Thyroid, Pituitary and Adrenal Flashcards
(41 cards)
How much circulating T3 and T4 are protein bound?
99% (there is VERY little active hormone)
True or False: Only free bound T4 can enter cells and carry out cellular activity
True
What are the two causes of primary hypothyroidism?
- Idiopathic atrophy
- Immune-mediated destruction (lymphocytic thyroiditis)
What will you see on a CBC with hypothyroidism?
Mild normocytic normochromic non-regenerative anemia (anemia of endocrine disease)
What is a major indication on biochemistry of hypothyroidism (three)?
- Moderate to marked hypercholesterolemia
- Mildly increased ALP (may or may not be seen)
- Mildly increased ALT (may or may not be seen)
True or False: Hypercholesterolemia is a diagnostic indicator of hypothyroidism
False. It must be paired with clinical signs
What will you see on a CBC with hyperthyroidism?
Mild to moderate erythrocytosis
What will you see on a biochemistry with hyperthyroidism (three)?
- Mild to moderate increases in ALP
- Mild to moderate increases in ALT (due to increased bone metabolism)
- Azotemia
Increased ALT combined with ALP is super common
When ALT and ALP is greater than ______ U/L in cats, you should investigate other disease
500
What is the cause of euthyroid sick syndrome?
T4 autoantibodies (T4 levels will appear falsely elevated and look normal when they are not)
True or False: You should just run a free T4 instead of a total T4 and TSH first to save time
False. T4 and TSH are still better tests to start with. If they are suspiciously normal, then proceed to free T4 test.
True or False: Feline hypothyroidism is rare so you don’t need to measure feline TSH
True. (TSH isn’t really used for hyperthyroidism diagnosis)
True or False: Euthyroid sick syndrome can be so severe in dogs that they appear hypothyroid
True. The suppression of thyroid hormones in euthyroid dogs can occur in response to concurrent illness
The closer the T4 is to normal range, the ________ likely the dog is euthyroid
More
The farther away the T4 is to normal range, the ________ likely the dog is hypothyroid
More
Which breed of dog typically has lower serum levels of T4 and can appear hypothyroid when they are not?
Greyhounds
True or False: Increased total T4 in cats reliably confirms diagnosis of hyperthyroidism
True (>90% cats)
What are three main causes of hyperadrenocorticism?
- Pituitary-dependent hyperadrenocorticism
- Functional adrenal neoplasia (adrenal-dependent hyperadrenocorticism)
- Iatrogenic hyperadrenocorticism
What is the most common clinical sign of Cushing’s in dogs?
- PUPD
- Polyphagia
- Cachexia (pot-belly)
- Alopecia
- Impaired wound healing
What will you see on a CBC with Cushing’s disease (two)?
- Thrombocytosis
- Stress leukogram
What will you see on a biochemistry with Cushing’s disease (five)?
- Markedly increased ALP
- Mildly increased ALT
- Hypercholesterolemia
- Hypertriglyceridemia
- Lipemia
Same markers that are affected in hypothyroidism but ALP is marked here because corticosteroids induce ALP
What will you see on a urinalysis with Cushing’s disease (two)?
- USG < 1.020 (can be hyposthenuric or isosthenuric)
- Mild proteinemia
70% of dogs with Cushing’s will also have what condition?
Cushing’s dogs commonly have concurrent secondary hypothyroidism (pituitary issue commonly affects TSH as well as ACTH)
Which screening tests can you use to diagnose hyperadrenocorticism?
- CBC/BCEM/UA
- ACTH stim
- LDDST
- Urine cortisol:creatinine ratio
