Endocrine Surgery — MCQs

Endocrine Surgery Indian Medical PG Practice Questions and MCQs

Question 201: In the early postoperative period after excision of a pheochromocytoma, which complication is least likely?

A. Infection
B. Hypertension (Correct Answer)
C. Atelectasis
D. Bleeding

Explanation: **Explanation:** The primary hemodynamic challenge in the early postoperative period following pheochromocytoma excision is **hypotension**, not hypertension. Once the tumor is removed, the sudden withdrawal of high levels of circulating catecholamines, combined with a chronically constricted vascular bed and potential down-regulation of adrenoceptors, leads to profound vasodilation and a drop in blood pressure. Therefore, **Hypertension (Option B)** is the least likely complication. * **Infection (Option A):** Like any major abdominal or retroperitoneal surgery, surgical site infections (SSI) are a standard postoperative risk. * **Atelectasis (Option C):** This is the most common respiratory complication in the first 24–48 hours post-surgery, especially in procedures involving upper abdominal incisions or prolonged anesthesia. * **Bleeding (Option D):** The adrenal glands are highly vascular, and the proximity to major vessels (IVC on the right, renal vein on the left) makes postoperative hemorrhage a recognized risk. **High-Yield Clinical Pearls for NEET-PG:** * **Triad of Pheochromocytoma:** Episodic headache, sweating, and tachycardia. * **Pre-operative Preparation:** Always start **Alpha-blockers first** (e.g., Phenoxybenzamine) for 10–14 days, followed by Beta-blockers. Starting Beta-blockers first can cause an unopposed alpha-agonistic effect, leading to a hypertensive crisis. * **Post-op Hypoglycemia:** Removal of the tumor eliminates catecholamine-induced inhibition of insulin; patients must be monitored for rebound hyperinsulinemia and hypoglycemia. * **Fluid Management:** Aggressive volume expansion is required post-excision to counteract the expanded vascular space.

Question 202: Regarding follicular carcinoma of the thyroid, which of the following statements is true?

A. It is the most common type of thyroid cancer.
B. It is readily diagnosed.
C. It spreads primarily through the hematogenous route. (Correct Answer)
D. It is commonly multifocal.

Explanation: **Explanation:** **1. Why Option C is Correct:** Follicular Thyroid Carcinoma (FTC) is characterized by its tendency for **hematogenous (blood-borne) spread**. Unlike Papillary Thyroid Carcinoma (PTC), which spreads via lymphatics, FTC cells invade blood vessels. This leads to distant metastases, most commonly to the **lungs and bones** (often presenting as osteolytic, pulsating bone lesions). **2. Why the Other Options are Incorrect:** * **Option A:** **Papillary Carcinoma** is the most common type of thyroid cancer (approx. 80-85%), whereas Follicular Carcinoma is the second most common (approx. 10-15%). * **Option B:** FTC is **not** readily diagnosed by Fine Needle Aspiration Cytology (FNAC). FNAC cannot distinguish between a benign follicular adenoma and a follicular carcinoma because the diagnosis of malignancy depends on identifying **capsular or vascular invasion**, which requires histological examination of the entire nodule. * **Option D:** FTC is typically a **solitary lesion**. Multifocality is a hallmark feature of Papillary Thyroid Carcinoma, not Follicular Carcinoma. **3. NEET-PG High-Yield Pearls:** * **Hürthle Cell Carcinoma:** A variant of FTC; it is less likely to take up iodine and has a higher rate of lymph node metastasis compared to typical FTC. * **Risk Factor:** FTC is more common in areas of **iodine deficiency** (endemic goiter belts). * **Tumor Marker:** **Thyroglobulin** is used to monitor for recurrence post-total thyroidectomy. * **Management:** Total thyroidectomy followed by Radioactive Iodine (RAI) ablation is the standard for tumors >1 cm or those with vascular invasion.

Question 203: Lymphatic spread is most commonly seen with which type of thyroid cancer?

