Endocrine surgery (Yr4)

Question 1

where might ectopic thyroid tissue be found?

Answer 1

along the trachea
thoracic inlet
mediastinum
thoracic descending aorta

Question 2

how many parathyroid glands are usually present?

Answer 2

two pairs (internal and external)

Question 3

what are the functions of the thyroid hormone?

Answer 3

increase metabolic rate
increase catabolism of fat/muscle
increase body temperature
increase sympathetic drive
increase HR/contractility

Question 4

what are the main clinical signs of feline hyperthyroidism?

Answer 4

weight loss (with polyphagia)
behavioural change… hyperactive. vocalisation, restless
PUPD
vomiting/diarrhoea

Question 5

why might cats with hyperthyroidism vomit?

Answer 5

over-eating, activation of emetic centre or concurrent disease

Question 6

what findings on a clinical examination may indicate feline hypethyroidism?

Answer 6

poor BCS
restless/vocal
thin/roughened coat
tachycardia, murmurs, gallop rhythm
hypertension
palpable thyroid glands

Question 7

what diagnostic tests are run for suspected feline hyperthyroidism?

Answer 7

haematology/biochemistry
total T4

Question 8

does an increased total T4 mean the cat has hyperthyroidism?

Answer 8

no (can also increase due to comorbidities so ensure to treat these first and then retest)

Question 9

what changes on biochemistry are consistent with feline hyperthyroidism?

Answer 9

increased liver enzymes (thyroid hormone is hepatotoxic)
decreased creatinine
decreased potassium (lost through vomiting, diarrhoea and polyuria)
increased phosphate

Question 10

what options are available for medical management of feline hyperthyroidism?

Answer 10

iodine-restricted diet
anti-thyroid drugs
radioiodine

Question 11

what surgery is used to treat feline hyperthyroidism?

Answer 11

thyroidectomy

Question 12

what anti-thyroid drugs are available for feline hyperthyroidism?

Answer 12

carbimazole or methimazole

Question 13

how do anti-thyroid medications work?

Answer 13

block oxidation of iodine within the thyroid (don’t inhibit iodine uptake)

Question 14

what are the clinical signs of hypocalcaemia associated with hypoparathyroidism that might follow thyroidectomy?

Answer 14

weakness, anorexia, restlessness, muscle twitching, seizures

Question 15

what is the most common thyroid tumour seen in dogs?

Answer 15

carcinoma (not usually functional so don’t cause hyperthyroidism)

Question 16

why do most dogs require calcium and vitamin D supplementation following bilateral thyroidectomy?

Answer 16

parathyroid hormone is typically removed (so get hypoparathyroidism)

Question 17

what are the clinical signs of primary hyperparathyroidism?

Answer 17

fibrous osteodystrophy (calcium resorption)
PUPD
urolithiasis and UTI
(primary hyperparathyroidism is rare)

Question 18

what are the layers of the cortex of the adrenal gland?

Answer 18

zona glomerulosa (salt)
zona fasciculata (sugar)
zona reticularis (sex)

Question 19

what does the zona glomerulosa secrete?

Answer 19

mineralocorticoids (aldosterone)

Question 20

what does the zona fasciculata secrete?

Answer 20

glucocorticoids (cortisol)

Question 21

what does the zona reticularis secrete?

Answer 21

sex hormones

Question 22

what does the medulla of the adrenal gland secrete?

Answer 22

catecholamines (adrenaline)

Question 23

what are the three main physiological effects of adrenaline?

Answer 23

increase blood glucose concentration
increase HR/contractility
generalised vasoconstriction

Question 24

what is hyperadrenocorticism known as?

Answer 24

cushings