Endocrine Surgery

Question 1

Thyroid Scintigraphy/Radioactive Iodine Uptake Test

Answer 1

Iodine-131 ingested and absorption
studied with scintillation counter
o Low uptake suggests Thyroiditis while high uptake occurs in Grave’s disease; Uneven
uptake suggests Thyroid nodule
o Test inappropriate for pregnant or breastfeeding women

Question 2

Sestamibi Parathyroid Scintigraphy

Answer 2

Technetium(Tc)-99m labelled Sestamibi ingested and
absorption studied with a gamma camera (Planar or SPECT)
o High uptake suggests Hyperparathyroidism; Correlates to number and activity of
mitochondria in the cells
o Also used to image the myocardium, rarely used for breast cancer

Question 3

Ultrasound imaging

Answer 3

Ultrasound imaging can be used to determine origin of goitre; e.g. Thyroglossal cysts, Thyroid
nodules or solid mass (unable to differentiate between malignant or benign)
o Also used to determine number of nodules and guide surgical intervention

Question 4

Adrenal glands

Answer 4

• Abdominal CT or MRI to determine if unilateral or bilateral enlargement; if unilateral, expect
to see contralateral gland to be atrophic due to negative feedback
o Adrenocortical Carcinoma (rare) suspected if larger than 7cm
• MIBC scanning for location of extra-adrenal Phaeochromocytoma (10% of cases)
• Pituitary MRI for Adenoma (Cushing’s Disease) if bilateral enlargement is found

Question 5

Anatomy of the Thyroid and Parathyroid

Answer 5

• Thyroid gland is typically bi-lobed with isthmus; produces Thyroid hormones and Calcitonin

• Parathyroid glands are usually four in number, each on the posteromedial aspect of mid-
upper and inferior poles of lateral lobes

• Blood supply – Superior Thyroid artery (From External Carotid artery) and Inferior Thyroid
artery (From Thyrocervical trunk); Superior and Middle Thyroid vein (To Internal Jugular vein)
and Inferior Thyroid vein (To Brachiocephalic/Subclavian veins)

Question 6

Hyperthyroid presentation

Answer 6

↑HR, ↑To, Restlessness and Agitation, Weight loss, Diarrhoea, Poor heat tolerance, Goitre; Will lead to Thyroid Storm is not treated
o Grave’s Eye Signs – Exophthalmos, Lid retraction, Proptosis, Chemosis, Periorbital Oedema, Lid lag and Ophthalmoplegia

Question 7

Hypothyroid presentation

Answer 7

↓HR, ↓To, Depression and Fatigue, Weight gain, Hair loss
(especially lateral third of eyebrows), Constipation, Poor cold tolerance, Growth delay
(Cretinism), Goitre (Especially in Iodine deficiency); Will lead to Myxoedema Coma

Question 8

Thyroid Function Tests

Answer 8

Serum TSH, Total and Free T3 and T4

o NB: FT3 is unreliable if Hypothyroidism is suspected

Question 9

Sporadic Nodular Goitre

Answer 9

Small, diffuse or nodular; generally, euthyroid but at risk of
compressive symptoms, especially retrosternally

Question 10

Grave’s Disease

Answer 10

Autoantibodies against the TSH receptor; diffuse goitre

Question 11

Thyroiditis including Hashimoto’s Thyroiditis

Answer 11

Typically diffuse and lobulated goitre

Question 12

Carcinoma (Papillary, Follicular, Medullary, Anaplastic)

Answer 12

Typically presents as uninodular

Question 13

Primary Thyroid (Non-Hodgkin’s) Lymphoma

Answer 13

Most commonly Large-cell ± MALT Lymphoma,

Question 14

Differential Diagnosis for Goitre

Answer 14

Sporadic Nodular Goitre
Multinodular Goitre and Toxic Thyroid Nodule
Grave’s Disease
Thyroiditis including Hashimoto’s Thyroiditis
Carcinoma
Primary Thyroid (Non-Hodgkin’s) Lymphoma

Question 15

Presentations of Parathyroid Disease

Answer 15

Parathyroid Hormone increases Calcium
levels through stimulating Osteoclast bone resorption, Active Vitamin D conversion
and Renal Calcium reabsorption;
Hyperparathyroidism results in increased
serum Calcium

Question 16

Hypercalcaemia

Answer 16

lassically Bones (MSK
Pain), Stones (Nephrolithiasis), Groans (GI
upset) and Psychic Moans (Depression)
o Weakness and Fatigue, ↓Appetite,
Polyuria and Polydipsia, Osteoporosis/Fractures
o ECG changes (Shortened QT, Peaked T with Osborn waves, Negatively chronotropic
and Positively Inotropic)

Question 17

Hypocalcaemia due to Hypoparathyroidism

Answer 17

Hyperexcitability/Tetany of muscle contraction
(Chvostek’s and Trousseau’s sign), Paraesthesia, Fatigue and Headaches, Bone pain, Insomnia,
Abdominal cramps, Seizures,
o ECG changes (QT prolongation, T wave flattening, risk of Torsade de Pointes)

Question 18

Thyroid Lobectomy,

Answer 18

including Isthmus and Pyramidal lobe if present; Curative for colloid
nodule, minimal Papillary and Follicular cancers; Aids diagnosis of suspicious lesions

Question 19

Total Thyroidectomy

Answer 19

Indicated for cytologically proven cancers; For Papillary cancers >2cm
in diameter or if proven to be widely invasive Follicular cancer
o ± Cervical Nodal Dissection – Indicated in Lymphadenopathy and Medullary cancers
o Iodine-131 administration for eradicating remaining thyroid or metastatic cells

