Endocrinology Practice Questions

Q: Ectopic ACTH production is most commonly seen in which of the following conditions?

Small cell carcinoma of the lung. ### Explanation **Correct Option: A. Small cell carcinoma of the lung** Ectopic ACTH syndrome occurs when non-pituitary tumors secrete adrenocorticotropic hormone, leading to hypercortisolism (Cushing’s syndrome) [1]. **Small cell carcinoma of the lung (SCLC)** is the most common cause, accounting for approximately 50% of all ectopic ACTH cases [2]. SCLC is a neuroendocrine tumor derived from Kulchitsky cells, which possess the biochemical machinery to synthesize and secrete polypeptide hormones like ACTH and ADH [2]. **Analysis of Incorrect Options:** * **B & C (Anaplastic and Squamous cell carcinoma):** While these are types of lung cancer, they are not typically associated with ACTH production. Squamous cell carcinoma is famously associated with the production of **PTHrP** (Parathyroid Hormone-related Protein), leading to hypercalcemia, rather than ACTH [2]. * **D (Adenocarcinoma of the cerebellum):** This is not a recognized clinical entity associated with ectopic hormone production. However, cerebellar **hemangioblastomas** can sometimes produce erythropoietin (EPO), leading to polycythemia [2]. **NEET-PG High-Yield Pearls:** 1. **Clinical Presentation:** Patients with ectopic ACTH from SCLC often present with rapid-onset hypertension, profound hypokalemia, and hyperpigmentation (due to MSH-like activity), rather than the classic "buffalo hump" or "moon facies" seen in pituitary Cushing’s. 2. **Dexamethasone Suppression Test (DST):** Unlike Cushing’s disease (pituitary adenoma), ectopic ACTH production from SCLC is **not suppressed** by high-dose dexamethasone. 3. **Other Causes:** Other neuroendocrine tumors causing ectopic ACTH include bronchial carcinoids, thymic carcinoids, and pancreatic islet cell tumors. 4. **Key Association:** SCLC = ACTH (Cushing’s) and ADH (SIADH). Squamous Cell = PTHrP (Hypercalcemia) [2].

Q: Which is the screening test for acromegaly?

Serum IGF-1. **Explanation:** The diagnosis of acromegaly relies on understanding the physiological secretion of Growth Hormone (GH). **1. Why Serum IGF-1 is the Correct Answer:** Serum **Insulin-like Growth Factor-1 (IGF-1)** is the preferred **screening test** because it has a long half-life and maintains stable plasma concentrations throughout the day. Unlike GH, which is secreted in pulsatile bursts and can be influenced by stress, exercise, or sleep, IGF-1 levels reflect the integrated GH secretion over the preceding 24 hours [2]. A normal age- and sex-matched IGF-1 level effectively rules out acromegaly [1]. **2. Why the Other Options are Incorrect:** * **Serum IGF-2 (A):** This factor is primarily involved in fetal development and is not used in the diagnostic algorithm for GH disorders. * **Oral Glucose Tolerance Test (B):** The 75g OGTT is the **gold standard confirmatory test**, not the screening test [1]. In a healthy individual, hyperglycemia suppresses GH to <1 ng/mL; failure of suppression confirms acromegaly. * **GH levels (C):** Random GH measurements are unreliable for screening due to the hormone's pulsatile nature and short half-life [2]. A single low value does not rule out the disease, and a single high value does not confirm it. **Clinical Pearls for NEET-PG:** * **Best Screening Test:** Serum IGF-1. * **Best Confirmatory Test:** GH suppression test (OGTT). * **Most Common Cause:** Pituitary Adenoma (Somatotroph adenoma). * **Imaging of Choice:** MRI of the Sella Turcica (performed after biochemical confirmation). * **Treatment of Choice:** Transsphenoidal surgery (except in cases where medical management with Somatostatin analogues like Octreotide is preferred) [1].

