Endocrinology Practice Questions

Q: Which of the following statements about MODY is false?

Requires insulin therapy. Maturity-Onset Diabetes of the Young (MODY) is a group of monogenic disorders characterized by non-insulin-dependent diabetes caused by mutations in genes affecting beta-cell function, rather than insulin resistance or autoimmune destruction [1]. Why Option D is the Correct Answer (False Statement): Unlike Type 1 Diabetes, MODY is primarily a defect in insulin secretion "sensing" or production, not a total absence of insulin. Most patients (especially those with MODY 1 and 3) have significant residual beta-cell function and do not require insulin therapy, at least in the early stages [1]. Many can be managed effectively with oral hypoglycemic agents or diet alone. Analysis of Incorrect Options: * Option A: MODY typically presents in adolescence or early adulthood, usually before age 25, distinguishing it from Type 2 Diabetes [1]. * Option B: The pathophysiology involves impaired insulin secretion due to genetic mutations (e.g., HNF1A, GCK), while insulin sensitivity remains normal. * Option C: Patients with MODY 3 (the most common type) and MODY 1 are exquisitely sensitive to Sulfonylureas, which is often the first-line treatment. High-Yield Clinical Pearls for NEET-PG: 1. Inheritance: Autosomal Dominant (look for a strong family history across 3 generations) [1]. 2. MODY 3 (HNF1A): Most common form; highly sensitive to low-dose sulfonylureas. 3. MODY 2 (GCK): Characterized by mild, stable fasting hyperglycemia; usually requires no treatment (diet only). 4. Diagnostic Clue: Absence of pancreatic autoantibodies (GAD, IA-2) and low/normal BMI.

Q: What is the first-line medication for a patient with diabetes mellitus and concurrent hypertension?

ACE inhibitors. **Explanation:** The management of hypertension in patients with Diabetes Mellitus (DM) requires medications that not only lower blood pressure but also provide organ protection. **ACE Inhibitors (ACEIs)** or **Angiotensin II Receptor Blockers (ARBs)** are the first-line agents because they offer significant **renoprotective effects** [1], [2]. They reduce intraglomerular pressure by dilating the efferent arteriole, thereby slowing the progression of diabetic nephropathy and reducing albuminuria [2]. **Analysis of Options:** * **ACE Inhibitors (Correct):** They are the drug of choice due to their ability to delay the onset of end-stage renal disease (ESRD) in diabetics [1], [2]. * **Calcium Channel Blockers (CCBs):** These are excellent antihypertensives and are often used as second-line or add-on therapy (especially Dihydropyridines like Amlodipine), but they lack the specific primary renoprotective profile of ACEIs [1]. * **Alpha-adrenergics:** These are not first-line agents due to a lack of evidence regarding long-term cardiovascular benefits and potential side effects like orthostatic hypotension. * **Beta-adrenergics:** These are generally avoided as first-line therapy in DM because they can mask the symptoms of hypoglycemia (except diaphoresis) and may impair glucose tolerance by decreasing insulin sensitivity. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** If a diabetic patient has **microalbuminuria** (30-300 mg/day), ACEIs/ARBs must be started regardless of the baseline blood pressure [2]. * **Contraindication:** Never combine ACEIs and ARBs due to the high risk of hyperkalemia and acute kidney injury. * **Side Effect:** The most common side effect of ACEIs is a dry cough (due to bradykinin accumulation); in such cases, switch the patient to an ARB (e.g., Losartan) [1].

Q: A 30-year-old woman complains of weakness and fatigability over the past 6 months. She has a 3-month acute history of severe hypertension that has required treatment with antihypertensive medications. Radiographic examination reveals a tumor of her right suprarenal gland. The patient is diagnosed with a pheochromocytoma (tumor of the adrenal medulla) and is scheduled for a laparoscopic adrenalectomy. Which of the following nerve fibers will need to be cut when the adrenal gland and tumor are removed?

