guidelines

acute kidney injury (aki)

nice-based prevention, recognition, staging, and first-line management of aki, including medication holds, investigation, and referral thresholds.

last reviewed: 2026-02-13
based on: NICE NG148 (published 18 Dec 2019; last updated 16 Oct 2024)
reviewer: Dr Kola Tytler MBBS CertHE MBA MRCGP
view official NICE source

Quick take

When to think AKI (primary care and urgent care): any acute illness plus risk factors (CKD, HF, liver disease, diabetes, prior AKI), oliguria, hypovolaemia, sepsis, obstruction symptoms, or recent nephrotoxic drugs.

Core diagnostic criteria (NICE): any of: (1) creatinine rise ≥26 µmol/L within 48 h, (2) ≥50% rise within 7 days, (3) urine output <0.5 mL/kg/hour for >6 h (adults) / >8 h (children), or (children) ≥25% fall in eGFR within 7 days.

Non-negotiables: compare creatinine to baseline, do urine dip (blood/protein/leucocytes/nitrite/glucose), check U&Es ± VBG/ABG if unwell, and review/hold kidney-stressing meds while you correct physiology.

Immediate management checklist

  • Assess severity: vitals, sepsis screen, fluid status, urine output; ECG if K+ concern.
  • Stop/hold triggers (until stable): NSAIDs, ACEi/ARB, diuretics and other nephrotoxins in the setting of vomiting/diarrhoea/sepsis/hypovolaemia; adjust doses of renally cleared meds (seek pharmacy advice if needed).
  • Identify cause: pre-renal (dehydration, sepsis, HF), intrinsic (GN/ATN/AIN), post-renal (retention, hydronephrosis).
  • Investigate: U&Es/creatinine, FBC, CRP, glucose; urine dip; consider ACR/PCR if protein; consider bladder scan if retention; ultrasound is not routine if cause is clear but is key if obstruction suspected.
  • Treat the driver: fluids if hypovolaemic (senior decision-making in HF/advanced CKD), antibiotics for sepsis, relieve obstruction urgently where indicated.

When to escalate or refer

Immediate escalation / hospital pathways:

  • Complications not responding to initial medical management: hyperkalaemia, metabolic acidosis, uraemic complications (e.g., encephalopathy/pericarditis), fluid overload or pulmonary oedema.
  • Suspected/confirmed upper tract obstruction: refer to urology; refer immediately for pyonephrosis, obstructed solitary kidney, bilateral obstruction, or AKI complications due to obstruction.

Nephrology discussion (same day / within 24h) is advised when: no clear cause, inadequate response to treatment, complications, suspected diagnoses needing specialist therapy (vasculitis/GN/AIN/myeloma), stage 3 AKI by recognised criteria, renal transplant, or CKD stage 4–5.

After AKI: plan repeat creatinine based on stability and degree of dysfunction; consider nephrology referral if eGFR ≤30 mL/min/1.73m² after recovery.

Frequently asked questions

What are “sick day” medication holds in AKI risk?
In vomiting/diarrhoea/sepsis/hypovolaemia, temporarily stop kidney-stressing or dehydration-worsening drugs (commonly NSAIDs, ACEi/ARB, diuretics) and review all renally cleared medicines until the patient is clinically stable and hydration is restored.
Do I need a renal ultrasound for everyone with AKI?
No. Ultrasound is not routine once a clear cause is identified. Use it when obstruction is suspected (retention symptoms, known stones, hydronephrosis risk) or if the picture does not fit a clear pre-renal trigger.
How quickly should I repeat U&Es?
Base frequency on severity and trajectory. If creatinine is rising, urine output is falling, or there are electrolyte abnormalities, repeat urgently (same day). If improving and clinically stable, repeat within days as per local pathway.

Transparency

This page is an educational, clinician-written summary of publicly available NICE guidance intended for trained healthcare professionals. It uses original wording (not copied text) and should be used alongside the full NICE source, local pathways, and clinical judgement. Doses provided are for general reference; always check the BNF/SPC.