Thyroid disease in the cat Flashcards
What causes hyperthryoidism?
thyroid tumours
What are the risk factors of hyperthryoidism?
- less common in siamese
- canned foot
- litter trays
- > 8yrs
- ectoparasiticides
Whaat are possible causes of hyperthyroidism?
age
diet- long term iodine levels
canned food genetics
goitrogens- flame retardants
What is commonly seen with hyperthryoidism in cats?
- dry coat
- behavioural changes
- GI signs- vomiting and diarrhoea
- increased HR
- increased metabolism
- mild polyuria/polydipsia
What is often seen on clinical exam?
- thin
- dehydrated
- poor hair coat
- tachycardia
- thyroid nodule
- cardiac murmur
What are causes of weight loss in older cats?
Hyperthyroidism Chronic renal failure Diabetes mellitus Neoplasia Inflammatory bowel disease Chronic hepatic disease Chronic pancreatitis
What may be causing the behavioural change in the older cat?
Painful disease- arthritis, pancreatitis, hypertension
Metabolic disease
Neurological diseases- FIV, CDS, neoplasia
How can feline hyperthyroidism be diagnosed?
increased total T4
how can hyperthyroid cats be looked after?
environment- no dogs, hiding places
diet- high energy, low fat diet (little and often)
Describe the dietary management of hyperthyroidism?
very low iodine diets- restricts T4 production
however- tumour still grows, outside sources of iodine with outdoor cats eating mice
What drugs can be usd to manage hyperthyroidism?
methimazole
one tablet x2 day
or
carbimazole
Describe the surgical treatment
70% bilateral disease- both need to be removed if both enlarged
Describe the use of radiotherapy as treatment
single SC injection of iodine-131
no anaesthesia needed
is effective
Compare feline hyperthyroidism with canine hypothyroidism
feline hyperthyroidism:
- weight loss
- increased activity
- starry coat
- fast heart beat
- common GI signs
- increased T4
Canine hypothyroidism:
- weight gain
- decreased activity
- alopecia in coat
- slow heart rate
- GI signs are rare
- decreased T4 and increased TSH
