Endocrine System Iii

Congenital Abnormalities - Congenital Adrenal Hyperplasia (CAH) o 21-Hydroxylase (P450c21) deficiencies  Simple virilizing CAH • Excess adrenal androgens are amplified by ACTH stimulation of the gland  Salt-Wasting CAH • Aldosterone synthesis impaired, rapidly fatal if untreated  Late-Onset CAH • No abnormalities until virilization (changes which make a person male or female) at puberty Adrenal Cortical Hypofunction - Addison’s Disease (primary) o Disease resulting in adrenocortical hypo functioning. o 70% due to idiopathic cortex atrophy, 30% result from gland destruction by tumor o Weakness, fatigue, orthostatic hypotension, anorexia, nausea, vomiting, diarrhea, cold intolerances, dizziness, syncope, hypoglycemia, weight loss o HYPERPIGMENTATION (10 Addison’s Only)  On all body areas esp skin folds. Black freckles on face, neck and shoulders, vitiligo, bluish-black discolorations of areola and mucous membranes, abnormal electrolytes (high Na, low K) o High plasma ACTH, low plasma Cortisol is diagnostic o To treat acute: delay in treating an adrenal crisis can be fatal o Shock and fever may be only signs, tx must not be delayed - Addison’s Disease (Secondary) o Caused by lack of ACTH, electrolytes are normal, low cortisol o No hyperpigmentation Adrenal Cortical Hyperfunction - Adrenal Virilism (Adrenogenital syndrome) o Excessive output of adrenal androgens causes virilization o Hirsutism, baldness, acne, deepening of voice, amenorrhea, clitoral hypertrophy, increased muscularity and libido o Mild cases may only show hirsutism - Delayed Virilizing Adrenal Hyperplasia (AKA Late onset CAH) o Results from defect in hydroxylation of cortisol precursors o Diminished urinary cortisol, elevated DHEA in urine o Diagnosis is confirmed by suppression of urinary DHEA and pregnanetriol with dexamethasone - Virilizing Adeonomas or Adenocarcinomas

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o Androgen secreting tumor o Dexamethasone either does not or only partially suppresses androgen excretion Cushing’s Syndrome o Chronic exposure to excess cortisol o Pituitary hypersecretion of ACTH o If primary Cushing’s = low ACTH, high cortisol o If secondary Cushing’s = high ACTH, high cortisol o Moon faces, buffalo hump on back of neck, stunted growth in children, irregular menses in adults o Elevated morning cortisol and lack of normal diurnal decline o Pituitary ACTH is somewhat resistant to suppression by dexamethasone o If it’s a tumor causing this condition it will be completely resistant to suppression by dexamethasone o If caused by Adrenal tumor = ACTH too low to measure o If caused by Ectopic tumor = ACTH markedly elevated o Cushing’s Disease = ACTH moderately elevated

Hyperaldosteronism - Conn’s Syndrome o Syndrome resulting from excess aldosterone secretion by an adenoma or hyperplastic gland o Hypokalemic alkalosis manifested as muscle weakness, paralysis and tetany o Polyuria, polydipsea o Personality changes, hyperglycemia and glycosuria may occur o Primary aldosteonism = low plasma rennin, decreased Na and K o Diagnosis = normal persons will have a marked increase in rennin output in the upright position, hyperaldosterone patients will not - Secondary Hyperaldosteronism o Increased production of aldosterone caused by stimuli originating outside the adrenals o Related to hypertension and edematous conditions Adrenal Adenomas - Functional neoplasm is a well documented cause of Cushing’s syndrome Adrenal Carcinomas - a functional neoplasm, up to 80% of adrenal carcinomas are functional and tend to invade locally - adrenal carcinomas responsible for 50% of children with Cushing’s