Acute kidney injury awareness

Overview

Acute kidney injury (AKI) is a sudden episode of kidney failure or damage that happens within a few hours or days. The kidneys stop working properly, so waste builds up in the blood and body fluids. AKI is different from chronic kidney disease, which develops slowly over time.

Yes, acute kidney injury is quite common, especially among people who are already very ill or in hospital. It affects about 1 in 5 adults admitted to hospital and up to 2 in 3 people in intensive care.

AKI can happen to anyone, but it is more likely in older adults (over 65), people with chronic diseases like diabetes or high blood pressure, those with existing kidney disease, and people who are severely dehydrated or have a serious infection.

Symptoms

Common symptoms

• Feeling very tired or weak
• Passing less urine than usual (or not urinating at all)
• Swelling in the legs, ankles, or feet (fluid retention)
• Shortness of breath
• Confusion or difficulty concentrating
• Nausea or vomiting

Symptoms in children

• Fussiness or irritability
• Not wanting to eat or drink
• Fewer wet nappies than normal
• Swelling around the eyes or face
• Vomiting or diarrhea

Symptoms in older adults

• Sudden confusion or feeling 'off'
• Dizziness or feeling faint
• Not urinating as much as usual
• Loss of appetite
• Feeling generally unwell with no clear cause

Causes

Main causes

• Reduced blood flow to the kidneys (e.g., severe dehydration, heavy bleeding, low blood pressure, or heart failure)
• Direct damage to the kidneys (e.g., from certain infections, medications like some antibiotics or NSAIDs, or contrast dye used in scans)
• Blockage in the urinary tract (e.g., from an enlarged prostate, kidney stones, or bladder tumor)

Risk factors

• Age over 65
• Having diabetes, high blood pressure, or heart disease
• Having chronic kidney disease
• Being in hospital, especially in intensive care
• Severe infections (sepsis)
• Taking medications that can harm the kidneys (like some painkillers or water pills)
• Major surgery or trauma

When to see a doctor

See a doctor urgently if:

• If you notice you are passing very little urine or none at all
• If you have sudden swelling in your legs, ankles, or face
• If you feel extremely short of breath or confused

Book a routine appointment if:

• If you are at higher risk (e.g., diabetes, heart disease) and have any new symptoms like changes in urination or fatigue, even if mild
• If you have been taking medications that can affect the kidneys and develop any symptoms

Diagnosis

A doctor or nurse will assess your symptoms, check your medical history, and do a physical exam. They will also order tests to check how well your kidneys are working.

Tests that may be done

• Blood tests to measure creatinine (a waste product) and estimate kidney function (eGFR)
• Urine tests to look for blood, protein, or signs of infection
• Imaging tests like an ultrasound to see if there is a blockage in the urinary tract
• Sometimes a kidney biopsy (taking a tiny piece of kidney tissue for analysis)

What to expect at your appointment

If AKI is suspected, you will likely need to be in hospital for close monitoring and treatment. The doctor will track your urine output and repeat blood tests daily. Most people recover with supportive care, but care can take days to weeks.

Treatment

Treatment focuses on treating the underlying cause and supporting the kidneys so they can heal. The goal is to prevent complications and allow kidney function to return to normal.

Self-care at home

• Drink enough fluids to stay hydrated, but do not overhydrate – follow your doctor's advice on fluid intake
• Avoid over-the-counter painkillers like ibuprofen, naproxen, or aspirin unless a doctor says they are safe
• Do not take any new medications or supplements without checking with your healthcare provider
• Monitor your urine output and any swelling, and report changes to your medical team

Medical treatments

In hospital, doctors may give intravenous fluids (through a drip) to correct dehydration and improve blood flow to the kidneys. They may adjust or stop medications that could be harmful to the kidneys. Some people need medications to control blood pressure, balance electrolytes like potassium, or treat infections. In severe cases, a short course of dialysis (a machine that cleans the blood) may be needed to give the kidneys time to heal.

When is surgery considered?

If the cause is a blockage in the urinary tract (e.g., from a kidney stone or enlarged prostate), a procedure to remove the blockage may be needed. This could involve minor surgery or the use of a tube (stent) to drain urine.

Living with this condition

Recovery from AKI varies. Most people feel better within a few weeks, but some may have ongoing fatigue or need to follow up with a kidney specialist. You may need regular blood tests to monitor kidney function for months after recovery.

Lifestyle tips

• Drink enough fluids each day, but stick to the amount your doctor recommends if you have fluid restrictions
• Eat a balanced diet with limited salt to help control blood pressure
• Avoid alcohol and smoking, as they can harm kidney health
• Get regular exercise as approved by your doctor—even gentle walking can help

Diet and exercise

Your doctor or a dietitian may advise a kidney-friendly diet, which often means limiting salt, potassium, and phosphorus. Eat a variety of fruits, vegetables, and whole grains, but avoid high-potassium foods (like bananas or potatoes) if your potassium is high. Exercise can improve overall health, but avoid heavy lifting or strenuous activity until your kidney function improves.

Mental health and emotional wellbeing

Having AKI can be frightening and stressful. You may feel anxious about your kidneys or frustrated during recovery. It is important to talk to your healthcare team about how you are feeling. Many hospitals have counsellors or support groups for people with kidney conditions.

Prevention

While not all cases of AKI can be prevented, you can reduce your risk by staying well hydrated, managing chronic conditions (like diabetes and high blood pressure), avoiding overuse of certain painkillers, and following medical advice when taking any new medicines.

Vaccines

Get vaccinated against flu and COVID-19 to reduce your risk of serious infections that can lead to AKI.

Screening programmes

If you are at high risk (e.g., kidney disease, diabetes, elderly), your doctor may recommend regular blood and urine tests to catch any early signs of AKI.

Complications

If left untreated

• Permanent kidney damage or chronic kidney disease
• Fluid buildup in the lungs (pulmonary edema) causing breathing trouble
• High potassium levels (hyperkalemia) that can affect heart rhythm
• Increased risk of infections and sepsis
• Need for ongoing dialysis or a kidney transplant in severe cases

Long-term outlook

Most people with acute kidney injury recover completely within weeks to months if treatment is started quickly. Even those who need dialysis often regain enough kidney function to stop dialysis. The outlook is generally good when the condition is caught early and the underlying cause is treated. With proper care and follow-up, many people return to normal activities and live full lives.

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