Endocrine Surgery Practice Questions

Q: What is the most common hormone, other than gastrin, found in a gastric secreting islet cell tumor?

ACTH. **Explanation:** Gastrinomas (Zollinger-Ellison Syndrome) are the most common functional pancreatic neuroendocrine tumors (pNETs). While they primarily secrete gastrin, they are frequently **multihormonal**. **1. Why ACTH is the correct answer:** Studies and clinical pathology reports indicate that **ACTH (Adrenocorticotropic Hormone)** is the most common secondary hormone produced by gastrin-secreting islet cell tumors. When a gastrinoma secretes ACTH, it can lead to ectopic Cushing syndrome, which is often a marker of a more aggressive or metastatic tumor. This association is particularly important in the context of **MEN-1 (Multiple Endocrine Neoplasia Type 1)**, where multiple tumors may coexist. **2. Why other options are incorrect:** * **B. Glucagon:** While glucagonomas exist, they are distinct clinical entities (presenting with necrolytic migratory erythema). Glucagon is less frequently co-secreted by gastrinomas compared to ACTH. * **C. Growth hormone-releasing factor (GHRF):** GHRF secretion from a pNET can cause acromegaly, but this is a rare occurrence compared to the frequency of ACTH co-secretion. * **D. Insulin:** Insulinomas are usually solitary and do not typically co-secrete gastrin. If a patient has both high insulin and high gastrin, it usually suggests two separate tumors (common in MEN-1) rather than a single tumor secreting both. **High-Yield Pearls for NEET-PG:** * **Passaro’s Triangle (Gastrinoma Triangle):** The anatomical area where 90% of gastrinomas are found (bounded by the cystic duct, junction of the 2nd and 3rd parts of the duodenum, and the neck of the pancreas). * **Most common site:** The **duodenum** is now recognized as the most common site for gastrinomas, especially in MEN-1. * **Malignancy:** Approximately 60-90% of gastrinomas are malignant. * **Clinical Hint:** If a gastrinoma patient presents with hypokalemia and hypercortisolism, suspect ectopic **ACTH** production.

Q: A 57-year-old female underwent a total thyroidectomy. Following the surgery, she developed stridor and dyspnea. What is the most likely cause?

Bilateral recurrent laryngeal nerve injury. **Explanation:** The development of acute **stridor and dyspnea** immediately following a total thyroidectomy is a surgical emergency, most commonly caused by **Bilateral Recurrent Laryngeal Nerve (RLN) injury**. **1. Why Option C is Correct:** The RLN supplies all the intrinsic muscles of the larynx except the cricothyroid. Its primary function is to **abduct** (open) the vocal cords via the posterior cricoarytenoid muscle. In a bilateral injury, both vocal cords assume a **paramedian position**. This significantly narrows the glottic aperture, leading to acute airway obstruction, inspiratory stridor, and respiratory distress, often necessitating an emergency tracheostomy. **2. Why Other Options are Incorrect:** * **Unilateral RLN injury (Option D):** This typically presents with **hoarseness of voice** or a weak cough. Because the unaffected vocal cord can still abduct, the airway remains patent, and stridor does not occur. * **Superior Laryngeal Nerve (SLN) injury (Options A & B):** The SLN (external branch) supplies the cricothyroid muscle, which tenses the vocal cords. Injury leads to a loss of high-pitched voice and vocal fatigue (the "monotone voice"), but it **never** causes airway obstruction or stridor. **Clinical Pearls for NEET-PG:** * **Most common cause of post-thyroidectomy stridor:** While bilateral RLN injury is the most common *nerve* cause, **Tension Hematoma** (compressive) is the most common *overall* cause in the immediate postoperative period. * **Nerve Vulnerability:** The RLN is most commonly injured at the **Ligament of Berry**. * **Management:** If stridor occurs due to a hematoma, the immediate step is to **open the wound sutures at the bedside** to decompress the airway. If due to bilateral RLN injury, re-intubation or tracheostomy is required.

Q: After thyroidectomy, a patient developed stridor within 2 hours. What is the most likely cause of stridor in this patient?

