AKI Flashcards
AKI definition
Insult to the kidney that causes rapid decrease in filtration rate of the kidneys
AKI stages
1-3
Stage 1
- Cr = >26 mmol/L increase, or 1.5-2x increase from baseline
- Oligouria= <0.5ml/kg/hr for 6 hours
Stage 2
- Cr > 2-3x from baseline
- Oligouria, <0.5ml/kg/hr for 12 hours
Stage 3
- Cr > 354, with at least 44 acute increase
- Cr> 3x from baseline
- Anuria for 12 hrs
- Oligouria <0.3ml/kg/hr for 24 hours.
Signs of AKI
Electrolyte imbalance
- HYPERKALAEMIA
- ECG changes
- Hyponatraemia
Fluid imbalance
- Oedema
- Pulmonary oedema when severe
Acidosis
- Dyspnoea/ tachypnoea
Phases of AKI
- Onset
Hours-days
- Triggers; blood loss, infection, infarct, burns, dehydration
- Filtration rate decreases, poor renal perfusion
- Renal blood flow and tissue perfusion 25% of norma.
- Urine output <0.5ml/kg/hr
Phases of AKI
- Oliguria/ Anuric
8-14+ days
- Oliguria <400mL/day, anuria for 12 hours.
- Electrolyte imbalance
- Increase in blood urea nitrogen (BUN)
- Fluid overload.
- Acidosis
Phases of AKI
- Diuretic
7-14 days
- Occurs after AKI has been corrected
- Renal tubules are scarred
- Oedema
- Increased GFR, Urine output >400mL/day
- Possible electrolyte depletion due to excretion of more water.
Phases of AKI
- Recovery
Months-days
- Filtration rate returns to 70-80% of normal
- Decreased oedema
- Normalisation of fluid and electrolyte balance.
Pre-renal cause of AKI
Causes of hypovolaemia/ hypotension/ infarction/ ischaemia.
- Blood loss
- Dehydration
- Vomiting and diarrhoea
- Burns
- Sepsis
- MI
- RA stenosis
Renal cause of AKI
Cause of direct injury to renal tissue
- Drugs: Diuretics, ARBs, ACEi, NSAIDs,
- Infection
- Trauma
- Autoimmune/ inflammation; SLE, RA, sjorgen’s etc
- Hypercalcium
- Metals; gold
Post-renal causes of AKI
Causes that block the urinary tract from renal pelvis downwards.
- Stones
- Prostate enlargement
- Strictures
- Neoplasm
- Urinary retention; neurogenic
Indications for dialysis
Refractory hyperkalaemia
Pulmonary oedema
Refractory acid/base disturbance
Uraemia consequences
- Coma
- Pericarditis
Examples of exogenous nephrotoxins
Causes of renal AKI
- Iodinated contrast
- Aminoglycosides
- Amphotericin B
- PPIs
- NSAIDs
Examples of endogenous nephrotoxins
Haemolysis
Rhabdomyolysis
Myeloma
Intratubular crystals
AKI risk factors
Elderly
CKD
Diabetes
Liver disease
Vascular disease
Nephrotoxic medications
Assessment of AKI
Fluid balance
- Fluid balance chart
- Urine output
Blood tests
- U+Es; electrolyte balance
- Renal function
VBG
- Acid/base balance
If indicated, scans for obstruction
- Ultrasound urinary tract
- Bladder scan
Urine Dip for infection
Drug review
