Endocrine Surgery Flashcards
(37 cards)
Thyroid Scintigraphy/Radioactive Iodine Uptake Test
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
Sestamibi Parathyroid Scintigraphy
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
Ultrasound imaging
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
Adrenal glands
• 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
Anatomy of the Thyroid and Parathyroid
• 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)
Hyperthyroid presentation
↑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
Hypothyroid presentation
↓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
Thyroid Function Tests
Serum TSH, Total and Free T3 and T4
o NB: FT3 is unreliable if Hypothyroidism is suspected
Sporadic Nodular Goitre
Small, diffuse or nodular; generally, euthyroid but at risk of
compressive symptoms, especially retrosternally
Grave’s Disease
Autoantibodies against the TSH receptor; diffuse goitre
Thyroiditis including Hashimoto’s Thyroiditis
Typically diffuse and lobulated goitre
Carcinoma (Papillary, Follicular, Medullary, Anaplastic)
Typically presents as uninodular
Primary Thyroid (Non-Hodgkin’s) Lymphoma
Most commonly Large-cell ± MALT Lymphoma,
Differential Diagnosis for Goitre
Sporadic Nodular Goitre
Multinodular Goitre and Toxic Thyroid Nodule
Grave’s Disease
Thyroiditis including Hashimoto’s Thyroiditis
Carcinoma
Primary Thyroid (Non-Hodgkin’s) Lymphoma
Presentations of Parathyroid Disease
Parathyroid Hormone increases Calcium levels through stimulating Osteoclast bone resorption, Active Vitamin D conversion and Renal Calcium reabsorption; Hyperparathyroidism results in increased serum Calcium
Hypercalcaemia
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)
Hypocalcaemia due to Hypoparathyroidism
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)
Thyroid Lobectomy,
including Isthmus and Pyramidal lobe if present; Curative for colloid
nodule, minimal Papillary and Follicular cancers; Aids diagnosis of suspicious lesions
Total Thyroidectomy
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
Post-operative T3 substitution
Levothyroxine (shorter half-life) to allow a rise of TSH (2
weeks after stopping) to favour Iodine-131 uptake
Bilateral Neck Exploration and Visualisation of Parathyroid glands
Used if localisation scans
were unhelpful
Minimally Invasive Parathyroidectomy
Focused neck exploration through lateral cervical
scar which targets specific glands indicated on scanning
Post-Operative • Neck bleeding Complications
– Compression might damage nerves or threaten airway; Return to theatre
upon stabilisation with emergency resuscitation
Post-Operative • Acute Bilateral Recurrent Laryngeal Nerve Injury
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
