Vocal cord palsy after thyroid surgery is due to injury to:
Q272
A 25 year old female patient with previous history of neck irradiation presents with thyroid swelling for last 6 months. The patient is clinically euthyroid. On examination, the right lobe of thyroid gland is enlarged with presence of ipsilateral cervical lymphadenopathy. The most probable clinical diagnosis in this patient is
Q273
A 29-year-old woman presents with a neck mass. Fine needle aspiration shows medullary thyroid carcinoma. Her calcitonin level is normal, but genetic testing reveals a RET proto-oncogene mutation. What is the most appropriate management strategy?
Q274
A 45-year-old woman undergoes thyroidectomy for papillary thyroid cancer. Postoperatively, she develops perioral numbness and tingling in her fingers. Her calcium is 7.2 mg/dL (normal 8.5-10.5), phosphorus is 5.8 mg/dL (normal 2.5-4.5), and intact PTH is 8 pg/mL (normal 15-65). What is the most likely cause of these findings?
Q275
A 45-year-old man with a strong family history of multiple endocrine neoplasia type 2 (MEN2) presents for genetic counseling. He has not undergone genetic testing but has three children. His brother recently died of metastatic medullary thyroid cancer. What is the most appropriate initial approach for this patient and his family?
Q276
After a total thyroidectomy, the surgeon is unable to extubate the patient, who shows cyanosis and respiratory distress. What is the most likely cause of the inability to extubate?
Q277
A 32-year-old female patient with Graves' disease with eye signs and enlarged thyroid planned for a total thyroidectomy. What can be given in the preoperative period to reduce intraoperative bleeding in the patient?
Q278
A 36-year-old woman comes to the physician for a follow-up visit after she had a PET scan that showed a nodule on the thyroid gland. She has no difficulty or pain while swallowing. She was treated for non-Hodgkin lymphoma at the age of 28 years, which included external beam radiation to the head and neck and 4 cycles of chemotherapy. She appears healthy. Vital signs are within normal limits. Physical examination shows no abnormalities. Serum studies show:
Glucose 82 mg/dL
Creatinine 0.7 mg/dL
Thyroid-stimulating hormone 3 μU/mL
Ultrasound of the neck shows a 1.2-cm (0.5-in) nodule on the left lobe of the thyroid with irregular margins and microcalcifications. A fine-needle aspiration biopsy shows Psammoma bodies and cells with clear, ground-glass, empty nuclei. Which of the following is the most appropriate next step in management?
Q279
A 27-year-old woman presents with 26 weeks of gestation with a thyroid lesion which is found to be papillary carcinoma of thyroid. Which is the best treatment for this patient?
Q280
Most common nerve injured in ligation of inferior thyroid artery
Endocrine Surgery Indian Medical PG Practice Questions and MCQs
Question 271: Vocal cord palsy after thyroid surgery is due to injury to:
A. Vagus nerve
B. Superior laryngeal nerve
C. Recurrent laryngeal nerve (Correct Answer)
D. Ansa cervicalis
Explanation: ***Recurrent laryngeal nerve***
- The **recurrent laryngeal nerves** innervate all intrinsic muscles of the larynx except the cricothyroid muscle, which are responsible for vocal cord movement.
- Injury to this nerve during thyroid surgery leads to **vocal cord palsy**, causing hoarseness or aphonia.
*Vagus nerve*
- The **vagus nerve** is the main trunk from which the recurrent laryngeal nerve branches, but direct injury to the vagus itself is less common in thyroid surgery and would cause widespread symptoms beyond just vocal cord palsy.
- Vagus nerve injury would also affect other structures in the neck, thorax, and abdomen, reflecting its broad autonomic and motor functions.
*Superior laryngeal nerve*
- The **superior laryngeal nerve** innervates the **cricothyroid muscle** (external branch) and provides sensation to the supraglottic larynx (internal branch).
- Damage to this nerve causes changes in vocal pitch (due to paralysis of the cricothyroid muscle, which tenses the vocal cords) and problems with voice modulation, but not complete vocal cord paralysis.
*Ansa cervicalis*
- The **ansa cervicalis** innervates the infrahyoid muscles (strap muscles), which depress the hyoid bone and larynx.
- Injury to the ansa cervicalis would affect neck movement and swallowing, but not directly cause vocal cord palsy.
