MCQ bank · 36 questions · free
Endocrine surgery MCQs with answers
36 single-best-answer questions on thyroid, parathyroid, adrenal and neuroendocrine tumours. Try each one, then open the answer to see the explanation, why the other options are wrong, and the guideline or trial behind it.
A 52-year-old woman has an 18-mm solid, hypoechoic thyroid nodule with microcalcifications and irregular margins on ultrasound. Her TSH is normal. What is the next step?
- Radioiodine (isotope) scan
- Levothyroxine to suppress the TSH
- Total thyroidectomy without cytology
- Ultrasound-guided fine-needle aspiration
- Repeat ultrasound in 12 months
Show the answer and explanation
Answer: D. Ultrasound-guided fine-needle aspiration. This nodule has a high-suspicion ultrasound pattern; the ATA recommends fine-needle aspiration for high-suspicion nodules of 1 cm or more. Cytology is then reported using the Bethesda system.
Why not the others? An isotope scan is useful only when the TSH is low. Surgery without cytology and TSH suppression are not recommended.
References
Fine-needle aspiration of a 15-mm thyroid nodule shows papillary carcinoma (Bethesda VI). Ultrasound shows no extrathyroidal extension and no abnormal lymph nodes. Which operation is appropriate?
- Thyroid lobectomy or total thyroidectomy; both are acceptable
- Total thyroidectomy with prophylactic bilateral central and lateral neck dissection
- Isthmusectomy only
- Observation, as papillary cancer never spreads
- Radioiodine without surgery
Show the answer and explanation
Answer: A. Thyroid lobectomy or total thyroidectomy; both are acceptable. For a low-risk papillary cancer of 1–4 cm without extrathyroidal extension or nodal disease, either lobectomy or total thyroidectomy is acceptable. The 2025 ATA guideline leans further towards lobectomy for these tumours, as it avoids lifelong thyroxine in many patients and halves the risk to the parathyroids and both recurrent laryngeal nerves. The choice depends on patient factors, preference, and whether radioiodine is likely to be needed.
Why not the others? Prophylactic lateral neck dissection is not indicated without nodal disease. Radioiodine cannot replace surgery.
References
A 61-year-old woman has primary hyperparathyroidism found on routine bloods: calcium 2.70 mmol/L (10.8 mg/dL), raised PTH, eGFR 85. She has no symptoms, but bone densitometry shows a lumbar spine T-score of −2.7. What do you advise?
- Repeat calcium in 5 years
- Observation, because the calcium is only mildly raised
- Bisphosphonate alone and no surgery
- Parathyroidectomy, because osteoporosis is an indication even without symptoms
- Cinacalcet as first-line treatment
Show the answer and explanation
Answer: D. Parathyroidectomy, because osteoporosis is an indication even without symptoms. Surgery is indicated in asymptomatic primary hyperparathyroidism when any criterion is met: calcium more than 0.25 mmol/L (1 mg/dL) above normal, osteoporosis (T-score −2.5 or less) or a vertebral fracture, eGFR below 60, kidney stones or high urinary calcium, or age under 50. Parathyroidectomy is the only cure and improves bone density.
Why not the others? Cinacalcet and bisphosphonates are for patients who cannot or will not have surgery.
References
- Bilezikian JP et al. Evaluation and management of primary hyperparathyroidism: summary statement and guidelines from the Fifth International Workshop. J Bone Miner Res 2022
- Wilhelm SM et al. The American Association of Endocrine Surgeons guidelines for definitive management of primary hyperparathyroidism. JAMA Surg 2016
A CT for renal colic shows a 3.2-cm homogeneous left adrenal mass with an unenhanced density of 8 Hounsfield units. Blood pressure and potassium are normal. What is the most appropriate next step?
- CT-guided biopsy
- No tests at all
- Repeat CT every 6 months for 2 years
- Laparoscopic adrenalectomy because it is larger than 3 cm
- A 1-mg overnight dexamethasone suppression test, with no further imaging needed for this lesion
Show the answer and explanation
Answer: E. A 1-mg overnight dexamethasone suppression test, with no further imaging needed for this lesion. A homogeneous adrenal mass of 10 HU or less is a benign adenoma, and the 2023 European guideline advises no further imaging. Every incidentaloma still needs hormonal assessment: the 1-mg dexamethasone test for autonomous cortisol secretion, and aldosterone/renin if there is hypertension or hypokalaemia.
