Flashcards in Hypothyroid Deck (11):
Inadequate thyroid hormone.
Primary MOST COMMON-
Hashimoto- autoimmune for follicles or Ab blocks TSH R
Primary atrophic hypothyroid due to diffuse lymphocytic infiltration.
Radiation to neck
Iodine deficiency or excess
Drugs eg lithium, sulphonamide, amiodarone.
LT iodide tx, thyroidectomy, radioiodine, antithyroid drugs.
Secondary- lack TSH
Pituitary dysfunction, postpartum necrosis, neoplasm, infiltrative disease.
Hypothalamic disease eg granuloma, neoplasm, radiation causing deficient TRH.
Rare- tissue resistance to thyroid hormone.
Systemic eg nephrotic syndrome, CHF, amyloidosis.
Often subtle and non specific
Reflexes slow to relax
Dry thin hair and skin, and slow growing.
Oedema (myxoedema= dry firm waxy swelling of skin and SC tissue)
Monitoring TSH and maybe T4.
Usually TSH high, T4 low.
TSH low too if pituitary problem.
High cholesterol and TG.
Risk heart disease as low thyroxine= increased cholesterol.
Pregnancy complications eg pre eclampsia, anaemia, premature labour, low birth weight, stillbirth, bleeding after birth.
Myxoedema coma rare.
Cretinism in neonate, now screened.
General effects of thyroid hormones
Stimulation of catabolic pathways
Normal tissue growth and development
Increased responsiveness of tissue to SNS
Specific effects of thyroid hormone
NS development- myelination, reflexes, mental activity.
CVS- increase CO
Skin and SC tissue- increase t/o protein and gp.