Disorders of the Adrenal Gland Flashcards
a class of endocrine disorders involving control by the anterior pituitary gland; intrinsic malfunction of the hormone-producing target gland
primary
a class of endocrine disorders involving control by the anterior pituitary gland; malfunction of the pituitary cells that control the hormone-producing target gland
secondary
a class of endocrine disorders involving control by the anterior pituitary gland; a malfunction of the hypothalamus
tertiary
in this situation, corticotropin-releasing hormone (CRH) elaborated by the median eminence of the hypothalamus stimulates secretion of arenocorticotropic hormone (ACTH) by the anterior pituitary. ACTH trigger the synthesis and release of cortisol, the principle glucocorticoid of the adrenal cortex. a risking level of cortisol inhibits the stimulatory action of CRH on ACTH release completing a negative feedback loop
normal
in primary destructive disease of the adrenal cortex, the level of plasma cortisol is very low and the effect of CRH on the anterior pituitary proceeds without inhibition, causing a marked increase in the secretion on ACTH. high levels of ACTH produce characteristic skin pigmentation changes.
addison disease
the primary lesion may be at the level of the pituitary or hypothalamus. in both cases, the production of ACTH and cortisol is excessive. the former causes bilateral adrenal hyperplasia, and the latter causes clinical manifestations of hypercorisolism. cells of the anterior pituitary are relatively resistant to the high levels of circulating cortisol
Cushing disease
in this rare syndrome, ACTH is elaborated by a tumour such as carcinoma of the lung. the adrenals are stimulated, circulating cortisol is increased and pituitary ACTH secretion is inhibited.
Ectopic ACTH
in this rare syndrome, CRH is elaborated by a tumour such as a bronchial carcinoid. the pituitary is stimulated, and there is an elaboration of excess ACTH. the adrenals are stimulated and circulating cortisol is increased. the hypercortisolism causes diminished hypothalamic CRH production; however the negative feedback on the pituitary proaction of ACTH is overcome by the ectopic CRH
ectopic CRH
this may produce cortisol autonomously. when the rate of production exceeds physiologic quantities, Cushing syndrome results. the effect of CRH on the anterior pituitary is inhibited by the high levels of circulating cortisol, with resultant diminished ACTH secretion and atrophy of normal adrenal tissue
adrenal adenoma or carcinoma
an exogenous corticosteroid administration in excess of physiological quantities of cortisol leads directly to peripheral manifestation of hypercortisolism and inhibits the effect of CRH on the anterior pituitary, with resultant diminished ACTH secretion, diminished cortisol production and atrophy of normal adrenal tissue
iatrogenic Cushing syndrome
the function of this structure is synthesizing:
- glucocorticoids (e.g. cortisol)
- mineralocorticoids
- androgens
adrenal cortex
what part of the adrenal cortex produces mineralocorticoids
- zona glomerulosa
- zona fasciculata
- zona reticularis
- medulla
zona glomerulosa
what part of the adrenal cortex produces glucocorticoids
- zona glomerulosa
- zona fasciculata
- zona reticularis
- medulla
zona fasciculata
what part of the adrenal cortex produces gonadocorticoids
- zona glomerulosa
- zona fasciculata
- zona reticularis
- medulla
zona reticularis
what part of the adrenal cortex produces catecholamines
- zona glomerulosa
- zona fasciculata
- zona reticularis
- medulla
medulla
are glucocorticoids water soluble or lipid soluble
lipid soluble therefore they need to travel on a protein that’s water soluble
what are some functions of glucocorticoids?
- accelerates breakdown of proteins and lipids
- helps maintain blood pressure
- immune suppression
- supports life under stressful events (e.g. fight or flight)
this is an adrenocortical insufficiency disorder.
- rare and life-threatening cause in pediatric patients
- enzymatic defects in the biosynthesis of cortisol by the adrenals
- causes severe and life-threatening symptoms
- overproduction of ACTH leads to hyperplasia of the adrenal glands and excessive androgen secretion
- a genetic defect causes enzyme deficiency
congenital adrenal hyperplasia
this is also known as Addison disease; destruction of the adrenal gland through idiopathic or autoimmune mechanisms. may be caused by tuberculosis, trauma or hemorrhage, fungal disease, neoplasia
primary adrenal insufficiency
this is known as hypothalamic/pituitary dysfunction. may be caused by corticosteroids. may also occur due to damage of the anterior pituitary or hypothalamus (such as tutors, infection, radiation, post-partum necrosis, trauma or surgery)
secondary adrenal insufficiency
this is a life threatening condition caused by inadequate levels of glucocorticoids and mineralocorticoids in circulation; may be caused by acute withdrawal or corticosteroids or stress or trauma
addisonian crisis
what are some clinical manifestations (signs and symptoms) of andrenocortical insufficiency
- anorexia
- weight loss
- weakness
- malaise
- apathy
- electrolyte disturbances
- hyperpigmentation of the skin
- diminished vascular tone
- reduced cardiac output
- inadequate circulation blood volume
can lead to cardiovascular collapse
how can people be diagnosed with adrenocortical insufficiency
- patient history and physical exam
- decreased plasma cortisol levels
- ACTH test
- abdominal CT/MRI may be performed to evaluate the size of the adrenal glands
this is also caused hypercortisolism and is the result of chronic exposure to excess circulating levels of glucocorticoids
Cushing syndrome