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

Explanation: **Explanation:** **Papillary Thyroid Carcinoma (PTC)** is the most common type of thyroid malignancy and is characterized by its propensity for **lymphatic spread**. Approximately 50–70% of patients have cervical lymph node involvement at the time of diagnosis. This occurs because PTC cells typically invade the rich lymphatic network of the thyroid gland rather than the blood vessels. **Analysis of Options:** * **Papillary (Correct):** It is the most common thyroid cancer and spreads primarily via lymphatics to the central (Level VI) and lateral neck nodes. * **Follicular:** This cancer is known for **hematogenous spread** (via the bloodstream). It tends to metastasize to distant sites like the lungs and bones because the tumor cells typically invade blood vessels rather than lymphatics. * **Medullary:** While MTC can spread to lymph nodes (often early), it is less common overall than Papillary. It is also associated with calcitonin secretion and MEN 2 syndromes. * **Lymphoma:** While it involves the lymphatic system, it is a primary malignancy of the lymphoid tissue itself, not a thyroid epithelial cancer that "spreads" via lymphatics in the same clinical context as PTC. **High-Yield Clinical Pearls for NEET-PG:** * **Most common thyroid cancer:** Papillary (85%). * **Psammoma bodies:** Characteristic microscopic finding in Papillary carcinoma. * **Orphan Annie eye nuclei:** Classic nuclear feature of Papillary carcinoma. * **Prognosis:** Papillary has an excellent prognosis, while Anaplastic has the worst. * **Route of spread:** Papillary = Lymphatic; Follicular = Hematogenous.

Question 204: All of the following are associated with Thyroid storm, EXCEPT:

A. Surgery for thyroiditis (Correct Answer)
B. Surgery for thyrotoxicosis
C. Stressful illness in thyrotoxicosis
D. I-131 therapy for thyrotoxicosis

Explanation: **Explanation:** Thyroid storm is a life-threatening exacerbation of hyperthyroidism characterized by a hypermetabolic state. It occurs when there is a sudden, massive release of thyroid hormones ($T_3$ and $T_4$) into the circulation. **1. Why "Surgery for thyroiditis" is the correct answer:** Thyroiditis (such as Hashimoto’s or De Quervain’s) typically involves inflammation of the gland. While it can cause a transient "leak" of hormones (thyrotoxicosis), it is not a chronic hyperfunctioning state like Graves' disease. More importantly, surgery is **not** a standard treatment for thyroiditis. Since the underlying pathology is inflammatory rather than autonomous hyperfunction, surgical intervention in these patients does not typically trigger the massive catecholamine-mediated surge required to cause a thyroid storm. **2. Analysis of Incorrect Options:** * **Surgery for thyrotoxicosis:** Historically the most common trigger. If a patient with Graves' disease is not rendered "euthyroid" preoperatively (using antithyroid drugs or Lugol’s iodine), surgical manipulation of the hyperactive gland can precipitate a storm. * **Stressful illness:** Systemic stressors such as sepsis, myocardial infarction, or trauma in a patient with underlying (often undiagnosed) thyrotoxicosis can trigger a storm due to increased sympathetic activity. * **I-131 therapy:** Radioactive iodine causes radiation-induced thyroiditis and follicular destruction, which can lead to a transient "dumping" of stored thyroid hormones into the bloodstream. **Clinical Pearls for NEET-PG:** * **Diagnosis:** Primarily clinical (Burch-Wartofsky Point Scale). Key features: Hyperpyrexia (>104°F), tachycardia/AFib, CNS agitation, and GI dysfunction. * **Management Priority:** 1. **Propranolol:** Blocks peripheral effects and $T_4$ to $T_3$ conversion. 2. **Antithyroid drugs (PTU preferred):** PTU is favored over Methimazole because it also inhibits peripheral conversion of $T_4$ to $T_3$. 3. **Lugol’s Iodine:** Given *after* PTU to prevent the iodine from being used as substrate for new hormone synthesis (Wolff-Chaikoff effect). 4. **Corticosteroids:** To treat relative adrenal insufficiency and inhibit $T_4 \to T_3$ conversion.

Question 205: What is the preferred approach for a retrosternal goitre?

