17. Adrenal Flashcards
What do each of the sections of the adrenals produce?
Glomerulosa - aldosterone
Fasciculata - cortisol
Reticularis - androgen precursors
Medulla - adrenaline/noradranaline
From outside to in
What is cushing’s syndrome?
High ACTH by multiple causes
Signs and symptoms incl. red cheeks, thin skin, purple striae etc.
Causes of cushing’s syndrome?
ACTH dependent - pituitary adenoma (disease), ectopic ACTH
ACTH independent - iatrogenic (MOST COMMON), adrenal tumours
Pseudo - alcohol excess, severe depression, obesity (these present the same with same hormone levels, need insulin stress test to differentiate)
How is ACTH assessed?
Administer insulin stress test
Stimulates a hypoglycaemia
Rise in cortisol for both
If <170nmol/L from basal = cushing’s because a tumour would not be responsive to physiology
If it response to insulin, then this is pseudo
Investigations for cushing’s syndrome?
- 24hr urinary free cortisol >50-100mcg a day
- Low dose dexamethasone suppression test, failure to suppress
- Inferior petrosal sampling/MRI pituitary to measure ACTH level in pituitary
How do we manage cushing’s syndrome?
Underlying cause - if steroid cause etc.
Radiotherapy, surgery etc.
What is adrenal insufficiency?
Hypocortisolism and hypoaldosteronism.
Primary - adrenal pathology
Secondary - pituitary/hypothalamic.
Caused by TB worldwide and AI destruction in UK. Associated with meningococcal septicaemia. Tumours.
Signs and symptoms of adrenal insufficiency?
Lethargy Anorexia N+V Weight loss Salt craving
Specific to primary due to POMC - pigmented skin, hyponatraemia and hyperkalaemia.
Signs and symptoms of an adrenal crisis? (one step past insufficiency)
Collapse
Shock
Hypotension
Pyrexia
How do we investigate adrenal insufficiency?
FBCs and U&Es (sodium and K)
Glucose
9am serum cortisol <500nmol/L
Short synACTHen test - diagnostic
Investigation for cause e.g. TB, adrenal and pituitary imaging
What is the short synACTHen test?
250 ug IM synthetic ACTH
Check cortisol at 30 and 60mins
Cortisol <550nM = diagnostic
How do we manage adrenal insufficiency?
Hormone replacement - hydrocortisone with/out fludrocortisone. Consider DHEA/androgen replacement
Sick day rules
Managing underlying cause if appropriate
How to manage an acute adrenal crisis?
- Hormone replacement - hydrocortisone IV/IM, continue this on infusion
- 500ml fluid bolus of NaCl, replace any deficits.
- Rehydration (3-4L of NaCl in 24 hrs)
- Continued management, refer to endo and sick day rules
What is hyperaldosteronism and what are the two types?
Excessive aldosterone production
Primary - adrenal adenoma (conn’s), bilateral adrenal hyperplasia, adrenal carcinoma
Secondary - anything driving excess activation of the RAAS e.g. renin secreting tumours, renal artery stenosis, genetic syndromes or hypovolemia
What are the signs and symptoms of hyperaldosteronism?
Hypertension in a young person - causes headaches, visual changes, SOB, CP
Hypokalaemia - causes cardiac arrhythimias, polyurias, polydipsia, muscle weakness