Why not the others? Size alone does not decide surgery in a lesion this clearly benign. Biopsy is rarely indicated and must never be done before excluding phaeochromocytoma.
References
A 38-year-old man has a thyroid nodule. Fine-needle aspiration suggests medullary thyroid carcinoma and his calcitonin is raised. Which test must be done before thyroidectomy?
- Plasma or urine metanephrines to exclude phaeochromocytoma
- Parathyroid sestamibi scan in every case
- Thyroid antibodies
- Thyroglobulin level
- Radioiodine scan
Show the answer and explanation
Answer: A. Plasma or urine metanephrines to exclude phaeochromocytoma. Up to a quarter of medullary cancers are hereditary (MEN2), and MEN2 includes phaeochromocytoma. An unrecognised phaeochromocytoma during thyroid surgery can cause a fatal hypertensive crisis, so it must be excluded and, if present, removed first. RET testing, CEA and calcium are also checked.
Why not the others? Medullary cancer arises from C cells, so radioiodine and thyroglobulin have no role.
References
Four hours after a total thyroidectomy, a patient becomes agitated with stridor and a tense, swelling neck. What do you do first?
- Arrange a return to theatre on the next list
- Give nebulised adrenaline and wait
- Send her for an urgent CT of the neck
- Give intravenous calcium
- Open the wound at the bedside: cut the skin sutures and open the strap muscles to release the haematoma, then call for help
Show the answer and explanation
Answer: E. Open the wound at the bedside: cut the skin sutures and open the strap muscles to release the haematoma, then call for help. A haematoma after thyroid surgery compresses the airway and venous drainage, and can kill within minutes. The airway is saved by opening the wound immediately at the bedside (the “SCOOP” sequence: skin exposure, cut sutures, open skin, open muscles, pack), then returning to theatre.
Why not the others? Imaging and waiting waste time. Hypocalcaemia causes tingling and spasms, not a swelling neck.
References
A 44-year-old woman has a biochemically confirmed phaeochromocytoma, a 4-cm right adrenal mass. She is booked for laparoscopic adrenalectomy. How should she be prepared?
- No preparation is needed for laparoscopic surgery
- A beta-blocker first, then an alpha-blocker
- Alpha-blockade (e.g. phenoxybenzamine or doxazosin) for 7–14 days, with a high-salt diet and fluids, adding a beta-blocker only after alpha-blockade
- Diuretics to control the blood pressure
- Start a beta-blocker alone
Show the answer and explanation
Answer: C. Alpha-blockade (e.g. phenoxybenzamine or doxazosin) for 7–14 days, with a high-salt diet and fluids, adding a beta-blocker only after alpha-blockade. Preoperative alpha-blockade prevents dangerous surges in blood pressure when the tumour is handled. Salt and fluid restore the contracted blood volume and reduce hypotension after removal. A beta-blocker may then be added for tachycardia.
Why not the others? Starting a beta-blocker first leaves alpha-receptor vasoconstriction unopposed and can precipitate a hypertensive crisis. Diuretics worsen the low blood volume.
References
A 52-year-old man has resistant hypertension and low potassium. Primary aldosteronism is confirmed, and CT shows a 1-cm left adrenal nodule. He wants surgery if it will help. What is the next step?
- Spironolactone and no further tests, as surgery never helps
- MRI of the adrenals
- Left adrenalectomy based on the CT
- Bilateral adrenalectomy
- Adrenal venous sampling to confirm that the excess aldosterone comes from one side
Show the answer and explanation
Answer: E. Adrenal venous sampling to confirm that the excess aldosterone comes from one side. In patients over about 35, small non-functioning adrenal nodules are common, so CT cannot reliably show which side is producing aldosterone. Adrenal venous sampling distinguishes unilateral disease (cured or improved by adrenalectomy) from bilateral hyperplasia (treated medically).
