Endocrinology Practice Questions

Q: Thyroid storm can be treated by all the following drugs except?

Aspirin. **Explanation:** Thyroid storm is a life-threatening medical emergency [2] characterized by extreme hypermetabolism. The management focuses on inhibiting thyroid hormone synthesis, blocking hormone release, preventing peripheral conversion of T4 to T3 [2], and controlling sympathetic overactivity [1]. **Why Aspirin is the Correct Answer (Contraindicated):** Aspirin (and other Salicylates) is strictly contraindicated in thyroid storm. It competes with thyroid hormones (T3 and T4) for binding sites on **Thyroid-Binding Globulin (TBG)**. By displacing T4/T3 from these proteins, aspirin increases the levels of **free (active) thyroid hormones** in the serum, which can acutely worsen the clinical features of the storm. **Analysis of Incorrect Options (Used in Treatment):** * **Propylthiouracil (PTU):** The preferred antithyroid drug in storm [3]. It inhibits the enzyme thyroid peroxidase (blocking synthesis) and, crucially, inhibits the **peripheral conversion of T4 to T3**. * **Dexamethasone:** Glucocorticoids are used because they inhibit the peripheral conversion of T4 to T3 and provide coverage for potential relative adrenal insufficiency associated with severe thyrotoxicosis. * **Propranolol:** A non-selective beta-blocker used to control sympathetic symptoms (tachycardia, tremors, agitation) [1]. Like PTU and Steroids, high-dose propranolol also helps decrease T4 to T3 conversion [2]. **NEET-PG High-Yield Pearls:** 1. **Drug of Choice for Fever:** Acetaminophen (Paracetamol) is the preferred antipyretic in thyroid storm. 2. **Sequence of Treatment:** Always give PTU/Methimazole *before* Iodine (Lugol’s solution/SSKI) to prevent the iodine from being used as a substrate for new hormone synthesis (Jod-Basedow phenomenon). 3. **Burch-Wartofsky Point Scale:** The clinical scoring system used to diagnose Thyroid Storm.

Q: A patient presents with palpitations, headaches, profuse sweating, and hypertension, raising suspicion for pheochromocytoma. Which diagnostic procedure is NOT typically performed in the evaluation of pheochromocytoma?

FNAC (Fine Needle Aspiration Cytology). **Explanation:** The diagnosis of pheochromocytoma relies on biochemical confirmation followed by anatomical and functional imaging. **FNAC (Fine Needle Aspiration Cytology)** is strictly **contraindicated** in suspected cases of pheochromocytoma [1]. Performing a needle biopsy on a catecholamine-secreting tumor can trigger a massive, life-threatening release of catecholamines, leading to a "hypertensive crisis," fatal arrhythmias, or hemorrhage. Furthermore, cytology cannot reliably distinguish between benign and malignant adrenal medullary tumors; malignancy is only confirmed by the presence of metastasis to non-chromaffin tissues. **Analysis of Incorrect Options:** * **CT Scan (with non-ionic contrast):** This is usually the initial imaging modality of choice for localization due to its excellent spatial resolution for adrenal masses [2]. * **MRI:** Highly sensitive and preferred in children, pregnant women, or patients with surgical clips [2]. Pheochromocytomas characteristically show a **"Light Bulb" appearance** (hyperintensity) on T2-weighted images. * **MIBG Scan:** A functional imaging technique using a norepinephrine analogue [2]. It is particularly useful for detecting extra-adrenal tumors (paragangliomas) and metastatic disease [2]. **NEET-PG Clinical Pearls:** * **Rule of 10s:** 10% are bilateral, 10% are extra-adrenal, 10% are malignant, and 10% occur in children. * **Biochemical Screening:** The most sensitive initial test is **plasma free metanephrines**; the most specific is **24-hour urinary metanephrines**. * **Pre-operative Management:** Always start **Alpha-blockade (e.g., Phenoxybenzamine)** before Beta-blockade to avoid an unopposed alpha-mediated hypertensive crisis.

Q: Which of the following conditions is NOT associated with weight gain?