A. Transcervical approach (Correct Answer)
B. Transthoracic approach at the 2nd intercostal space
C. Transthoracic approach at the 4th intercostal space
D. Transsternal approach to the anterior mediastinum

Explanation: **Explanation:** The **transcervical approach** is the preferred and most common surgical route for the management of a retrosternal goitre. **1. Why the Transcervical approach is correct:** The vast majority (over 90%) of retrosternal goitres are "secondary" goitres. This means they originate from the thyroid gland in the neck and descend into the mediastinum due to gravity, negative intrathoracic pressure, and the weight of the gland. Crucially, these goitres maintain their **blood supply from the superior and inferior thyroid arteries**, which arise in the neck. Therefore, they can almost always be safely delivered into the neck through a standard Kocher’s collar incision by gentle traction and digital dissection. **2. Why the other options are incorrect:** * **Options B & C (Transthoracic):** A thoracotomy is rarely indicated for thyroid surgery. It carries significantly higher morbidity and does not provide adequate access to the primary blood supply in the neck. * **Option D (Transsternal/Sternotomy):** While a sternotomy provides excellent exposure to the anterior mediastinum, it is reserved for specific indications (less than 5-10% of cases), such as: * Primary intrathoracic goitres (blood supply from internal mammary or aorta). * Recurrent goitres or malignancy with mediastinal extension. * Goitres causing "Incarceration" (wider diameter in the chest than the thoracic inlet). **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** A goitre is considered retrosternal if more than 50% of its volume is below the level of the thoracic inlet. * **Pemberton’s Sign:** Facial flushing and inspiratory stridor upon raising both arms (due to thoracic inlet obstruction); a classic sign of retrosternal goitre. * **Imaging:** CT scan is the gold standard for preoperative planning to assess the extent and relationship to great vessels. * **Key Fact:** Always ligate the superior thyroid pole first to allow mobility for delivering the retrosternal portion.

Question 206: Which vessels supply a secondary retrosternal goitre?

A. Mediastinal vessels
B. Thyroid vessels (Correct Answer)
C. Arch of aorta
D. Bronchial vessels

Explanation: **Explanation:** The classification and surgical management of retrosternal goitres depend heavily on their embryological origin and blood supply. **1. Why Thyroid Vessels are Correct:** A **secondary retrosternal goitre** (the most common type, accounting for >95% of cases) originates in the neck from the thyroid gland. Due to negative intrathoracic pressure, gravity, and the constraints of the pretracheal fascia, the enlarging thyroid gland is "pushed" or "sucked" down into the superior mediastinum. Because it originates in the neck, it **retains its original blood supply** from the **superior and inferior thyroid arteries**. This is a critical surgical fact: most secondary goitres can be delivered through a standard cervical incision because their vascular pedicle is accessible from the neck. **2. Why Other Options are Incorrect:** * **Mediastinal vessels:** These supply **primary** retrosternal goitres (ectopic thyroid tissue), which are rare (<1%) and located entirely in the chest without a connection to the cervical thyroid. * **Arch of aorta & Bronchial vessels:** These do not provide the primary blood supply to thyroid tissue. While the *Thyroidea ima* artery (an anatomical variant) can arise from the aortic arch or brachiocephalic trunk, it is not the standard supply for a secondary goitre. **Clinical Pearls for NEET-PG:** * **Primary vs. Secondary:** Primary goitres are ectopic and supplied by intrathoracic vessels; Secondary goitres are migrations and supplied by cervical vessels. * **Surgical Approach:** Most secondary goitres can be removed via a **cervical incision**. A sternotomy is rarely required (<5%) unless the goitre is primary, malignant, or larger than the thoracic inlet. * **Definition:** A goitre is typically defined as retrosternal if more than 50% of its volume lies below the plane of the thoracic inlet.

Question 207: Thyroid storm is characterized by which of the following?