Why not the others? Operating on the CT alone risks removing the wrong gland. Bilateral adrenalectomy causes lifelong adrenal insufficiency.
References
The day after total thyroidectomy, a patient has tingling around the mouth and fingers and a positive Chvostek’s sign. Adjusted calcium is 1.82 mmol/L. What is the immediate treatment?
- Intravenous calcium chloride as a rapid bolus through a small hand vein
- Intravenous calcium gluconate 10% (10–20 mL over about 10 minutes), then an infusion, with ECG monitoring
- Oral calcium only and review tomorrow
- Wait for the parathyroid glands to recover
- Vitamin D alone
Show the answer and explanation
Answer: B. Intravenous calcium gluconate 10% (10–20 mL over about 10 minutes), then an infusion, with ECG monitoring. Symptomatic hypocalcaemia or a calcium below about 1.9 mmol/L needs intravenous calcium gluconate, followed by an infusion and oral calcium with activated vitamin D (alfacalcidol or calcitriol). Magnesium should also be checked and corrected.
Why not the others? Calcium chloride is irritant and can cause tissue necrosis if it leaks from a peripheral vein.
References
A 32-year-old man with primary hyperparathyroidism has a family history of pituitary and pancreatic tumours. Genetic testing confirms MEN1. Which operation is recommended?
- No surgery, because MEN1 disease is mild
- Subtotal (3½-gland) parathyroidectomy or total parathyroidectomy with autotransplantation, plus transcervical thymectomy
- Cinacalcet as the only treatment
- Thyroidectomy
- Focused removal of a single gland seen on sestamibi
Show the answer and explanation
Answer: B. Subtotal (3½-gland) parathyroidectomy or total parathyroidectomy with autotransplantation, plus transcervical thymectomy. In MEN1, all four parathyroid glands are abnormal (multigland hyperplasia), so a focused single-gland operation leads to persistent or recurrent disease. The thymus is removed because it may contain supernumerary glands and carries a risk of thymic carcinoid.
Why not the others? Imaging may show one dominant gland, but the others are also affected.
References
A 34-year-old woman with Graves’ disease is booked for total thyroidectomy. How should she be prepared?
- Stop all antithyroid drugs 2 weeks before
- Make her euthyroid with an antithyroid drug, and give potassium iodide (e.g. Lugol’s iodine) for about 10 days before surgery
- Operate while she is still thyrotoxic
- Levothyroxine before surgery
- Radioactive iodine the week before surgery
Show the answer and explanation
Answer: B. Make her euthyroid with an antithyroid drug, and give potassium iodide (e.g. Lugol’s iodine) for about 10 days before surgery. Operating on a thyrotoxic patient risks thyroid storm. The patient is made euthyroid with methimazole (or carbimazole), with a beta-blocker for symptoms. Preoperative iodine reduces gland vascularity and blood loss.
Why not the others? Radioiodine is an alternative treatment, not preparation for surgery.
References
After a thyroid lobectomy, a patient’s voice is weak and breathy, and she coughs when drinking water. What should be arranged?
- Reassurance only; no examination needed
- Repeat neck surgery immediately
- Wait 2 years before assessment
- Antibiotics for laryngitis
- Laryngoscopy to assess vocal cord movement, with referral to speech and language therapy and ENT
Show the answer and explanation
Answer: E. Laryngoscopy to assess vocal cord movement, with referral to speech and language therapy and ENT. A weak, breathy voice and aspiration of fluids suggest recurrent laryngeal nerve palsy. Laryngoscopy confirms vocal cord paralysis. Many palsies recover within months; voice therapy helps, and injection laryngoplasty can improve the voice and swallowing earlier. Vocal cords should also be assessed before thyroid surgery.
Why not the others? Early assessment matters, especially before operating on the other side.
References
A 41-year-old woman has a laparoscopic left adrenalectomy for a cortisol-secreting adenoma causing Cushing’s syndrome. What does she need after surgery?
