AKI Flashcards
Symptoms of AKI
Fatigue Weight loss Nocturia Oliguria Haematuria
Signs of AKI
Rash
Hypotension/hypertension
Signs of HF
Palpable bladder - obstructive
Specific questions in an AKI history
Volume restriction? Nephrotoxic medications? Trauma? Blood loss? History of renal stones/ abdominal surgery/ prostatism?
3 types of AKI and causes
PRERENAL: due to reduced renal perfusion, untreated leads to ATN
- Reduced ECF volume in hypovolaemia/systemic vasodilation/HF
- impaired renal autoregulation eg. Sepsis/drugs (NSAIDs, ACEIs)
RENAL: direct injury to the kidney
- Acute tubular necrosis due to ischaemia or nephrotoxins
- Acute Glomerulonephritis: immune disease eg. IgA Nephropathy, SLE
- Acute Tubulo-interstitial nephritis: inflammation of kidney interstitium due to infection/toxins
POSTRENAL: obstruction to urine flow, dilates renal pelvis (hydronephrosis), impairs renal function
- within lumen eg. Stones/ within wall eg. Stricture post TB/ pressure from outside eg. Malignancy, AAA
Investigations of AKI
FBC - increased urea & creatinine, hyperkalaemia, hyponatraemia
Urine dipstick - Haematuria, proteinuria, leucocytes
Urine microscopy - Hyaline cast (prerenal), muddy brown cast (ATN)
Antibody assays
Kidney biopsy
Management of AKI
Depends on cause
Eg. Give fluids in hypovolaemia
ATN: fluid restriction, avoid nephrotoxins
Can use dialysis if hyperkalaemia and fluid overload persists despite treatment, or in presence of a dialysable nephrotoxin
Prognosis of AKI
If uncomplicated, patient usually recovers in 2-3 weeks
Mortality rate = 25%
Increased risk of developing CKD
What criteria is used to diagnose AKI
One of:
- Serum creatinine >26.5 micromol/L in 48hrs
- Serum creatinine >1.5 X baseline within 7 days
- Urine output <0.5ml/kg/hr for >6hrs
AKI differentials
CKD Heart failure Diabetic ketoacidosis/metabolic acidosis Dehydration UTI