Recurrent laryngeal nerve palsy. **Explanation:** The development of stridor within the immediate post-operative period (0–2 hours) after thyroidectomy is a surgical emergency. **1. Why Recurrent Laryngeal Nerve (RLN) Palsy is Correct:** The RLN supplies all intrinsic muscles of the larynx except the cricothyroid. **Bilateral RLN injury** results in both vocal cords assuming a paramedian position, narrowing the glottic opening significantly. This leads to acute airway obstruction and **inspiratory stridor** immediately upon extubation or shortly thereafter. While unilateral injury causes hoarseness, bilateral injury is a classic cause of post-thyroidectomy respiratory distress. **2. Why the other options are incorrect:** * **Hypocalcemia (Option A):** While hypocalcemia can cause laryngospasm and stridor (tetany), it typically manifests **24 to 72 hours** post-surgery as the serum calcium levels drop. It is unlikely to occur within the first 2 hours. * **Carotid Artery/Jugular Vein Injury (Options C & D):** While injury to these vessels can cause a **tension hematoma**, the primary mechanism of stridor in that scenario is external compression of the trachea, not the vascular injury itself. If "Hematoma" were an option, it would be a strong differential, but the vessels themselves do not cause stridor. **NEET-PG High-Yield Pearls:** * **Most common cause of stridor <2 hours:** 1. Tension Hematoma (most common overall), 2. Bilateral RLN palsy. * **Management of Post-op Hematoma:** Immediate bedside opening of the wound (evacuation of clots) to decompress the trachea, followed by surgery. * **Tracheomalacia:** Occurs in patients with long-standing large goiters where the tracheal rings have weakened; stridor occurs due to tracheal collapse upon extubation. * **Nerve Monitoring:** Intraoperative nerve monitoring (IONM) is used to identify and preserve the RLN during dissection.

Q: What is the most common cause of primary hyperparathyroidism?

Solitary adenoma. **Explanation:** Primary hyperparathyroidism (PHPT) is characterized by the autonomous overproduction of parathyroid hormone (PTH), leading to hypercalcemia. **1. Why Solitary Adenoma is Correct:** A **solitary parathyroid adenoma** is the most common cause, accounting for approximately **85–90%** of all cases of PHPT. It typically involves a single enlarged gland (usually the inferior parathyroid) while the remaining glands remain suppressed due to high serum calcium levels. **2. Why the Other Options are Incorrect:** * **Hyperplasia (Option A):** This involves the enlargement of all four parathyroid glands and accounts for about **10–15%** of cases. It is frequently associated with hereditary syndromes like MEN 1 and MEN 2A. * **Multiple Adenomas (Option D):** These occur in approximately **4–5%** of cases. Distinguishing multiple adenomas from hyperplasia can be surgically challenging. * **Carcinoma (Option C):** Parathyroid carcinoma is extremely rare, occurring in ** 14 mg/dL) and a palpable neck mass. **Clinical Pearls for NEET-PG:** * **Most common symptom:** Most patients are currently **asymptomatic** (detected on routine biochemical screening). * **Classic presentation:** "Bones, stones, abdominal groans, and psychic moans" (Osteitis fibrosa cystica, nephrolithiasis, peptic ulcers/pancreatitis, and depression). * **Localization:** Sestamibi (Technetium-99m) scan is the gold standard for preoperative localization of an adenoma. * **Definitive Treatment:** Surgical excision (Parathyroidectomy). A drop in intraoperative PTH by >50% (Miami criteria) indicates successful removal.

Q: Which of the following statements is false regarding medullary carcinoma of the thyroid?

Arises from follicular cells. **Explanation:** **1. Why Option A is False (The Correct Answer):** Medullary Thyroid Carcinoma (MTC) does **not** arise from follicular cells. Instead, it originates from the **Parafollicular cells (C-cells)**, which are derived from the **ultimobranchial body (neural crest cells)**. Follicular cells give rise to differentiated thyroid cancers like Papillary and Follicular carcinoma. **2. Analysis of Other Options:** * **Option B (Secretes Calcitonin):** This is true. Since MTC arises from C-cells, it produces **Calcitonin**, which serves as a highly specific tumor marker for diagnosis and monitoring recurrence. * **Option C (Occurs in families):** This is true. Approximately 25% of MTC cases are hereditary, occurring as part of **MEN 2A, MEN 2B**, or Familial MTC syndromes, usually associated with the **RET proto-oncogene** mutation. * **Option D (Amyloid in stroma):** This is true. A classic histological hallmark of MTC is the presence of **amyloid deposits** in the stroma, which represent pro-calcitonin fibrils stained by **Congo Red** (showing apple-green birefringence). **Clinical Pearls for NEET-PG:** * **Tumor Marker:** Calcitonin (for diagnosis) and CEA (for prognosis). * **Genetic Testing:** All patients with MTC must be screened for **RET mutations** and co-existing **Pheochromocytoma** (especially before surgery). * **Spread:** Unlike papillary CA (lymphatic) or follicular CA (hematogenous), MTC spreads via **both** routes. * **Management:** Total thyroidectomy with central compartment neck dissection is the treatment of choice; it is **not** responsive to radioactive iodine (RAI) because C-cells do not take up iodine.

