Thyroid disorders

Question 1

functions of thyroid gland

Answer 1

hormonal regulation, secretes thyroid hormone, homeostasis of metabolic/thermogenic processes

Question 2

Hypothalamic pituitary axis

Answer 2

Hypothalamus commuicates with ant. pituitary
-thyrotropin releasing hormone (TRH)
Ant. pituitary communicates with thyroid gland
-thyroid stimulating hormone (TSH)
Thyroid gland responds to TSH
-increased release of stored thyroid hormone, increase iodine uptake/oxidation, increase thyroid hormone synthesis, stimulates thyroid cell growth
Thyroid hormone (T3) then inhibits further TRH and TSH release
T4 and T3; T4 is inactive and is converted to T3 within tissues

Question 3

Normal lab values for thyroid labs

Answer 3

TSH: 0.4-4.8 mIU/mL
T3 (total): 80-200 ng/dL
T4 (free): 0.8-1.7 ng/dL
Anti-TG or anti-PO: abnormal; present in autoimmune diseases

Question 4

Hyperthyroidism

Answer 4

Etiologies: Graves disease, toxic multinodular goiter, toxic adenoma, carcinoma/pituitary adenoma, thyroiditis, thyroitocosis factitia

Sequelae: increased CV morbidity/mortality; osteoporosis

Important hyperthyroid effects: weight loss, fatigue, goiter, sweating, increased DTR

Question 5

Hypothyroidism

Answer 5

most common clinical thyroid disorder

Etiologies: hashimoto’s thyroiditis, subacute thyroiditis, silent thyroiditis, postpartum thyroiditis, post therapeutis/iatrogenic

Important hypothyroid effects: fatigue, cold intolerance, dry, constipation, delayed DTR relaxation phase with brisk contraction