Feline hyperthyroidism

Question 1

Describe the clinical signs of hyperthyroidism

Answer 1

Goiter
Aggressiveness
increased appetite
hyperactivity
weight loss

Question 2

Describe the structure of the thyroid

Answer 2

consists of secretory parts called follicles filled with hormones-storing colloid

Question 3

what do 98% of hyperthyroid cats have

Answer 3

a palpable goitre

Question 4

how does hyperthyroidism cause the heart to have a HCM appearance

Answer 4

increased thyroid hormone
increases the response to the SNS, this causes vasoconstriction
LV hypertrophy occurs due to increased catecholamines

Question 5

How can we check for systemic hypertension on clinical exam

Answer 5

check the eyes and take a blood pressure reading

Question 6

Describe a thyroid crisis

Answer 6

A sudden increase in the output of thyroxine and resultant extreme elevation of all body processes
e.g. >300bpm, resp distres, sudden blindness

Question 7

how to test for hyperthyroidism in cats

Answer 7

haematology
biochem
urinalysis
Total T4 and free T4 are the best ways to test specific thyroid function

Question 8

why can cats with hypertension have urinary infections with no clinical signs

Answer 8

the cat may have PUPD and this will lead to hyposthenuric urine and masked UTI signs

Question 9

what is commonly raised on biochemistry tests during hyperthyroidism

Answer 9

Liver enzymes
ALT and ALP

Question 10

why can total T4 tests give false negatives

Answer 10

because the T4 levels fluctuate daily

Question 11

If TT4 comes back normal and you only have a few clinical signs - how should you interret

Answer 11

doesn’t rule out hyperthyroidism-you need another test!

Question 12

Describe euthyroid sick syndrome

Answer 12

abnormal findings on thyroid function tests that occur in the setting of a nonthyroidal illness, without preexisting hypothalamic-pituitary and thyroid gland dysfunction.

Normal thyroid but they are still ill

Question 13

List 4 treatment options for feline hyperthyroidism

Answer 13

radioactive iodine (131I)
surgery
anti-thyroid medication
dietary management

Question 14

Describe radioactive iodine treatment for hyperthyroidism

Answer 14

single S/C injection of radioactive iodine 131I

Question 15

List 2 advantages and 2 disadvantage of the radioactive iodine treatment of hyperthyroidism

Answer 15

simple and effective
curative

requires licensing and hospitalisation facilities
cats become radioactive

Question 16

for what two causes of hyperthyroidism would we specifically want to use radioactive iodine

Answer 16

ectopic tumours
locally invasive carcinomas

Question 17

why would we possibly do a scintograph in cases of hyperthyroidism

Answer 17

to confirm hyperthyroid disgnosis and identify any ectopic tissue

Question 18

when performing surgical thyroid removal, what do we have to be careful of

Answer 18

the parathyroid gland

Question 19

why is using medical therapy for hyperthyroidism risky

Answer 19

you run the risk of malignant transformation

Question 20

List 2 anti-thyroid drugs

Answer 20

carbimazole
methimazole
oral, transdermal ointment, liquid

Question 21

what are some adverse reactions that can occur due to anti-thyroid medications

Answer 21

anorexia
vomiting
lethargy
face and neck excoriation
dyscrasia
hepatopathy

Question 22

what type of diet can be given to cats with hyperthyroidism

Answer 22

restricted-iodine diet

Question 23

what monitoring of a treated hyperthyroid cat should be done

Answer 23

clinical exam
BCS and nutritional assessment should be done regularly
Blood tests should be done depending on the treatment of choice

Question 24

What issues can occur when treating hyperthyroidism with low-iodine diet

Answer 24

must be fed exclusively
questionable palatability
low protein content

Question 25

Describe how you palpate the thyroid in cats

Answer 25

run your fingers up and down the trachea to feel for a goitre

Question 26

Why is doing nothing not an option in hyperthyroidism

Answer 26

because the effect on organs can be deadly

Question 27

why do cats have to be hospitalised for a week following radioactive iodine injection

Answer 27

in order to collect all faeces as it may be radioactive