Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 191: A patient presents with perioral paresthesia following thyroid surgery. Serum calcium levels are 7 mg/dL. What is the most appropriate management?

A. Oral vitamin D3
B. Oral vitamin D3 with calcium
C. IV calcium gluconate
D. Oral calcium (Correct Answer)

Explanation: **Explanation:** The patient is presenting with **symptomatic hypocalcemia** (perioral paresthesia) following thyroid surgery, a common complication due to transient ischemia or accidental removal of the parathyroid glands. **1. Why Oral Calcium is correct:** The management of post-thyroidectomy hypocalcemia depends on the severity of symptoms and the absolute calcium level. In patients with **mild symptoms** (like isolated perioral paresthesia) and a serum calcium level above 6.5–7.0 mg/dL, **oral calcium supplementation** is the first-line treatment. It is effective, safer than IV administration, and sufficient to alleviate mild neuromuscular irritability. **2. Why other options are incorrect:** * **IV Calcium Gluconate:** This is reserved for **emergency management** of severe hypocalcemia (e.g., tetany, carpopedal spasm, seizures, or QTc prolongation). While the patient is symptomatic, perioral paresthesia alone does not necessitate the risks associated with rapid IV calcium infusion unless oral therapy fails or symptoms progress. * **Oral Vitamin D3 (with or without Calcium):** Vitamin D3 (Cholecalciferol) requires hepatic and renal hydroxylation and has a slow onset of action. In acute post-surgical hypoparathyroidism, **Calcitriol** (active Vitamin D) is preferred over D3 if oral calcium alone is insufficient. **NEET-PG High-Yield Pearls:** * **Most common cause** of post-thyroidectomy hypocalcemia: Devitalization of parathyroid glands. * **Chvostek’s sign:** Tapping the facial nerve leads to facial twitching. * **Trousseau’s sign:** Carpal spasm induced by inflating a BP cuff (more sensitive than Chvostek). * **ECG finding:** Prolonged QT interval. * **Hungry Bone Syndrome:** Severe, prolonged hypocalcemia seen after surgery for hyperparathyroidism (not thyroidectomy).

Question 192: A 40-year-old male presents with papillary thyroid cancer confined to one lobe of the thyroid, measuring 3x3 cm, with no palpable nodes. What is the ideal treatment?

A. Hemithyroidectomy
B. Subtotal Thyroidectomy
C. Total thyroidectomy with nodal dissection
D. Total thyroidectomy (Correct Answer)

Explanation: **Explanation:** The management of Papillary Thyroid Carcinoma (PTC) is guided by risk stratification. According to the American Thyroid Association (ATA) and British Thyroid Association (BTA) guidelines, the size of the primary tumor is a critical determinant for the extent of surgery. **1. Why Total Thyroidectomy is Correct:** For tumors **>4 cm**, or those between **1–4 cm** with high-risk features (extrathyroidal extension, vascular invasion, or patient preference for simpler follow-up), **Total Thyroidectomy** is the preferred treatment. In this case, a **3 cm tumor** in a 40-year-old male warrants total thyroidectomy to facilitate the use of Radioiodine (RAI) ablation post-operatively and to allow for accurate monitoring of serum Thyroglobulin (Tg) as a tumor marker. **2. Why Other Options are Incorrect:** * **Hemithyroidectomy:** This is generally reserved for low-risk, unifocal tumors **<1 cm** (microcarcinoma) or selected cases between 1–4 cm without any suspicious features. A 3 cm tumor often carries a higher risk of multifocality (up to 30-40% in the contralateral lobe). * **Subtotal Thyroidectomy:** This is no longer recommended for thyroid malignancies as it leaves behind significant tissue, making RAI therapy ineffective and increasing the risk of recurrence. * **Total Thyroidectomy with Nodal Dissection:** While total thyroidectomy is correct, **prophylactic** nodal dissection is not indicated if there are no palpable or radiologically suspicious nodes (cN0). Nodal dissection is reserved for biopsy-proven or clinically evident nodal involvement (cN1). **Clinical Pearls for NEET-PG:** * **Most common site of metastasis:** Level VI (Central compartment) lymph nodes. * **Orphan Annie Eye nuclei** and **Psammoma bodies** are classic histological hallmarks of PTC. * **Prognosis:** Excellent; the most important prognostic factor is the age of the patient (cut-off is 55 years in the AJCC 8th edition). * **Follow-up:** Serum Thyroglobulin is the "gold standard" marker after total thyroidectomy.