Question 272: A 25 year old female patient with previous history of neck irradiation presents with thyroid swelling for last 6 months. The patient is clinically euthyroid. On examination, the right lobe of thyroid gland is enlarged with presence of ipsilateral cervical lymphadenopathy. The most probable clinical diagnosis in this patient is
A. Papillary carcinoma thyroid (Correct Answer)
B. Lymphoma
C. Medullary carcinoma thyroid
D. Follicular carcinoma thyroid
Explanation: ***Papillary carcinoma thyroid***
- A history of **neck irradiation** is a significant risk factor for **papillary thyroid carcinoma**.
- **Cervical lymphadenopathy** is a common presentation, as papillary carcinoma frequently metastasizes to regional lymph nodes, and the patient is **euthyroid**.
*Lymphoma*
- While neck mass and lymphadenopathy can occur with lymphoma, a history of **previous neck irradiation** is a stronger predisposing factor for thyroid carcinoma, and **thyroid lymphoma** often presents with a rapidly enlarging goiter or compressive symptoms.
- Though irradiation can increase the risk of some lymphomas, it's a more direct and strong risk factor for thyroid cancer in the setting of thyroid swelling.
*Medullary carcinoma thyroid*
- **Medullary thyroid carcinoma** typically arises from **parafollicular C cells** and is often associated with elevated **calcitonin levels** and may be familial (e.g., MEN 2 syndromes), which are not mentioned.
- While it can present with lymphadenopathy, the history of irradiation points more strongly towards papillary carcinoma.
*Follicular carcinoma thyroid*
- **Follicular carcinoma** is less commonly associated with a history of **neck irradiation** compared to papillary carcinoma and tends to metastasize hematogenously rather than primarily to regional lymph nodes.
- It often presents as a solitary nodule, and while lymph node involvement can occur, it's less characteristic than in papillary carcinoma.
Question 273: A 29-year-old woman presents with a neck mass. Fine needle aspiration shows medullary thyroid carcinoma. Her calcitonin level is normal, but genetic testing reveals a RET proto-oncogene mutation. What is the most appropriate management strategy?
A. Observation with serial imaging
B. Thyroid lobectomy only
C. Total thyroidectomy with central lymph node dissection (Correct Answer)
D. Radioactive iodine therapy without surgery
Explanation: ***Total thyroidectomy with central lymph node dissection***
- The presence of a **RET proto-oncogene mutation** strongly suggests a familial medullary thyroid carcinoma (MTC) syndrome, even though calcitonin is normal (due to diagnosis at an earlier stage or a less aggressive mutation).
- **Prophylactic total thyroidectomy** is recommended in patients with RET mutations to prevent or manage MTC, which is aggressive and often multicentric; central neck dissection is crucial due to the high risk of lymph node metastasis in MTC.
*Observation with serial imaging*
- This is inappropriate for a patient with a **RET mutation**, given the high risk of developing **medullary thyroid carcinoma (MTC)**, an aggressive type of thyroid cancer.
- Delaying definitive treatment can lead to more advanced disease, making cure less likely.
*Thyroid lobectomy only*
- **Thyroid lobectomy** is insufficient for a patient with a **RET mutation**, as MTC is often **multicentric** and affects both lobes.
- This approach would leave residual diseased thyroid tissue and increase the risk of recurrence.
*Radioactive iodine therapy without surgery*
- **Radioactive iodine (RAI) therapy** is effective for differentiated thyroid cancers (e.g., papillary, follicular) by targeting iodine-avid cells.
- **Medullary thyroid carcinoma (MTC)**, often associated with RET mutations, does not take up iodine and is therefore **not responsive to RAI therapy**.
*Total thyroidectomy only*
- While **total thyroidectomy** addresses the primary tumor, it omits removal of potentially involved **central lymph nodes**.
- **Central lymph node dissection** is essential in MTC due to the high incidence of early lymphatic spread.
Question 274: A 45-year-old woman undergoes thyroidectomy for papillary thyroid cancer. Postoperatively, she develops perioral numbness and tingling in her fingers. Her calcium is 7.2 mg/dL (normal 8.5-10.5), phosphorus is 5.8 mg/dL (normal 2.5-4.5), and intact PTH is 8 pg/mL (normal 15-65). What is the most likely cause of these findings?
