P33 - Thyroid Flashcards
total thyroxine [tT4] is mostly ____ bound
- protein
free thyroxine [tT4] is biologically ____
- active
thyroglobulin (Tg) is a protein containing what
- thyroid hormone precursors that are iodinated in colloid
hyperthyroxemia - increase in what
- increase in [tT4]
hypothyroxemia - decrease in what
- decrease [tT4]
clinical sings of hyperthyroxemia
- weight loss
- alopecia
- polydipsia
- GI signs
- nervous signs
reasons for hyperthyroxemia
- thyroid neoplasm
- administration of T4, TSH, TRH or iodine containing compounds
clinical signs of hypothyroxemia
- weight gain
- lethargy
- mild anemia
- hypercholesterolemia
- hypertriglyceridemia
hypothyroxemia caused by
- decrease production of T4 (primary or secondary)
- multifactoral (decrease production of T4 for unknown cause - drugs or inflammatory disease)
primary hypothyrodisim due to
- decrease in thyroid gland (damage or inflammation)
secondary hypothyroidism due to
- TSH deficiency (pituitary damage)
three processes of hypothyroxemia due to drugs
- decrease protein-bound
- inhibit TSH secretion
- inhibit T4 production
primary hypothyroidism in canine - expect [tT4] and [TSH] values
- [tT4] - decrease
- [TSH] increase
sick euthyroidism in canine - expect [tT4] and [TSH] values
- [tT4] - decrease
- [ TSH] WRI
lymphocytic thyroiditis causes damaged cells to release ____ -> reaction to “foreign” protein -> formation of ____
- thyroglobulin
- TgAA (thyroglobulin autoantibody)
what titer is low if the thyroid gland is destroyed
- autoantibody
- no thyroglobulin leaves thyroid tissue -> no stimulus for TgAA production
dogs with lymphocytic thyroiditis have more of what autoantibody
- more TgAA than T4AA or T3AA
in a hyperthyroid cat, the thyroid gland is producing too much of what
- T4
T3 suppression test results in healthy cat
- increase [tT3]
- decrease [tT4]
T3 suppression test in hyperthyroid cat
- increase [tT3]
- no decrease [tT4] - production continues