- Glucocorticoid replacement, tapered over months until the other adrenal recovers, with sick-day advice
- Lifelong high-dose prednisolone
- Ketoconazole
- No steroids, because the tumour is removed
- Fludrocortisone only
Show the answer and explanation
Answer: A. Glucocorticoid replacement, tapered over months until the other adrenal recovers, with sick-day advice. Long-term cortisol excess suppresses ACTH and the opposite adrenal gland, so adrenal insufficiency follows removal of the tumour. Hydrocortisone is given and slowly reduced, with testing of adrenal recovery, which can take months to more than a year.
Why not the others? Mineralocorticoid production is usually preserved, so fludrocortisone alone is not the answer.
References
Fine-needle aspiration of a 2-cm thyroid nodule is reported as Bethesda III (atypia of undetermined significance). What is the appropriate next step?
- Radioiodine ablation
- Discharge without follow-up
- Total thyroidectomy with neck dissection
- Start levothyroxine to shrink the nodule
- Repeat FNA or molecular testing, then surveillance or diagnostic lobectomy depending on the result and patient preference
Show the answer and explanation
Answer: E. Repeat FNA or molecular testing, then surveillance or diagnostic lobectomy depending on the result and patient preference. Indeterminate cytology (Bethesda III and IV) has an intermediate risk of cancer. Repeating the FNA or molecular testing can refine the risk, and diagnostic lobectomy is an option. Total thyroidectomy with neck dissection is excessive without a cancer diagnosis.
Why not the others? TSH suppression to shrink nodules is not recommended.
References
A 70-year-old woman has hyperthyroidism from a large toxic multinodular goitre extending behind the sternum, with breathlessness when lying flat and tracheal narrowing on CT. What is the best treatment?
- Levothyroxine
- Lifelong antithyroid drugs without further treatment
- Tracheal stent
- Radioiodine as the only treatment
- Total thyroidectomy after making her euthyroid
Show the answer and explanation
Answer: E. Total thyroidectomy after making her euthyroid. A toxic multinodular goitre causing compression is best treated surgically: total thyroidectomy cures the hyperthyroidism and relieves the compression immediately. Most retrosternal goitres can be removed through a neck incision.
Why not the others? Radioiodine works slowly, may transiently enlarge the gland, and shrinks large goitres only partly.
References
A patient on dialysis has a very high PTH, normal-to-low calcium and high phosphate. What is the first line of treatment?
- Immediate focused parathyroidectomy
- Bisphosphonates
- Medical treatment: control phosphate (diet and binders), active vitamin D and/or a calcimimetic; parathyroidectomy only if this fails
- Stop dialysis
- Thyroidectomy
Show the answer and explanation
Answer: C. Medical treatment: control phosphate (diet and binders), active vitamin D and/or a calcimimetic; parathyroidectomy only if this fails. This is secondary hyperparathyroidism from chronic kidney disease, driven by phosphate retention and low active vitamin D. It is treated medically. Parathyroidectomy (subtotal, or total with autotransplantation) is reserved for severe disease that does not respond.
Why not the others? Disease involves all four glands, so a focused single-gland operation is inappropriate.
References
A 58-year-old woman has biochemically confirmed primary hyperparathyroidism and meets the criteria for surgery. What is the role of imaging (ultrasound, sestamibi or 4D-CT)?
- To localise the abnormal gland and plan the operation; imaging is not used to make or exclude the diagnosis
- To confirm the diagnosis before calcium is measured
- Negative imaging means surgery should not be offered
- Imaging is not needed for any operation
- Imaging replaces the need for PTH testing
Show the answer and explanation
Answer: A. To localise the abnormal gland and plan the operation; imaging is not used to make or exclude the diagnosis. The diagnosis is biochemical. Imaging only guides the surgical approach: a well-localised single adenoma allows a focused operation, whereas negative or discordant imaging leads to bilateral neck exploration by an experienced surgeon.
Why not the others? Patients with negative imaging still benefit from surgery.
References
A 67-year-old with metastatic lung cancer is drowsy and dehydrated, with a corrected calcium of 3.6 mmol/L and a suppressed PTH. What is the initial treatment?
