Endocrinology Practice Questions

Q: A 45-year-old male with type 2 diabetes mellitus on metformin 1000 mg twice daily presents with HbA1c of 8.5%. His serum creatinine is 2.8 mg/dL (eGFR 28 mL/min/1.73m²) and he has a history of two episodes of heart failure in the past year. His BMI is 32 kg/m². Which of the following would be the most appropriate addition to his current therapy?

Empagliflozin. ***Empagliflozin*** - **SGLT2 inhibitors** like empagliflozin are now recommended down to **eGFR ≥20 mL/min/1.73m²** per **ADA 2024 guidelines** for **cardiorenal protection**, making this patient with eGFR 28 an appropriate candidate. - This patient has **two episodes of heart failure**, which is a **Class I indication** for SGLT2 inhibitor therapy due to proven cardiovascular benefits and **heart failure risk reduction**. *Sitagliptin* - **DPP-4 inhibitors** can be used in renal failure with **dose adjustment**, but they only offer a modest HbA1c reduction (**0.5–0.8%**). - This reduction would be **insufficient** to reach the target glycemic goal for a patient starting at an **HbA1c of 8.5%**. *Pioglitazone* - **Pioglitazone** is strictly contraindicated in patients with a history of **heart failure** because it causes **fluid retention** and peripheral edema. - Initiation of this medication could lead to an acute **exacerbation** of the patient's pre-existing cardiac condition. *Insulin glargine* - While **insulin** has no renal contraindications and provides potent glycemic control, it does not offer the **cardiorenal protective benefits** that this high-risk patient requires. - **SGLT2 inhibitors** are preferred in patients with **heart failure** and **CKD** due to their proven cardiovascular and renal outcomes, making empagliflozin the superior choice.

Q: Which is an immunological marker of type I diabetes?

GAD. **Explanation:** Type 1 Diabetes Mellitus (T1DM) is characterized by the autoimmune destruction of insulin-producing pancreatic beta cells [1]. This process is mediated by T-cells and is associated with the presence of specific autoantibodies that serve as diagnostic and predictive markers [2]. **Why GAD is correct:** **Glutamic Acid Decarboxylase (GAD65) antibodies** are the most sensitive and persistent immunological markers for T1DM. GAD is an enzyme involved in the synthesis of the neurotransmitter GABA, but it is also expressed in pancreatic beta cells. GAD antibodies are particularly useful in clinical practice because they remain detectable for years after diagnosis, unlike other antibodies that may disappear shortly after the onset of the disease. They are also used to diagnose **LADA** (Latent Autoimmune Diabetes in Adults). **Analysis of Incorrect Options:** * **Anti-endothelial antibody:** These are associated with systemic vasculitides (like Kawasaki disease) or certain connective tissue disorders, not diabetes. * **Anti-saccharomyces cerevisiae antibody (ASCA):** This is a classic marker for **Crohn’s Disease**, used to differentiate it from Ulcerative Colitis. **High-Yield Clinical Pearls for NEET-PG:** * **Other T1DM Markers:** Islet Cell Antibodies (ICA), Insulin Autoantibodies (IAA), and **Zinc Transporter 8 (ZnT8)** antibodies. * **ZnT8** is often cited as the most specific marker for beta-cell destruction. * **HLA Association:** T1DM is strongly linked to **HLA-DR3 and HLA-DR4** [2]. * **Screening:** The presence of two or more of these antibodies in an asymptomatic child indicates a near 100% lifetime risk of developing clinical T1DM.

Q: Acute adrenal insufficiency can present as?

All of the above. **Explanation:** Acute adrenal insufficiency (Addisonian Crisis) is a life-threatening emergency caused by a sudden, severe deficiency of cortisol (and often aldosterone). It typically occurs in patients with known chronic adrenal insufficiency during periods of stress (infection, surgery) [1] or due to sudden withdrawal of long-term steroid therapy [1]. **Why "All of the Above" is correct:** * **Acute Abdomen (Option A):** Cortisol deficiency leads to severe gastrointestinal symptoms. Patients often present with intense abdominal pain, tenderness, nausea, vomiting, and fever. This clinical picture can mimic a surgical emergency like peritonitis or appendicitis. * **Neurologic Disease (Option B):** Profound hypotension, electrolyte imbalances (hyponatremia), and hypoglycemia associated with adrenal crisis can lead to altered mental status. This manifests as lethargy, confusion, and decreased responsiveness, which can progress to stupor and coma. * **Hypovolemic Shock (Option C):** Aldosterone deficiency leads to "salt wasting" (loss of sodium and water) and hyperkalemia. This causes severe volume depletion and peripheral vascular collapse. The shock is often refractory to vasopressors until glucocorticoids are administered [1]. **Clinical Pearls for NEET-PG:** * **Classic Electrolyte Triad:** Hyponatremia, Hyperkalemia, and Hypoglycemia (due to lack of cortisol's gluconeogenic effect). * **Diagnosis:** Do not delay treatment for testing. A random plasma cortisol level <18 mcg/dL in a stressed patient is highly suggestive [1]. * **Management:** Immediate IV fluid resuscitation (Normal Saline) and high-dose **IV Hydrocortisone** (100mg bolus, then 200mg/24h) [1]. Hydrocortisone is preferred because it provides both glucocorticoid and mineralocorticoid activity. * **Waterhouse-Friderichsen Syndrome:** Bilateral adrenal hemorrhage due to meningococcemia is a classic cause of acute crisis.

Q: A man presents with weakness, tachycardia, sweating, and palpitations on fasting, which are promptly relieved with food intake. What is the most probable diagnosis?

