Adrenal Disorders Flashcards
Precursor for steroid hormones
Cholesterol
different types of corticosteroid?
mineralocorticoid, glucocorticoid, sex steroids
Made in the adrenal cortex
effect of angiotensin II on adrenal glands?
activation of many metabolic enzymes leading to increased corticosteroid production
aldosterone main actions?
controls blood pressure → increases sodium reabsorption and potassium excretion
effect of ACTH on adrenal cortex?
activates many enzymes including 11-, 21-, 17-hydroxylase → more production of corticosteroids
one lifestyle factor increasing ACTH production?
Stress (cortisol is a stress hormone)
first steps of metabolic pathway for cholesterol?
cholesterol → pregnenolone → progesterone
what is addison’s disease?
primary adrenal failure
mediated by autoimmune adrenal cortex destruction or tuberculosis of adrenal glands
ACTH levels in Addison’s?
high → melanocyte stimulating hormone MSH high too
Symptoms of addisons
hyperpigmentation and possible coexistent autoimmune vitiligo, low blood pressure, weakness, weight loss, nausea, diarrhoea/constipation, vomiting
what is an adrenal crisis?
fever, syncope, convulsions, hypoglycaemia, hyponatraemia, severe vomiting and diarrhoea
why hyperpigmentation?
ACTH and MSH come from the same precursor that is cleaved during formation (pro-opio-melanocortin POMC
- biochemical consequences of adrenal failure?
hyponatraemia, (postural) hypotension, hyperkalaemia, low glucose (glucocorticoid deficiency), high ACTH
- blood → Na+ and K+9am cortisol (at peak so can observe too low), ACTH
Tests for addisons
blood → Na+ and K+ . Sodium would be low and potassium high
9am cortisol (at peak so can observe too low), ACTH
what is a synACTHen test?
inject synACTHen and observe cortisol before and after e.g. 9:00 and 9:30
should be higher in response
treatment for primary adrenal failure?
replacement of cortisol and aldosterone