Endocrine Surgery

Question 1

Thyroid glands

Answer 1

Paired - dogs - may communicate ventrally
Lateral tracheal rings 5-8
Right structures - carotid sheath, RLN
Left structures - oesophagus RLN
Parathyroid

Question 2

Thyroid anatomy

Answer 2

Normally flat and not palpable
Blood - Cr thyroid art (common carotid)
- Cd thyroid artery (brachycephalic Art(not cats))
Innervation - thyroid nerve (vagus)
Ectopic tissue
- common along trachea

Question 3

Parathyroid glands

Answer 3

Para - beside (2 pairs)
External - Cr thyroid pole
Internal - embedded in Cd pole
Small ellipsoid discs of tissue
Ectopic tissue common for cats
(Ass. with thymus)

Question 4

Thyroid hormone function

Answer 4

Metabolic rate
Catabolism (msc and fat)
Body temperature
Sympathetic drive
Emetic centre and heart msc

Question 5

Clinical exam findings (Hyper Thy)

Answer 5

Poor BCS
Restless
Rough coat
Cardiac signs
Hypertension
Palpable thyroid

Question 6

Radioiodine

Answer 6

Subcut I-131
Accumulates in hyperactive tissue (destroys)
95% success 1 dose
Adv -
Curative
Low risk
Cheaper long term
No compliance issues
Dis-
Hospitalised 7d
Non reversible hypothyroidism
Specialist procedure

Question 7

Thyroidectomy

Answer 7

Adv - curative, long term cheap, low compliance
Dis- not reversible, hypoCa, Sx
Pre-op- Euthyroid state (3m drugs)
Tx Hyper BP and kalaemia
Unilat - contralateral atrophy
Preserve parathyroid
Modified intracapsular technique

Question 8

Parathyroid autotransplantation

Answer 8

If Ext PTH removed
Small pocket in sternohyoid
Dissected PTH insert into pocket
Takes 2wks for function resumption

Question 9

Iatrogenic HypoPTH

Answer 9

Mild transient decrease in serum CA post Sx
Monitor Ca 1 wk postop

Question 10

Canine thyroid tumours

Answer 10

90% carcinoma
Mostly non functional and high metastasis risk
Old large breeds, palpable mass
Dx - US
Biopsy contraindicated (bad bleed)
Tx -Thyroidectomy
Don’t need euthyroidism

Question 11

1° Hyper PTH

Answer 11

Uncommon - dogs
Solitary PTH adenoma
Often incidental finding
Pu/PD
Urolithiasis
Fibrous osteodystrophy (rubber jaw)
Dx - US, biochem (HIgh Ionised Ca, high PTH)
Tx - parathyoidectomy
Postop- monitor Ca, keep calm

Question 12

Adrenal glands

Answer 12

Med - Cr to kidneys
Left blood - aorta
Right blood - adhered Cd VC
Medulla - catecholamines (epinephrine)
Cortex-
Z glomerulosa - mineralocorticoids (aldosterone) (out)
Z fasciculata - glucocorticoids (cortisol) (mid)
Z reticularis - Sex Hrm, glucocorticoids (in)

Question 13

Adrenal tumours

Answer 13

Not always functional
Cortisol secreting- adeno(carcino)ma hyperadrenocorticism
(Cushings)
Catecholamine sec- phaechromocytoma- sev paroxysmal high BP, tachyArrh
Dx - haematology, biochem, LDDST, imaging

Question 14

Adrenalectomy pre-op

Answer 14

Cortisol sec - Trilostane 1m (ACE Inh if high BP)
Phaechromocytoma- alpha blocker 2wks
- difficult GA

Question 15

Adrenalectomy Sx

Answer 15

Vtl Midline coeliotomy
R side harder to expose
incise peritoneum at gland’s lateral aspect
Refer for the Sx (high mortality rate)