Q: A lady presented with recurrent attacks of giddiness and abdominal pain since three months. Endoscopy was normal. Her fasting blood glucose was 40 mg% and insulin levels were elevated. CT abdomen showed a well-defined 8 mm enhancing lesion in the head of the pancreas, with no other abnormal findings. What should be the treatment plan for this patient?

Enucleation. ### Explanation **Diagnosis:** The patient presents with the classic **Whipple’s Triad**: symptoms of hypoglycemia (giddiness), low fasting blood glucose (40 mg%), and relief of symptoms upon glucose administration. Elevated insulin levels in the presence of hypoglycemia confirm an **Insulinoma**. The CT finding of a small (8 mm), solitary, enhancing lesion in the pancreatic head is characteristic of this neuroendocrine tumor. **Why Enucleation is the Correct Answer:** 1. **Benign Nature:** Over 90% of insulinomas are solitary and benign. 2. **Size and Location:** For small (<2 cm), solitary, and superficial insulinomas that are not in direct contact with the main pancreatic duct, **Enucleation** is the surgical treatment of choice. It preserves pancreatic exocrine and endocrine function and avoids the morbidity of major resections. **Why Other Options are Incorrect:** * **Whipple’s Operation:** This is a radical resection (Pancreaticoduodenectomy). It is reserved for large, malignant tumors or those involving the main pancreatic duct in the head. It is "overkill" for a small, benign 8 mm lesion. * **Enucleation with Radiotherapy:** Insulinomas are generally not radiosensitive, and radiotherapy is not indicated for benign, localized neuroendocrine tumors. * **Streptozotocin:** This is a chemotherapeutic agent used for metastatic or unresectable malignant insulinomas. It is not a primary treatment for a localized, resectable lesion. **Clinical Pearls for NEET-PG:** * **Most common** islet cell tumor: Insulinoma. * **Rule of 10s:** 10% are malignant, 10% are multiple (often associated with **MEN-1**), and 10% are ectopic. * **Localization:** Intraoperative ultrasound (IOUS) is the most sensitive method to localize the tumor and its relation to the pancreatic duct. * **Medical Management:** Diazoxide can be used pre-operatively to inhibit insulin release and control hypoglycemia.

Q: Medullary carcinoma of the thyroid is associated with an increase in which of the following?

Calcitonin. ### Explanation **Correct Answer: A. Calcitonin** **Underlying Medical Concept:** Medullary Thyroid Carcinoma (MTC) originates from the **Parafollicular C-cells** of the thyroid gland. These cells are neuroendocrine in origin (derived from the neural crest) and their primary physiological function is the secretion of **Calcitonin**, a hormone involved in calcium homeostasis. Because MTC is a tumor of these specific cells, serum calcitonin levels are significantly elevated and serve as a highly sensitive and specific **tumor marker** for diagnosis, screening (especially in familial cases), and monitoring for recurrence after surgery. **Analysis of Incorrect Options:** * **B. Thyroglobulin:** This is a protein produced by the follicular cells of the thyroid. It is a tumor marker for differentiated thyroid cancers (DTC) like **Papillary and Follicular carcinoma**, but not for MTC. * **C & D. T3 and T4:** These are thyroid hormones produced by the follicular cells under the influence of TSH. MTC does not involve the follicular epithelium; therefore, patients are typically euthyroid, and these levels remain normal unless there is a co-existing thyroid pathology. **High-Yield Clinical Pearls for NEET-PG:** * **Carcinoembryonic Antigen (CEA):** Also elevated in MTC and used as a secondary tumor marker for prognosis and monitoring. * **Genetics:** Approximately 25% of MTC cases are familial, associated with **MEN 2A and 2B** syndromes due to mutations in the **RET proto-oncogene**. * **Amyloid Stroma:** Histologically, MTC is characterized by polygonal cells with **amyloid deposits** (derived from pro-calcitonin) that stain with Congo Red. * **Management:** The primary treatment is Total Thyroidectomy with central compartment neck dissection. MTC does **not** respond to Radioiodine (I-131) therapy because C-cells do not uptake iodine.

Q: Which of the following will not lead to respiratory distress after thyroid surgery?

