P33 - Thyroid

Question 1

total thyroxine [tT4] is mostly ____ bound

Answer 1

• protein

Question 2

free thyroxine [tT4] is biologically ____

Answer 2

• active

Question 3

thyroglobulin (Tg) is a protein containing what

Answer 3

• thyroid hormone precursors that are iodinated in colloid

Question 4

hyperthyroxemia - increase in what

Answer 4

• increase in [tT4]

Question 5

hypothyroxemia - decrease in what

Answer 5

• decrease [tT4]

Question 6

clinical sings of hyperthyroxemia

Answer 6

• weight loss
• alopecia
• polydipsia
• GI signs
• nervous signs

Question 7

reasons for hyperthyroxemia

Answer 7

• thyroid neoplasm

- administration of T4, TSH, TRH or iodine containing compounds

Question 8

clinical signs of hypothyroxemia

Answer 8

• weight gain
• lethargy
• mild anemia
• hypercholesterolemia
• hypertriglyceridemia

Question 9

hypothyroxemia caused by

Answer 9

• decrease production of T4 (primary or secondary)

- multifactoral (decrease production of T4 for unknown cause - drugs or inflammatory disease)

Question 10

primary hypothyrodisim due to

Answer 10

• decrease in thyroid gland (damage or inflammation)

Question 11

secondary hypothyroidism due to

Answer 11

• TSH deficiency (pituitary damage)

Question 12

three processes of hypothyroxemia due to drugs

Answer 12

• decrease protein-bound
• inhibit TSH secretion
• inhibit T4 production

Question 13

primary hypothyroidism in canine - expect [tT4] and [TSH] values

Answer 13

• [tT4] - decrease

- [TSH] increase

Question 14

sick euthyroidism in canine - expect [tT4] and [TSH] values

Answer 14

• [tT4] - decrease

- [ TSH] WRI

Question 15

lymphocytic thyroiditis causes damaged cells to release ____ -> reaction to “foreign” protein -> formation of ____

Answer 15

• thyroglobulin

- TgAA (thyroglobulin autoantibody)

Question 16

what titer is low if the thyroid gland is destroyed

Answer 16

• autoantibody

- no thyroglobulin leaves thyroid tissue -> no stimulus for TgAA production

Question 17

dogs with lymphocytic thyroiditis have more of what autoantibody

Answer 17

• more TgAA than T4AA or T3AA

Question 18

in a hyperthyroid cat, the thyroid gland is producing too much of what

Answer 18

• T4

Question 19

T3 suppression test results in healthy cat

Answer 19

• increase [tT3]

- decrease [tT4]

Question 20

T3 suppression test in hyperthyroid cat

Answer 20

• increase [tT3]

- no decrease [tT4] - production continues