Adrenal disorders - Cushing's Flashcards
What are 9 signs of Cushing’s syndrome?
MR CUSHING
(moon face,
red striae,
centripetal obesity,
urine cortisol,
skin thinning,
hypertension,
impaired wound healing,
greater bruising) + Proximal myopathy
Causes of Cushing’s
- Taking too much steroid (usually prednisolone)
- pituitary dependent cushing’s disease
- Ectopic ACTH from lung cancer
- Adrenal adenoma secreting cortisol
What are the three investigations to diagnose Cushing’s syndrome?
24h urine collection for free urine cortisol,
Late night cortisol levels, (should be low)
low dose dexamethasone suppression test
Dexamethasone suppression test
Potent version of cortisol, in normal people this would switch off cortisol production due to negative feedback
Cushing’s will fail to suppress cortisol to 0
What would you ask a patient you suspect has Cushing’s to perform to suggest a diagnosis?
Squat - will be difficult to perform due to proximal myopathy and peripheral oedema
11BHSD action on aldosterone receptors (MR)
11 beta hydroxysteroid dehydrogenase
Prevents action of cortisol on MR, making inactive cortisone
What are the three drugs given for Cushing’s syndrome and what do they target?
Metyrapone (11-hydroxylase inhibitor and 11BHSD),
Ketoconazole (17-hydroxylase inhibitor)
Osilidrostat (new drug)
What are the two adverse effects of metyrapone?
Short term solution
Hypertension (11-deoxycorticosterone),
Hirsutism (increased tesosterone) - meTYrapone (testosterone, ypertension)
What are the two uses for metyrapone?
Prior to surgery, control of radiotherapy
What is the adverse effect of ketoconazole?
Liver damage from hepatotoxicity
What are the three surgical treatments for Cushing’s?
Pituitary surgery (trans-sphenoidal hypophysectomy), Bilateral adrenalectomy, (in rare cases)
Unilateral adrenalectomy for an adrenal tumour
What is Conn’s syndrome?
Benign adrenal cortical tumour in zona glomerulosa - aldosterone excess produced (primary hyperaldosteronism)
What are the two effects of Conn’s syndrome?
Hypertension, Hypokalaemia
Conn’s diagnosis
Renin-angiotensin system should be suppressed due to hypertension
What two drugs are used to treat Conn’s syndrome?
Spironolactone and Epleronone
Spironolactone action
Competitive antagonist of mineralocorticoid receptor
Blocks Na+ resorption and K+ excretion in the kidney tubules (potassium sparing diuretic).
Adverse effects of Spironolactone
Menstrual irregularities, gynaecomastia
What is the difference in epleronone’s action to spironolactone?
Less binding to androgen and progesterone receptors, better tolerated in the body
What are phaeochromocytomas?
Tumours of adrenal medulla which secrete catecholamines (adrenaline and noradrenaline)
What are some body signs of the effects of phaeochromocytomas?
High blood pressure,
high basal metabolic rate,
high heart rate,
high blood glucose
Pale due to vasoconstriction
What are the clinical features of phaeochromocytomas?
Hypertension in young people,
with severe episodic hypertension following abdominal palpitation
can be genetic
What are two medical emergencies that can arise from phaeochromocytomas?
Severe hypertension - myocardial infarction and stroke // High adrenaline - ventricular fibrillation
What do anaesthetists need to be aware of when operating on phaeochromocytomas?
Anaesthesia can invoke panic - leading to temporary hypertension, which should be avoided in this case
What are the three solutions to the htn caused by anasthesia in phaechromacytoma?
Alpha-blockers, followed by intravenous fluid. Beta-blockers for tachycardia
Why do we prescribe alpha blockers
Alpha receptors on arteries cause vasoconstriction. Blockers prevent hypertension during surgery
