adrenal Flashcards
adrenal medullary tumours
phaeochromocytoma
neuroblastoma - kids
phaeochromocytoma
a tumour of the chromaffin cells that secretes unregulated + excessive amounts of catecholaine (adrenaline)
rare asf
incidence of phaeochromocytoma
10% rule
- bilateral
- cancerous
- outside adrenal gland = paragangliomas
- assoc. with hyperglycaemia
- kids
25% are familial + assoc. with MEN2
phaeochromocytoma pathophysio
adrenaline is secreted by chromaffin cells in the adrenal medulla
in phaeochromocytoma, adrenaline is secreted in burts giving periods of worse symptoms folled by more settled periods
phaeochromocytoma classic triad
hypertension
headache
sweating
phaeochromocytoma presentation
paroxysmal signs + symptoms - fight or flight anxiety, sweating headache hypertension postural hypotension palpitations, tachycardia
paroxysmal atrial fibrillation
adipose tissue turns brown
diagnosis of phaeochromocytoma
24hr catecholimes
plasma free metaphrines
MRI, PET
patients with a high clinical suspicion of phaeochromocytoma
young with resistant hypertension + hyperglycaemia
also fam members with it
why can 24hr catecholamines be an unreliable test?
catecholamines rise in heart failure
secretion of catecholamines in phaeochromocytoma is episodic so results may be normal
malignant + extra-adrenal tumours less efficient at catecholamine synthesis
management of phaeochromocytoma
alpha blockers - phenoxybenzamine
beta blocker once established on alpha blockers (propranolo, atenolol)
adrenalectomy = definitive, symptoms must be medically controlled prior to surgery
fam tracing
signs of complication in phaeochromocytoma
left ventricular failure myocardial necrosis stroke shock paralytic ileus of bowel
syndromes associated with phaeochromocytoma
MEN2 Von-Hippel-Lindau syndrome succinate dehyrogenase mutations neurofibromatosis tuberose sclerosis
effects of cortocosteroids on bone
direct
- reduction of osteoblast activity + lifespan
- suppression of replication of osteoblast precursors
- reduction in calcium absorption
indirect
- inhibition of gonadal + adrenal steroid production
what is addisons?
primary adrenal insufficiency
where adrenal glands do not produce enough steroid hormones esp cortisol + aldosterone
causes of addisons
(primary adrenal insufficiency)
autoimmune = commenest
infections - TB, fungal, HIV
metastatic malignancy
adrenal insufficiency presentation
fatigue, nausea
cramps, abdo pain
reduced libido
postural hypotension
bronze hyperpigmentation with increased ACTH
pigmentation of skin in primary vs secondary adrenal insufficiency
(ACTH is secreted with MSH which stimulates maleanocytes to produce melanin)
primary (addisons) - bronze hyperpigmentation
secondary - pale skin (no increase in ACTH)
secondary adrenal insufficiency
inadequate ACTH stimulating the adrenal glands = low cortisol released
caused by damage to pituitary
causes of secondary adrenal insufficiency
caused by loss or damage to pituitary via - congenital underdevelopment (hypoplasia) surgery exogenous steroids infection loss of blood flow radiotherapy
cause of tertiary adrenal insufficiency
inadequate CRH released by hypothalamus
caused by patients on long term steroids (>3weeks) - supresses hypothalamus
adrenal autoantibodies
adrenal cortex antibodies
21-hydroxylase autoantibodies
sodium and potassium levels in adrenal insufficiency
hyponatraemia
hyperkalaemia
adrenal insufficiency diagnosis
short synacthen test (ACTH)
cortisol level should double in response to aynacthen, if less = positive
–> do serial levels, 0, 30 and 60mins
hormone levels in addisons
cortisol = low aldosterone = low
ACTH = high renin = high
management of adrenal insufficiency
replacement steroids
- hydrocortisone = glucocorticoid (replaces cortisol)
- fludrocortisone = mineralocorticoid (replaces aldosterone)
(fludro in primary only)
management of adrenal crisis
IV hydrocortisone
IV fluid resus
correct hypoglycaemia
intensive monitoring
steriods management
steroid ID
educate - dont stop suddenly
sick day rules-
- increase dose when acute ill
- blood sugar monitored - eat regular carbs
- D+V - IM or admission for IV
adrenal crisis (addisonian crisis)
medical emergency, immediate treatment, no time for investigations
triggered by -
- infection
- trauma
- rapid withdrawal of steroids from long term users
what presentation gives a high clinical suspicion of hyperaldosteronism?