- Intravenous 0.9% saline rehydration, then an intravenous bisphosphonate (e.g. zoledronic acid) or denosumab
- Thiazide diuretic
- Furosemide before any fluids
- Parathyroidectomy
- Oral calcium restriction only
Show the answer and explanation
Answer: A. Intravenous 0.9% saline rehydration, then an intravenous bisphosphonate (e.g. zoledronic acid) or denosumab. Hypercalcaemia of malignancy causes dehydration, which worsens the hypercalcaemia. Fluids come first, followed by a bisphosphonate or denosumab, which act over 2–4 days; calcitonin can lower calcium quickly in the first 48 hours. The suppressed PTH rules out hyperparathyroidism.
Why not the others? Thiazides raise calcium. Loop diuretics are used only for fluid overload after rehydration.
References
A 28-year-old man has mildly raised calcium with a mildly raised PTH. His father had a “failed” parathyroid operation. His 24-hour calcium/creatinine clearance ratio is 0.005. What is the most likely diagnosis?
- Familial hypocalciuric hypercalcaemia; no surgery is needed
- Primary hyperparathyroidism needing urgent parathyroidectomy
- Sarcoidosis
- Vitamin D toxicity
- Parathyroid carcinoma
Show the answer and explanation
Answer: A. Familial hypocalciuric hypercalcaemia; no surgery is needed. Familial hypocalciuric hypercalcaemia is an inherited condition (usually a CASR mutation) with mild hypercalcaemia, normal or mildly raised PTH and very low urinary calcium (clearance ratio below 0.01). It is benign, and parathyroidectomy does not cure it, so it must be excluded before surgery.
Why not the others? A failed operation in a relative is a clue to FHH.
References
A 45-year-old woman has episodes of confusion and sweating relieved by eating. During one episode, her glucose is 2.2 mmol/L. A supervised 72-hour fast shows hypoglycaemia with inappropriately high insulin and C-peptide. What is the likely diagnosis and treatment?
- Insulinoma; localise it with imaging (CT, MRI, endoscopic ultrasound) and remove it surgically, often by enucleation
- Reactive hypoglycaemia; diet only
- Factitious insulin injection; no imaging needed
- Type 2 diabetes; start metformin
- Addison’s disease; give hydrocortisone
Show the answer and explanation
Answer: A. Insulinoma; localise it with imaging (CT, MRI, endoscopic ultrasound) and remove it surgically, often by enucleation. Whipple’s triad with endogenous hyperinsulinism (high insulin and C-peptide, negative sulphonylurea screen) indicates an insulinoma. Most are small, solitary and benign; surgical removal cures the patient.
Why not the others? Injected insulin suppresses C-peptide, so a high C-peptide points to endogenous insulin.
References
An 80-year-old woman has a hard neck mass that has grown rapidly over 3 weeks, with hoarseness and difficulty swallowing. What is the most urgent step?
- Levothyroxine
- Urgent tissue diagnosis (core biopsy) with BRAF testing, airway assessment and rapid multidisciplinary review for suspected anaplastic thyroid cancer
- Radioiodine
- Repeat ultrasound in 6 months
- Routine outpatient FNA in 3 months
Show the answer and explanation
Answer: B. Urgent tissue diagnosis (core biopsy) with BRAF testing, airway assessment and rapid multidisciplinary review for suspected anaplastic thyroid cancer. A rapidly growing hard thyroid mass in an older person suggests anaplastic thyroid cancer, which progresses in days to weeks. Rapid diagnosis is essential; BRAF V600E-mutated tumours can respond to targeted therapy (dabrafenib plus trametinib), which has improved survival.
Why not the others? Anaplastic cancer does not take up iodine.
References
After total thyroidectomy for a 1.5-cm papillary thyroid cancer with no adverse features (low risk), is radioiodine ablation required?
- Yes; every patient needs high-dose radioiodine
- Only external beam radiotherapy is used
- Chemotherapy is needed instead
- No; routine radioiodine is not needed for low-risk disease
- Yes; it is required to measure TSH
Show the answer and explanation
Answer: D. No; routine radioiodine is not needed for low-risk disease. Trials (ESTIMABL2, IoN) showed that in low-risk differentiated thyroid cancer, omitting radioiodine after thyroidectomy did not worsen outcomes. Radioiodine is reserved for intermediate- and high-risk disease.
