Endocrine surgery- thyroid and parathyroid

Question 1

What hormones are secreted by thyrocytes?

Answer 1

T3- active form

T4 (thyroxine)- peripherally converted to T3

Question 2

Hormone released by the parafollicular cells and its action?

Answer 2

Calcitonin- lowers serum calcium (but not an essential hormone)

Question 3

Investigations required for thyroid disease? (2)

Answer 3

Thyroid function tests (mainly TSH)

Ultrasound/FNA cytology

Question 4

Which conditions reduce the amount of free thyroid hormone? (2)

Answer 4

Pregnancy, exogenous oestrogen

Question 5

How does toxic multinodular goitre develop?

Answer 5

Long-standing non-toxic goitre develops hyperactive nodules which function independently of TSH

Question 6

Solitary thyroid nodules can be…(3)

Answer 6

Cyst
Adenoma
Cancer

Question 7

Rare condition where thyroid is replaced by dense fibrous tissue?

Answer 7

Riedel’s thyroiditis

Question 8

Self-limiting condition associated with viral infection, which presents with thyroid pain and may cause hypo/hyper/euthyroidism?

Answer 8

Sub-acute thyroiditis (de Quervain’s disease)

Question 9

Autoimmune condition causing destruction of follicles and hypothyroidism?

Answer 9

Hashimoto’s disease (autoimmune thyroiditis)

Question 10

Three main conditions which present with thyrotoxicosis?

Answer 10

Grave’s disease (primary thyrotoxicosis)
Toxic multinodular goitre
Toxic adenoma

Question 11

Management options for Grave’s disease?

Answer 11

Carbimazole (blocks incorporation of iodine into tyrosine)
Radio-iodine
Thyroidectomy

Question 12

What needs to happen before surgery for thyrotoxicosis can take place? Why?

Answer 12

Patient must be rendered euthyroid by anti-thyroid drugs (e.g. carbimazole)

To prevent peri-operative thyroid storm

Question 13

How do toxic multinodular goitre/toxic adenoma present distinctly from Grave’s disease?

Answer 13

Eye signs (e.g. exopthalmos, opthalmoplegia) are rare

Question 14

Management of toxic multinodular goitre/toxic adenoma?

Answer 14

Thyroidectomy/thyroid lobectomy

Question 15

Four types of thyroid cancer in order of prevalence?

Answer 15

Epthelial: Papillary (50%) and Follicular (30%)
Anaplastic
Medullary

Question 16

Main risk factors for thyroid cancer to inquire about?

Answer 16

Family history

History of radiation exposure

Question 17

Main differences between papillary and follicular thryoid cancers?

Answer 17

Papillary spreads to local lymph nodes but rarely disseminates widely; 10yr survival is around 90%

Follicular spreads haematogenously usually to bone; 10yr survival around 75%

Question 18

Treatment of epithelial thyroid cancers?

Answer 18

Total or near-total thyroidectomy; thyroid replacement to suppress TSH

Question 19

Clinical features of anaplastic thyroid cancer? (3)

Answer 19

Rapid growth and highly malignant
Local invasion and pulmonary metastases are common
Curative resection rarely possible, most patients die within a year

Question 20

Lymphoma of the thyroid is a rare complication of…?

Answer 20

Autoimmune thyroiditis

Question 21

Tumour arising from the parafollicular C cells?

Answer 21

Medullary carcinoma

Question 22

Medullary carcinoma often arises as part of what syndrome?

Answer 22

Multiple endocrine neoplasia Type II

Question 23

Important considerations in thyroid surgery?

Answer 23

Protection of the recurrent laryngeal nerve
Meticulous haemostasis
Protection of the parathyroid glands

Question 24

Possible consequences of secondary haemorrhage in neck surgery?

Answer 24

Compression of structures in the thoracic inlet causing laryngeal oedema, tracheal compression, asphyxia

Question 25

Post-operative complications of thyroid surgery? (4)

Answer 25

Recurrent laryngeal nerve damage Hypoparathyroidism Hypothyroidism Hypertrophic/keloid scar

Question 26

Causes of hypercalcaemia? (4)

Answer 26

Hyperparathyroidism Increased calcium absorption Excessive bone breakdown Ectopic secretion of PTH-like hormone

Question 27

How does PTH bring about a rise in serum calcium? (3)

Answer 27

Increases the activity of osteoclasts Increases renal synthesis of vitamin D (which increases gut absorption of calcium) Increases renal reabsorption of calcium

Question 28

Primary hyperparathyroidism is usually due to...?

Answer 28

``` Adenoma of the parathyroid gland (90%) Diffuse hyperplasia (10%) ```

Question 29

Clinical features of hyperparathyroidism?

Answer 29

``` Polyuria leading to dehydration Kidney stones Peptic ulcer (and abdominal pain) Pancreatitis Psychosis ```

Question 30

Investigations in suspected hyperparathyroidism?

Answer 30

Hypercalcaemia in the presence of circulating PTH Low serum phosphate Increased urinary calcium excretion

Question 31

Over-secretion of PTH in response to low levels of ionized calcium?

Answer 31

Secondary hyperparathyroidism

Question 32

What typically causes secondary hyperparathyroidism?

Answer 32

Renal disease or calcium malabsorption from the gut

Question 33

What is tertiary hyperparathyroidism?

Answer 33

Autonomous secretion of PTH from gland in secondary hyperparathyroidism

Question 34

Management of primary hyperparathyroidism?

Answer 34

Removal of adenoma; if hyperplasia, subtotal parathyroidectomy

Question 35

What may occur temporarily after parathyroidectomy?

Answer 35

Hypoparathyroidism (causing hypocalcaemia)

Question 36

Symptoms of hypocalcaemia? (3)

Answer 36

Paraesthesia in hands and feet Muscle cramps and tetany Lethargy and depression

Question 37

Clinical signs of hypocalcaemia? (3)

Answer 37

Chvostek's (twitching of the facial muscles on facial nerve tapping) Trousseau's (spasm of hand muscles after applying a tourniquet) Erb's sign (hyperexcitability of muscles on electrical stimulation)

Question 38

ECG abnormality in hypocalcaemia?

Answer 38

Lengthened QT interval

Question 39

Possible life-threatening complication of acute hypoparathyroidism?

Answer 39

Respiratory obstruction with stridor due to spasm of laryngeal muscles

Question 40

Important aspects of patient consent for parathyroidectomy? (2)

Answer 40

Patient should be informed of: variable position of the gland and therefore difficulty in finding it potential need for calcium/Vitamin D supplementation after surgery

Question 41

Medullary thyroid cancers often secrete which hormone?

Answer 41

Calcitonin

Question 42

Psammoma calcification is diagnostic of...

Answer 42

Papillary thyroid cancer