Renal

Question 1

How does the KDIGO criteria define AKI?

Answer 1

An increase in serum creatinine by ≥ 26.5 micromol/L within 48 hours

An increase in serum creatinine to ≥ 1.5 times baseline within 7 days

Urine output < 0.5 mL/kg/hr for six hours

Question 2

How can KDIGO stage AKI?

Answer 2

Question 3

What are the pre-renal causes of AKI? Consequence if untreated?

Answer 3

Generally due to renal hypoperfusion:
- Can due to hypovolemia
- Reduced cardiac output
- Systemic vasodilation eg Sepsis
- Arteriolar changes eg secondary to ACEi or NSAID use

Renal hypoperfusion causes ischaemia of the renal parenchyma -> prolonged ischaemia can lead to ATN (most common cause of intrinsic AKIs)

Question 4

What are the intrinsic causes of AKI?

Answer 4

Vascular:
- Large vessel = atherosclerotic disease, thromboembolic disease and dissections (eg aortic) + renal artery stenosis / thrombosis
- Small vessel = secondary to vasculitidies, MAHA and malignant HTN

Golmerular:
- Primary
- Secondary

Tubulointerstitial:
- Damage to renal parenchyma that can lead to scarring and fibrosis in long-term
- Most common cause = ATN
- Can also get acute interstitial nephritis due to meds eg NSAIDs, PPIs + penicillins