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 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: In Sipple syndrome (MEN 2A), which of the following is typically absent?

Pituitary hyperplasia. Explanation: The correct answer is Pituitary hyperplasia because it is a classic feature of MEN 1 (Wermer Syndrome), not MEN 2A (Sipple Syndrome). Both syndromes are autosomal dominant neuroendocrine disorders, but they involve different genetic mutations and organ systems. 1. Why Pituitary Hyperplasia is the correct answer: MEN 2A is caused by a germline mutation in the RET proto-oncogene. Its clinical spectrum is strictly limited to the "MPH" triad: Medullary thyroid carcinoma, Pheochromocytoma, and Hyperparathyroidism. Pituitary adenomas or hyperplasia are characteristic of MEN 1 (the "3 Ps": Pituitary, Parathyroid, and Pancreas). 2. Analysis of Incorrect Options: * Pheochromocytoma (Option A): Present in approximately 50% of MEN 2A cases. They are often bilateral and almost always occur within the adrenal gland. * Medullary Carcinoma of Thyroid (MTC) (Option C): This is the most common feature (nearly 100% penetrance) and usually the first manifestation of MEN 2A. It arises from calcitonin-secreting C-cells. * Parathyroid Hyperplasia (Option D): Occurs in about 20-30% of MEN 2A patients, leading to primary hyperparathyroidism. High-Yield Clinical Pearls for NEET-PG: * MEN 2A (Sipple): MTC + Pheochromocytoma + Parathyroid hyperplasia. * MEN 2B (Williams): MTC + Pheochromocytoma + Mucosal neuromas + Marfanoid habitus (Note: Parathyroid involvement is rare in 2B). * Screening: For MEN 2A/2B, genetic testing for RET mutations is the gold standard. Prophylactic thyroidectomy is often indicated in childhood based on the specific codon mutation. * Rule of Thumb: Always rule out Pheochromocytoma (via plasma metanephrines) before performing surgery for MTC or Hyperparathyroidism to prevent a hypertensive crisis.

Q: What is the most likely diagnosis in a patient with generalized weakness and the given cutaneous finding?

Diffuse melanosis cutis. ***Diffuse melanosis cutis*** - Generalized weakness combined with diffuse cutaneous hyperpigmentation suggests **Addison's disease** (primary adrenal insufficiency) causing excess **ACTH and MSH** stimulation. - The **melanosis cutis** results from increased melanin deposition due to elevated **melanocyte-stimulating hormone** levels when cortisol feedback is lost. *Lichen planus pigmentosus* - Presents with **localized hyperpigmented patches** rather than generalized melanosis, typically following inflammatory lichen planus lesions. - Does not cause **systemic weakness** or constitutional symptoms like adrenal insufficiency. *Smoker's melanosis* - Characterized by **localized oral mucosal pigmentation** from chronic smoking, not generalized cutaneous involvement. - Associated with **tobacco use** and does not cause generalized weakness or systemic symptoms. *Cushing's disease* - Typically causes **central obesity**, **purple striae**, and **moon facies** rather than generalized hyperpigmentation. - Results in **hyperglycemia** and **hypertension**, not the weakness and hyperpigmentation seen in adrenal insufficiency.

Q: A patient presents with symptoms of hypoglycemia. Investigations reveal decreased blood glucose and increased insulin levels. A C-peptide assay shows normal levels of C-peptide. What is the most likely diagnosis?

Accidental exogenous insulin administration. ### Explanation The key to solving this clinical scenario lies in understanding the synthesis of endogenous insulin. Insulin is synthesized as **proinsulin**, which is cleaved into equal molar amounts of **active insulin** and **C-peptide** before being released into the bloodstream. **1. Why Option C is Correct:** In **exogenous insulin administration**, the patient injects pre-formed, purified insulin. This commercial insulin does not contain C-peptide. Therefore, the patient will present with the biochemical triad of: * **Low Blood Glucose** (Hypoglycemia) [3] * **High Insulin** (Exogenous) * **Low/Normal C-peptide** (Endogenous production is actually suppressed due to negative feedback from hypoglycemia) [1]. **2. Why the other options are incorrect:** * **Insulinoma (A):** This is an insulin-secreting tumor of the pancreas. Since it produces endogenous insulin, both **Insulin and C-peptide levels will be elevated** [1]. * **Sulfonylurea Ingestion (B):** Sulfonylureas are secretagogues that stimulate the pancreas to release its own insulin [2]. Consequently, both **Insulin and C-peptide levels will be elevated**, mimicking an insulinoma [1]. * **Metformin Ingestion (D):** Metformin works by increasing insulin sensitivity and decreasing hepatic glucose production; it does not increase insulin secretion and typically does not cause hypoglycemia in isolation. **3. NEET-PG High-Yield Pearls:** * **Factitious Hypoglycemia:** Suspect this in healthcare workers or relatives of diabetics. [1] * **Differential Diagnosis:** To differentiate Insulinoma from Sulfonylurea abuse (as both have high C-peptide), a **Screening for Oral Hypoglycemic Agents** in the urine or plasma is required [1]. * **Whipple’s Triad:** 1. Symptoms of hypoglycemia, 2. Low plasma glucose, 3. Relief of symptoms after glucose administration. This triad confirms a hypoglycemic disorder.

Question 1

Which disorder is associated with thyrotoxicosis but not with hyperthyroidism?

Accepted Answer

De Quervain thyroiditis

Answer

Graves disease

Answer

Hyperfunctioning ("toxic") multinodular goiter

Answer

Iodine-induced hyperthyroidism

Question 2

Sarcodiosis can be associated with which of the following?

Accepted Answer

Cranial diabetes insipidus

Answer

Psychogenic polydypsia

Answer

Nephrogenic diabetes insipidus

Answer

Syndrome of inappropriate antidiuretic hormone secretion (SIADH)

Question 3

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 4

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

Accepted Answer

Aspirin

Answer

Propylthiouracil

Answer

Dexamethasone

Answer

Propranolol

Question 5

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 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

In Sipple syndrome (MEN 2A), which of the following is typically absent?

Accepted Answer

Pituitary hyperplasia

Answer

Pheochromocytoma

Answer

Medullary carcinoma of the thyroid

Answer

Parathyroid hyperplasia

Question 9

What is the most likely diagnosis in a patient with generalized weakness and the given cutaneous finding?

Accepted Answer

Diffuse melanosis cutis

Answer

Lichen planus pigmentosus

Answer

Smoker's melanosis

Answer

Cushing's disease

Question 10

A patient presents with symptoms of hypoglycemia. Investigations reveal decreased blood glucose and increased insulin levels. A C-peptide assay shows normal levels of C-peptide. What is the most likely diagnosis?

Accepted Answer

Accidental exogenous insulin administration

Answer

Insulinoma

Answer

Accidental sulfonylurea ingestion

Answer

Accidental metformin ingestion

Endocrinology — MCQs

Endocrinology — MCQs

On this page

Practice by Chapter

Want unlimited practice?