Why not the others? Radioiodine has side effects, including salivary gland damage, and a small risk of second cancers.
References
Immediately after extubation following total thyroidectomy, a patient has stridor and respiratory distress, with a normal voice before surgery. Neck examination is normal, with no haematoma. What is the likely cause and action?
- Anxiety: reassure
- Pneumonia: antibiotics
- Thyroid storm: beta-blockers
- Bilateral recurrent laryngeal nerve palsy: re-intubate and assess the vocal cords; tracheostomy may be needed
- Hypocalcaemia: oral calcium only
Show the answer and explanation
Answer: D. Bilateral recurrent laryngeal nerve palsy: re-intubate and assess the vocal cords; tracheostomy may be needed. Bilateral vocal cord palsy leaves the cords near the midline, narrowing the airway and causing stridor straight after extubation. The airway is secured, and the cords are examined. Many palsies are temporary, but some patients need a tracheostomy.
Why not the others? Haematoma would cause neck swelling; hypocalcaemia develops later, over hours to days.
References
CT shows a 6-cm heterogeneous left adrenal mass with irregular margins and an unenhanced density of 38 HU. Hormonal tests show excess androgen and cortisol. What is the most likely diagnosis and treatment?
- Myelolipoma; no treatment
- CT-guided biopsy before any decision
- Benign adenoma; observe
- Adrenocortical carcinoma; complete en-bloc resection (usually open) in an experienced centre, without preoperative biopsy
- Radiotherapy alone
Show the answer and explanation
Answer: D. Adrenocortical carcinoma; complete en-bloc resection (usually open) in an experienced centre, without preoperative biopsy. Large size, heterogeneity, high density and mixed hormone excess (especially androgens) suggest adrenocortical carcinoma. Complete resection without breaching the tumour capsule offers the best chance of cure; tumour rupture worsens outcome. Biopsy is avoided because it risks seeding and is rarely diagnostic.
Why not the others? Myelolipomas contain fat (negative HU), which this lesion does not.
References
A woman who is 14 weeks pregnant has a 2-cm suspicious thyroid nodule. Which statement is correct?
- Immediate termination is required
- No investigation until after delivery in every case
- FNA is contraindicated in pregnancy
- Radioiodine scanning is the first test
- Ultrasound-guided FNA can be performed in pregnancy; if cancer is confirmed, surgery is usually deferred until after delivery or done in the second trimester if needed
Show the answer and explanation
Answer: E. Ultrasound-guided FNA can be performed in pregnancy; if cancer is confirmed, surgery is usually deferred until after delivery or done in the second trimester if needed. Thyroid nodules in pregnancy are assessed with ultrasound and FNA as usual. For well-differentiated cancer, delaying surgery until after delivery does not worsen outcome. Surgery in the second trimester is considered for growing tumours or advanced disease.
Why not the others? Radioiodine is contraindicated in pregnancy.
References
A 55-year-old has a calcium of 3.7 mmol/L, a PTH 10 times the upper limit, and a hard 3-cm palpable neck mass. What is suspected and how is it treated?
- Parathyroid carcinoma; en-bloc resection of the tumour with the adjacent thyroid lobe, avoiding capsule rupture
- Parathyroid adenoma; focused removal by shelling out
- Hypercalcaemia of malignancy; bisphosphonates only
- Thyroid cancer; radioiodine
- Lymphoma; chemotherapy
Show the answer and explanation
Answer: A. Parathyroid carcinoma; en-bloc resection of the tumour with the adjacent thyroid lobe, avoiding capsule rupture. Very high calcium and PTH with a palpable mass suggest parathyroid carcinoma. The best chance of cure is en-bloc resection at the first operation, because rupture leads to recurrence. Calcium is controlled medically before surgery.
Why not the others? Ordinary adenomas are rarely palpable and cause only mild hypercalcaemia.
References
A 60-year-old woman has a high PTH but repeatedly normal calcium (corrected and ionised). What must be excluded before diagnosing normocalcaemic primary hyperparathyroidism?