A. Inadvertent removal of parathyroid glands (Correct Answer)
B. Temporary thyroid hormone deficiency
C. Injury to recurrent laryngeal nerve
D. Postoperative infection
Explanation: ***Inadvertent removal of parathyroid glands***
- The combination of **hypocalcemia** (calcium 7.2 mg/dL), **hyperphosphatemia** (phosphorus 5.8 mg/dL), and a **low intact PTH** (8 pg/mL) after thyroidectomy is characteristic of **hypoparathyroidism**, most often caused by accidental removal or damage to the parathyroid glands during surgery.
- **Perioral numbness and tingling** in the fingers are classic symptoms of hypocalcemia, secondary to reduced parathyroid hormone (PTH) secretion.
*Temporary thyroid hormone deficiency*
- This would lead to symptoms of **hypothyroidism**, such as fatigue, weight gain, and cold intolerance, not acute hypocalcemic symptoms.
- Thyroid hormone deficiency primarily affects metabolism and energy levels, not calcium homeostasis in this acute context.
*Injury to recurrent laryngeal nerve*
- Injury to the **recurrent laryngeal nerve** would manifest as **hoarseness** or **vocal cord paralysis**, not perioral numbness, tingling, or electrolyte abnormalities.
- This complication affects vocal function but has no direct impact on calcium and phosphorus metabolism.
*Postoperative infection*
- A **postoperative infection** would typically present with **fever**, **pain**, **redness**, and **swelling** at the surgical site, none of which are described.
- Infections do not directly cause this specific pattern of hypocalcemia, hyperphosphatemia, and low PTH.
Question 275: A 45-year-old man with a strong family history of multiple endocrine neoplasia type 2 (MEN2) presents for genetic counseling. He has not undergone genetic testing but has three children. His brother recently died of metastatic medullary thyroid cancer. What is the most appropriate initial approach for this patient and his family?
A. Immediate prophylactic thyroidectomy without genetic testing
B. Screening with calcitonin levels only
C. Observation with annual screening
D. Genetic counseling with testing and family cascade screening (Correct Answer)
Explanation: ***Genetic counseling with testing and family cascade screening***
- Given the strong family history of **MEN2** and the brother's death from **medullary thyroid cancer (MTC)**, genetic counseling and testing for **RET proto-oncogene mutations** are essential to determine the patient's risk.
- If the patient tests positive, **cascade screening** of his children and other at-risk family members is crucial for early detection and intervention, as **MEN2** is an autosomal dominant condition.
*Immediate prophylactic thyroidectomy without genetic testing*
- Performing a **prophylactic thyroidectomy** without confirmed genetic mutation is overly aggressive and unnecessary, as the patient might not carry the **RET mutation**.
- Genetic testing provides definitive diagnosis and guidance for intervention, preventing unnecessary surgery and its associated risks.
*Screening with calcitonin levels only*
- While **calcitonin** is a marker for **MTC**, relying solely on it for screening is insufficient, especially in a patient with a strong family history.
- Calcitonin levels can be elevated due to other conditions and may not detect **early-stage disease** as reliably as genetic testing, which identifies the underlying genetic predisposition.
*Observation with annual screening*
- Simply observing with annual screening, without genetic insights, does not address the high-risk nature of **MEN2** and the potential for aggressive **MTC**.
- **Early detection** through genetic testing allows for timely prophylactic measures or close monitoring, significantly improving prognosis.
*Genetic testing followed by family screening if positive*
- This option is partially correct but less comprehensive than "genetic counseling with testing and family cascade screening."
- **Genetic counseling** is a vital first step to educate the patient on the implications of testing, potential results, and the importance of family screening.
Question 276: After a total thyroidectomy, the surgeon is unable to extubate the patient, who shows cyanosis and respiratory distress. What is the most likely cause of the inability to extubate?
A. Bilateral recurrent laryngeal nerve palsy (Correct Answer)
B. Unilateral recurrent laryngeal nerve palsy
C. Superior laryngeal nerve palsy
D. Hemorrhage
Explanation: ***Bilateral recurrent laryngeal nerve palsy***
- After total thyroidectomy, injury to both **recurrent laryngeal nerves** can lead to paralysis of the abductor muscles of the vocal cords causing them to approximate, leading to **airway obstruction**, cyanosis, and respiratory distress.
- This condition prevents successful extubation and often necessitates **reintubation** or **tracheostomy**.
