SURGERY
The thyroid gland 217 practice questions · 92 study notes
Start chapter practice
Questions QUESTION 1
A patient with a toxic thyroid nodule becomes euthyroid during antithyroid drug therapy. Why is hyperthyroidism certain to recur when the drug is discontinued?
QUESTION 2
A thyroid FNAC report is categorised as Thy4. What does this indicate?
QUESTION 3
What is the relative incidence of follicular carcinoma among primary malignant thyroid tumours?
QUESTION 4
What is the stated benefit of ultrasound guidance during thyroid FNAC?
QUESTION 5
How does surgery cure an autonomous toxic thyroid nodule?
QUESTION 6
Which postoperative consequence is deliberately accepted with total/near-total thyroidectomy for toxic goitre to eliminate recurrence?
QUESTION 7
What is the most important aetiological factor in endemic goitre?
QUESTION 8
How may the duration of antithyroid drug therapy be tailored to the severity of thyroid toxicity?
QUESTION 9
What is the investigation of choice for a discrete thyroid swelling?
QUESTION 10
Which primary malignant thyroid tumour has the highest relative incidence?
QUESTION 11
What is the mechanism by which radioiodine treats thyroid overactivity?
QUESTION 12
What minimum recurrence rate of thyrotoxicosis is stated after subtotal thyroidectomy?
QUESTION 13
Which mechanism probably accounts for many sporadic goitres?
QUESTION 14
A patient with thyroid overactivity and existing eye signs is being considered for radioiodine. What effect on the eye signs should be discussed?
QUESTION 15
What proposed cellular feature explains the heterogeneous response that produces characteristic thyroid nodularity?
QUESTION 16
The thyroglossal duct develops from which embryological structure?
QUESTION 17
During mobilisation of the superior thyroid pole, dissection below which landmark places the recurrent laryngeal nerve at risk?
QUESTION 18
An elderly patient has an incidentally discovered retrosternal goitre without symptoms or significant airway compression. Which management approach would most surgeons favour?
QUESTION 19
A patient with a thyroid cyst develops sudden painful neck swelling. Aspiration yields altered blood. What most likely caused the acute enlargement?
QUESTION 20
Which anatomical finding in a retrosternal goitre increases the risk of requiring conversion to an open sternotomy?
QUESTION 21
When identifying the trachea below the thyroid isthmus, the surgeon stays on the cartilage and close to the gland. This manoeuvre protects vessels supplying which structure?
QUESTION 22
Which surgical approach permits removal of the vast majority of retrosternal goitres?
QUESTION 23
What cyst resolution rate can be achieved with ethanol or thermal ablation for recurrent symptomatic thyroid cysts?
QUESTION 24
Which thyroid autoantibody is often present in Graves’ disease?
QUESTION 25
During thyroidectomy, stimulation of the right vagus nerve produces an unexpectedly short latency on the nerve monitor. Which anatomical variant should be considered?
QUESTION 26
Why does the inferior parathyroid gland normally lie below the superior parathyroid gland despite arising from the third pharyngeal pouch?
QUESTION 27
Which serum thyroid peroxidase antibody level is considered significant?
QUESTION 28
During thyroid cancer follow-up, which antibody interferes with assays of serum thyroglobulin?
QUESTION 29
Through which structure do neural crest-derived parafollicular cells reach the thyroid?
QUESTION 30
Ultrasonography of a thyroid cyst reveals an associated solid element. Which area should be targeted for ultrasound-guided FNAC?
QUESTION 31
Which lymph node compartment receives the principal initial drainage from the thyroid subcapsular lymphatic plexus?
QUESTION 32
Where is the thyrotrophin-releasing hormone that regulates TSH secretion produced?
QUESTION 33
What is the functioning unit of the thyroid gland?
QUESTION 34
What is the stated time to onset of action of thyroxine (T4)?
QUESTION 35
Why does the right recurrent laryngeal nerve take a more oblique course towards the tracheo-oesophageal groove than the left?