None of the above. **Explanation:** Respiratory distress is a critical postoperative complication of thyroid surgery. The correct answer is **None of the above** because all three listed conditions (A, B, and C) are recognized causes of airway compromise following thyroidectomy. 1. **Laryngomalacia (Tracheomalacia):** Long-standing, large goiters can cause pressure necrosis and softening of the tracheal rings (tracheomalacia). When the thyroid is removed, the structural support for the trachea is lost, leading to tracheal collapse during inspiration, resulting in acute respiratory distress. 2. **Bilateral Recurrent Laryngeal Nerve (RLN) Injury:** While unilateral injury causes hoarseness, bilateral injury results in both vocal cords assuming a paramedian position. This narrows the glottic chink significantly, causing immediate postoperative stridor and airway obstruction. 3. **Hypocalcemia:** Accidental removal or devascularization of the parathyroid glands leads to hypocalcemia. Severe hypocalcemia increases neuromuscular irritability, which can manifest as **laryngospasm**, leading to acute respiratory distress (typically 24–72 hours post-op). **Clinical Pearls for NEET-PG:** * **Most common cause** of respiratory distress in the first 24 hours is a **tension hematoma** (reactionary hemorrhage). The immediate management is bedside evacuation of the clot by opening the wound. * **Laryngeal Edema:** Often caused by traumatic intubation or venous/lymphatic obstruction; managed with steroids or re-intubation. * **Bilateral RLN injury** requires immediate tracheostomy or re-intubation. * **Chvostek’s and Trousseau’s signs** are classic clinical indicators of the hypocalcemia that leads to the aforementioned laryngospasm.

Question 1

What is the most common hormone, other than gastrin, found in a gastric secreting islet cell tumor?

Accepted Answer

ACTH

Answer

Glucagon

Answer

Growth hormone releasing factor

Answer

Insulin

Question 2

A 57-year-old female underwent a total thyroidectomy. Following the surgery, she developed stridor and dyspnea. What is the most likely cause?

Accepted Answer

Bilateral recurrent laryngeal nerve injury

Answer

Bilateral superior laryngeal nerve injury

Answer

Unilateral superior laryngeal nerve injury

Answer

Unilateral recurrent laryngeal nerve injury

Question 3

After thyroidectomy, a patient developed stridor within 2 hours. What is the most likely cause of stridor in this patient?

Accepted Answer

Recurrent laryngeal nerve palsy

Answer

Hypocalcemia

Answer

Carotid artery injury

Answer

Jugular vein injury

Question 4

What is the most common cause of primary hyperparathyroidism?

Accepted Answer

Solitary adenoma

Answer

Hyperplasia

Answer

Carcinoma

Answer

Multiple adenomas

Question 5

A 26-year-old woman presents with a palpable thyroid nodule. Needle biopsy demonstrates amyloid in the stroma of the lesion. A cervical lymph node is palpable on the same side as the lesion. What is the preferred treatment?

Accepted Answer

Total thyroidectomy and modified neck dissection on the side of the enlarged lymph node.

Answer

Removal of the involved node, the isthmus, and the enlarged lymph node.

Answer

Removal of the involved lobe, the isthmus, a portion of the opposite lobe, and the enlarged lymph node.

Answer

Total thyroidectomy and irradiation of the cervical lymph nodes.

Question 6

Which of the following statements is false regarding medullary carcinoma of the thyroid?

Accepted Answer

Arises from follicular cells

Answer

Secretes calcitonin

Answer

Occurs in families

Answer

Amyloid in stroma

Question 7

A lady presented with recurrent attacks of giddiness and abdominal pain since three months. Endoscopy was normal. Her fasting blood glucose was 40 mg% and insulin levels were elevated. CT abdomen showed a well-defined 8 mm enhancing lesion in the head of the pancreas, with no other abnormal findings. What should be the treatment plan for this patient?

Accepted Answer

Enucleation

Answer

Whipple's operation

Answer

Enucleation with radiotherapy

Answer

Administration of streptozotocin

Question 8

Medullary carcinoma of the thyroid is associated with an increase in which of the following?

Accepted Answer

Calcitonin

Answer

Thyroglobulin

Answer

T3

Answer

T4

Question 9

Which of the following will not lead to respiratory distress after thyroid surgery?

Accepted Answer

None of the above

Answer

Laryngomalacia

Answer

Bilateral recurrent laryngeal nerve injury

Answer

Hypocalcemia

Question 10

Which of the following statements about papillary carcinoma of the thyroid are true?

Accepted Answer

Radiation is a risk factor, Multifocal, Distant metastasis is seen, and Most common in iodine deficient areas.

Answer

Radiation is a risk factor, Multifocal, Hematogenous spread is common, and Distant metastasis is seen.

Answer

Multifocal, Hematogenous spread is common, Distant metastasis is seen, and Most common in iodine deficient areas.

Answer

All statements are true.

Endocrine Surgery — MCQs

Endocrine Surgery — MCQs

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