fatigue. Blood tests show calcium 3.1 mmol/L, phosphate 0.7 mmol/L, and suppressed PTH. She has a history of sarcoidosis. What is the most likely cause of hypercalcemia?

Accepted Answer

Granulomatous disease

Answer

Primary hyperparathyroidism

Answer

Malignancy

Answer

Vitamin D intoxication

Answer

Milk-alkali syndrome

Question 5

A 47-year-old woman presents with fatigue, muscle weakness, and depression. She has purple striae and central obesity. 24-hour urine cortisol is elevated. What is the next most appropriate test?

Accepted Answer

Dexamethasone suppression test

Answer

MRI pituitary

Answer

ACTH levels

Answer

Adrenal CT

Answer

CRH stimulation test

Endocrinology & Diabetes — MCQs

Endocrinology & Diabetes — MCQs

On this page

Practice by Chapter

Want unlimited practice?