QUESTION 36
Through which structure do the calcitonin-producing parafollicular C cells reach the thyroid?
QUESTION 37
A patient has hyperthyroidism. What change in pituitary TSH production is expected through negative feedback?
QUESTION 38
During thyroid hormone synthesis, iodine binds to which substrate to form iodotyrosine?
QUESTION 39
Which circulating fraction of thyroid hormone is biologically active?
QUESTION 40
At which ligament is the recurrent laryngeal nerve at greatest risk of injury during thyroid surgery?
Study notes Embryology of the thyroid and parathyroid glands
Embryological development explains the positions, anatomical variations and congenital conditions of the thyroid and parathyroid glands. →
Thyroid structure, lymphatic drainage and recurrent laryngeal nerve anatomy
Thyroid surgery requires knowledge of glandular organisation, lymphatic pathways and the differing courses of the recurrent laryngeal nerves. →
Surgical landmarks for the recurrent laryngeal nerve
The recurrent laryngeal nerve can be located using defined landmarks during mobilisation of the thyroid. →
Thyroid hormone synthesis, transport and activity
Tri-iodothyronine (T3) and l-thyroxine (T4) are stored with thyroglobulin in colloid and released into blood when required. →
Calcitonin-producing thyroid C cells
Parafollicular C cells are the thyroid cells responsible for calcitonin production. →
Regulation of the pituitary–thyroid axis
Thyroid hormone synthesis and release are regulated by anterior pituitary thyroid-stimulating hormone and hypothalamic input. →
Thyroid-stimulating antibodies: action and diagnostic relevance
Thyroid-stimulating antibodies activate thyroid follicular cells through TSH receptors and account for most thyrotoxicosis outside autonomous toxic nodules. →
Serum TSH measurement and thyroid function patterns
Serum thyroid-stimulating hormone (TSH) must be interpreted alongside T3 and T4 to identify the thyroid functional state. →
Thyroid autoantibodies: interpretation and assay interference
Thyroid antibody measurements help establish the cause of thyroid dysfunction and thyroid swellings. →
Essential and optional investigations for thyroid disease
The investigation scheme separates essential biochemical and cytological tests from optional tests selected for specific clinical findings. →
Thyroid imaging: ultrasonography, CT, MRI and PET
Ultrasonography is the surgeon’s main imaging investigation for thyroid disease, with additional modalities used to assess disease extent, invasion and recurrence. →
Thyroid isotope scanning and whole-body scanning
Isotope scanning demonstrates thyroid activity distribution and is principally useful in patients with thyroid toxicity and nodularity. →
Fine-needle aspiration cytology of thyroid swellings
Fine-needle aspiration cytology (FNAC) is the investigation of choice for discrete thyroid swellings, and its results should use standard reporting terminology. →
Terminology for thyroid enlargement and discrete swellings
Thyroid enlargement is described by whether it is generalised or discrete and whether other palpable abnormalities are present. →
Simple goitre: causes of thyroid growth and nodularity
Simple goitre can develop through thyroid stimulation by TSH and other growth factors. Iodine deficiency and defective hormone synthesis contribute to different patterns of disease. →
Iodine deficiency and endemic simple goitre
Iodine deficiency can reflect low environmental availability or impaired intestinal absorption. →
Dyshormonogenesis in sporadic goitre
Enzyme deficiencies and iodine intake can interact to determine goitre formation in non-endemic areas. →
Goitrogens and their effects on iodine handling
Dietary substances, drugs and excessive iodide can interfere with steps involved in thyroid hormone synthesis. →
Progression of simple goitre from diffuse hyperplasia to nodularity
Repeated growth stimulation and tissue injury produce the structural changes of nodular goitre. →
Diffuse hyperplastic goitre and its colloid stage
Diffuse hyperplasia represents the early stages of simple goitre and can change with thyroid-stimulating hormone stimulation. →
Nodular goitre: structure, onset and sex distribution
Simple goitre usually develops multiple nodules, although a single visible nodule may conceal widespread microscopic changes. →
