Clinical Learning
Clinical 2: Acute kidney injury
Practical recognition, risk assessment, investigation and early management of acute kidney injury using NICE NG148.
Clinical safety: Use current guidance, local policy and patient-specific judgement.
Learning objectives
• Recognise patients at risk of acute kidney injury • Apply accepted creatinine and urine-output criteria for AKI detection • Identify common reversible contributors and medicines issues • Know when specialist discussion or urgent escalation is appropriate • Plan monitoring and communication after an episode of AKI
Clinical safety note
AKI management is highly dependent on haemodynamics, comorbidity, medicines and the underlying cause. Use local renal/AKI pathways and current prescribing information. Urgent complications require senior and specialist escalation rather than reliance on this module.
Recognising AKI
AKI is a sudden deterioration in kidney function. NICE supports detection using accepted AKIN/KDIGO-style criteria, including a serum creatinine rise of at least 26 micromol/L within 48 hours, a rise of at least 50% within 7 days, or oliguria below 0.5 mL/kg/hour for more than 6 hours in adults. Do not rely on eGFR alone in rapidly changing kidney function. Compare current results with a known or plausible baseline and review urine output and clinical status.
Risk factors and causes
Risk rises with older age, chronic kidney disease, heart failure, liver disease, diabetes, sepsis, hypovolaemia, urinary obstruction and exposure to medicines or procedures that affect renal perfusion or function. Think in practical categories: reduced perfusion, intrinsic renal disease, obstruction, infection/sepsis, and medication-related contributors. More than one factor may be present.
Initial management
Assess volume status and haemodynamics, look for infection and obstruction, review recent medicines and contrast exposure, and repeat renal function according to clinical need. Daily creatinine measurement is typical for hospital inpatients with AKI, but frequency should be determined by clinical need. Management is directed at the cause. Avoid reflexive fluid administration without assessing the patient: congestion, cardiac failure and other conditions may make additional fluid harmful.
Escalation and follow-up
Urgent specialist input is appropriate when there are complications, uncertain cause, suspected intrinsic renal disease, severe or worsening AKI, or a possible need for renal replacement therapy. Local pathways should define exact thresholds and routes. After AKI, communicate the episode clearly, review medicines and arrange follow-up renal assessment according to severity, recovery and comorbidity.