Question 193: What is considered the gold standard for diagnosing pheochromocytoma?

A. Urinary metanephrines
B. CT Abdomen
C. MIBG scan
D. Biopsy (Correct Answer)

Explanation: In the context of medical diagnostics, the **"Gold Standard"** refers to the definitive test that provides the absolute confirmation of a disease. For **Pheochromocytoma**, while biochemical and imaging tests are used for screening and localization, the definitive diagnosis is always **Histopathology (Biopsy/Excision)**. ### Why Biopsy is the Gold Standard: Pheochromocytoma is a catecholamine-secreting tumor of the adrenal medulla. The definitive confirmation requires microscopic examination to identify characteristic features like the **"Zellballen" pattern** (nested clusters of chromaffin cells). However, it is critical to note that in clinical practice, a biopsy is **never** performed before biochemical stabilization and surgical excision due to the risk of a life-threatening hypertensive crisis. ### Why Other Options are Incorrect: * **Urinary/Plasma Metanephrines:** These are the **best initial screening tests** due to their high sensitivity. While they suggest the diagnosis, they are not "gold standard" confirmatory tests. * **CT Abdomen:** This is the **investigation of choice for localization** once the diagnosis is biochemically established. It cannot differentiate between a pheochromocytoma and other adrenal masses (like adenomas) with 100% certainty. * **MIBG Scan:** This is a functional imaging modality used primarily to detect **extra-adrenal (paragangliomas)** or metastatic disease. ### High-Yield Clinical Pearls for NEET-PG: * **Rule of 10s:** 10% are bilateral, 10% are malignant, 10% are extra-adrenal, and 10% are familial. * **Pre-op Management:** Always give **Alpha-blockers first** (e.g., Phenoxybenzamine) followed by Beta-blockers to prevent a hypertensive crisis. * **Histology:** Look for the **Zellballen pattern** and **Chromogranin A** positivity. * **Malignancy:** The only absolute criterion for malignancy in pheochromocytoma is the **presence of distant metastasis** (not local invasion or cellular atypia).

Question 194: Lymphatic spread is most commonly seen in which type of thyroid malignancy?

A. Papillary carcinoma (Correct Answer)
B. Follicular carcinoma
C. Medullary carcinoma
D. Anaplastic carcinoma

Explanation: **Explanation:** The correct answer is **Papillary Carcinoma (Option A)**. **Why Papillary Carcinoma is correct:** Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Its hallmark characteristic is a strong predilection for **lymphatic spread**. Approximately 30–80% of patients have cervical lymph node involvement at the time of diagnosis. This occurs via the intrathyroidal lymphatic network, typically involving the central compartment (Level VI) first, followed by the lateral neck nodes. **Why the other options are incorrect:** * **Follicular Carcinoma (Option B):** This tumor characteristically spreads via the **hematogenous (bloodborne) route** rather than lymphatics. This is because follicular cells tend to invade thin-walled blood vessels, leading to distant metastases in the bones and lungs. * **Medullary Carcinoma (Option C):** While medullary carcinoma frequently involves lymph nodes (early and aggressively), it is less common overall than Papillary carcinoma. In the context of "most common thyroid malignancy with lymphatic spread," Papillary remains the definitive answer. * **Anaplastic Carcinoma (Option D):** This is a highly aggressive, undifferentiated tumor. While it spreads via both lymphatics and blood, its primary clinical feature is rapid **local invasion** of surrounding structures (trachea, esophagus, nerves) rather than isolated lymphatic spread. **High-Yield Clinical Pearls for NEET-PG:** * **Psammoma bodies:** Laminated calcifications seen on histology in Papillary carcinoma (Pathognomonic). * **Orphan Annie Eye nuclei:** Clear, ground-glass nuclei seen in Papillary carcinoma. * **Prognosis:** Papillary has the best prognosis, while Anaplastic has the worst. * **Route of Spread Mnemonic:** **P**apillary = **P**alpable Nodes (Lymphatic); **F**ollicular = **F**ar-away organs (Hematogenous).

Question 195: What is the treatment for localized and well-differentiated carcinoma of the thyroid?