Q: Complications in Diabetes Mellitus Type II typically occur around:

20 years of onset. **Explanation:** In Type 2 Diabetes Mellitus (T2DM), the development of chronic microvascular and macrovascular complications is a progressive process driven by chronic hyperglycemia, advanced glycation end-products (AGEs), and oxidative stress [1]. **Why Option D is Correct:** Statistically, clinically significant complications (such as proliferative retinopathy, end-stage renal disease, or symptomatic neuropathy) typically manifest approximately **20 years after the onset** of the disease. While the biochemical damage begins much earlier, the "clinical threshold" for organ failure or severe disability usually peaks at the two-decade mark [2]. It is important to note that because T2DM has an insidious onset and may remain undiagnosed for years, many patients already have complications at the time of diagnosis [3]. **Analysis of Incorrect Options:** * **A (5 years):** This is too early for most chronic complications to become clinically apparent, though subclinical changes (like microalbuminuria) may begin. * **B & C (10-15 years):** While complications often start appearing during this window (e.g., background retinopathy), the classic teaching for the peak incidence of cumulative, severe complications remains the 20-year mark [2]. **High-Yield Clinical Pearls for NEET-PG:** * **The "Rule of 20":** Diabetic Retinopathy is present in nearly 99% of Type 1 and about 60% of Type 2 patients after 20 years of disease duration. * **Screening:** Unlike Type 1 DM (where screening starts 5 years after diagnosis), screening for complications in Type 2 DM must begin **at the time of diagnosis** because the actual date of onset is usually unknown [3]. * **UKPDS Study:** This landmark trial confirmed that intensive glycemic control significantly reduces microvascular complications over long-term follow-up [1]. * **Most Common Complication:** Distal Symmetrical Polyneuropathy is the most common chronic complication of DM.

Q: Anti-TPO antibodies are present in which of the following conditions?

Hashimoto's thyroiditis. Explanation: 1. Why Hashimoto’s Thyroiditis is Correct: Hashimoto’s thyroiditis (Chronic Lymphocytic Thyroiditis) is an autoimmune disorder characterized by the destruction of the thyroid gland by cell-mediated and antibody-mediated immune processes. Anti-TPO (Anti-Thyroid Peroxidase) antibodies are the hallmark of this condition, present in over 95% of patients. They are not just markers but are involved in the pathogenesis of thyroid failure. Anti-thyroglobulin (Anti-Tg) antibodies are also frequently present (60-80%). 2. Analysis of Incorrect Options: * A. Riedel’s Thyroiditis: This is a rare condition characterized by dense fibrous replacement of the thyroid tissue (IgG4-related disease). While some patients may have antibodies, it is primarily a fibrotic process, not an autoimmune destruction defined by Anti-TPO. * B. Graves’ Disease: While Anti-TPO can be present in ~70% of Graves' cases, the pathognomonic antibody is TSI (Thyroid Stimulating Immunoglobulin) or TRAb (TSH Receptor Antibody), which causes hyperthyroidism [1]. * C. DeQuervain’s Thyroiditis (Subacute Granulomatous): This is typically a post-viral inflammatory condition. It is characterized by a high ESR and painful goiter; thyroid antibodies are usually absent or only transiently present in low titers [2]. 3. NEET-PG Clinical Pearls: * Most sensitive marker for Hashimoto’s: Anti-TPO antibodies. * Best initial test for thyroid function: TSH. * Histology of Hashimoto’s: Hurthle cells (Askanazy cells) and lymphocytic infiltration with germinal centers. * Risk: Patients with Hashimoto’s have an increased risk of B-cell Non-Hodgkin Lymphoma of the thyroid. * Anti-TPO in Pregnancy: Presence of these antibodies increases the risk of post-partum thyroiditis and miscarriage.

Q: In which condition is an intravenous glucose tolerance test typically performed?