Pheochromocytoma. **Explanation:** The correct answer is **Pheochromocytoma**. This condition is characterized by a catecholamine-secreting tumor (usually of the adrenal medulla). Excess epinephrine and norepinephrine increase the basal metabolic rate (BMR) and promote glycogenolysis and lipolysis [2]. Consequently, patients typically present with **weight loss** despite a normal or increased appetite [1], alongside the classic triad of episodic headache, sweating, and tachycardia [1]. **Analysis of Incorrect Options:** * **Cushing’s Syndrome:** Excess cortisol leads to increased gluconeogenesis and adipogenesis. It causes **central obesity** with a characteristic distribution of fat (buffalo hump, moon facies, and supraclavicular fat pads) [1]. * **Hypothyroidism:** A deficiency in thyroid hormones leads to a significant decrease in the BMR. Weight gain in these patients is primarily due to **accumulation of glycosaminoglycans** (myxedema) and water retention, rather than just fat [1]. * **Insulin-secreting tumor (Insulinoma):** High levels of insulin promote anabolic processes and inhibit lipolysis. Patients often experience recurrent hypoglycemia, which triggers compensatory **hyperphagia** (increased eating to relieve symptoms), leading to significant weight gain. **High-Yield Clinical Pearls for NEET-PG:** * **Rule of 10s for Pheochromocytoma:** 10% bilateral, 10% malignant, 10% extra-adrenal (Paraganglioma), and 10% pediatric. * **MEN 2A & 2B:** Always screen for Pheochromocytoma before surgery for Medullary Thyroid Carcinoma to prevent a hypertensive crisis. * **Diagnosis:** The most sensitive initial screening test is **plasma free metanephrines**; the most specific is 24-hour urinary metanephrines.

Q: Which of the following is NOT a feature of hypercalcemia?

All of the above. Explanation: Hypercalcemia, most commonly caused by Primary Hyperparathyroidism (PHPT) or malignancy, affects multiple organ systems [1]. The classic mnemonic "Stones, Bones, Abdominal Groans, and Psychic Moans" summarizes its clinical presentation. 1. **Bones (Options A & B):** Excess Parathyroid Hormone (PTH) increases osteoclastic activity, leading to bone resorption [1]. This results in **Osteitis fibrosa cystica** (characterized by "brown tumors" and subperiosteal resorption of the phalanges) and **Pathological fractures** due to decreased bone mineral density [1]. 2. **Abdominal Groans (Option C):** Hypercalcemia is a known cause of **Pancreatitis**. High calcium levels can lead to the activation of trypsinogen within the pancreas and the formation of calcium deposits in the pancreatic ducts, triggering inflammation. It is also associated with peptic ulcer disease due to increased gastrin secretion [1]. **Why "All of the above" is correct:** The question asks which of the following is NOT a feature; however, based on the provided key, all listed options (A, B, and C) are actually **well-established features** of hypercalcemia. Therefore, the option "All of the above" serves to confirm that every preceding choice is a valid clinical manifestation of the condition. **High-Yield Clinical Pearls for NEET-PG:** * **ECG Findings:** Hypercalcemia causes a **shortened QT interval**, whereas hypocalcemia causes QT prolongation. * **Renal Effects:** Nephrolithiasis (calcium oxalate stones) and Polyuria (due to nephrogenic diabetes insipidus) are common [1]. * **Most Common Cause:** In outpatients, it is Primary Hyperparathyroidism; in hospitalized patients, it is Malignancy (often via PTHrP) [1]. * **Treatment:** The first-line management for severe hypercalcemia is aggressive **IV hydration with Normal Saline**, followed by loop diuretics (only after rehydration) and Bisphosphonates [1].

Q: All of the following conditions are indications for radioactive iodine use, EXCEPT:

Hyperthyroid children. **Explanation:** Radioactive Iodine (RAI), specifically **I-131**, is a definitive treatment for hyperthyroidism (Graves' disease or toxic multinodular goiter) [1]. However, its use is governed by specific indications and contraindications based on age and clinical status. **Why "Hyperthyroid children" is the correct answer:** Radioactive iodine is generally **avoided in children and adolescents** (especially those under 10–15 years of age). The primary concerns are the theoretical long-term risk of thyroid carcinoma, potential genetic damage to germ cells, and the high sensitivity of developing tissues to radiation. In pediatric populations, anti-thyroid drugs (ATDs) or surgery are the preferred modalities [1]. **Analysis of incorrect options:** * **Age > 40 years & Elderly:** RAI is often the **treatment of choice** for patients over 40 and the elderly. It provides a permanent cure for hyperthyroidism without the surgical risks associated with anesthesia in older populations. * **Presence of comorbidities:** Patients with significant cardiac disease (e.g., atrial fibrillation, heart failure) or other systemic comorbidities are ideal candidates for RAI. It avoids the physiological stress of surgery while effectively controlling the thyrotoxic state that exacerbates these conditions. **NEET-PG High-Yield Pearls:** * **Absolute Contraindications for RAI:** Pregnancy (risk of fetal thyroid ablation) and Breastfeeding [1]. * **Relative Contraindication:** Active/Moderate-to-severe Graves' Ophthalmopathy (RAI can worsen the condition; steroids are given if RAI is used) [1]. * **Pre-treatment:** In elderly or cardiac patients, it is mandatory to achieve euthyroidism with ATDs *before* giving RAI to prevent a thyroid storm caused by the release of stored hormones. * **Follow-up:** The most common long-term complication of RAI is **hypothyroidism**, requiring lifelong levothyroxine.