Insulinoma. ### Explanation The clinical presentation described is a classic manifestation of **Whipple’s Triad**, which is the hallmark of an **Insulinoma**. **1. Why Insulinoma is correct:** Insulinoma is a rare neuroendocrine tumor of the pancreatic beta cells that secretes insulin autonomously, regardless of blood glucose levels. The patient exhibits symptoms of **fasting hypoglycemia**: * **Autonomic symptoms:** Tachycardia, sweating, and palpitations (due to catecholamine release). * **Neuroglycopenic symptoms:** Weakness and confusion. * **Relief with food:** The prompt resolution of symptoms after eating completes Whipple’s Triad, making Insulinoma the most probable diagnosis. **2. Why the other options are incorrect:** * **Pancreatic carcinoma:** Typically presents with painless obstructive jaundice, weight loss, and abdominal pain. It does not cause fasting hypoglycemia. * **Carcinoid syndrome:** Characterized by flushing, diarrhea, and wheezing due to serotonin release [1]. Symptoms are usually triggered by alcohol or stress, not fasting. * **Zollinger-Ellison syndrome (Gastrinoma):** Caused by excessive gastrin secretion leading to severe peptic ulcers and chronic diarrhea, not hypoglycemia. **3. High-Yield NEET-PG Pearls:** * **Whipple’s Triad:** 1. Symptoms of hypoglycemia; 2. Low plasma glucose (<55 mg/dL); 3. Relief of symptoms after glucose administration. * **Diagnosis:** The gold standard is the **72-hour supervised fast**. * **Biochemical markers:** During hypoglycemia, an insulinoma patient will show **elevated Insulin**, **elevated C-peptide**, and **elevated Pro-insulin** levels, with **absent urinary sulfonylureas** [1]. * **Localization:** Most insulinomas are small, benign, and solitary. Endoscopic ultrasound (EUS) is highly sensitive for localization. * **Association:** 10% are associated with **MEN1 syndrome** (usually multiple tumors).

Q: A mother brings her 10-year-old son to the OPD due to a family history of medullary carcinoma of the thyroid in his father and grandparents. There are no abnormal findings on physical examination. Which of the following tests would you perform?

Urine vanillylmandelic acid (VMA) level. **Explanation:** The clinical scenario describes a child with a strong family history of **Medullary Thyroid Carcinoma (MTC)**, which strongly suggests **Multiple Endocrine Neoplasia Type 2 (MEN 2)** syndrome (specifically MEN 2A or 2B). These syndromes are inherited in an autosomal dominant fashion due to mutations in the **RET proto-oncogene** [1]. **Why Option C is correct:** Patients with MEN 2 are at high risk for developing **Pheochromocytoma** (often bilateral) in addition to MTC [1]. In clinical practice, when a patient is suspected of having MEN 2, it is mandatory to **rule out Pheochromocytoma before any surgical intervention** for the thyroid. This is because an undiagnosed pheochromocytoma can lead to a fatal hypertensive crisis during anesthesia or surgery. Screening is done via 24-hour **Urine VMA**, metanephrines, or plasma free metanephrines [1]. **Why other options are incorrect:** * **Options A, B, and D:** Serum insulin, glucagon, and somatostatin are markers for pancreatic islet cell tumors [1]. These are characteristic of **MEN 1** (Wermer’s Syndrome), which involves the "3 Ps": Pituitary, Parathyroid, and Pancreas. MEN 1 is *not* associated with Medullary Thyroid Carcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **MEN 2A (Sipple Syndrome):** MTC + Pheochromocytoma + Parathyroid Hyperplasia. * **MEN 2B:** MTC + Pheochromocytoma + Mucosal Neuromas + Marfanoid Habitus. * **Prophylactic Thyroidectomy:** In children with known RET mutations, thyroidectomy is often performed early (before age 5 in MEN 2A, or within the 1st year in MEN 2B) because MTC in these patients is highly aggressive [1]. * **Rule of thumb:** Always screen for and treat Pheochromocytoma *first* before addressing the thyroid.

Question 1

A 45-year-old male with type 2 diabetes mellitus on metformin 1000 mg twice daily presents with HbA1c of 8.5%. His serum creatinine is 2.8 mg/dL (eGFR 28 mL/min/1.73m²) and he has a history of two episodes of heart failure in the past year. His BMI is 32 kg/m². Which of the following would be the most appropriate addition to his current therapy?

Accepted Answer

Empagliflozin

Answer

Sitagliptin

Answer

Pioglitazone

Answer

Insulin glargine

Question 2

Which is an immunological marker of type I diabetes?

Accepted Answer

GAD

Answer

Anti-endothelial antibody

Answer

Anti-saccharomyces antibody

Answer

None of the above

Question 3

Acute adrenal insufficiency can present as?

Accepted Answer

All of the above

Answer

Acute abdomen with abdominal tenderness, nausea, vomiting and fever

Answer

Neurologic disease with decreased responsiveness progressing to stupor and coma

Answer

Hypovolemic shock

Question 4

A man presents with weakness, tachycardia, sweating, and palpitations on fasting, which are promptly relieved with food intake. What is the most probable diagnosis?

Accepted Answer

Insulinoma

Answer

Pancreatic carcinoma

Answer

Carcinoid syndrome

Answer

Zollinger-Ellison syndrome

Question 5

A mother brings her 10-year-old son to the OPD due to a family history of medullary carcinoma of the thyroid in his father and grandparents. There are no abnormal findings on physical examination. Which of the following tests would you perform?

Accepted Answer

Urine vanillylmandelic acid (VMA) level

Answer

Serum insulin level

Answer

Serum glucagon level

Answer

Serum somatostatin level

Endocrinology — MCQs

Endocrinology — MCQs

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