most common cause of secondary hypertension
high clinical suspicion = young, resistant hypertension, hypokalaemia
–> also alkalosis
aldosterones effects on the kidneys
increase sodium reabsorption from distal tubule
increase potassium secretion from distal tubule
increase hydrogen secretion from collecting ducts
causes of primary hyperaldosteronism (Conn’s)
primay = adrenal glands directly responsible for too much aldosterone
adrenal adenoma secreting alsosterone = commonest
bilateral adrenal hyperplasia
familial hyperaldosteronism
adrenal carcinoma
renin levels in primary vs secondary hyperaldosteronism
primary (Conns) = low - supressed bt high bp
secondary = high
cause of secondary hyperaldosteronism
excessive renin stimulationg adrenal to produce more aldosterone
cause = bp in kidney disproportionately lower than bp in rest of body, due to -
- renal artery stenosis - atherosclerosis
- renal artery obstruction
- heartfailure
hyperaldosteronism investigation
renin: aldosterone ratio
- high aldo + low renin = primary (Conns)
- high aldo + high renin = secondary
saline supression test
look for cause
hyperaldosteronism / Conns management
aldosterone antagonists -
- eplerenone
- spironolactone
treat underlying cause -
- remove adenoma
- percutaneous renal artery angioplasty
congenital adrenal hyperplasia
rare conditions associated with enzyme defects in steroid pathway
21alpha hydroxylase deficiency = commonest
autosomal recessive
pathophysio of congenital adrenal hyperplasia
21-hydroxylase is responsible for converting progesterone into aldosterone + cortisol, it is also used to create testosterone (this conversion does NOT rely on 21-hydroxylase enzyme)
deficiency of 21-hydroxylase means that there is extra progesterone that cannot be converted to aldo or cortisol so is vonverted to testoterone
congenital adrenal hyperplasia mild presentation during childhood/post-puberty
tall for their age
deep voice
early puberty
skin hyperpigmentation - low cortisol causes increased ACTH
girls - absent periods, facial hair, genital ambiguity, big clit
boys - large penis, small testes
congenital adrenal hyperplasia investigation
basal or stimulated 17-OH progesterone
gene analysis
congenital adrenal hyperplasia management
hydrocortisone - to replace glucocorticoid (cortisol)
fludrocortisone - to replace mineralcorticoid (aldosterone)
surgical correction of genital ambiguity
biochemistry results in congenital adrenal hyperplasia
hyponatraemia
hyperkalaemia
hypoglycaemia
leads to poor feeding, V+D, arrhythmias shortly after birth if severe
Multiple Endocrine Neoplasia (MEN) type I
3 P’s
parathyroid
pituitary (eg prolactinoma)
pancreas (eg insulinoma, gastrinoma)
(also adrenal + thyroid)
MEN1 gene
most common presentation of MEN I
hypercalcaemia
(hyperparathyroidism due to parathyroid hyperplasia)
recurrent peptic ulceration - due to gastrinoma
MEN type IIa
2 P’s
parathyroid
phaeochromocytoma
RET oncogene
medullary thyroid cancer (70%)
MEN type IIb
1P = phaeochromocytoma
RET oncogene
medullary thyroid cancer
neuromas (usually between toes)
Marfans body
inheritance of MEN
autosomal dominant