Clinical diagnosis of nodular goitre
Nodular goitre usually has a straightforward clinical presentation, although some findings can resemble carcinoma or autoimmune thyroiditis. →
Investigations for nodular goitre
Investigation assesses thyroid function, distinguishes autoimmune thyroiditis, identifies nodules requiring cytology and evaluates compression. →
Airway obstruction from goitre
Goitre can obstruct the trachea through displacement or compression, and haemorrhage can precipitate acute obstruction. →
Carcinoma risk and cytology in longstanding goitre
The passage describes a reported cancer association in endemic areas and identifies nodules requiring aspiration cytology. →
Prevention and treatment selection in simple goitre
Management depends on the stage of simple goitre, symptoms, concern for malignancy and the individual balance of surgical risks and benefits. →
Choice of operation for multinodular goitre
The extent of thyroid resection balances preservation of thyroid function, complications and the risk of recurrent nodularity. →
Frequency of palpable thyroid nodules
Discrete thyroid swellings are also called thyroid nodules. →
Classification and neoplastic risk of discrete thyroid swellings
Discrete thyroid swellings are classified by the clinical findings in the surrounding gland, but clinical examination may miss additional nodules. →
Thyroid function testing in discrete thyroid swellings
Biochemical assessment identifies whether a discrete thyroid swelling is associated with hyperthyroidism and guides functional imaging. →
Autoantibodies in thyroid swellings
Autoantibody status can help assess the cause of a thyroid swelling and the risk of thyroid failure following lobectomy. →
Role of isotope scanning in thyroid nodules
Isotope scanning has a restricted role in investigating discrete thyroid swellings. →
Ultrasonography of thyroid nodules
Ultrasonography assesses the physical characteristics of thyroid swellings and is the primary investigation for any thyroid nodule. →
Fine-needle aspiration cytology of thyroid nodules
Fine-needle aspiration cytology (FNAC) helps evaluate thyroid nodules selected by their ultrasound appearance, but some diagnoses require histology. →
Computed tomography in thyroid enlargement
Computed tomography (CT) assesses the effects and extent of thyroid disease relevant to operative planning. →
Laryngoscopy before thyroid surgery
Preoperative laryngeal examination assesses vocal cord movement and can identify a finding strongly associated with thyroid malignancy. →
Limited role of core biopsy in thyroid masses
Core biopsy has selected diagnostic uses in thyroid disease despite a procedure-related bleeding risk. →
Indications for thyroid surgery and clinical suspicion of malignancy
The decision to operate on a thyroid swelling depends primarily on neoplasia risk, with clinical findings and patient characteristics providing additional guidance. →
Thyroid cysts: presentation, malignancy risk and management
Clinically isolated thyroid swellings may be wholly or partly cystic. Ultrasound assessment of a solid component guides further investigation. →
Choosing the extent of thyroid surgery
Selection of a thyroid operation balances the underlying diagnosis, preservation of thyroid function, recurrence risk, and risks to the recurrent laryngeal nerve and parathyroid glands. →
Components of thyroid operations
Thyroid operations are assembled from three basic surgical elements: total lobectomy, isthmusectomy and subtotal lobectomy. →
Retrosternal goitre: indications for surgery and operative planning
A retrosternal goitre usually develops through slow growth of a multinodular thyroid into the mediastinum. →
Operative delivery of a retrosternal goitre
Retrosternal goitre surgery requires adequate cervical access, careful mobilisation and conversion to sternotomy when cervical delivery is unsafe or impossible. →
Meaning and clinical types of thyrotoxicosis
Thyrotoxicosis is retained as a term because raised circulating thyroid hormones do not explain every manifestation of the disease. →
Graves’ disease: presentation and thyroid stimulation
Graves’ disease is a diffuse toxic goitre producing the syndrome of primary thyrotoxicosis. →
Toxic nodular goitre: clinical sequence and active tissue
Toxic nodular goitre produces secondary thyrotoxicosis after a simple nodular goitre has been present for a long time. →
