DR Medhat MRCP

Diagnosis pre-renal Vs intrinsic renal AKI
Prerenal uraemia - kidneys hold on to sodium to preserve volume
Pre-renal AKI
Intrinsic renal AKI
Urine Na (mmol/L) < 20 > 30
Fe Na% < 1% > 1%
Fractional urea excretion < 35 % > 35 %
Urine : plasma osmolarity >1.5 < 1.1
Urine : plasma urea >10 :1 < 8: 1
Specific gravity >1020 < 1010
Urine Bland sediment Brown granular cast
Response to fluid challange yes No
Fractional excretion of Na (FeNa%) = X 100
Fractional urea excretion = X 100
Chronic kidney disease (CKD)
Persistent irreversible impairment of renal functions for longer than 3 months.
Classification (stages according to GFR) :
Stage
GFR (ml/min)
1 >90 ml/min but with evidence of renal impairment (proteinuria/U&Es)
[ if no proteinuria , normal U& Es No CKD)
2 60-90 ml/min + evidence of renal impairment [ if normal U&Es,no
proteinuria No CKD)
3a 45-59 ml/min , moderate reduction of kidney function
3b 30-44 ml/min , moderate reduction in kidney function
4 15-29 ml/min , severe reduction in kidney function
5 < 15 ml/min , ESRD requiring RRT (dialysis or transplantation)
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