12.12.04 AKI

Prevalence

    • 5% on ward

    • 15% critically ill

    • 40% mortality if on RRT

Aetiology

    • 80% pre-renal

      • Clinical assessment

    • 10-20% renal

      • Urine dip

    • 10% post-renal

      • Ultrasound

Definitions

    • RIFLE

      • Risk

      • Injury

      • Failure

    • Working

      • Acute onset

      • Deterioration in function

      • Retention of nitrogenous and non-nitrogenous substances:

        • Urea, cretinine

        • Potassium, water, protons

      • May be associated with a urine production problem

        • Anuria (< 50 ml/day)

        • Oliguria (< 300 ml/day)

Killers - Fix urgently, before taking history

    • Potassium

      • Check ABG

      • Wide QRS and flat P is a peri-arrest situation => Crash call

      • Calcium gluconate

        • Skin necrosis => Check the cannula

        • Acts fast (seconds) but only lasts 10 mins

      • Insulin-dextrose

        • Lasts 4-6 hours => Don't forget to hand over and recheck

    • Acidosis

      • Check ABG

      • 100 ml of 8.4% NaHCO3

    • Fluid

      • ABG, CXR, SpO2

      • Diuretics

        • Furusemide 40 mg or 80 mg if acute-on-chronic

        • Try max. 2 boluses

        • Monitor urine o/p

      • GTN

      • CPAP

        • Keeps alveloi open and pushes fluid out

      • Dialysis

Aetiologies

    • Pre-renal

      • Hypovolaemia

      • Sepsis

      • Renal artery stenosis or thrombosis

    • Renal

      • HTN

      • Diabetes

      • Drugs (big 5)

        • Diuretics

        • NSAIDS

        • ACEi

        • Aminoglycosides

        • Contrast

      • GN

      • Rhabdomyolysis

      • Multiple myeloma

    • Post-renal

      • BOO

        • Stones

        • Prostate

        • Strictures

      • Strictures

      • Cervical cancer (in resource-poor settings)

      • Anti-cholinergics

Investigations

    • Bloods

      • FBC

        • Anaemia of chronic disease

        • WCC

      • CRP, ESR

      • Cultures

      • U+Es

      • Group + save

      • Glucose

      • CK

      • Bone profile

      • PSA

      • LFTs

      • Plasma electrophoresis

      • Autoantibodies if suspicion (2nd line)

    • Urine

      • Dip

      • UPCR

        • cf Nephrotic range > 3 g/24hr

      • Microscopy

      • MC+S

      • Electrophoresis

Management

    • Hypovolaemia

      • Fluid challenge

        • Monitor urine o/p

        • No response indicates the hypovolaemia has caused ATN => Need dialysis

    • Sepsis

      • Fluid challenge

        • No response indicates fluid is all going to interstitial space

        • => Need inotropes +/- RRT

    • Renal cause

      • Stop nephrotoxic drugs

        • Remember the PRN side!

    • Obstruction

      • Catheter (everyone should have one anyway, for monitoring)

Notes

    • Acute-on-chronic kidney injury causes a big jump in creatinine for a small reduction in GFR

      • Completely the opposite to the usual situation

    • When checking for the killers the key investigation is ARTERIAL BLOOD GAS

    • Patient may look and sound well, even though the killers are marching forwards

      • Sort them out straight away, before taking history

    • It's the CHARGE that normally keeps proteins in the glomerulus

    • Dysmorphic RBCs have been squeezed out of the glomerulus

    • Golden hour for antibiotics

    • Uraemia can cause pericarditis and tamponade