A. It is common in inadequately prepared patients for surgery and is accompanied by excess release of thyroid hormone.
B. Tachycardia, hyperpyrexia, dehydration, and hyperexcitability are seen.
C. It is a condition of hyperthyroidism accompanied by fever, CNS agitation, or depression.
D. All of the above. (Correct Answer)

Explanation: **Explanation:** Thyroid storm (thyrotoxic crisis) is a life-threatening clinical manifestation of extreme hyperthyroidism. It is a **clinical diagnosis** characterized by a decompensated state of thyrotoxicosis. 1. **Why Option D is correct:** * **Pathophysiology (Option A):** It most commonly occurs in patients with pre-existing hyperthyroidism (usually Graves' disease) who are **inadequately prepared** for surgery or subjected to major stressors (infection, trauma, or non-thyroid surgery). The sudden surge in free thyroid hormones (T3/T4) or increased cellular sensitivity to catecholamines triggers the crisis. * **Clinical Presentation (Option B & C):** The hallmark features include severe **hyperpyrexia** (fever often >104°F), marked **tachycardia** (out of proportion to fever), and **CNS dysfunction** (ranging from extreme agitation and delirium to coma/depression). Dehydration occurs due to diaphoresis and gastrointestinal losses (vomiting/diarrhea). 2. **Why other options are not "wrong" individually:** Options A, B, and C all describe essential facets of the condition—its etiology, physical signs, and neurological impact. Since all three statements are medically accurate, "All of the above" is the most comprehensive choice. **NEET-PG High-Yield Pearls:** * **Diagnosis:** Primarily clinical; the **Burch-Wartofsky Point Scale (BWPS)** is used (score ≥45 is highly suggestive). * **Management (The "5 Ps"):** 1. **P**ropylthiouracil (PTU): Inhibits hormone synthesis and peripheral conversion of T4 to T3. 2. **P**ropranolol: Controls tachycardia and inhibits peripheral T4 to T3 conversion. 3. **P**otassium Iodide (Lugol’s iodine): Blocks hormone release (Wolff-Chaikoff effect); give *after* PTU. 4. **P**rednisolone (Steroids): Inhibits T4 to T3 conversion and treats potential adrenal insufficiency. 5. **P**aracetamol/Cooling: For hyperpyrexia (Avoid Aspirin as it displaces T4 from binding globulins).

Question 208: What is the most common type of thyroid carcinoma?

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

Explanation: **Explanation:** Thyroid carcinomas are classified based on their histological origin. **Papillary Thyroid Carcinoma (PTC)** is the most common type, accounting for approximately **80–85%** of all thyroid malignancies. It typically presents as a slow-growing, painless thyroid nodule and has an excellent prognosis. It is associated with radiation exposure and specific genetic mutations like **BRAF** and **RET/PTC** rearrangements. **Analysis of Options:** * **A. Papillary (Correct):** It is the most frequent thyroid cancer. Key histological features include **Orphan Annie eye nuclei** (clear nuclei), **Psammoma bodies** (calcifications), and nuclear grooves. It spreads primarily via the **lymphatics**. * **B. Follicular:** The second most common type (approx. 10%). Unlike PTC, it spreads **hematogenously** (to lungs/bones) and is more common in iodine-deficient areas. * **C. Medullary:** Accounts for about 5% of cases. It arises from **Parafollicular C-cells** and secretes **Calcitonin**. It can be sporadic or part of MEN 2A/2B syndromes. * **D. Anaplastic:** Rare (<2%) but highly aggressive. It has the worst prognosis among thyroid cancers, often presenting in elderly patients with rapid local invasion. **High-Yield Clinical Pearls for NEET-PG:** * **Most common thyroid cancer:** Papillary. * **Most common thyroid cancer in children:** Papillary. * **Most common thyroid cancer post-radiation:** Papillary. * **Route of spread:** Papillary = Lymphatic; Follicular = Hematogenous. * **Diagnosis:** FNAC can diagnose Papillary, Medullary, and Anaplastic, but **cannot** distinguish between Follicular Adenoma and Carcinoma (requires biopsy to see capsular/vascular invasion).

Question 209: Which metastatic sites are most common to the thyroid gland?