Gastrectomy. The **Oral Glucose Tolerance Test (OGTT)** is the standard diagnostic tool for diabetes [2]. However, it relies on normal gastric emptying and intestinal absorption. In patients who have undergone a **Gastrectomy** (Option C), the "gastric brake" is lost, leading to abnormally rapid gastric emptying [1]. This causes a rapid surge in blood glucose followed by an exaggerated insulin response (Alimentary Hypoglycemia/Dumping Syndrome). Because the oral route yields unreliable, "lag-storage" type curves in these patients, the **Intravenous Glucose Tolerance Test (IVGTT)** is preferred to bypass the gastrointestinal tract and assess pancreatic beta-cell function directly. **Analysis of Incorrect Options:** * **A. Children:** OGTT is the standard for children when diabetes is suspected, though it is less frequently required than in adults. * **B. Pregnancy:** This is the most common indication for **OGTT** (specifically the 75g or 100g test) to screen for Gestational Diabetes Mellitus (GDM). The IVGTT is not used as it does not reflect the physiological challenge of a meal. * **C. Old Age:** Aging is associated with decreased glucose tolerance, but the standard OGTT remains the diagnostic method of choice. **NEET-PG High-Yield Pearls:** * **IVGTT Procedure:** 0.5 g/kg of glucose is given as a 25% solution over 2–4 minutes. * **K-value:** The result of an IVGTT is expressed as the "glucose disappearance rate" (K-value). A K-value < 1.0 is suggestive of diabetes. * **Indications for IVGTT:** Malabsorption syndromes, chronic diarrhea, and post-gastric surgery (Gastrectomy/Gastrojejunostomy) [1]. * **Diagnostic Choice:** While IVGTT exists, the **HbA1c** and **Fasting Plasma Glucose** are now the primary clinical tools, with OGTT reserved for pregnancy.

Question 1

Ectopic ACTH production is most commonly seen in which of the following conditions?

Accepted Answer

Small cell carcinoma of the lung

Answer

Anaplastic carcinoma of the lung

Answer

Squamous cell carcinoma of the lung

Answer

Adenocarcinoma of the cerebellum

Question 2

Which is the screening test for acromegaly?

Accepted Answer

Serum IGF-1

Answer

Serum IGF-2

Answer

Oral glucose tolerance test

Answer

GH levels

Question 3

Complications in Diabetes Mellitus Type II typically occur around:

Accepted Answer

20 years of onset

Answer

5 years of onset

Answer

10 years of onset

Answer

15 years of onset

Question 4

In parathyroid crisis with sudden elevations of calcium over 16 mg/dL, what is the appropriate initial treatment?

Accepted Answer

Parathyroidectomy for removal of adenoma

Answer

Thyrocalcitonin

Answer

Intravenous bicarbonate

Answer

Intravenous fluids and loop diuretics

Question 5

Which of the following statements about pseudohypoparathyroidism is true?

Accepted Answer

Decreased formation of c-AMP is observed

Answer

Caused by 'Gain of function' inherited mutation in Gsa subunit

Answer

Decreased formation of cyclic GMP is observed

Answer

Decreased formation of Inositol triphosphate is observed

Question 6

In a patient with pheochromocytoma, all of the following are seen except?

Accepted Answer

Weight gain

Answer

Diarrhea

Answer

Orthostatic hypotension

Answer

Episodic hypertension

Question 7

All of the following are true about Cushing's syndrome, except?

Accepted Answer

Increased adrenaline

Answer

Red striae

Answer

Proximal muscle weakness

Answer

Edema

Question 8

Anti-TPO antibodies are present in which of the following conditions?

Accepted Answer

Hashimoto's thyroiditis

Answer

Reidel's thyroiditis

Answer

Grave's disease

Answer

DeQuervain's thyroiditis

Question 9

In which condition is an intravenous glucose tolerance test typically performed?

Accepted Answer

Gastrectomy

Answer

Children

Answer

Pregnancy

Answer

Old age

Question 10

Diabetic amyotrophy characteristically presents with which of the following?

Accepted Answer

Pain in the anterior thigh

Answer

Third nerve palsy with pupillary sparing

Answer

Distal areflexia

Answer

Asymmetric motor weakness

Endocrinology — MCQs

Endocrinology — MCQs

On this page

Practice by Chapter

Want unlimited practice?