A. Near total thyroidectomy, radioisotope (Correct Answer)
B. Subtotal thyroidectomy with external beam irradiation
C. Near total thyroidectomy, iodine, external beam irradiation
D. Total thyroidectomy, external beam radiation, lifelong levothyroxine

Explanation: **Explanation:** The management of well-differentiated thyroid carcinoma (WDTC), which includes **Papillary** and **Follicular** thyroid cancers, is centered on surgical clearance followed by adjuvant therapy to eliminate microscopic residual disease. **1. Why Option A is Correct:** For localized WDTC, the standard of care is **Near-total thyroidectomy (NTT)** or **Total thyroidectomy (TT)**. NTT involves removing all visible thyroid tissue except for a small amount (<1 gram) near the recurrent laryngeal nerve or parathyroid glands to prevent injury. Following surgery, **Radioactive Iodine (RAI/Radioisotope - I-131)** is administered. RAI serves two purposes: it ablates any remaining thyroid remnant and acts as a diagnostic tool to detect and treat distant metastases. **2. Why Other Options are Incorrect:** * **Option B:** Subtotal thyroidectomy is inadequate for malignancy as it leaves too much tissue behind, making RAI ablation ineffective and increasing recurrence risk. **External Beam Radiation (EBRT)** is not a primary treatment for WDTC; it is reserved for palliative care or unresectable anaplastic cases. * **Option C & D:** These include EBRT. WDTC is highly **radioresistant** to external radiation but **radiosensitive** to internal radioisotopes (I-131). Therefore, EBRT is not part of the standard protocol for localized, well-differentiated disease. **Clinical Pearls for NEET-PG:** * **Thyroglobulin (Tg):** Used as a tumor marker for follow-up *after* total thyroidectomy and ablation. * **McHenry’s Rule:** If the nodule is >1 cm, TT/NTT is preferred; if <1 cm (microcarcinoma) and low risk, hemithyroidectomy may be considered. * **Levothyroxine:** Post-operatively, patients require lifelong TSH suppression therapy (keeping TSH <0.1 mU/L) to prevent stimulation of any dormant cancer cells.

Question 196: What is the most common site of ectopic pheochromocytoma?

A. Organ of Zuckerkandl (Correct Answer)
B. Bladder
C. Filum terminale
D. Celiac plexus

Explanation: **Explanation:** Pheochromocytomas are catecholamine-secreting tumors arising from chromaffin cells. While 90% occur in the adrenal medulla, 10% are extra-adrenal, referred to as **paragangliomas**. **1. Why Organ of Zuckerkandl is correct:** The **Organ of Zuckerkandl** is a collection of chromaffin tissue located at the origin of the **inferior mesenteric artery** (near the aortic bifurcation). It is the largest collection of extra-adrenal chromaffin tissue in the body and is the **most common site** for ectopic (extra-adrenal) pheochromocytomas, accounting for approximately 50–75% of such cases. **2. Analysis of Incorrect Options:** * **Bladder:** While the urinary bladder is a well-known site for paragangliomas (often presenting with micturition-induced syncope or palpitations), it is less common than the Organ of Zuckerkandl. * **Filum terminale & Celiac plexus:** These are recognized but rare sites for paragangliomas. The celiac plexus is the second most common abdominal site, but still lags significantly behind the Organ of Zuckerkandl. **3. Clinical Pearls for NEET-PG:** * **The Rule of 10s:** Traditionally, Pheochromocytoma is 10% bilateral, 10% malignant, 10% pediatric, and **10% extra-adrenal**. (Note: Modern genetics suggest up to 30-35% may be hereditary). * **Malignancy Risk:** Extra-adrenal tumors (paragangliomas) have a **higher risk of malignancy** compared to adrenal pheochromocytomas. * **Diagnosis:** Best initial screening test is **24-hour urinary fractionated metanephrines** or plasma free metanephrines. * **Localization:** **MIBG scan** (123I-MIBG) is highly specific for locating ectopic or metastatic sites.

Question 197: What is true about follicular carcinoma of the thyroid?

