Acute Kidney Injury

Acute kidney injury is a medical emergency


Acute Kidney Injury Stages



Stage  3


↑Creatinine  3.0 x baseline known or presumed to have occurred within prior 7 days


Or Creatinine  >354 umol/L with ↑ >44 umol/L in <24hrs


Stage 2


↑Creatinine  2.0-2.9 x baseline known or presumed to have occurred within prior 7 days




Stage 1

↑Creatinine  1.5-1.9 x baseline known or presumed to have occurred within prior 7 days


Or ↑Creatinine  >26 umom/L in 48hrs


  • If no baseline creatinine value is available use normal range.
  • AKI also is present if urine vol<0.5ml/Kg for 6 hours (measured by catheter output).
  • If a patient receives regular haemodialysis or peritoneal dialysis then changes in creatinine will not reflect AKI. However, other abnormal electrolyte results such as hyperkalaemia are still clinically relevant and need to be managed carefully.

Admit if:

  • Clinically indicated egsepsis
  • AKI stage 3

Consider admission/discuss with renal team if:

  • Suspected obstruction
  • Suspected intrinsic renal disease with
  • Urinalysis  ≥1+ blood AND protein +/-Systemic symptoms eg. arthralgia, rash, bleeding

If unsure contact renal registrar or consultant via RCH switchboard



Trimethoprim can cause a mild rise in creatininewithout a genuine drop in glomerular filtration rate.  If the patient is unwell or has hyperkalaemia assume there is acute kidney injury.


If not admitted

  • Assess for cause of AKI and treat eginfection
  • Avoid/correct dehydration
  • Stop nephrotoxic drugs egACEi/ARB/diuretic/NSAID or new drugs especially PPI, antibiotics, allopurinol
  • Stop metformin(to avoid lactic acidosis).
  • If suspected intrinsic renal disease discuss with renal registrar or consultant via RCH switchboard.
  • Arrange early review and repeat creatinineand electrolytes . Repeat more urgently in more severe AKI-generally 24hrs in Stage 3, 48-72 hrsin stage 1-2. If not improving phone the renal registrar or consultant via RCH switchboard.


Ongoing Management


  • Has renal function fully recovered?- if not repeat creatinineafter 2-4 weeks. If still not recovered to baseline repeat creatinineafter 3 months and manage as per NICE CKD guidelines .
  • Review need for ongoinguse of nephrotoxic medications and consider alternatives.
  • If needed ACEi/ARB can usually be  restarted once renal function is stable. Initiate at usual starting dose and titrate monitoring  creatinine  1 week after each dose increase.
  • After any AKI, monitor creatinineperiodically for 2-3 years as per NICE guidance.
  • Inform patients on ACEi/ARB of sick day rules


Kidney Sick Day Rules

What should I do with my medicines if I become dehydrated?

If you

  • are not able to drink a normal amount of fluid,
  • develop diarrhoea or vomiting or
  • develop fevers,


you should temporarily stop taking the medicine named ___________________

This is to help protect your kidneys.


Once you are better and can drink normally, you should restart your medicine.  For most people this is within 48 hours. 


If you remain unwell for longer than this, contact your doctor. It is important to seek medical advice if your symptoms last for more than 48 hours.


Is there anything else I should do when I am dehydrated?


You cantake paracetamolfor pain relief or for a high temperature.



Avoidanti-inflammatory drugs (a type of pain killer) whilst you are dehydrated.  Examples of these medications are Ibuprofen, Diclofenacor Naproxen.