Endocrinology Practice Questions

Q: What is the confirmatory investigation for Acromegaly?

Glucose-induced growth hormone suppression test. **Explanation:** Acromegaly is characterized by the autonomous secretion of Growth Hormone (GH), usually due to a pituitary adenoma [1]. Understanding the physiological regulation of GH is key to diagnosing this condition. **1. Why Option B is Correct:** The **75g Oral Glucose Tolerance Test (OGTT)** is the **Gold Standard/Confirmatory test** for Acromegaly [1]. In a healthy individual, a glucose load triggers hyperglycemia, which physiologically suppresses GH secretion to <1 ng/mL (or <0.4 ng/mL with highly sensitive assays). In Acromegaly, GH secretion is autonomous; therefore, GH levels **fail to suppress** below these thresholds, confirming the diagnosis [1]. **2. Why the other options are incorrect:** * **Option A:** Insulin induces hypoglycemia, which is a potent *stimulator* of GH. This is used to diagnose GH deficiency, not excess. * **Option C:** GH is secreted in a pulsatile fashion and has a short half-life. A single random measurement is unreliable because a normal peak could be mistaken for acromegaly, or a trough could mask the disease. * **Option D:** **IGF-1 (Insulin-like Growth Factor-1)** is the **Best Screening Test** [2]. It has a long half-life and reflects 24-hour GH activity [1]. While highly sensitive, it is not considered the "confirmatory" dynamic test. **High-Yield Clinical Pearls for NEET-PG:** * **Sequence of Diagnosis:** Screen with IGF-1 levels → Confirm with OGTT (GH suppression test) → Localize with MRI of the Sella Turcica. * **False Positives in OGTT:** GH may fail to suppress in uncontrolled Diabetes Mellitus, Chronic Kidney Disease, Liver disease, or during adolescence. * **Treatment of Choice:** Transsphenoidal surgery (TSS) is the primary treatment for most patients [1].

Q: A 20-year-old male presents with chronic constipation, headache, Marfanoid habitus, neuromas of the tongue, medullated corneal nerve fibers, and a 2x2 cm nodule in the left lobe of the thyroid. What is the most probable diagnosis?

Multiple Endocrine Neoplasia (MEN) 2B. ### Explanation The correct diagnosis is **Multiple Endocrine Neoplasia (MEN) 2B**. [1] **1. Why MEN 2B is correct:** MEN 2B (formerly MEN 3) is characterized by a triad of **Medullary Thyroid Carcinoma (MTC)**, **Pheochromocytoma**, and distinctive **mucocutaneous manifestations**. [1] This patient exhibits the classic "phenotype" of MEN 2B: * **Marfanoid Habitus:** Long limbs and lax joints (without the lens dislocation or aortic issues seen in true Marfan syndrome). * **Mucosal Neuromas:** Fleshy bumps on the tongue, lips, and eyelids. * **Intestinal Ganglioneuromatosis:** This leads to chronic constipation or megacolon. * **Medullated Corneal Nerve Fibers:** A high-yield ophthalmological finding specific to this syndrome. * **Thyroid Nodule:** In MEN 2B, MTC occurs early (often in childhood) and is highly aggressive. [1] **2. Why other options are incorrect:** * **MEN 2A:** While it also features MTC and Pheochromocytoma, it is associated with **Primary Hyperparathyroidism** and *Lichen Amyloidosis*, not Marfanoid habitus or mucosal neuromas. * **Sporadic/Familial MTC:** These involve MTC without the associated syndromic features like neuromas, Marfanoid habitus, or other endocrine tumors (like pheochromocytoma). **3. NEET-PG High-Yield Pearls:** * **Genetics:** All MEN 2 syndromes are caused by a germline mutation in the **RET proto-oncogene** (Chromosome 10). [1] * **Management:** Due to the extreme aggressiveness of MTC in MEN 2B, prophylactic thyroidectomy is recommended **within the first year of life**. [1] * **Screening:** Always rule out **Pheochromocytoma** (via urinary/plasma metanephrines) before performing thyroid surgery to prevent a hypertensive crisis during anesthesia. [2]

Question 1

A 42-year-old man has recurrent duodenal ulceration with bleeding, despite omeprazole therapy. Helicobacter pylori serology has been negative on three occasions. An abnormality is noticed on imaging of his pancreas. What other health problems might this man have?

Accepted Answer

Phaeochromocytoma

Answer

Marfan's syndrome

Answer

Medullary thyroid cancer

Answer

Pituitary adenoma

Question 2

What is the confirmatory investigation for Acromegaly?

Accepted Answer

Glucose-induced growth hormone suppression test

Answer

Insulin-induced growth hormone suppression test

Answer

Random growth hormone assay

Answer

IGF-I level

Question 3

What is the most sensitive test for diagnosing pheochromocytoma?

Accepted Answer

Plasma free metanephrines

Answer

MRI

Answer

24-hour urinary VMA

Answer

MIBG scan

Question 4

In a patient with Non-Insulin Dependent Diabetes Mellitus (NIDDM), which of the following conditions is commonly seen?

Accepted Answer

There are increased levels of insulin in the blood.

Answer

Ketosis commonly occurs on stopping treatment.

Answer

Hypertriglyceridemia never occurs.

Answer

Pancreatic beta cells stop producing insulin.

Question 5

A 25-year-old man presents with 3 months of polyuria and increased thirst. The patient suffered trauma to the base of the skull in a motorcycle accident 4 months ago. A 24-hour urine collection shows polyuria but no evidence of hematuria, glucosuria, or proteinuria. The pathogenesis of polyuria in this patient is most likely caused by a lesion in which of the following areas of the brain?

Accepted Answer

Neurohypophysis

Answer

Adenohypophysis

Answer

Brain stem

Answer

Mammillothalamic tract

Question 6

High T3, high T4, low TSH, and low radioiodine uptake is seen in which condition?

Accepted Answer

Subacute thyroiditis

Answer

Hashimoto's thyroiditis

Answer

Graves' disease

Answer

Toxic nodule

Question 7

Anemia is typically more severe in which of the following endocrine conditions?

Accepted Answer

Addison's disease

Answer

Hypothyroidism

Answer

Castration

Answer

Hyperparathyroidism

Question 8

Which of the following is NOT a risk factor for severe hypoglycemia?

Accepted Answer

Sleep

Answer

Short duration of diabetes mellitus

Answer

ACE genotype

Answer

Strict control of blood sugar level

Question 9

A 65-year-old woman with a history of multinodular goiter complains of increasing nervousness, insomnia, and heart palpitations. She has lost 9 kg over the past 6 months. There is no evidence of exophthalmos. Laboratory studies show elevated serum levels of free T3 and T4. Serologic tests for antithyroid antibodies are negative. Which of the following is the likely endocrinopathy in this patient?

Accepted Answer

Thyrotoxicosis

Answer

Thyroid storm

Answer

Graves disease

Answer

Hypothyroidism

Question 10

A 20-year-old male presents with chronic constipation, headache, Marfanoid habitus, neuromas of the tongue, medullated corneal nerve fibers, and a 2x2 cm nodule in the left lobe of the thyroid. What is the most probable diagnosis?

Accepted Answer

Multiple Endocrine Neoplasia (MEN) 2B

Answer

Sporadic medullary carcinoma of the thyroid

Answer

Familial medullary carcinoma of the thyroid

Answer

Multiple Endocrine Neoplasia (MEN) 2A

Endocrinology — MCQs

Endocrinology — MCQs

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