- Pituitary tumour
- Secondary causes: vitamin D deficiency, reduced kidney function, calcium malabsorption and drugs such as thiazides or lithium
- Nothing; proceed to surgery
- Pancreatitis
- Thyroid cancer
Show the answer and explanation
Answer: B. Secondary causes: vitamin D deficiency, reduced kidney function, calcium malabsorption and drugs such as thiazides or lithium. A raised PTH with normal calcium is usually secondary hyperparathyroidism, most often due to vitamin D deficiency or kidney disease. Normocalcaemic primary hyperparathyroidism is diagnosed only once these are excluded and corrected.
Why not the others? Operating on secondary hyperparathyroidism does not help.
References
A 3-year-old girl tests positive for a RET mutation in codon 634 because her mother has MEN2A. What do you advise?
- Prophylactic total thyroidectomy at or before age 5, guided by calcitonin, by an experienced surgeon
- Annual chest X-ray only
- Thyroidectomy only at age 30
- Radioiodine
- Wait until a thyroid lump appears
Show the answer and explanation
Answer: A. Prophylactic total thyroidectomy at or before age 5, guided by calcitonin, by an experienced surgeon. Hereditary medullary thyroid cancer develops early in RET carriers, and timing of prophylactic thyroidectomy depends on the mutation risk level. Codon 634 is high risk, so surgery is recommended at or before age 5; the highest-risk mutation (M918T, MEN2B) is operated in the first year of life.
Why not the others? Waiting for a lump means the cancer may already have spread.
References
A 70-year-old woman with long-standing Hashimoto’s thyroiditis has a thyroid swelling that has grown rapidly over a few weeks. Ultrasound shows a markedly hypoechoic mass. What should be suspected and how is it diagnosed?
- Thyroiditis; steroids
- Simple goitre; levothyroxine
- Primary thyroid lymphoma; core biopsy with flow cytometry, as treatment is chemotherapy (with or without radiotherapy), not thyroidectomy
- Anaplastic cancer is the only possibility; radioiodine
- Cyst; aspirate
Show the answer and explanation
Answer: C. Primary thyroid lymphoma; core biopsy with flow cytometry, as treatment is chemotherapy (with or without radiotherapy), not thyroidectomy. Hashimoto’s thyroiditis increases the risk of thyroid lymphoma, usually diffuse large B-cell lymphoma. Rapid growth in an older woman with Hashimoto’s should prompt a core biopsy. Treatment is systemic (such as R-CHOP), sometimes with radiotherapy; surgery is mostly limited to diagnosis or airway relief.
Why not the others? FNA alone often cannot type lymphoma.
References
A woman with untreated Graves’ disease has fever of 40 °C, agitation, a heart rate of 160 in atrial fibrillation and vomiting after an infection. What is the treatment of thyroid storm?
- Immediate emergency thyroidectomy
- Beta-blocker, a thionamide (propylthiouracil or methimazole), iodine given at least 1 hour after the thionamide, glucocorticoids, cooling and treatment of the trigger, in intensive care
- Levothyroxine
- Iodine alone before any thionamide
- Aspirin to reduce the fever
Show the answer and explanation
Answer: B. Beta-blocker, a thionamide (propylthiouracil or methimazole), iodine given at least 1 hour after the thionamide, glucocorticoids, cooling and treatment of the trigger, in intensive care. Thyroid storm is life-threatening. Treatment blocks hormone synthesis (thionamide), then release (iodine, given after the thionamide so it is not used to make more hormone), reduces conversion of T4 to T3 (steroids, propranolol) and controls the effects (beta-blockade, cooling).
Why not the others? Aspirin displaces thyroid hormone from binding proteins and should be avoided; paracetamol is used instead.
References
After total thyroidectomy for a benign goitre, a 70-kg woman needs thyroid hormone replacement. What is the usual starting plan?
- Check TSH weekly and change the dose every week
- No replacement is needed
- Liothyronine three times a day for life
- Levothyroxine 25 µg and never adjust
- Levothyroxine about 1.6 µg/kg/day (about 100–125 µg), checking TSH after 6–8 weeks
Show the answer and explanation
Answer: E. Levothyroxine about 1.6 µg/kg/day (about 100–125 µg), checking TSH after 6–8 weeks. After total thyroidectomy, full replacement dose is based on weight (about 1.6 µg/kg/day), with lower starting doses in the elderly or those with heart disease. TSH takes about 6 weeks to reach steady state, so dose changes are made at that interval.