Question 20

Post-operative T3 substitution

Answer 20

Levothyroxine (shorter half-life) to allow a rise of TSH (2

weeks after stopping) to favour Iodine-131 uptake

Question 21

Bilateral Neck Exploration and Visualisation of Parathyroid glands

Answer 21

Used if localisation scans

were unhelpful

Question 22

Minimally Invasive Parathyroidectomy

Answer 22

Focused neck exploration through lateral cervical

scar which targets specific glands indicated on scanning

Question 23

Post-Operative • Neck bleeding Complications

Answer 23

– Compression might damage nerves or threaten airway; Return to theatre
upon stabilisation with emergency resuscitation

Question 24

Post-Operative • Acute Bilateral Recurrent Laryngeal Nerve Injury

Answer 24

Paralysis of the Vocal cords leads to Acute
Airway obstruction, typically noticed on extubation; Reintubation or Emergency
Cricothyroidectomy
o Nerve injury usually recovers unless nerve is completely severed

Question 25

Post-Operative • Acute Thyrotoxic Crisis

Answer 25

May occur due to handling of the gland, presents similarly to Thyroid
storm; Resuscitation for fluid depletion if appropriate
o Full-dose Propanolol, Potassium Iodide, Antithyroid Drugs, Corticosteroids, and Full
Supportive Measures; Can lead to reversible Thyrotoxic Cardiomyopathy (TWI)

Question 26

Anatomy and Histology of the Adrenal Gland

Answer 26

• Bilateral glands on Superior/Superomedial aspect of
kidneys; Arteries from Abdominal Aorta and drains to
Inferior Vena Cava/Renal veins
• Zona Glomerulosa (Mineralocorticoids), Fasciculata
(Glucocorticoid) and Reticularis (Sex hormones) of
the Adrenal Cortex; Adrenal Medulla (Adrenaline,
Noradrenaline)

Question 27

CUSHING’S SYNDROME

Answer 27

Glucocorticoid excess leading to Weight gain, Muscle
weakness, Headaches, Backache, Menstrual
abnormalities, Striae and Bruising, Hypertension,
Osteoporosis and Diabetes
o Including Psychiatric changes (Depression,
Paranoia, Hallucinations, Suicide ideation)

Question 28

Cushing’s Syndrome Causes

Answer 28

• Pituitary Adenoma – Trans-sphenoidal Resection for
primary tumour, or Bilateral Adrenalectomy if failed
pituitary surgery/Gamma-knife
• Primary Adrenal Disease – Unilateral Adrenalectomy, or bilateral if ACTH-independent
Bilateral Adrenal Hyperplasia

Question 29

Cushing’s Syndrome Management

Answer 29

Cortisol Replacement after Unilateral/Bilateral Adrenalectomy; Unilateral tumour would still
lead to contralateral atrophy (due to suppressed ACTH) which takes up to 1yr to recover
o +Mineralocorticoid replacement post Bilateral Adrenalectomy

Question 30

CONN’S DISEASE

Answer 30

Aldosterone-producing Adenomas – Normally solitary tumours involving one gland
o Other causes of excessive mineralocorticoids include Bilateral Adrenal Hyperplasia
and Familial Hyperaldosteronism

Question 31

Primary Hyperaldosteronism

Answer 31

presents with Hypertension and Hypokalaemia (Muscle

weakness, Cramping, Intermittent paralysis, Headaches, Polydipsia, Polyuria, Nocturia

Question 32

Conn’s Disease Management

Answer 32

Adrenalectomy after medical optimisation for Hypokalaemia (Oral potassium replacement)
and BP normalisation (Aldosterone antagonists e.g. Spironolactone)

Question 33

PHAEOCHROMOCYTOMA

Answer 33

Rare Adrenal Medulla tumour; Paroxysmal attacks (due to rhythmic secretions) of Headache,
Sweating, Palpitations, Hypertension, Tachyarrhythmia and Angor Animi
o Only 50% of patients have persistent hypertension; 50% normotensive or hypotensive
between acute episodes
o Attacks triggered by mechanical stimulation, alcohol, labour, general anaesthesia and
surgical procedures

Question 34

Management of Phaeochromocytoma

Answer 34

• Short-acting IV Alpha Blockade to maintain safe BP (IV Phentolamine 2 – 5mg)
o Long-acting blocker (PO Phenoxybenzamine) after control established
o SE: Postural Hypotension, Dizziness, Tachycardia, Nasal Congestion, Miosis
• Beta Blockade after Alpha Blockade established, to control Tachycardia or Ischaemia
• Surgery Electively 4 – 6/52 to allow full alpha blockade and volume expansion; When
admitted for surgery, dose of Alpha blockade raised till significant Postural Hypotension
o Adrenalectomy for complete resection of tumour; Laparoscopic Adrenalectomy for
smaller tumours, Local/Radical excision for extra-adrenal tumours

Question 35

MEN I

Wermer’s

Answer 35

Pituitary Adenoma
Parathyroid Hyperplasia/Adenomas
Pancreatic Tumours (Islet cell tumours)

Question 36

MEN IIa

Sipple’s

Answer 36

Parathyroid Hyperplasia
Medullary Thyroid Cancer
Phaeochromocytoma

Question 37

MEN IIb

Answer 37

Marfanoid Features
Mucosal Neuromas
Medullary Thyroid Cancer
Phaeochromocytoma