Adrenal disease Flashcards
(34 cards)
What are the parts of the adrenal gland?
- Capsule
- Cortex
- Medulla
What are the layers of the cortex?
- Zona glomerulosa
- ZonaFasciculata
- Zone reticularis
What is the function of the glomerulosa?
•Mineralcorticoids: Aldosterone - salt
What is the function of the fasciculata?
•Glucocortiocid production: cortisol - sugar
What is the function of the reticularis?
•Androgens - sex
Explain the regulation of the renin angiotensin system
- Renin is the major regulator of aldosterone production (zona glomerulosa)
- Activated in response to decreased blood pressure
- Leads to the production of angiotensin II which causes direct (vasoconstriction) and indirect (aldosterone) methods of BP elevation
Explain the regulation of cortisol/androgen production
•Hypothalamus releases CRH - corticotropin releasing hormone
•CRH acts on the anterior pituitary which is stimulated to release ACTH -adrenocoricotropic hormone
•ACTH acts on the adrenal cortex, stimulating it
to release cortisol
•Negative feedback from cortisol acts on the anterior pituitary and hypothalamus
What normal physiological things effect the release of CRH?
- Illness
- Stress
- time of day
What is the appearance of someone with Cushing’s?
- Moon face, flushed
- Increased abdominal fat with striae
- Easy bruising
- Poor wound healing
- Thin arms and legs due to muscle wasting
- Thinning of skin
- Buffalo hump
What are the signs of Cushing’s?
- Benign intracranial hypertension
- Cataracts
- Avascular necrosis of femoral head
- Hypertension
Explain the different measurements of cortisol
You should perform 2 of the following:
•24 hour urinary free cortisol
•Urine cortisol: creatinine ratio x3
•Dexamethasone suppression test:
- overnight or low dose test over 48 hours
- plasma cortisol should be undetectable in normal circumstances
•Late night salivary cortisol
- should be undetectable or very low in normals
What are the causes of Cushing’s syndrome?
•ACTH dependent:
- pituitary adenoma
- Cushing’s disease
- Ectopic ACTH
- Ectopic CRH
•ACTH independent:
- adrenal adenoma
- adrenal carcinoma
- nodular hyperplasia
What is the management of adrenal adenoma?
- Laparascopic adrenalectomy
* Short term requirement for hydrocortisone replacement therapy
What are the causes of primary adrenal insufficiency?
- Addison’s disease
* Autoimmune destruction
What are the clinical features of adrenal insufficiency?
- Anorexia and weight loss
- Fatigue/lethargy
- Dizziness and low BP
- Abdominal pain
- Vomiting and diarrhoea
- Skin pigmentation
Explain the investigations of adrenal insufficiency
•Biochemistry: Low Na, High K+, hypoglycaemia
•Short synacthen test:
- measure plasma cortisol before and 30 minutes after IV ACTH injection
- should see a rise in cortisol
•ACTH levels
•Renin/aldosteone levels
- Increased renin, decreased aldosterone
•Adrenal autoantibodies
What is congenital adrenal hyperplasia?
- Autosomal recessive disorder
- Range of genetic disorders relating to defects in steroidogenic genes
- Most common = CYP21 affecting the glomerulosa and fasciculata
- Means there is a reduction/no aldosterone and cortisol
What are the signs of congenital adrenal hyperplasia?
- Female: ambiguous genitalia
* Boys: Adrenal crisis (hypotension, hyponatraemia), early virilisation
What is the treatment of congenital adrenal hyperplasia?
Mineralocorticoid and glucocorticoid replacement
Why is there an increased androgen production in congenital adrenal hyperplasia?
- Increased feedback so more ACTH is released
* Because the reticularis is not affected, this continues to be stimulated, producing more androgens
What are the signs of late onset congenital adrenal hyperplasia?
- Oligomenorrhoea
- Hirsuitism
- Reduced fertility
Explain late onset CAH
- Partial 21 alpha hydroxylase deficiency
- Increased ACTH drive leads to increased 17 OPH and adrenal androgens
- Diagnosis: Synacthen test with 17OHP
What are hypertension and hypokalaemia likely a result of?
Primary aldosteronism
What is the most common cause of secondary hypertension?
Primary aldosteronism