Q: Hypomagnesemia is associated with which of the following conditions?

Alcoholism. Hypomagnesemia is associated with which of the following conditions? **Explanation:** **1. Why Alcoholism is Correct:** Chronic alcoholism is the most common cause of hypomagnesemia in clinical practice. The underlying mechanisms are multifactorial: * **Renal Loss:** Ethanol acts as a direct tubular toxin, causing reversible impairment of magnesium reabsorption in the loop of Henle and distal tubules, leading to hypermagnesuria. * **Nutritional Deficiency:** Alcoholics often have poor dietary intake of magnesium-rich foods. * **Gastrointestinal Loss:** Chronic diarrhea and malabsorption associated with alcoholism further deplete magnesium stores [1]. **2. Why Hypothyroidism is Incorrect:** Hypothyroidism is typically associated with **hypermagnesemia** (mildly elevated magnesium levels). This occurs because thyroid hormones normally promote the renal clearance of magnesium; a deficiency in these hormones leads to increased renal tubular reabsorption. Conversely, *hyperthyroidism* is a known cause of hypomagnesemia due to increased renal excretion. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Refractory Hypokalemia" Rule:** If a patient has hypokalemia that does not respond to potassium supplementation, always check magnesium levels [1]. Magnesium is a cofactor for the ROMK channels; its deficiency leads to excessive potassium secretion in the distal tubule. * **Hypocalcemia Link:** Severe hypomagnesemia causes hypocalcemia by inducing PTH resistance and inhibiting PTH secretion. * **ECG Findings:** Look for prolonged PR and QT intervals, T-wave flattening, and specifically **Torsades de Pointes** (treated with IV Magnesium Sulfate). * **Other Causes:** Loop/Thiazide diuretics, Aminoglycosides, Amphotericin B, and Cisplatin are frequent pharmacological culprits [1].

Question 1

A young lady presents with tremors, diarrhea, and elevated T4. TSH levels were 8.5 mIU/L. Further examination reveals bi-temporal hemianopia. What is the next step in management?

Accepted Answer

Start anti-thyroid drugs and do urgent MRI Brain

Answer

Start beta blockers

Answer

Conservative management

Answer

Start anti-thyroid drugs and wait for symptoms to resolve

Question 2

Thyroid storm can be treated by all the following drugs except?

Accepted Answer

Aspirin

Answer

Propylthiouracil

Answer

Dexamethasone

Answer

Propranolol

Question 3

A patient presents with palpitations, headaches, profuse sweating, and hypertension, raising suspicion for pheochromocytoma. Which diagnostic procedure is NOT typically performed in the evaluation of pheochromocytoma?

Accepted Answer

FNAC (Fine Needle Aspiration Cytology)

Answer

CT scan

Answer

MRI

Answer

MIBG scan (Iodine-131 metaiodobenzylguanidine scan)

Question 4

Which of the following conditions is NOT associated with weight gain?

Accepted Answer

Pheochromocytoma

Answer

Cushing's syndrome

Answer

Hypothyroidism

Answer

Insulin secreting tumor

Question 5

All of the following are increased in pheochromocytomas, except?

Accepted Answer

5-Hydroxyindoleacetic acid (5-HIAA)

Answer

Vanillylmandelic acid (VMA)

Answer

Metanephrines

Answer

Catecholamines

Question 6

All of the following are associated with hypergonadotropic hypogonadism in males, EXCEPT?

Accepted Answer

Kallman's syndrome

Answer

Viral orchitis

Answer

Klinefelter's syndrome

Answer

Noonan syndrome

Question 7

Which of the following is NOT a feature of hypercalcemia?

Accepted Answer

All of the above

Answer

Osteitis fibrosa cystica

Answer

Pathological fractures

Answer

Pancreatitis

Question 8

All of the following conditions are indications for radioactive iodine use, EXCEPT:

Accepted Answer

Hyperthyroid children

Answer

Age > 40 years

Answer

Elderly

Answer

Presence of comorbidities

Question 9

What is the investigation of choice for hyperprolactinemia?

Accepted Answer

Prolactin estimation

Answer

TRH estimation

Answer

LH estimation

Answer

Estradiol estimation

Question 10

Hypomagnesemia is associated with which of the following conditions?

Accepted Answer

Alcoholism

Answer

Hypothyroidism

Answer

Both

Answer

None

Endocrinology — MCQs

Endocrinology — MCQs

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