Endocrine

Question 1

What is the aetiology of hyperthyroidism?

Answer 1

Enlarged thyroid gland - usually due to hyperplasia.
Leads to: increased thyroid production hypermetabolic state (increased HR and BP)
Common in cats, rare in dogs

Question 2

What is the aetiology of hyperadrenocorticism?

Answer 2

Caused by either:
Pituitary gland - increased production of ACTH
Adrenal tumour - direct increase of cortisol
Both lead to serum cortisol
Middle - old aged dogs. Predisposed breeds include: terriers, bichon fries, dauschound, boxers and GSD

Question 3

What is the pathophysiology of Hyperthyroidism?

Answer 3

increased thyroid production

Hypermetabolic state

Question 4

What is the pathophysiology of Hyperadrenocorticism?

Answer 4

Overactive tissue in pituitary or adrenal glands leads to increased production of cortisol.
High levels of cortisol lead to hyperglycaemia and inhibit ADH - leads to PUPD.
High cortisol also causes protein catabolism leading to muscle wasting and poor wound healing. Cortisol affects hair growth and distribution of fat.

Question 5

What are the clinical signs of hyperthyroidism?

Answer 5

polyphagia
hyperactive/ aggressive
Weight loss
restless
hypertrophic cardiomyopathy 
tachycardia 
vomit and diarrhoea

Question 6

What are the clinical signs of hyperadrenocorticism?

Answer 6

'The P disease'
Polyuria
Polydipsia 
Panting 
Pot-bellied 
Weight loss
Alopecia 
Muscle weakness
Hepatomegaly 
Thinning of the skin

Question 7

How is hyperthyroidism diagnosed?

Answer 7

history and clinical signs
physical examination - high T4 levels
Scintigraphy

Question 8

how is hyperadrenocorticism diagnosed?

Answer 8

history and clinical signs
ACTH stimulation test - blood at 0 hrs and 1hr. Inject with ACTH after 1st sample.
Low dose dexamethasone - blood at 0,4 and 8hrs. Inject after 1st sample.
Endogenous ACTH
Imaging
Urine testing - finding the cortisol:creatine ratio. (UCCR)