A. More common in endemic areas (Correct Answer)
B. Non-encapsulated
C. Mean age of presentation is 40 years
D. Histopathology easily differentiates it from an adenoma

Explanation: **Explanation:** Follicular Thyroid Carcinoma (FTC) is the second most common thyroid malignancy. Understanding its distinct pathological and epidemiological features is crucial for NEET-PG. **1. Why Option A is Correct:** FTC is significantly **more common in iodine-deficient (endemic) areas**. While Papillary carcinoma is the most common thyroid cancer overall, its relative incidence decreases in endemic regions, where FTC can account for up to 25-40% of cases. Chronic TSH stimulation due to low iodine is thought to contribute to its pathogenesis. **2. Why the other options are Incorrect:** * **Option B:** FTC is typically **encapsulated**. Unlike Papillary carcinoma, which is often unencapsulated and multifocal, FTC usually presents as a solitary, well-circumscribed, and encapsulated mass. * **Option C:** The mean age of presentation is usually **50 years** (the 5th decade). It typically presents about 10 years later than Papillary carcinoma (which peaks at 30–40 years). * **Option D:** This is a classic trap. Histopathology **cannot** easily differentiate FTC from a follicular adenoma based on cellular features alone. The diagnosis of malignancy requires the demonstration of **capsular invasion** or **vascular invasion**, which necessitates a formal histopathological examination of the entire capsule. Therefore, **FNAC cannot distinguish between the two.** **Clinical Pearls for NEET-PG:** * **Spread:** FTC spreads primarily via the **hematogenous route** (to lungs and bone), unlike Papillary carcinoma which spreads via lymphatics. * **Diagnosis:** "Follicular neoplasm" on FNAC is an indication for diagnostic lobectomy because cytology cannot assess capsular integrity. * **Hürthle Cell Carcinoma:** A variant of FTC characterized by oxyphilic cells; it is more aggressive and less likely to take up radioactive iodine. * **Molecular Marker:** Often associated with **RAS mutations** or **PAX8-PPARγ rearrangements**.

Question 198: A 40-year-old female presents with a slow-growing, painless mass. She is recently diagnosed with thyroid cancer. Which is the most common subtype of thyroid cancer?

A. Medullary carcinoma
B. Papillary carcinoma (Correct Answer)
C. Follicular carcinoma
D. Anaplastic carcinoma

Explanation: **Explanation:** **Papillary Thyroid Carcinoma (PTC)** is the most common subtype of thyroid cancer, accounting for approximately **80–85%** of all thyroid malignancies. It typically presents as a slow-growing, painless, "cold" nodule in females (3rd–5th decades). The diagnosis is primarily made via Fine Needle Aspiration Cytology (FNAC), which reveals characteristic nuclear features like **Orphan Annie eye nuclei** (cleared-out chromatin), **Psammoma bodies** (laminated calcifications), and nuclear grooves. **Analysis of Incorrect Options:** * **Follicular Carcinoma (Option C):** The second most common (10–15%). Unlike PTC, it spreads **hematogenously** (to bone/lungs) and cannot be diagnosed by FNAC alone, as it requires histological evidence of capsular or vascular invasion. * **Medullary Carcinoma (Option A):** Accounts for ~5%. It arises from **Parafollicular C-cells** and secretes calcitonin. It is associated with MEN 2A and 2B syndromes. * **Anaplastic Carcinoma (Option D):** Rare (<2%) but highly aggressive. It typically presents in elderly patients as a rapidly enlarging mass with a very poor prognosis. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Spread:** PTC spreads primarily via **lymphatics** (Level VI nodes first). * **Risk Factor:** Prior exposure to **ionizing radiation** is the most significant risk factor for PTC. * **Prognosis:** PTC has an excellent 10-year survival rate (>90%). * **Molecular Marker:** **BRAF V600E** mutation is the most common genetic alteration in PTC.

Question 199: Which of the following complications will NOT lead to respiratory distress after thyroid surgery?