Preganglionic sympathetic fibers. ### Explanation **1. Why Preganglionic Sympathetic Fibers is Correct:** The adrenal medulla is embryologically and functionally unique. It is derived from **neural crest cells** and is considered a **modified sympathetic ganglion**. Unlike other effector organs in the sympathetic nervous system, which receive postganglionic fibers, the chromaffin cells of the adrenal medulla are directly innervated by **preganglionic sympathetic fibers** (primarily via the Greater Splanchnic nerve). These fibers release acetylcholine (ACh), which triggers the chromaffin cells to release epinephrine and norepinephrine directly into the bloodstream. Therefore, during an adrenalectomy, these preganglionic fibers must be severed. **2. Why the Other Options are Incorrect:** * **Postganglionic sympathetic fibers:** These typically originate in the paravertebral or prevertebral ganglia and travel to target organs (e.g., heart, blood vessels). The adrenal medulla itself acts as the "postganglionic neuron," so it does not receive postganglionic input. * **Somatic motor fibers:** These innervate skeletal muscles under voluntary control. The adrenal gland is an endocrine organ under autonomic control. * **Postganglionic parasympathetic fibers:** The adrenal medulla does not have a functional parasympathetic nerve supply; its secretion is regulated purely by the sympathetic nervous system. **3. High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s for Pheochromocytoma:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), 10% pediatric, and 10% familial. * **Surgical Management:** In pheochromocytoma surgery, **Alpha-blockade (e.g., Phenoxybenzamine)** must be started 7–14 days *before* Beta-blockade to prevent a hypertensive crisis (unopposed alpha-stimulation). [1] * **Neurotransmitter:** The preganglionic fibers to the adrenal medulla are **cholinergic** (release ACh), even though the medulla's output is adrenergic.

Q: Enlargement of a pituitary tumor after adrenalectomy is called as:

Nelson syndrome. **Explanation:** **Nelson Syndrome** is the correct answer. It refers to the rapid enlargement of a pre-existing ACTH-secreting pituitary adenoma following **bilateral adrenalectomy**. * **Pathophysiology:** In a normal physiological state (or in Cushing’s disease), cortisol exerts negative feedback on the hypothalamus and pituitary. When both adrenal glands are removed (often as a treatment for refractory Cushing’s disease), this negative feedback is lost. The resulting lack of cortisol leads to uncontrolled hypersecretion of CRH and ACTH, causing the pituitary tumor to grow aggressively. * **Clinical Features:** Patients typically present with **hyperpigmentation** (due to high ACTH/MSH levels) and local mass effects such as visual field defects (bitemporal hemianopia) and headaches. **Analysis of Incorrect Options:** * **Steel-Richardson Syndrome:** Also known as Progressive Supranuclear Palsy (PSP), it is a neurodegenerative disease characterized by vertical gaze palsy, postural instability, and falls. * **Hamman-Rich Syndrome:** Also known as Acute Interstitial Pneumonia (AIP), it is a rare, fulminant form of idiopathic interstitial pneumonia. * **Job’s Syndrome:** Also known as Hyper-IgE Syndrome, it is an immunodeficiency characterized by "cold" staphylococcal abscesses, eczema, and high serum IgE levels. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Marker:** Extremely high plasma ACTH levels and MRI evidence of an enlarging pituitary mass. * **Prevention:** The incidence has decreased due to better pituitary imaging and the use of transsphenoidal surgery or pituitary radiation instead of bilateral adrenalectomy. * **Treatment:** Transsphenoidal surgery or radiotherapy.

Q: In which of the following conditions do Total T3, Total T4, and TSH all decrease?

Hypopituitarism. ### Explanation **Correct Option: B. Hypopituitarism** In **Hypopituitarism**, there is a failure of the anterior pituitary gland to secrete **Thyroid Stimulating Hormone (TSH)** [2]. This leads to **Secondary Hypothyroidism**, where the lack of TSH results in decreased stimulation of the thyroid gland, subsequently causing a drop in **Total T4 and Total T3** [2]. This pattern—low TSH accompanied by low thyroid hormones—is the hallmark of central (pituitary or hypothalamic) endocrine failure. **Analysis of Incorrect Options:** * **A. Primary Hypothyroidism:** The defect is in the thyroid gland itself. While T3 and T4 are low, the pituitary responds to the lack of negative feedback by significantly **increasing TSH** levels [1]. * **C. Nephrotic Syndrome:** This condition involves massive urinary loss of **Thyroid Binding Globulin (TBG)**. While **Total T4 and T3** decrease (due to loss of carrier proteins), the **Free T4/T3 and TSH remain normal** (euthyroid state). * **D. Pregnancy:** High estrogen levels stimulate the liver to increase TBG production. This leads to an **increase in Total T4 and T3**, while Free T4 and TSH typically remain within normal physiological limits. **High-Yield NEET-PG Pearls:** * **Sick Euthyroid Syndrome:** Can also present with low T3, low T4, and low/normal TSH during severe systemic illness. It is distinguished from hypopituitarism by clinical context and elevated **Reverse T3 (rT3)**. * **TSH is the most sensitive screening test** for primary thyroid disorders, but it is **unreliable** in suspected pituitary disease; in such cases, Free T4 must be measured. * **Rule of Thumb:** If TSH and T4 move in the **opposite** direction, the problem is **Primary** [1]. If they move in the **same** direction, the problem is **Central/Secondary** [2].

Q: Characteristic feature of the urine in diabetes insipidus include the following EXCEPT?

