Nephrology & Urology

Question 1

What are the two most common causes of AKI?

Answer 1

Prerenal

Acute tubular necrosis

Question 2

What change does alkalaemia have on calcium levels?

Answer 2

Produces HYPOcalcaemia

Alkalaemia produces an increase in the fraction of bound calcium -> decrease in ionised calcium produces symptoms of hypocalcaemia (diffuse paresthesia/numbness and muscle spasm)

**Note: total serum calcium level is unchanges (= ionised + bound)

Question 3

What is difference between ACEI vs NSAIDs in terms of their mechanistic effects on renal perfusion?

Answer 3

ACEI
= inhibit EFFerent renal arteriolar vasconstriction -> lowers GFR

NSAIDs
= inhibition of prostaglandin and bradykinin -> vasoconstriction of AFFerent renal arteriole -> reduces ability of kidney to increase glomerular blood flow

Question 4

What electrolyte abnormality does cisplastin cause?

Answer 4

Hypomagnesaemia

Aminoglycosides also cause hypomagnesaemia - both drugs cause drug-induced ATN

Question 5

What is the role of bradykinin in BP?

Answer 5

Bradykinin LOWERS blood pressure
= potent endothelium-dependent vasodilator
Also causes natriuresis ->
drop BP

ACEI increase levels of bradykinin (by inhibiting its degradation)

Question 6

What is the role of prostaglandins in BP?

Answer 6

Cause vasodilation

NSAIDs block prostaglandins -> decrease in vasodilation -> decrease GFR

Question 7

What is the most common cause of AKI in children?

Answer 7

Acute tubular necrosis (an intrinsic AKI)

Question 8

How can you classify intrinsic AKI causes?

Answer 8

Can think of them as disorders that affect the renal:

1. Vasculature
2. Glomeruli
3. Tubule
4. Interstitium

Question 9

What are drugs that cause ATN?

Answer 9

Amphotericin B
Aminoglycosides
Cisplastin
Cyclosporine