AKI Flashcards
Define AKI
Sudden loss of renal function, characterised by either abnormal urine output or increased urea and creatinine in the urine
What are the stages of AKI
1: 1.5-1.9x baseline Cr OR UO : <0.5 ml/kg/h for 6-12 hours
2: 2-2.9x baseline Cr OR UO : <0.5 ml.kg/h for <12 hours
3: 3x baseline or increase to >4.0mg/dl OR UO <0.5 ml/kg/h for >24 hours
Pre-renal aetiology for AKI
Impaired perfusion due to: Shock Hypovolaemia (sepsis, major haemorrhage, vomiting/diarrhoea, congestive HF) Trauma Renal artery stenosis Drugs e.g. NSAIDs, ACEi
Renal aetiology of AKI
Glomerulonephritis (glomerular) Interstitial nephritis (interstitial) Acute tubular necrosis (tubular) Drugs and nephrotoxic contrast Vascular
Post-renal aetiology of AKI
Enlarged prostate Kidney stones Calcified ureter Cancer Fibrosis Urethral stricture
Risk factors for AKI
>75 Underlying kidney disease DM Sepsis Exposure to nephrotoxins Major surgery
Give examples of nephrotoxins
Aminoglycosides
Vancomycin
Piperacillin-taxobactam
Symptoms of AKI
Malaise Anorexia Nausea/vomiting Pruritus Dizziness Drowsiness, convulsions, coma Symptoms of the cause
Pre: -
Renal: rash, bruising
Post: frequency, urgency, hesitance, flank pain, haematuria
Signs of AKI
Oedema
Pre-renal: tachycardia
Renal: Rash, petechiae, ecchymoses, oedema, protein uria
Post: haematuria, distended palpable bladder
Investigations for AKI
Dipstick: Protein +, haematuria +
Bladder scan: >150ml when void
ECG: check for hyperkalaemia
U+Es: raised Cr
FBC: normal or low Hb: deranged WCC
ABG/VBF: assess acid-base status
USS: exclude renal obstruction
CXR: monitor fluid overload
What features would point towards a CKI instead of AKI
Anaemia suggests chronic
Kidneys <9cm suggests chronic
Hypocalcaemia and hyperphosphataemia suggests chronic
What is the significance of trimethoprim in AKI
Can lead to a rise in serum creatinine that does reflect any change in GFR
What is the short-term management for AKI
- Diuretic for pulmonary oedema
- Oxygen or CPAP for low sats
- Calcium gluconate or chloride for hyperkalaemia -> insulin + dextrose
- IV fluids for hypovolaemia
- Manage hyper-uraemia
- Treat the cause
What is the management plan for AKI if it progresses
Dialysis short-term
Ultimately transplant
Complications of AKI
Metabolic acidosis Water retention Hyperkalaemia Hyponatraemia Toxin accumulation e.g. urea
