Define AKI
abrupt deterioration in renal function, usually over hours or days
What is the KDIGO definition of AKI? (3)
- rise in serum creatinine >26μmol/L within 48 hours
- rise in serum creatinine 1.5x baseline within 7 days
- urine output <0.5ml/kg/hr for >6 consecutive hours
In terms of serum creatinine and urine output, define the three stages of AKI
- serum creatinine 1.5-1.9x baseline
urine output <0.5ml/kg/hr for 6-12 hours - serum creatinine 2-2.9x baseline
<0.5ml/kg/hr for ≥12 hours - serum creatinine >3x baseline or ≥345
urine output <0.3ml/kg/hr for ≥24 hours or anuria for 12 hours
Name 4 risk factors for the development of AKI
- pre-existing CKD
- increasing age
- male
- co-morbidities
- What is true hypovolaemia?
2. What is relative hypovolaemia?
- reduced circulating blood volume
2. normal/increased circulating volume but kidney’s inadequately perfused
Name causes of pre-renal AKI
true hypovolaemia - haemorrhage, burns, D&V, DKA/HSS
relative hypovolaemia - sepsis, hepatorenal syndrome, NSAIDs, ACE/ARB
Name causes of renal AKI
glomerular - glomerulonephriyis, acute tubular necrosis
interstitial - drug reaction, infection, infiltration
vessels - vasculitis
Name causes of post-renal AKI
stone, malignancy, stricture, clot, prostatic hypertrophy
What initial investigations should be done for ?AKI
- Basic Obs and NEWS2 score
- are there signs of hypovolaemia?
- VBG to obtain serum K+
- serum creatinine
What needs to be monitored for patients with AKI?
- catheterise to monitor urine output
- serum potassium
- observations every 4 hours
- lactate
- daily creatinine
What investigations can be useful in determining cause of AKI
- urine dip - proteinuria and/or haematuria may indicate intrinsic renal disease
- ultrasound - renal size (can indicate CKD); evaluation of post-obstructive causes
- LFTs (hepatorenal syndrome)
- specific tests for intrinsic renal diseases
What medical support is given to patients with AKI?
- stop nephrotoxic medication - NSAIDs, ACE/ARB, aminoglycosides
- stop drugs that may increase complications - diuretics, metformin
- check all drug doses and adjust for renal impairment
- consider gastroprotection and nutritional support
- avoid radiological contrast
- What is given for cardioprotection in patients with hyperkalaemia?
- How is hyperkalaemia reduced?
- IV calcium chloride
2. IV insulin, salbutamol, renal replacement
Name causes of acute-on-chronic kidney failure (10)
systemic infection Drugs - diuretics, ACE inhibitors, aminoglycosides Dehydration Urinary tract obstruction/urinary retention Volume depletion DKA, HSS Hypercalcaemia Hyperuricaemia Progression of underlying diseases Pregnancy
