Feline Hyperthyroidism and Canine Hypothyriodism

Question 1

Hyperthyroidism incidence?

Answer 1

older cats

no breed or sex preference

Question 2

Hyperthyroidism pathology incidence?

Answer 2

Bilateral 70%
Unilateral 30%
Adenomatous hyperplasia 98%
Adenocarcinoma 2%

Question 3

Hyperthyroidism clinical signs?

Answer 3

weight loss, despite polyphagia
hyperdefectaion
vomiting/diarrhea
PD/PU
restlessness, nervousness
unkempt hair

Question 4

Hyperthyroidism physical exam findings?

Answer 4

Tachycardia +/- murmur
tachypnea
palpable goiters***
\+/- hypertension
\+/- retinal hemorrhage

Question 5

Hyperthyroidism dx tests?

Answer 5

Total T4***
Free T4
T3 suppression
TRH stim
TSH response
Radionuclide uptake on imaging

Question 6

Thyrotoxicosis?

Answer 6

Can cause heart failure

Question 7

Apathetic Hyperthyroidism?

Answer 7

lacks useful features
heart dz signs dominate
usually undiagnosed until in heart failure - septal hypertrophy on necropsy

Question 8

What would be a sign that there is other heart pathology other than just Hyperthyroidism?

Answer 8

sinus arrhythmia

Question 9

non-surgical Hyperthyroidism treatment

Answer 9

propanolol/atenolol
amlodipine (if hypertensive)
methimazole***
I-131
new low iodide hills diet?

Question 10

Methimazole aka?

Answer 10

tapazole

Question 11

methimazole toxic effects

Answer 11

anorexia***
facial pruritis ---> STOP when see this 
vomiting
lethargy
bleeding diathesis (secondary coagulopathy from hepatopathy)
icterus (hepatopathy)

Question 12

methimazole hematologic side effects

Answer 12

eosinophilia
lymphocytosis
leukopenia
agranulocytosis ---> STOP when see this 
thrombocytopenia
positive ANA

Question 13

Hyperthyroidism surgery treatment is not as common anymore. Pre-op and post-op care?

Answer 13

Pre-op: restore euthyroidism, asses KIDNEY fx, propanalol for tachycardia, avoid atropine during anesthesia.

Taking out thyroid lowers BP and GFR, can cause renal dz because they are used to being in high BP state

Post-op: watch for hypoCa with bilateral removal (hypoPTH), thyroxine and ca gluconate if indicated

Question 14

frequency of relapse after surgery?

Answer 14

intracapsular > extracapsular

Question 15

If evaluate kidneys before Hyperthyroid surgery and find underlying kidney disease, how should you treat?

Answer 15

Oral treatment and maintain mild hyperthyroid state

Question 16

hints for underlying kidney disease with Hyperthyroidism

Answer 16

small kidneys on palpation

dilute urine

Question 17

Hyperthyroidism lab findings?

Answer 17

High T4!!
elevated liver enzymes
mild hyperK and elevated PCV

Question 18

Hypothyroidism incidence?

Answer 18

middle-aged dogs or mid- to large-sized breeds

golden retriever, doberman, irish setter, schanuzer, dachshund, cocker spaniel, airedale terrier, great dane, old english sheepdog

Question 19

Hypothyroidism clinical signs?

Answer 19

lethargy, cold intolerance, decreased cerebration, mild increased body weight

alopecia, skin thickening, hyperpigmentation

constipation, myotonia, anemia, neuropathy

Question 20

Hypothyroid myxedema syndrome

Answer 20

severe mental depression terminating in coma and hypothermia, usually acutely caused by anesthesia

Question 21

Hypothyroidism dx?

Answer 21

recent hyperthyroid surgical resection
serum T4> serum T3
TSH response test
free T4

Question 22

Hypothyroidism treatment?

Answer 22

thyroxine

Question 23

Hypothyroidism causes?

Answer 23

primary*** - congenital/autoimmune/neoplasia
secondary (hypopituitary) - pituitary neoplasia or iatrogenic through glucocorticoid dugs
tertiary - hypothalamic destruction/malformation

Question 24

Hypothyroidism lab findings?

Answer 24

high cholersterol/TGs/CK

normocytic normochromic anemia