A. Lung (Correct Answer)
B. Breast
C. Brain
D. Gastrointestinal tract

Explanation: **Explanation:** Metastasis to the thyroid gland is an infrequent clinical finding but is increasingly identified in autopsy series. Among non-thyroidal primary malignancies, the **Lung** is the most common site of origin for thyroid metastases, followed closely by the kidney (Renal Cell Carcinoma) and the breast. * **Lung (Correct):** Large-scale autopsy studies consistently identify lung cancer as the most frequent primary source. This is attributed to the high incidence of lung cancer and its propensity for hematogenous spread. In clinical practice (symptomatic patients), Renal Cell Carcinoma is often the most common, but for the NEET-PG context, Lung is the established answer for overall frequency. * **Breast:** While breast cancer is a common source of metastasis to various organs, it typically ranks second or third behind lung and kidney in its frequency of spread to the thyroid. * **Brain:** Primary brain tumors rarely metastasize outside the central nervous system. Conversely, the thyroid frequently metastasizes *to* the brain (especially papillary and follicular types), but the reverse is not true. * **Gastrointestinal Tract:** While cancers of the colon or stomach can metastasize to the thyroid, they are significantly less common than thoracic or renal primaries. **High-Yield Clinical Pearls for NEET-PG:** * **Most common clinical presentation:** A rapidly enlarging, firm, painless thyroid mass in a patient with a known history of malignancy. * **Renal Cell Carcinoma (RCC):** Often presents with the longest latency period (metastasis may appear years after the primary tumor is treated). * **Diagnosis:** Fine Needle Aspiration Cytology (FNAC) is the gold standard, often requiring immunohistochemistry (IHC) to differentiate from primary thyroid medullary or anaplastic carcinoma. * **Prognosis:** Generally poor, as thyroid involvement usually signifies disseminated systemic disease.

Question 210: Thyroid storm after operation is due to?

A. Inadequate control of hyperthyroidism (Correct Answer)
B. Massive bleeding
C. Recurrent laryngeal nerve injury
D. Postoperative infection

Explanation: ### Explanation **Correct Answer: A. Inadequate control of hyperthyroidism** Thyroid storm (thyrotoxic crisis) is a life-threatening exacerbation of hyperthyroidism. In the context of surgery, it typically occurs in patients with Graves' disease or toxic multinodular goiter who are **inadequately prepared** preoperatively. The underlying mechanism involves a sudden, massive release of thyroid hormones (T3 and T4) into the circulation, often triggered by the stress of surgery or manual manipulation of the gland. To prevent this, patients must be rendered **euthyroid** before surgery using antithyroid drugs (Propylthiouracil or Methimazole) and Lugol’s iodine (to decrease vascularity and hormone release). **Analysis of Incorrect Options:** * **B. Massive bleeding:** While a serious complication (potentially causing airway obstruction due to tension hematoma), it leads to hypovolemic shock, not a thyrotoxic crisis. * **C. Recurrent laryngeal nerve injury:** This results in vocal cord palsy (hoarseness if unilateral; airway obstruction if bilateral) but does not trigger metabolic storm. * **D. Postoperative infection:** While infection can *trigger* a thyroid storm in an uncontrolled patient, the primary surgical cause remains the failure to control the hyperthyroid state prior to the procedure. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Presentation:** Hyperpyrexia (>104°F), extreme tachycardia, agitation, delirium, and high-output heart failure. * **Timing:** Usually occurs within the first **6–18 hours** postoperatively. * **Management (The "P" Rule):** 1. **P**ropylthiouracil (blocks synthesis and peripheral T4→T3 conversion). 2. **P**ropranolol (controls sympathetic overactivity). 3. **P**rednisolone/Hydrocortisone (blocks T4→T3 conversion and treats relative adrenal insufficiency). 4. **P**otassium Iodide (Lugol’s iodine) – administered *after* antithyroid drugs to prevent the Jod-Basedow effect.

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

Practice Questions

Pheochromocytoma

Practice Questions

Adrenal Incidentalomas

Practice Questions

Multiple Endocrine Neoplasia

Practice Questions

Neuroendocrine Tumors

Practice Questions

Intraoperative Monitoring in Endocrine Surgery

Practice Questions

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