Adrenal Flashcards
Functions of adrenal cortex
Glucocorticoids
Mineralocorticoids
Androgens
Functions of glucocorticoids
Affects carbohydrate, lipid and protein metabolism
Functions of mineralocorticoids (aldosterone)
Renin angiotensin aldosterone system
Activates Na/K pump in distal tubule
Reabsorption of Na and water
Stimualtion of glucocorticoid and androgen release
CRF from hypothalamus
ACTH from pituitary
Cortisol and androgen from adrenal glands
CRF
Corticotrophin releasing factor
Released from hypothalamus
Cushing’s syndrome
Clinical state
Excess glucocorticoid
Loss of normal feedback mechanisms
When is cortisol secretion usually highest
On waking up
Causes of Cushing’s syndrome
Oral steroids
Cushing’s disease
Ectopic ACTH production
Adrenal adenoma
Cushing’s disease definition
ACTH secreting pituitary adenoma
Leads to bilateral adrenal hyperplasia
Causes of ectopic ACTH production
Small cell lung cancer
Carcinoid tumours
Sx of Cushing’s syndrome
Weight gain
Depression
Lethargy
Hirsutism
Proximal muscle weakness
Signs of Cushing’s syndrome
Moon face
Buffalo hump
Striae / bruises
HTN
Impaired glucose tolerance
Specific sign of ectopic ACTH production causing Cushing’s syndrome
Skin pigmentation
Ix for Cushing’s syndrome
Raised plasma cortisol
Overnight dexamethasome suppression test
24 hr urinary free cortisol
48 hr dexamethasone suppression test
48 hr high dose dexamethasone suppression test
Overnight dexamethasome suppression test
Dexamethasone 1 mg at midnight
Serum cortisol at 8 am
Normal: cortisol < 50 mmol/L
Cushing’s: failure to suppress cortisol
48 hr dexamethasone suppression test
Dexamethasone 0.5mg/6hrs for 2 days
Serum cortisol at 0 and 48 hrs
Cushing’s: failure to suppress cortisol
48 hr high dose dexamethasone suppression test
Dexamthasone 2mg/6hrs
Pituitary cause: cortisol suppression
Other cause: little suppression
Mx of Cushing’s disease
Remove pituitary adenome
Mx of iatrogenic Cushing’s syndrome
Stop steroids
Mx of ectopic ACTH producing Cushing’s syndrome
Remove causative tumour
Mx of adrenal adenoma causing Cushing’s syndrome
Adrenalectomy
Nelson’s syndrome
Skin hyperpigmentation
Post adrenalectomy
Loss of negative feedback
Raised ACTH
Addison’s disease definition
Primary adrenocortical insufficiency
Cortisol and Aldosterone deficiency
Causes of Addison’s disease
Autoimmune
TB
Adrenal metastases
Opportunistic infections in HIV
Adrenal haemorrhage
Causes of adrenal haemorrhage
Waterhouse-Friderichsen syndrome
Antiphospholipid syndrome
SLE
Waterhouse-Friderichsen syndrome definition
Bilateral adrenal cortex haemorrhage
Most common cause of Waterhouse-Friderichsen syndrome
Rapidly deteriorating sepsis
Mx of Waterhouse-Friderichsen syndrome
Abx (ceftriaxone)
Hydrocortisone
Sx of Addison’s disease
Weight loss
Fatigue
Depression
N/V
Abdo pain
Diarrhoea/Constipation
Signs of Addison’s disease
Hyperpigmentation
Postural hypotension
Hyperkalaemia
Hypoglycaemia
Diagnosis of Addison’s disease
Short synacthen test
(synthetic ACTH)
Short synacthen test
Plasma cortisol before and 30 mins after synthetic ACTH (250 microg)
Addison’s excluded if 30 min cortisol > 550 nmol/L
Causes of false negative in short synacthen test
Pregnancy or COCP
Due to raised cortisol-binding globulin
Mx of Addison’s disease
Hydrocortisone
Fludrocortisone
Sick day rules for steroid use
Double steroid dose in febrile illness, injury or stress
Causes of secondary adrenal insufficiency
Iatrogenic
Hypothalamic-pituitary disease (rare)
Iatrogenic cause of secondary adrenal insufficiency
Long term steroid use
Inhibits pituitary adrenal axis
Sudden withdrawal of steroids
Primary hyperaldosteronism definition
Excess production of aldosterone
Independent of RAAS
Na and water retention
Sx of primary hyperaldosteronism
Hypokalaemia
HTN
Weakness
Cramps
Paraesthesia
Causes of primary hyperaldosteronism
Conn’s syndrome
Bilateral adrenocortical hyperplasia
Conn’s syndrome definition
Solitary aldosterone producing adenoma
Mx of Conn’s syndrome
Spironolactone
Adrenalectomy
Mx of bilateral adrenocortical hyperplasia
Spironolactone
Aldosterone receptor antagonist
Aldosterone receptor antagonist examples
Amiloride
Eplerenone
Secondary hyperaldosteronism definition
High aldosterone due to high renin
Causes of secondary hyperaldosteronism
Reduced renal perfusion
Renal artery stenosis
CCF
Diuretics
Bartter’s syndrome definition
Autosomal recessive
Congenital salt wasting
Bartter’s syndrome pathology
Defective channel in loop of Henle
Na and Cl leak
Bartter’s syndrome presentation
Presents in childhood
Failure to thrive
Hypokalaemia / Alkalosis
Polyuria / Polydipsia
Normal BP
Mx of Bartter’s syndrome
K replacement
NSAIDs (inhibits prostaglandins)
ACEi
Phaeochromocytoma definition
Rare chatecholamine producing tumour
Phaeochromocytoma cell origins
From sympathetic paraganglia cells
(Collections of chromaffin cells)
Usually in adrenal medulla
Function of adrenal medulla
Catecholamines:
Adrenaline
Noradrenaline
Classic triad of phaeochromocytoma
Episodic headache
Sweating
Tachycardia
+/- HTN
Ix for phaeochromocytoma
3 x 24 hr urine for free metadrenaline
CT/MRI
Metadrenaline
Metabolite of adrenaline
Mx of phaeochromocytoma
Surgery
Precipitating factors to Addisonian crisis
(Acute Adrenal Crisis)
Sepsis / Infection
Trauma
Surgery
Missed medication
Sx of Addisonian crisis
Shock:
Tachycardia
Postural hypotension
Oligouria
Confusion
Weak
Ix for Addisonian crisis
If suspected, treat before biochemical results
Serum cortisol and ACTH
U+Es for Na and K
Mx of Addisonian crisis
Hydrocortisone 100mg
IV fluid
Monitor blood glucose
Sepsis screen and Rx
