Hyperthyroidism Flashcards
Hyperthyroidism is caused by
excessive production of T4 and T3
The most common cause of hyperthyroidism is
functional tumor, adenoma
T/F: 70% of cats with hyperthyroidism have unilateral tumors
false - 70% have bilateral tumors
\_\_\_\_\_\_\_ is the most common endocrinopathy of older cats. A) Diabetes mellitus B) Hypothyroidism C) Hyperthyroidism D) Obesity
Hyperthyroidism
Clinical signs of hyperthyroidism
weight loss, unkept “scraggly” coat, PU/PD (osmotic diuresis, renal medullary washout, physiologic or concurrent RF), GI signs (vomiting: gastric distension, overeating; diarrhea: osmotic, hyper motility)
What is apathetic hyperthyroidism
a subset of cats with weight loss and poor appetite
PE findings in a hyperthyroid cat
loiter, tachycardia, murmur/gallop
Lab work you’d expect with a hyperthyroid cat
CBC: variable stress leukogram, maybe erythrocytosis
Biochem: increased ALP and ALT, variable BUN/Creat/Phos
UA: may be dilute (isosthenuric to hyposthenuric)
T/F: it is very difficult to diagnose hyperthyroid cats
False - 95% can be diagnosed based on Hx, exam, lab work and T4 level
If T4 levels are normal and you still suspect hyperthyroidism, what can you do?
Repeat T4 in a few days
if high normal levels of T4, submit for a fT4 by eqd
What can you see in pertechnetate scans?
adenomas
4 hyperthyroid treatment options
medical, dietary, surgical, radioactive iodine
Why is renal disease unmasked by treating hyperthyroidism?
hyperT4 increases GFR
when you treat hyperT4, GFR decreases revealing azotemia
hyperT4 not good for kidneys
Treatment of choice for hyperthyroid cats
Iodine 131 pretreated with methimazole has best prognosis
T/F: you should monitor renal parameters and T4 levels with any hyperthyroid treatment plan
True
Most common canine thyroid tumor
malignant, highly invasive, non-functional tumors
A dog comes into your clinic because the owner noticed a lump in its neck. Upon palpation, you determine it is a thyroid mass. There are no clinical signs that suggest this mass is functional. What is the dog’s prognosis
Poor, these tumors are usually very invasive and malignant
T/F: A dog with a benign but functional adenoma has a poor prognosis.
False, can have surgery, good prognosis!
