Acute Kidney Injury Flashcards
How is AKI diagnosed?
Measure serum creatinine
What are the NICE criteria for AKI?
- Rise in serum creatinine >/= 25 in 48 hours
- Rise in creatinine >/= 50% in 7 days
- Urine output of <0.5ml/kg/hour for > 6 hours
Which risk factors predispose patients to developing an AKI?
CKD Heart failure Diabetes Liver disease Age > 65 Cognitive impairment Nephrotoxic medication e.g. NSAIDs, ACE inhibitors Use of contrast
How can the causes of AKI be classified?
Pre-renal
Renal
Post-renal
What are the pre-renal causes of AKI?
Inadequate blood supply to kidneys:
- dehydration
- hypotension (shock)
- heart failure
What are the renal causes of AKI?
Intrinsic disease –> reduced filtration:
- glomerulonephritis
- interstitial nephritis
- acute tubular necrosis
What are the post-renal causes of AKI?
Obstruction to outflow causing back pressure:
- kidney stones
- masses e.g. cancer in abdomen or pelvis
- ureter or urethral strictures
- enlarged prostate or prostate cancer
Which investigations are done for an AKI?
Urinalysis: - leucocytes + nitrites --> infection - protein + blood --> acute nephritis - glucose --> diabetes US KUB for obstruction
How is an AKI managed?
Fluids in pre-renal AKI
Stop nephrotoxic medications
Relieve obstruction in post-renal AKI e.g. with catheter
If severe/complications –> renal review, may need dialysis
What are the complications of AKI?
Hyperkalaemia
Fluid overload, HF, pulmonary oedema
Metabolic acidosis
Uraemia –> encephalopathy or pericarditis
What is acute tubular necrosis?
Damage and death of epithelial cells of the renal tubules
Most common cause of AKI
Takes 1-3 weeks to recover
What causes acute tubular necrosis?
Ischaemia/hypoperfusion: - shock - sepsis - dehydration Toxins: - contrast - gentamicin - NSAIDs - lithium - heroin
What is seen on urinalysis in acute tubular necrosis?
Muddy brown casts
