Adrenal disorders Flashcards
2 main causes of primary adrenal insufficiency
addisons disease
adrenal enzyme defects eg congenital adrenal hyperplasia - 21 hydroxylase deficiency
6 “I” causes of addisons disease
Immune destruction iatrogenic infection invasion infarction infiltration
What antibodies are found in Addison’s?
adrenal autoantibodies - to 21-OHase
common symptoms of primary adrenal failure
tiredness, weight loss, anorexia, fatigue, weakness vomiting and diarrhoea skin pigmentation or vitiligo hypotension salt craving postural symptoms
4 possible clues to diagnose adrenal failure
unexplained hypoglycaemia
disproportion between severity of illness and circulatory collapse
other endocrine features eg body hair loss, amenorrhoea
previous depression or weight loss
Diagnosis of adrenal insufficiency - addisons
non specific symptoms
U+E, glucose, FBC
random cortisol
synacthen test
If the patient is unwell and addisons suspicion is high what do you do?
treat with steroids
do synacthen test later
What does the synacthen test help determine?
primary or secondary adrenal insufficiency
If plasma ACTH is elevated in rapid ACTH test is this primary or secondary adrenal insufficiency?
primary
If plasma ACTH is suppressed in rapid ACTH test is this primary or secondary adrenal insufficiency?
secondary
Glucocorticoid replacements for adrenal insufficiency
Hydrocortisone
prednisolone
dexamethasone
Mineralocorticoid replacement
synthetic steroid - fludrocortisone
How does fludrocortisone work?
bind to aldosterone receptors
How are mineralocorticoid doses adjusted?
according to U+E, clinical status eg bp, oedema and plasma renin level
Who needs special care in terms of stress and steroids?
hypoadrenal patients on replacement steroids
steroid doses sufficient to suppress pituitary adrenal axis
What action should be taken with steroids in
a - short lived illness
b - major illness or operation
a - double glucocorticoid dose
b - 11mh HC iv stat or 50-100mg HC iv 8 hourly and reduce HC 50% per day as symptoms resolve until previous dose is reached
3 important self care rules for people on steroids
do not miss a dose
double HC dose in intercurrent illness
severe vomit or diarrhoea = call for help for intramuscular HC
primary hyperaldosteronism causes of hypertension
unilateral adenoma
bilateral hyperplasia
Rarer endocrine causes of hypertension
phaechromocytoma cushings acromegaly hyperparathyroidism hypothyroidism congenital adrenal hyperplasia
Cortex - hypersecretion syndromes
cushings - cortisol and androgens
conn’s - aldosterone
Causes of cushings syndrome
adenoma, carcinoma or bilateral hyperplasia
Causes of conns syndrome
adenoma, bilateral hyperplasia
medulla - hypersecretion syndromes
phaechromocytoma
Symptoms of cushings syndrome
central obesity easily bruised hypertension moon face hirsutism purple striae oedema glucose intolerance amenorrhoea etc
2 causes of ACTH dependent cushings
pituitary tumour = cushings disease
ectopic ACTH secretion eg lung carcinoid
2 causes of ACTH independent cushings
adrenal tumour - adenoma, carcinoma
CCS therapy eg IBD, asthma
Screening test for cushings
overnight dex test
24 hour urine free cortisol
Confirmation test for cushings
24 hour urine free cortisol
low dose dex test
Localising tumour in cushings
MRI sella, CT adrenal, CT chest, BIPSS
What ratio is used in conns syndrome?
plasma aldosterone
plasma renin
If PA/PRA >20 is there primary or secondary hyperaldosteronism?
primary
If PA/PRA <20 is there primary or secondary hyperaldosteronism?
secondary
essential hypertension
Causes of secondary hyperaldosteronism with increased PRA, PCA
diuretic, renin secreting tumour, coarctation aorta
Causes of PRA and PCA reduction
congenital adrenal hyperplasia
exogenous mineralocorticoid
Screening test for hyperaldosteronism
PRA/PCA ratio
24 hour test for hyperaldosteronism
24 hour urine aldosterone and sodium during 4 days of salt loading
Scans for hyperaldosteronism
CT scan adrenals
upright postue test
plasma 18-hydroxycorticosterone
Phaechromocytoma symptoms/signs
hypertension
paroxysmal attacks - sweating, tremor, pallor, anxiety, headache
Aetiology of phaechromocytoma
10% tumour - extra adrenal, malignant, multiple, hyperglycaemia
30% inherited - GENETIC TESTING
Phaechromocytoma investigations
24 hour urine catecholamines
localise adrenal on MRI/CT
PET
remove tumour
General investigation of adrenal mass
free metanephrine in plasma/urine
dex test, ALD/PRA ratio, potassium
CT, MRI, surgery
What is the main cause of congenital adrenal hyperplasia?
21-hydroxylase deficiency
What occurs in severe cases of CAH?
neonatal salt losing crisis
ambiguous genitalia in girls
Incomplete defects in CAH
pseudoprecocious puberty in boys
hirsutism