Toxic nodule: autonomy and suppression of surrounding tissue
A toxic nodule is a solitary overactive nodule that may occur within generalised nodularity or represent a true toxic adenoma. →
Thyroid histology in hyperthyroidism
Hyperthyroidism changes both the acinar epithelium and the appearance of thyroid colloid. →
Nonspecific and specific treatment of thyrotoxicosis
Treatment of established thyrotoxicosis combines supportive measures with specific therapy. →
Antithyroid drugs: treatment aims and limitations
Carbimazole and propylthiouracil are commonly used antithyroid drugs for restoring and maintaining a euthyroid state. →
Surgery for thyrotoxicosis: mechanisms, outcomes and risks
Surgery treats thyrotoxicosis by reducing or removing overactive thyroid tissue; the mechanism and subsequent thyroid function depend on the pattern of disease and extent of resection. →
Radioiodine for thyrotoxicosis
Radioiodine reduces functioning thyroid tissue by destroying thyroid cells. →
Individualising therapy for toxic goitre
Treatment guidance based on the type of toxic goitre and the patient's age must be adapted to individual circumstances. →
Treatment sequence for diffuse toxic goitre
Most patients follow an initial drug-treatment approach, with specified exceptions to the usual treatment sequence. →
Management of large toxic nodular goitre
Goitre size and its response to nonsurgical treatment influence management of toxic nodular goitre. →
Treatment options for a toxic nodule
Both surgery and radioiodine are appropriate treatments for a toxic nodule. →
Preoperative preparation for surgery in thyrotoxicosis
Preparation may aim for biochemical euthyroidism with carbimazole or rapid control of clinical manifestations with β-adrenergic blockade. →
Choosing the extent of thyroid resection
The extent of resection for thyrotoxicosis depends on patient, gland and surgical considerations. →
Thyroidectomy: positioning, incision and initial exposure
Thyroidectomy aims to remove the entire affected lobe, or both lobes for total thyroidectomy, while preserving surrounding structures and minimising cosmetic impact. →
Thyroidectomy: exposure and mobilisation of the gland
Dissection during thyroidectomy requires careful exposure of the gland while protecting laryngeal nerves and parathyroid blood supply. →
Identifying and freeing the recurrent laryngeal nerve during thyroidectomy
As thyroid mobilisation progresses, careful fascial dissection identifies the recurrent laryngeal nerve and permits further mobilisation towards Berry’s ligament. →
Thyroidectomy: Berry’s ligament, gland delivery and final inspection
Final thyroid mobilisation requires careful management of Berry’s ligament because of its variable relationship to the recurrent laryngeal nerve. →
Thyroidectomy wound closure
Closure addresses trachea-to-skin adhesion while avoiding a watertight muscle layer that could promote pressure if a haematoma develops. →
Haemostatic technology and nerve monitoring in thyroidectomy
New devices support haemostasis and nerve assessment during thyroid surgery, although benefits and adoption vary. →
Video-assisted and remote access thyroid surgery
Alternative approaches to thyroidectomy offer smaller or remotely placed incisions but have limitations in patient selection and operative demands. →
Post-thyroidectomy haemorrhage and vocal cord assessment
Early postoperative surveillance focuses on potentially fatal neck bleeding and assessment of vocal cord function. →
Laryngeal nerve injury management and thyroid hormone replacement
Thyroid surgery can affect voice through nerve injury or subtler changes, and the extent of resection influences the need for thyroxine. →
Parathyroid insufficiency, thyroid storm and wound complications
Additional complications of thyroid surgery include impaired parathyroid function, acute exacerbation of hyperthyroidism, infection and abnormal scarring. →
Stitch granuloma after thyroid surgery
Suture material influences the risk of postoperative stitch granuloma. →
Postoperative care after thyroid surgery
Care after thyroid surgery includes early wound surveillance, calcium assessment after total thyroidectomy, hormone replacement and outpatient review. →
Thyroid neoplasms: benign tumour and relative incidence of malignancies
