hypo - pit - thyroid axis stimulates ... which in turn ... - hypo-pit-thyroid axis produces TRH which stimulates pituitary production of TSH, TSH stimulates the thyroid gland to secrete T4 which is converted to T3. The T4 inhibits TRH and pituitary TSH secretion
free, unbound T3 and T4 - is...
hypo - pit - thyroid axis stimulates ... which in turn ... - hypo-pit-thyroid axis produces TRH which
stimulates pituitary production of TSH, TSH stimulates the thyroid gland to secrete T4 which is converted
to T3. The T4 inhibits TRH and pituitary TSH secretion
free, unbound T3 and T4 - is biologically active
primary hypothyroidism - congenital/aquired f>m
due to abnormality of thyroid formation in fetal life or problem with thyroid
Hashimotos - most common cause of aquired primary hypothyroidism.
autoimmune condition leading to destruction of the thyroid gland
features: dry skin, constipation, hair loss, fatigue, cold intolerance, apathy, depressed relaxation of
tendons, and weakness and sharp deceleration in growth
present with borad nasal bridge, coarse facial features, mental retardation, short stature, puffy
appearance of hands, protuberant tongue. Treatment by 3-4 wks of age eliminates this from happening
Hyperthryoidism - excessive thyroid hormone secretion from the thyroid gland.
hyperthyroidism can be caused by - graves or hyperthyroid phase of Hashimotos thyroiditis
less common causes:
functioning adenomas
toxic multinodular goiters
selective pituitary T3 resistance
Graves disease - stimulating antibody overrides the TSH receptor increases the production of thyroid
hormone.
features: hyperthyroidism features plus lid lag, proptosis, exophthalmos
hyperthyroid gland can increase 3-4x its size
warm to palpation
bruit may be heard over the gland
T4 AND T3 are elevated and TSH concentration is suppressed.
Cushings syndrome - excessive glucocorticoids due to either excess endogenous or exogenous steroid
exposure.
cushings syndroem physical features - rounded face, plethora, central obesity, impaired linear growth,
fatigue, and hypertension. irritable, muscle weakness, muscle wasting causing thin extremities, buffalo
hump.
skin is thin frail and easily brusied.
osteopenia, osteoporosis
amenorrhea
, CNS efffects: moody, psychosis, and idiopathic intracranial hypertension
Cushings disease treatment - removal of tumor that is secreting ACTH and/or removal of the adrenal
gland
endogenous syndrome due to adrenal tumors, pit tumors, f>M
dianostic for cushing disease - confirmation of elevated cortisol concentrations
24 h urine with cortisol
midnight salivary cortisol measurements
high ACTH concentration
CT for evaluation of adrenal tumor
**if cushing disease pituitary MRI is study of choice
addisons disease presents with - primary adrenal insufficiceny
presents with: weight loss, anorexia, electrolyte abnormalities, hyperpigmentation of genitalia, palms,
flexor creases, and areolae, ill appearance, thin habitus, and microcardia on CXR, vitiligo, weak and
confused.
Primary adrenal insufficiency is characterized by
and the 4 main causes are - conditions that directly affect the adrenal glands ie adrenal tumor or
destruction of adrenal tissue via autoimmune disease. glucocorticoid and mineralcorticoid deficiences
which is caused by the loss of cortisol negative feedback which leads to increase ACTH and melanin
secretion
4 causes
adrenal destruction
adrenal hypoplasia
familial glucocorticoid deficiency
impaired steroidogenesis
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