*Unilateral recurrent laryngeal nerve palsy*
- Causes **hoarseness** due to unilateral vocal cord paralysis but typically does not result in severe airway obstruction or inability to extubate.
- The unaffected vocal cord can usually compensate sufficiently to maintain an adequate airway for breathing.
*Superior laryngeal nerve palsy*
- Primarily affects the **protective reflexes of the larynx** and vocal cord tension (pitch), leading to issues like **aspiration risk** and a weak, breathy voice.
- It does not directly cause vocal cord paralysis in a position that obstructs the airway.
*Hemorrhage*
- While a significant **post-operative hemorrhage** in the neck can cause airway compression and respiratory distress, it usually manifests as **neck swelling** and possibly hypovolemic shock.
- The scenario explicitly states "inability to extubate," suggesting a vocal cord issue rather than external compression by a hematoma.
Question 277: A 32-year-old female patient with Graves' disease with eye signs and enlarged thyroid planned for a total thyroidectomy. What can be given in the preoperative period to reduce intraoperative bleeding in the patient?
A. Propylthiouracil
B. Potassium iodide (Correct Answer)
C. Betamethasone
D. Propranolol
Explanation: ***Potassium iodide***
- **Potassium iodide** (e.g., Lugol's solution) is given preoperatively to patients with Graves' disease undergoing thyroidectomy because it **decreases the vascularity** of the thyroid gland, thereby reducing intraoperative bleeding.
- It also helps to **block the release of thyroid hormones** from the thyroid gland, stabilizing the patient's thyroid function.
*Propylthiouracil*
- **Propylthiouracil (PTU)** is an **antithyroid drug** that prevents the synthesis of thyroid hormones by inhibiting the organification of iodine and the coupling of iodotyrosines.
- Although it helps to achieve a **euthyroid state** before surgery, it does not directly reduce the vascularity of the thyroid gland to decrease intraoperative bleeding.
*Betamethasone*
- **Betamethasone** is a corticosteroid used for its **anti-inflammatory** and immunosuppressive effects.
- It is not typically used preoperatively in Graves' disease to reduce thyroid vascularity or bleeding; its primary role might be in managing severe **ophthalmopathy** or thyroid storm, not surgical bleeding.
*Propranolol*
- **Propranolol** is a **beta-blocker** used to control the adrenergic symptoms of hyperthyroidism, such as **tachycardia**, palpitations, and tremors.
- While it helps to achieve a more stable cardiac state for surgery, it does not directly impact the **vascularity** of the thyroid gland or reduce surgical bleeding.
Question 278: A 36-year-old woman comes to the physician for a follow-up visit after she had a PET scan that showed a nodule on the thyroid gland. She has no difficulty or pain while swallowing. She was treated for non-Hodgkin lymphoma at the age of 28 years, which included external beam radiation to the head and neck and 4 cycles of chemotherapy. She appears healthy. Vital signs are within normal limits. Physical examination shows no abnormalities. Serum studies show:
Glucose 82 mg/dL
Creatinine 0.7 mg/dL
Thyroid-stimulating hormone 3 μU/mL
Ultrasound of the neck shows a 1.2-cm (0.5-in) nodule on the left lobe of the thyroid with irregular margins and microcalcifications. A fine-needle aspiration biopsy shows Psammoma bodies and cells with clear, ground-glass, empty nuclei. Which of the following is the most appropriate next step in management?
A. Thyroid scintigraphy
B. Observation and follow-up in 3 months
C. Radioiodine therapy
D. Total thyroidectomy (Correct Answer)
Explanation: ***Total thyroidectomy***
- The fine-needle aspiration biopsy findings of **Psammoma bodies** and **clear, ground-glass, empty nuclei** are classic for **papillary thyroid carcinoma**, which is the most common type of thyroid cancer.
- Given the patient's history of **neck radiation** for lymphoma (a risk factor for thyroid cancer), the concerning ultrasound features (irregular margins, microcalcifications), and the confirmed diagnosis of papillary thyroid carcinoma, **total thyroidectomy** is the definitive treatment.
*Thyroid scintigraphy*
- **Thyroid scintigraphy** is primarily used to assess the functional status of thyroid nodules (hot vs. cold) and is helpful if the TSH is suppressed or if the FNA is indeterminate.
- In this case, the **fine-needle aspiration (FNA) biopsy** has already provided a definitive diagnosis of papillary thyroid cancer, making scintigraphy unnecessary for initial management.
