adrenal gland disorders Flashcards
where are the adrenal glands located?
above the kidneys
where are the hormones that regulate cortisol and androgen production produced?
hypothalamus and anterior pituitary
what regulates aldosterone?
renin-angiotensin system and plasma potassium
when is the Renin angiotensin system activated?
in response to low BP
what does renin-angiotensin system lead to?
production of angiotensin II
what is the action of cortisol upon the CNS?
Mood lability
Euphoria/psychosis
reduced libido
what is the affect of cortisol on the immune system
decreased capillary dilatation/permeability
decreased leucocyte migration
decreased macrophage activity
decreased inflammatory cytokine production
what is the action of cortisol on bone/connective tissue?
Accelerates osteoporosis
reduced Serum calcium
reduced collagen formation
reduced wound healing
what is the affect of cortisol on the metabolic system?
increase blood sugar
increase lipolysis
increase proteolysis
what is the affect of cortisol on the circulatory/renal system?
increased Cardiac output
increased BP
increased renal blood flow and GFR
what is the main principles of use of corticosteroids?
suppress inflammation
suppress immune system
replacement treatment
when are corticosteroids used?
allergic disease
inflammatory disease
malignant disease
what does addisons disease indicate?
cortisol/adrenal insufficiency
what conditions are caused by primary adrenal insufficiency?
addisons disease
congenital adrenal hyperplasia
adrenal TB/malignancy
what are the classical features of addisons disease?
Anorexia, weight loss
fatigue/lethargy
Dizziness and low BP
Abdominal pain, vomiting,
diarrhoea
Skin pigmentation
in what % of cases of addisons are autoantibodies involved?
70%
is addisons associated with other autoimmune diseases?
yes
how is addisons diagnosed?
low sodium
high postassium
short synthetic ACTH test
increased renin and low aldosterone
adrenal antibodies
how is adrenal insufficiency managed?
hydrocortisone as cortisol replacement (if unwell give via IV first)
fludrocortisone as aldosterone replacement
education
what is the treatment in adrenal crisis?
fluids (saline)
steroids IV/IM hydrocortisone
(50mg/6hrs)
IF IN DOUBT TREAT
what causes secondary adrenal insufficiency?
pituitary/hypothalamic disease tumours
exogenous steroid use (most common cause)
what are the clinical features of secondary adrenal insufficiency?
similar to addisons EXCEPT
-pale skin (no raised ACTH)
-aldosterone production intact
how is secondary adrenal insufficiency treated?
hydrocortisone
No fludrocortisone necessary
what is caused by excess cortisol secretion?
cushings disease
what are the clinical features of cushings?
easy bruising
thin skin
striae
proximal myopathy
how do we screen for cortisol excess?
Overnight dexamethasone suppression test
24 hour urinary free cortisol
Late night salivary cortisol
Repeat to confirm
what is the diagnostic test for cushings syndrome?
low dose dexomethasone suppression test
what are the implications of atrophy of the adrenal cortex?
Unable to respond to stress (illness/surgery)
Need extra doses of steroid when ill/surgical procedure
Cannot stop suddenly
Gradual withdrawal of steroid therapy if >4-6 week
what can indicate primary aldosterone?
hypertension and hypokalaemia (hypokalaemia is only in around 30% of cases though)
what is the definition of primary aldosterone?
autonomous over production of aldosterone independent of its regulators
does aldosterone increase BP?
yes
what is the most common type of primary aldosterone?
bilateral adrenal hyperplasia (60% of cases)
how is aldosterone excess confirmed?
Measure plasma aldosterone and renin and express as ratio (ARR-aldosterone to renin ratio)
→ If ratio raised (assay dependent) then investigate further with saline suppression test
→ Failure of plasma aldosterone to suppress by > 50% with 2 litres of normal saline confirms PA
how do we confirm which subtype of primary aldosterone a patient has?
Adrenal CT to demonstrate adenoma
→ Sometimes adrenal vein sampling to confirm adenoma is true source of aldosterone excess
how is primary aldosterone managed surgically?
Unilateral laparoscopic adrenalectomy
→ Only if adrenal adenoma (and excess confirmed in adrenal vein
sampling)
→ Cure of hypokalaemia
→ Cures hypertension in 30-70% cases
generally only used in those with a clear adenoma
how is primary aldosterone managed medically?
generally only used in bilateral adrenal hyperplasia
Use MR antagonists (spironolactone or eplerenone)
what is congenital adrenal hyperplasia?
an inherited group of disorders characterised by a deficiency in one of the enzymes necessary for cortisol synthesis
when is classical CAH diagnosed?
in infancy
when is non classical CAH usually diagnosed?
in adolescence/adulthood
what are the symptoms of non classical CAH?
hirsutism, menstrual disturbance and infertility due to anovulation
what are the symptoms of classical CAH?
virilisation/salt wasting
how is CAH diagnosed?
Basal [or stimulated] 17-OH Progesterone
increasingly supported by genetic mutation analysis
what is the presentation of classical CAH?
Adrenal insufficiency
→ Often around two to three weeks
→ Poor weight gain
→ Biochemical pattern of Addison’s disease
Females
→ Genital ambiguity (virilisation)
what is the presentation of non classical CAH (typically in females)
Hirsute
Acne
Oligomenorrhoea
Precocious puberty
Infertility or sub-fertility
what is the main treatments of CAH in childhoof?
Timely recognition
Glucorticoid replacement
Mineralocorticoid replacement in some
Surgical correction
Achieve maximal growth potential
what is the main treatments of CAH in adults?
Control androgen excess
Restore fertility
Avoid steroid over-replacement
what are things that indicate phaeochromocytoma?
Labile hypertension
* Postural hypotension
* Paroxysmal sweating, headache, pallor,
tachycardia
Also none of the above!
why is phaeochromocytoma known as the 10% tumour?
10% malignant
10% bilateral
10% extra adrenal
10% not associated with hypertension
when are 50% of phaeochromocytomas diagnosed?
during post mortem
what is the classic triad of symptoms in phaeochromocytoma?
hypertension
headache
sweating
up to 90% of cases
what are the signs of phaeochromocytoma?
hypertension
pallor
brady/tachycardia
pyrexia
how is phaeochromocytoma diagnosed?
through identifying the source of catecholamines
MRI scan
MIBG- meta iodobenzylguanidine
how would a phaeochromocytoma be treated?
SURGICAL MANAGEMENT
preparation for surgery- Full α and β- blockade
(A before B)
Phenoxybenzamine (α-blocker)
Propranolol, atenolol or metoprolol (β-
blocker)