A. Seroma at the surgical site
B. Recurrent laryngeal nerve injury
C. Hypocalcemia (Correct Answer)
D. Hematoma at the surgical site

Explanation: ### Explanation **Correct Answer: C. Hypocalcemia** **Why Hypocalcemia is the correct answer:** Hypocalcemia typically occurs 24–72 hours post-thyroidectomy due to accidental removal or devascularization of the parathyroid glands. Its hallmark clinical features are **neuromuscular irritability**, such as circumoral paresthesia, Trousseau’s sign, and Chvostek’s sign. While severe hypocalcemia can lead to **laryngospasm** (which causes stridor), it does not typically present as primary respiratory distress in the immediate postoperative period. In the context of this question, it is the least likely cause of mechanical airway obstruction compared to the other surgical complications listed. **Analysis of Incorrect Options:** * **Hematoma (Option D):** This is the most common cause of life-threatening respiratory distress in the first 24 hours. A tension hematoma compresses the trachea and causes venous congestion, leading to laryngeal edema. * **Recurrent Laryngeal Nerve (RLN) Injury (Option B):** While unilateral injury causes hoarseness, **bilateral RLN injury** results in both vocal cords remaining in the paramedian position, causing acute airway obstruction and immediate respiratory distress. * **Seroma (Option A):** Although less common than hematoma, a large, tense seroma in the confined subplatysmal space can exert pressure on the trachea, leading to respiratory compromise. **High-Yield Clinical Pearls for NEET-PG:** * **Immediate Management of Post-op Hematoma:** The priority is to **open the wound at the bedside** (stitch removal) to evacuate the clot and relieve pressure, followed by a return to the OR. * **Tracheomalacia:** Long-standing large goiters can cause softening of tracheal rings; this is another cause of post-op collapse, though rarer than hematoma. * **Hypocalcemia Timeline:** Transient hypocalcemia is common; permanent hypoparathyroidism is defined if symptoms persist >6 months. * **Most common nerve injured:** External branch of the Superior Laryngeal Nerve (leads to loss of high-pitched voice/easy fatigue).

Question 200: A 40-year-old female who underwent subtotal thyroidectomy developed respiratory distress 8 hours after the operation. The skin sutures were opened in the ward but the distress persisted. What is the next likely step in management?

A. Immediately shift the patient to the operation theatre.
B. Patient should be intubated in the ward.
C. External pressure should be applied over the neck to stop bleeding.
D. Open the layers of the wound in the ward. (Correct Answer)

Explanation: ### Explanation **1. Why Option D is Correct:** The patient is presenting with **post-operative respiratory distress** following a thyroidectomy, which is a surgical emergency most commonly caused by a **tension hematoma**. This occurs when blood accumulates deep to the deep cervical fascia (investing layer), compressing the trachea and causing venous congestion of the glottis (laryngeal edema). The key clinical point here is that **opening only the skin sutures is insufficient** because the hematoma is trapped beneath the strap muscles and the deep fascia. To relieve the life-threatening pressure, the clinician must **open all layers of the wound** (including the deep fascia and muscle layers) at the bedside to evacuate the clot immediately. **2. Why Other Options are Incorrect:** * **Option A:** Shifting to the OT causes a fatal delay. The decompression must be done immediately in the ward to restore the airway. * **Option B:** Intubation is often technically impossible due to laryngeal edema and tracheal deviation/compression caused by the hematoma. Decompression must precede or facilitate airway management. * **Option C:** External pressure will worsen the respiratory distress by further compressing the trachea. **3. Clinical Pearls for NEET-PG:** * **Most common cause of post-thyroidectomy respiratory distress:** Tension hematoma (usually due to slipping of a ligature on the superior thyroid artery). * **Timing:** Typically occurs within the first 6–24 hours post-surgery. * **Management Sequence:** 1. Immediate bedside decompression (opening all layers). 2. Once the airway is stabilized, shift to OT for formal exploration and hemostasis. * **Other causes of distress:** Recurrent laryngeal nerve injury (bilateral), tracheomalacia (long-standing goiters), and laryngeal edema. * **Hypocalcemia (Tetany):** Usually occurs 24–72 hours post-op, not typically presenting as acute respiratory distress in the first 8 hours.

Practice by Chapter

Thyroid Nodules

Practice Questions

Thyroid Cancer

Practice Questions

Graves' Disease

Practice Questions

Thyroiditis

Practice Questions

Primary Hyperparathyroidism

Practice Questions

Secondary and Tertiary Hyperparathyroidism

Practice Questions

Adrenal Cortical Tumors

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Pheochromocytoma

Practice Questions

Adrenal Incidentalomas

Practice Questions

Multiple Endocrine Neoplasia

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Neuroendocrine Tumors

Practice Questions

Intraoperative Monitoring in Endocrine Surgery

Practice Questions

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