Thyroid neoplasms include benign follicular adenoma and several malignant tumour types with different relative frequencies. →
Follicular adenoma: diagnosis and treatment
Follicular adenomas usually present as clinically solitary thyroid nodules. Distinguishing an adenoma from follicular carcinoma requires tissue architecture. →
Origins, differentiation and spread of thyroid malignancies
Primary thyroid malignancies predominantly arise from follicular cells, but other cellular origins and secondary involvement of the thyroid also occur. →
Aetiological associations of malignant thyroid tumours
Most thyroid cancers have no known aetiological factor. The passage identifies radiation exposure and several tumour-specific associations. →
Clinical presentation and outcome patterns of thyroid cancer
Thyroid cancers commonly present with a thyroid swelling, but nodal disease, nerve involvement and tumour consistency provide additional clinical clues. →
Diagnostic assessment of thyroid neoplasms
Assessment proceeds from clinical evaluation to ultrasonography and selective cytology, with functional or cross-sectional imaging reserved for particular situations. →
Diagnosing a rapidly growing thyroid mass
A rapidly growing thyroid mass, particularly one that is solid and fixed, raises concern for anaplastic carcinoma and requires accurate tissue diagnosis. →
Papillary thyroid carcinoma: metastases and microcarcinoma
Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy. Many small lesions remain undetected or have little clinical impact. →
Follicular carcinoma and Hürthle cell tumours
Follicular carcinoma requires architectural assessment for diagnosis and differs from papillary thyroid carcinoma in its pattern of spread. →
Prognosis and staging of differentiated thyroid carcinoma
Differentiated thyroid carcinoma generally has an excellent prognosis, but age, tumour extent and distant spread substantially alter individual risk. →
Selecting surgery for differentiated thyroid cancer
Surgery balances removal of macroscopic disease, reduction of recurrence and minimization of morbidity. Risk assessment guides the extent of surgery and use of radioactive iodine. →
Elective neck surgery and management after diagnostic lobectomy
When thyroid cancer has no preoperatively detected nodal disease, elective neck surgery is controversial. Management after diagnostic lobectomy also depends on renewed risk assessment. →
Risk-adapted thyroxine therapy after thyroid cancer surgery
Postoperative thyroxine therapy in differentiated thyroid cancer is tailored to disease risk and the potential harms of prolonged TSH suppression. →
Radioiodine treatment in thyroid cancer
Radioiodine delivers tumoricidal radioactivity to thyroid tissue and is used after appropriate surgery or in selected recurrent and metastatic disease. →
Thyroglobulin surveillance after thyroid cancer surgery
Thyroglobulin is produced by normal thyroid cells and most differentiated thyroid cancers, making its postoperative interpretation dependent on the extent of surgery. →
Anaplastic thyroid carcinoma: diagnosis and management
Undifferentiated, or anaplastic, thyroid carcinoma is rare and is among the most aggressive human malignancies, with an extremely poor prognosis. →
Medullary thyroid carcinoma: biology, inherited syndromes and surveillance
Medullary carcinoma arises from neural crest-derived parafollicular C cells and may occur sporadically or as familial disease. →
Staging and surgical treatment of medullary thyroid carcinoma
Treatment planning for medullary thyroid carcinoma depends on staging and whether disease is confined to the thyroid or involves lymph nodes. →
Malignant lymphoma of the thyroid
Thyroid malignant lymphoma commonly occurs on a background of lymphocytic thyroiditis and has a dramatic response to irradiation. →
Hashimoto’s chronic lymphocytic thyroiditis
Hashimoto’s disease is a common autoimmune thyroiditis that may present with goitre or thyroid failure. →
Granulomatous thyroiditis: de Quervain’s thyroiditis
Granulomatous thyroiditis, also called subacute or de Quervain’s thyroiditis, may follow a viral infection and usually resolves spontaneously. →
Riedel’s thyroiditis: invasive fibrosis of the thyroid
Riedel’s thyroiditis is very rare, accounting for 0.5% of goitres, and produces a very hard, fixed thyroid enlargement. →
NEETx
Learn. Practise. Remember.