*Observation and follow-up in 3 months*
- **Observation** is not appropriate given the definitive diagnosis of **papillary thyroid carcinoma** confirmed by biopsy and the patient's history of neck radiation.
- Papillary thyroid cancer, although often slow-growing, requires active management, especially with adverse features on ultrasound and a clear diagnosis.
*Radioiodine therapy*
- **Radioiodine therapy** is typically used as **adjuvant treatment** *after* thyroidectomy to ablate residual thyroid tissue or treat metastatic disease, particularly in higher-risk cases.
- It is not the primary treatment for localized papillary thyroid carcinoma.
Question 279: A 27-year-old woman presents with 26 weeks of gestation with a thyroid lesion which is found to be papillary carcinoma of thyroid. Which is the best treatment for this patient?
A. Hemi-thyroidectomy
B. Total thyroidectomy
C. Thyroid ablation using radioactive Iodine
D. Observation (Correct Answer)
Explanation: ***Observation***
- For **papillary thyroid carcinoma** diagnosed at **26 weeks of gestation**, **observation with close monitoring** is the best management approach.
- At 26 weeks (late second trimester/approaching third trimester), the optimal surgical window (14-24 weeks) has passed, and surgery in the third trimester carries increased risk of preterm labor and maternal complications.
- **Papillary thyroid carcinoma** has an **indolent course**, and delaying definitive treatment by 3-4 months until after delivery poses **minimal risk** to the mother.
- **Close monitoring with ultrasound** should be performed, and **total thyroidectomy** should be planned for **after delivery**.
- Surgery during pregnancy is only indicated for **rapidly growing tumors** or evidence of **aggressive features**, which are not mentioned in this case.
*Total thyroidectomy*
- While **total thyroidectomy** is the definitive treatment for papillary thyroid carcinoma, the **timing is critical** during pregnancy.
- Surgery is ideally performed in the **second trimester (14-24 weeks)** to minimize risks to both mother and fetus.
- At **26 weeks**, the patient is beyond the optimal surgical window, and performing surgery at this stage or in the third trimester increases the risk of **preterm labor** and other obstetric complications.
- Definitive surgery should be **deferred until after delivery** unless there are aggressive features requiring urgent intervention.
*Hemi-thyroidectomy*
- **Hemi-thyroidectomy** is inadequate for papillary thyroid carcinoma and is only considered for very low-risk papillary microcarcinomas (<1 cm).
- It does not provide adequate oncological control for diagnosed papillary carcinoma.
*Thyroid ablation using radioactive Iodine*
- **Radioactive iodine ablation** is absolutely **contraindicated during pregnancy** due to the risk of fetal thyroid destruction, leading to congenital hypothyroidism or cretinism.
- While it is used as adjuvant therapy post-thyroidectomy in non-pregnant patients, it must be delayed until after delivery and cessation of breastfeeding.
Question 280: Most common nerve injured in ligation of inferior thyroid artery
A. Sympathetic trunk
B. Phrenic nerve
C. Recurrent laryngeal nerve (Correct Answer)
D. External branch of superior laryngeal nerve
Explanation: **Recurrent laryngeal nerve**
- The **recurrent laryngeal nerve (RLN)** runs in close proximity to the inferior thyroid artery, especially on the right side, making it highly vulnerable during ligation or thyroid surgery.
- Injury to the RLN can cause **hoarseness** due to paralysis of the vocal cords, as it innervates most intrinsic laryngeal muscles.
*Sympathetic trunk*
- The **sympathetic trunk** lies more medially and posteriorly in the neck, generally not in the immediate surgical field for inferior thyroid artery ligation.
- Injury to the sympathetic trunk typically leads to **Horner's syndrome** (ptosis, miosis, anhidrosis).
*Phrenic nerve*
- The **phrenic nerve** courses over the anterior scalene muscle, lateral to the thyroid gland and major vessels, making it relatively safe during standard thyroid surgery.
- Damage to the phrenic nerve would result in **diaphragmatic paralysis** and respiratory compromise.
*External branch of superior laryngeal nerve*
- The **external branch of the superior laryngeal nerve (EBSLN)** is located more superiorly, running with the superior thyroid artery to the cricothyroid muscle.
- Injury to the EBSLN would affect the **pitch of the voice** but is less commonly injured during inferior thyroid artery ligation compared to the RLN.
