11 - Thyroid Disorders Flashcards
(36 cards)
What can be concluded from a px w/ normal levels of T4 but high levels of TSH?
They have a thyroid problem b/c the px has to produce more to keep the thyroid levels normal
What is the difference between T4 and T3?
T4 is an inactive form that is activated to T3 at the site of action
What is the function of TSH? Where is it released from and where does it go?
- Function = stimulate thyroid to release T4
- Released from anterior pituitary and acts on thyroid
The majority of _____ in the body goes to the thyroid
Iodine
What happens when T4 is metabolized?
- 20% inactivated
- 80% converted to T3
What is the relationship between TSH and T4 and T3?
T4 and T3 provide negative feedback on TSH
Does T3 or T4 have a longer half life?
T4 (7 days), while T3 (1 day)
What are the levels of T4, T3, TSH, and serum thyroglobulin in hypothyroidism?
- T4 = low
- T3 = normal or low
- TSH = high
- Serum thyroglobulin = low
What are the levels of T4, T3, TSH, and serum thyroglobulin in hyperthyroidism?
- T4 = high
- T3 = high
- TSH = low
- Serum thyroglobulin = high
Do children have higher or lower T3 than adults?
Higher
Is hypothyroidism more common in men or women?
Women
What is Hashimoto’s thyroiditis?
- Autoimmune disorder
- Antibodies against thyroid peroxidase and/or thyroglobulin gradually destroy thyroid gland follicles
What is the presentation of hypothyroidism?
- Slowing of body functions (heart, mental acuity, strength, cold and scaly skin, sparse hair)
- Puffiness (myxadema)
- Droopy eyelids
What is the function of thyroid hormone in infants?
Critical for brain development, and important in physical features
What are sx of hashimoto’s thyroiditis?
- Slower metabolism
- Reduced CNS activity
- Weight gain
- Fatigue
- Depression
- Constipation
- Memory loss
- Can also cause reactive hyperthyroidism (=> mania, tachycardia, panic attacks)
How is hashimoto’s thyroiditis detected?
- Presence of specific antibodies
- Also will see increased TSH and often lymphocyte invasion of thyroid gland
- Enlargement of thyroid (goiter)
What effect do thyroid hormones have on catecholamines?
Increase adrenergic receptor sensitivity to catecholamines
What effect do hypothyroidism and hyperthyroidism have on ability to get pregnant?
- Hypothyroidism makes it difficult to get pregnant
- Hyperthyroidism increases chances of spontaneous abortion
What is the tx for hypothyroidism?
- If due to iodine deficiency, add iodine to diet
- For gland failure, levothyroxine (T4) is tx of choice
What happens if a person w/ normal T4 levels is given more T4?
Body only converts T4 to T3 as needed, so it will do no harm
How long is it before effects of T4 tx is seen?
2-3 weeks
What are sx of hyperthyroidism?
- Exophthalmos (bug eyes)
- Goiter
- Under 40 y/o mainly experience nervous system effects (anxiety, paranoia, mood swings)
- Over 40 y/o mainly experience CV effects
What is the prevalence of hyperthyroidism?
- Most common btwn 20-60 y/o
- More prevalent in females
What is the most common form of hyperthyroidism?
- Graves’ disease
- Activating antibody to TSH receptor, causes increased T3 and T4
