Hyper/Hypothyroidism Flashcards
which thyroid hormones are measured?
TSH
T4
T3
which are the free thyroid hormones?
T4
T3
hypothyroidism
results from a variety of abnormalities that cause insufficient secretion of thyroid hormones
myxoedema coma
severe hypothyroidism
pretibial myxoedema
accumulation of hydrophilic mucopolysaccharides in the ground substance of the dermis & other tissues causing doughy induration of the skin usually in the shins
what disease is pretibial myxoedema usually seen in?
Graves disease (thyrotoxicosis)
hashimoto’s thyroiditis
autoimmune hypothyroidism
what are the causes of goitrous primary hypothyroidism?
chronic thyroiditis iodine deficiency (drug induced)
what are the causes of non-goitrous hypothyroidism?
- congenital developmental defect
- atrophic thyroiditis
- post-ablative (radioiodine, surgery)
- postradiation (eg for lymphoma)
what are the secondary causes of hypothyroidism?
hypothalamic
pituitary
what can cause hypothalamic secondary hypothyroidism?
- congenital
- infection: encephalitis
- infiltration: sarcoidois
- malignancy eg craniopharyngioma
what can cause pituitary secondary hypothyroidism?
panhypopituitarism
isolated TSH deficiency
what can cause panhypopituitarism?
trauma
infection
infiltration
neoplasm
what is hashimoto’s thyroiditis?
AI hypothyroidism
- autoimmune destruction of thyroid gland resulting in reduced thyroid hormone production
in which sex is hashimoto’s thyroiditis more common in?
females
what is hashimoto’s thyroiditis characterised by?
Presence of Thyroid Peroxidase Antibodies (in blood)
T-cell infiltrate and inflammation on microscopy
what would you expect TSH to be in hypothyroidism?
high
what would you expect T3 & T4 to be in hypothyroidism?
low
what would you expect cholesterol to be in hypothyroidism?
high
how should metabolic rate be restored?
gradually
what could rapid restoration of metabolic rate cause?
cardiac arrhythmias
what is the main treatment of hypothyroidism?
thyroxine (T4)
what is the main treatment of hyperthyroidism?
carbimazole
propylthiouracil