Steroids around surgery Flashcards
1
Q
Why do exogenous steroids cause HPA supression?
A
- Negative feedback
- Inhibit release of CRH and ACTH
- Prolonged exposure also causes atrophy of adrenal cortex and downregulation of glucocorticoid receptors
2
Q
What is ACTH response to surgery?
A
- Increase ACTH
- = increased cortisol
- Sometimes if severe/prolonged stress, ACTH response can be delayed/blunted so there is inadequate stress response
3
Q
How does raised ACTH and cortisol during surgery help the patient?
A
- Increased blood sugar = increased energy for higher activity of body during stress response
- Anti-inflammatory - reduces swelling and tissue damage
- Supresses immune system - prevents excessive inflammation and tissue damage, promotes healing
- Maintains BP via potentiating catecholamines vasoconstriction
4
Q
Cushingoid features
A
- Facial roundness
- Central obesity
- Purple striae
- Buffalo hump - fat at base of neck
- Thin/fragile skin - easily brusing etc
5
Q
Features of addisonian crisis
A
- Hypotensive
- Dehydrated
- Hyponatraemia
- Hypoglycaemia
- Hyperkalaemia
4 lows, one high
6
Q
What is given to patients prior to surgery who take exogenous steroids?
A
- IV hydrocortisone 25mg 4 times daily
- To cover intra and post op phase as hypoadrenalism is difficult to detect in these scenarios
7
Q
Why is intra-op phase hard to identify Addisonian crisis?
A
- Anaesthesia agents often have side effects that are similar to symptoms of Addisonian crisis
- eg hypotension, reduced concious level
- IV fluids running so these can mask initial hypovolaemia and electrolyte disturbances
8
Q
Half life of IV hydrocortisone if given every 6 hrs
A
- 24hrs in a day
- 24/4 = given every 6 hrs
- 4-5 half lives for drug to be cleared
- 6hrs / 4 half lives = 1.5hrs per half life
9
Q
Prophylactic antibiotics example for elective knee replacement
A
- Teicoplanin + gentamicin
- Given at induction, single dose
- Teicoplanin covers gram +ve, Gentamicin covers gram -ve
10
Q
Screening prior to operation?
A
MRSA skin swabs
11
Q
A