Why not the others? Very frequent dose changes do not allow TSH to stabilise.
References
During a focused parathyroidectomy for a single adenoma, intraoperative PTH is measured. Which result indicates a successful operation (Miami criterion)?
- A rise in PTH
- A normal calcium during surgery
- A PTH of zero
- Any fall at all
- A fall of more than 50% from the highest pre-excision level, 10 minutes after removal
Show the answer and explanation
Answer: E. A fall of more than 50% from the highest pre-excision level, 10 minutes after removal. PTH has a short half-life. A drop of more than 50% from the highest baseline value 10 minutes after the gland is removed predicts cure. If it does not fall adequately, a second adenoma or hyperplasia is suspected and the other glands are explored.
Why not the others? Intraoperative calcium changes too slowly to guide surgery.
References
A 3-cm adrenal mass with an unenhanced density of 30 HU is found on CT. The patient has episodic headaches and palpitations. Which test should be done first?
- CT-guided biopsy
- Serum cortisol only
- Adrenalectomy without tests
- MIBG scan as the first test
- Plasma free metanephrines (or 24-hour urine fractionated metanephrines)
Show the answer and explanation
Answer: E. Plasma free metanephrines (or 24-hour urine fractionated metanephrines). Phaeochromocytoma must be excluded biochemically in any adrenal mass that is not clearly a lipid-rich adenoma, and in anyone with suggestive symptoms. Metanephrines are the most sensitive test. Functional imaging follows a positive result.
Why not the others? Biopsy of an undiagnosed phaeochromocytoma can trigger a hypertensive crisis.
References
A patient who has taken prednisolone for years did not take it while vomiting for 2 days and now has hypotension, confusion and abdominal pain. What is the immediate treatment?
- Oral prednisolone only
- Wait for a cortisol result before treating
- Antibiotics alone
- Fludrocortisone alone
- Hydrocortisone 100 mg intravenously or intramuscularly immediately, then continued hydrocortisone and intravenous fluids
Show the answer and explanation
Answer: E. Hydrocortisone 100 mg intravenously or intramuscularly immediately, then continued hydrocortisone and intravenous fluids. Adrenal crisis is a medical emergency. Hydrocortisone is given without waiting for tests (a blood sample can be taken first if it does not delay treatment), with fluids and treatment of the trigger. Patients need sick-day rules and an emergency injection kit.
Why not the others? Delay for confirmation can be fatal.
References
A woman is thyrotoxic, and a scan shows a single “hot” nodule with suppression of the rest of the gland (toxic adenoma). What are the definitive treatment options?
- Radioiodine or thyroid lobectomy, after making her euthyroid
- Lifelong antithyroid drugs are the only option
- Total thyroidectomy with neck dissection
- Steroids
- Levothyroxine
Show the answer and explanation
Answer: A. Radioiodine or thyroid lobectomy, after making her euthyroid. A toxic adenoma is cured by radioiodine (taken up by the hot nodule while the suppressed tissue is spared) or by lobectomy, which gives a rapid cure and is preferred for large nodules or compressive symptoms. Long-term antithyroid drugs do not cure the disease.
Why not the others? Hot nodules are rarely malignant, so FNA is usually not needed.
References
A patient with a small bowel neuroendocrine tumour and liver metastases has flushing and diarrhoea. He is going for surgery. What must be given to prevent a carcinoid crisis?
- Nothing special
- Histamine
- Beta-agonists
- Somatostatin analogue (octreotide) cover before and during surgery
- Adrenaline before induction
Show the answer and explanation
Answer: D. Somatostatin analogue (octreotide) cover before and during surgery. Handling a tumour that secretes serotonin and other vasoactive substances can cause a carcinoid crisis with severe hypotension, flushing and bronchospasm. Perioperative octreotide prevents and treats it. Urinary 5-HIAA and chromogranin A help diagnosis and follow-up.
Why not the others? Catecholamines can worsen a carcinoid crisis.
References