Specific gravity > 1.020. Diabetes Insipidus (DI) is a clinical syndrome characterized by the excretion of large volumes of dilute urine (polyuria) due to either a deficiency of Antidiuretic Hormone (ADH) (Central DI) or resistance to its action (Nephrogenic DI) [2]. **Why Option C is the correct answer:** The hallmark of DI is the inability of the kidneys to concentrate urine [1]. In a normal physiological state, ADH acts on the collecting ducts to reabsorb water [2]. In DI, the lack of ADH effect leads to the excretion of highly dilute urine. Consequently, the **urinary specific gravity is characteristically low**, typically ** 1.020 indicates concentrated urine, which is physiologically inconsistent with a diagnosis of DI. **Why other options are incorrect:** * **Options A, B, and D:** Diabetes Insipidus is a disorder of water homeostasis, not a glomerular or tubular inflammatory disease. Therefore, the urine is "bland." It typically contains **no protein, no sugar (glucose), and no casts**. The presence of sugar would suggest Diabetes Mellitus, while proteins or casts would suggest underlying renal parenchymal disease. **High-Yield Clinical Pearls for NEET-PG:** * **Water Deprivation Test:** The gold standard for diagnosis [1]. In DI, urine remains dilute despite dehydration. * **Desmopressin (DDAVP) Trial:** Used to differentiate Central DI (urine osmolality increases by >50%) from Nephrogenic DI (no significant increase) [1]. * **Treatment:** Central DI is treated with **Desmopressin** [1]; Nephrogenic DI is treated with **Thiazide diuretics**, Amiloride, or NSAIDs (Indomethacin). * **Triphasic Response:** May occur after pituitary surgery (Transient DI → SIADH → Permanent DI).

Question 1

Which of the following statements about MODY is false?

Accepted Answer

Requires insulin therapy

Answer

Onset typically before 25 years of age

Answer

Characterized by impaired insulin secretion

Answer

Often responsive to sulfonylureas

Question 2

All of the following are true about hyperparathyroidism, except?

Accepted Answer

None of the above

Answer

Commonly occurs after thyroidectomy

Answer

May cause hypercalcemia

Answer

Solitary adenoma is the most common cause

Question 3

Which of the following is true about Conn's syndrome?

Accepted Answer

Decreased K+

Answer

Increased K+

Answer

Proximal myopathy

Answer

Decreased plasma renin activity

Question 4

What is the first-line medication for a patient with diabetes mellitus and concurrent hypertension?

Accepted Answer

ACE inhibitors

Answer

Calcium channel blockers

Answer

Alpha-adrenergics

Answer

Beta-adrenergics

Question 5

A 30-year-old woman complains of weakness and fatigability over the past 6 months. She has a 3-month acute history of severe hypertension that has required treatment with antihypertensive medications. Radiographic examination reveals a tumor of her right suprarenal gland. The patient is diagnosed with a pheochromocytoma (tumor of the adrenal medulla) and is scheduled for a laparoscopic adrenalectomy. Which of the following nerve fibers will need to be cut when the adrenal gland and tumor are removed?

Accepted Answer

Preganglionic sympathetic fibers

Answer

Postganglionic sympathetic fibers

Answer

Somatic motor fibers

Answer

Postganglionic parasympathetic fibers

Question 6

Enlargement of a pituitary tumor after adrenalectomy is called as:

Accepted Answer

Nelson syndrome

Answer

Steel-Richardson syndrome

Answer

Hamman-Rich syndrome

Answer

Job's syndrome

Question 7

In which of the following conditions do Total T3, Total T4, and TSH all decrease?

Accepted Answer

Hypopituitarism

Answer

Primary hypothyroidism

Answer

Nephrotic syndrome

Answer

Pregnancy

Question 8

Characteristic feature of the urine in diabetes insipidus include the following EXCEPT?

Accepted Answer

Specific gravity > 1.020

Answer

No proteins

Answer

No sugar

Answer

No casts

Question 9

Which of the following conditions is associated with autonomic disturbances?

Accepted Answer

Diabetes mellitus

Answer

Hyperthyroidism

Answer

Hyperaldosteronism

Answer

Hyperparathyroidism

Question 10

A 25-year-old female presents with episodes of bizarre behavior, memory lapse, and unconsciousness. She also demonstrated previous episodes of extreme hunger, sweating, and tachycardia. During one of these episodes, her blood sugar was tested and was found to be 40 mg/dL. Which of the following would most appropriately indicate a diagnosis of insulinoma?

Accepted Answer

Hypoglycemia during a symptomatic episode with relief of symptoms by intravenous glucose

Answer

Demonstration of insulin antibodies in blood

Answer

Abnormal glucagon level

Answer

CT of the pancreas showing a mass

Endocrinology — MCQs

Endocrinology — MCQs

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