| AKI definition | AKI is defined as any one of the following:
Increase in Serum Creatinine by 26.5 μmol/l within 48 hours or
Increase in Serum Creatinine to ≥ 1.5 times baseline, known/presumed to have occurred within the prior 7 days or
Urine volume < 0.5 ml/kg/h for 6 hours. |
| Risk factors for AKI | Age
Diabetes
immunosuppression
polypharmacy
dehydration
infection
CKD
Renal stones
BPH |
| Classification of AKI | Stage 1: 1.5-1.9 times baseline serum creatinine, urine output of less than 0.5 ml/kg/h for 6-12 hours
Stage 2: 2-2.9 times baseline serum creatinine, urine output of less than 0.5 ml/kg/h for 12 hours or greater
Stage 3: 3times baseline serum creatinine, urine output of less than 0.3 ml/kg/h for 24 hours or greater or anuria for 12 hours or more |
| Causes of Prerenal AKI | Hypovolemia
Decreased Cardiac Output
Decreased Effective circulating volume (caused by CHF and liver failure)
Impaired Renal Autoregulation (caused by NSAIDS, Angiotensin receptor Blockers, ACE inhibitors, Cyclosporine) |
| Drug induced Pre-renal AKI pathophysiology | Decreased Renal blood flow -> leads to increase in vasodilating prostaglandins to dilate the afferent arteriole.
Blunted by NSAIDS that inhibit prostaglandin production
Decreased Renal blood flow-> leads to Angiotensin 2 constricting the efferent arteriole.
Blunted by ACE inhibitors/ARBs that inhibit angiotensin 2 production
Both processes overcome by sever hypovolaemia |
| Intrinsic Renal AKI causes | Acute Glomerulonephritis
Tubular Damage (caused by Ischaemia, Sepsis, Nephrotoxins)
Vascular (caused by Vasculitis, thrombotic thrombocytopenic purpura/Hemolytic uremic syndrome, Malignant hypertension) |
| Glomerular diseases (Nephrotic vs Nephritic) | Nephrotic
Injury to podocytes
Changed architecture: Scarring, Deposition of matrix or other elements
Proteinuria
Nephritic
Inflammation
Reactive cell proliferation
Breaks in GBM
Crescent formation
Haematuria |
| Postrenal AKI causes | Bilateral uretopelvic obstruction
Bladder outlet obstruction |
| AKI signs and symptoms | Nausea and lethargy
Decreased urine output
Fluid overload
Electrolyte abnormalities
Acid base disturbance |
| Risk factors for AKI | Age 65+
CKD
Cardiac Failure
Liver disease
Diabetes
Vascular disease
Nephrotoxic medications
ACUTE 'STOP'
Sepsis and hypoperfusion
Toxicity
Obstruction
Parenchymal kidney disease |
| AKI Prevention | Monitor patient
Maintain circulation
Minimise kidney insults
Manage the acute illness |
