adrenals Flashcards
what does the adrenal cortex secrete
o Mineralocorticoids eg aldosterone
o Glucocorticoids eg cortisol
o Adrenal androgens eg DHEA
what does the adrenal medulla secrete
o Catecholamines eg epinephrine and norepinephrine
what are steroids derived from
cholesterol
function steroids
increase CO, BP, renal flow // increases blood sugars, lipolysis, proteolysis // lowers libido and mood // reduces Ca (osteoporosis) // reduces wound healing // reduces immune response
apart from adrenals, where else in the body produces steroids
gonads + placenta
commonest primary causes of adrenal insufficiency
addisons // congenital adrenal hyperplasia // malignancy // Tb
common secondary causes of adrenal insufficiency
pituitary (ACTH) or hypothalamus (CRH) disorder // excess steroids
most common cause adrenal insufficiency
addisons
what is addisons
autoimmune destruction adrenal glands –> reduced cortisol + aldosterone
symptoms addisons
lethargy, anorexia, crave salt // hyperpigentation // vitiligo // hypotension
electrolyte imbalance seen in addisons
hyperK, hypoNa, hypoglycaemia, met acidosis
what symptom distinguishes addisons from secondary renal insufficiency
hyperpigmentation (from increased ACTH)
primary care invx for addisons
9am cortisol // 100-500 –> further testing
diagnostic test addisons
synacthen (ACTH) test // measure cortisol before and 30 mins after giving injection // should rise in a normal patient
antibodies addisons
anti-21hydroxlase
mx addisons
hydrocortisone (half in morning, half in evening) // fludrocortisone
what should patients with addisons carry in case of adrenal crisis
hydrocortisone injection
what should happen to meds in addisons if acute illness
double glucocorticoid (eg hydrocortisone) but keep fludrocortisone the same
what can cause addisonian crisis
sepsis // surgery // adrenal haemorrhage // steroid withdrawal
what can cause adrenal haemorrhage
Waterhouse-Friderichsen syndrome
mx adisonian crisis
100mg hydrocortisone IM orIV // 1L saline +/- dextrose over 30-60mins
when can oral steroid replacement begin after addisonian crisis
24 hours
inheritance CAH
recessive
deficiecy in CAH
21 hydroxylase
invx CAH
ACTH test
symptoms CAH
males = early puberty (rarely intersex) // females = ambigious genetalia // hypokalaemia, poor weight gain
what type of steroids increae in CAH
adrenal androgens
commonest secondary cause adrenal insufficiency
too much steroids // mx hydrocortisone only
what causes cushings diseae
pit adenoma –> ACTH –> renal hyperplasia
what can cause ectopic ACTH procuction
small cell lung cancer
what are ACTH independent causes of cushings syndrome
steroids, adrenal adenoma
what can cause pseudo cushings
alcohol or severe depression
what test can differentiate pseudo-cushings from cushings
insulin stress test
what metabolic changes are seen with cushings
hypoK met alkalosis (+ impaired glucose tolerance)
invx to confirm cushings
overnight dex suppression test // and (24 urinary free cortisol test)
1st line invx to localise cushings cause (eg adrenal or pituitary propblem)
9am and midnight (cortisol and) ACTH // if ACTH supressed likely adrenal cause
what definitive test is used to localise cushings
high dose dexamethasone test
what dexamethasone suppresion test would indicate cushings syndrome
normal cortisol // suppressed ACTH
what dexamethasone suppresion test would indicate cushings disease
suppressed cortisol + ACTH
what dexamethasone suppresion test would indicate ectopic ACTCH syndrome
neither cortisol or ACTH supressed
cushings symptoms
muscle wasting, bruising, osteoporosis, hypertension + oedema, viriulism, acne, alopecia
mx cushings
surgical removal of source // metryapone med
most common causes primary hyperaldosteronism
adrenal adenoma (conn’s) // bilateral idiopathic adrenal hyperplasia (most common)
symptoms primary hyperaldosteronism
HTN, hypokalaemia (weakness), met acidosis
first invx primary hyperaldosteronism
aldosterone:renin ration –> (high aldosterone + low renin)
diagnostic invx primary hyperaldosteronism
CT abdo –> adrenal vein sampling (differntiates between unilat adenoma or bilat hyperplasia)
mx primary hyperaldosteronism adrenal adenoma
surgery
mx primary hyperaldosteronism bilateral hyperplasia
aldosterone antagonist eg sprinolactone
where do tumours arise in neuroblastoma
adrenal medulla and sympathetic nervous system
age neuroblastoma
20 months
symptoms neuroblastoma
mass, pallor, bone pain, hepatomegaly, paraplegia
invx neuroblastoma
raised urinary vanillymandelic acid (VMA) + HVA // xray // biopsy
assoc conditions Phaeochromocytoma
MEN II, NFT, von-hippel lindae
what do Phaeochromocytoma secrete
catecholamines
symptoms Phaeochromocytoma
HTN, headache, palpitations, sweating, anxiety
invx Phaeochromocytoma
24hr urinary metanephrines
mx Phaeochromocytoma
alpha blocker eg phenoxybenzamine –> BB –> surgery
