Acute Kidney Injury

A sudden drop in kidney function over hours or days, often in people who are already unwell.

KidneysEmergencyLast updated: 21 October 2026

Quick Summary

Primary Symptoms

Passing less urine, swelling, tiredness, confusion, nausea and breathlessness. Sometimes found only on blood tests.

Common Treatments

Treating the cause, correcting fluids and salts, stopping harmful medicines and, if needed, dialysis.

Risk Factors

Severe dehydration, infections, low blood pressure, some medicines, older age and existing kidney disease.

OverviewSymptomsCausesTreatmentFAQ

Overview

Acute kidney injury (AKI) can happen with severe diarrhoea, serious infections, surgery or after some medicines and dyes.

It can often be reversed if treated quickly, but it can be life-threatening.

Symptoms

Less urine

Passing much less than usual.

Swelling

Legs and ankles.

Confusion

Or drowsiness.

Nausea and tiredness

Feeling generally unwell.

Causes & Risk Factors

Biological Causes

Reduced blood flow to the kidneys, direct kidney damage, or blockage of urine flow.

Key Risk Factors

  • Dehydration From vomiting, diarrhoea or heat.
  • Medicines NSAIDs, some antibiotics, and contrast dye.
  • Existing conditions Diabetes, heart failure and chronic kidney disease.

Management & Treatment

01. Treat the cause

Fluids, antibiotics or relieving a blockage.

02. Medicine review

Stop medicines that harm the kidneys.

03. Dialysis

Temporarily, if needed.

Frequently Asked Questions

Can the kidneys recover?
Often yes, especially with prompt treatment.
How is it found?
With blood tests for creatinine and urine output.

Sources and further reading

Last updated 21 October 2026. For more detail, see these trusted health organisations.