Addisons + secondary adrenal Insufficiency Flashcards
(70 cards)
Most common cause of primary adrenal insufficiency?
Autoimmune adrenalitis
What are the Infectious causes of adrenal insufficiency?
TB, CMV, HIV
What are the cancer types that metastasise to the adrenal glands?
Lung, breast carcinoma
Name the condition with adrenal haemorrhage in sepsis?
Waterhouse-Friderichsen syndrome
Why does Addison’s cause hyperpigmentation?
Excess ACTH → excess MSH
Electrolyte imbalances in Addison’s?
↓ Na+
↑ K+
acidosis, hypoglycemia
Why does Addison’s cause salt craving?
Low aldosterone → Na+ loss
Key symptoms of Addison’s?
(1) Weakness
(2) Fatigue
(4) Weight loss
(5) N+V
(6) Low BP
(7) Abdominal pain
What are the signs of hyperpigmentation?
Tanned skin, dark buccal mucosa, palmar creases
1st-line test for Addison’s?
Short Synacthen test
ACTH & aldosterone levels in Addison’s?
↑↑ ACTH
↓ aldosterone
↑↑ renin
When should Addison’s be suspected in blood tests?
Hyponatremia + hyperkalemia
What is used for cortisol replacement?
Hydrocortisone
What is used for aldosterone replacement?
Fludrocortisone
Why must steroids not be stopped suddenly?
Risk of adrenal crisis
What are the “sick day rules”?
increase steroid replacement when unwell or undergoing other stress
What is the 1st-line test for Addison’s disease?
Short Synacthen Test
= checks ACTH response
How is the Short Synacthen Test performed?
Measure plasma cortisol before and 30 mins after IV/IM ACTH injection
What is a normal cortisol response in the Short Synacthen Test?
(1) Baseline >250 nmol/L
(2) Post-ACTH >550 nmol/L
What is secondary adrenal insufficiency?
Lack of ACTH production by the pituitary gland
= ↓ cortisol
What is tertiary adrenal insufficiency?
Lack of CRH secretion by the hypothalamus
= ↓ ACTH → ↓ cortisol
What is the most common cause of secondary/tertiary adrenal insufficiency?
Iatrogenic
(long-term exogenous steroid use)
(1) → suppresses CRH & ACTH
(2) → adrenal atrophy
What are the other causes of secondary adrenal insufficiency?
(1) Pituitary/hypothalamic tumors
(2) Surgery
(3) Radiotherapy
How does iatrogenic steroid use cause adrenal insufficiency?
Chronic steroids inhibit CRH & ACTH
= Leading to adrenal atrophy
The adrenal glands fail to produce cortisol even if ACTH is given