Information for patients
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What is Acute Kidney Injury(AKI)?
Acute kidney Injury (AKI) used to be known as ‘acute renal failure’. However, the name was changed because in most people with the condition, the kidneys do not ‘FAIL’ completely: they just suddenly work less well than they did before. This reduced kidney functions can vary from a small amount of complete failure. The word ‘injury’ in this case does not mean that your kidneys have been physically wounded such as a physical blow to the kidneys, but rather that something has stopped them from working properly, an internal process such as volume depletion due to dehydration or a blockage that stops you passing urine, for example constipation. If your kidneys stop working properly it can be dangerous or even life threatening.
What do my kidneys do normally?
Your kidneys do a lot of important jobs to keep you healthy:
- Clean your blood
- Get rid of waste products
- Keep the right amount of chemicals and salts in your blood, like sodium and potassium
- Help to keep the right amount of fluid in your body and help make urine
- Help make red blood cells (prevent you getting anaemic)
- Help keep acid levels right in your body
- Help with maintaining healthy bones and blood pressures.
What causes AKI?
| Having Chronic Kidney Disease (CKD) | Having sepsis (infection of the blood) |
| Autoimmune causes | Vasculitis (inflammation of the blood vessels) |
| Other health conditions: Diabetes and Severe Pancreatitis | Physical blockage of the kidneys such as: An enlarged prostate Kidney stone A tumour in your bladder |
| Urinary infection that spreads to the kidneys | Use of some recreational drugs |
| Severe dehydration Diarrhoea Vomiting Heavy blood loss | Long term use of some medications such as non-steroidal anti-inflammatory (NSAIDS) e.g. ibuprofen |
| Heart failure. Heart failure is when the heart is unable to pump blood around the body properly and may need treatment to help it work. | Colour of urine may change |
| Urinating a lot less than usual | Shortness of breath when you lie down |
| Swelling of the feet, legs and around the eyes | Increased heart rate |
| Feeling itchy | Tiredness/ drowsiness |
| Extreme thirst | Confusion |
| Dizziness | Loss of appetite/ nausea and vomiting |
| Attacks of shortness of breath and coughing during the night |
If you have any of these symptoms, seek medical help. Additionally, always get urgent medical help if you have trouble breathing or your heart beats in a way that it is not usual. On their own, they do not usually suggest anything serious.
What investigations do I need?
- Blood tests
- Urine Samples
- Ultrasound of kidneys, bladder and urinary tract
- May require chest X-ray/CT Scan/Biopsy
How do we treat AKI?
It depends on the primary cause. Some patients will need:
- Intravenous therapy (fluid drip) if you are dehydrated
- It is also possible to be over-hydrated when you have AKI. Therefore, you might need to take medication to make you urinate more (a diuretic).
- You will be on a strict fluid balance chart. A fluid balance chart is a non-invasive tool to assess hydration status. It is used to document water/fluid input and output in a 24-hour period.
- Antibiotics if there is an infection
- A bladder catheter if there is a blockage to the bladder to allow close monitoring of how much urine you are making. The catheter is passed through the urethra (the tube that carries urine from your kidneys out of your body).
- If a blockage is found in either your kidneys or bladder, you will need to have either surgery or another procedure to remove it.
In some cases, the kidney functions gets worse despite treatment and you might need dialysis (renal replacement therapy) to clean/filter your blood and help remove waste products, until your kidneys improve. If dialysis is needed you will be transferred to critical care to have a special line inserted into your vein to allow the machine to be attached. There are a small number of patients whose kidneys will never recover from AKI and if this happens you will remain under the care of kidney specialists, you may need permanent dialysis and further treatment options then discussed.
When you are severely dehydrated because of AKI, it can reduce how much blood you have in your veins and arteries. This can cause your blood pressure to fall too low. You may need to be given medication to raise your blood pressure until your blood level is back to normal.
You may need drugs called corticosteroids (steroids) to help reduce swelling in your kidneys. (These are not the same as the anabolic steroids used by some bodybuilders and athletes).
Some people die from AKI, although the cause of death is often an underlying condition that caused the kidney problem, rather than AKI itself. Death is more likely in people whose AKI is more severe.
What about medications?
Sometimes medications taken for other reasons can affect the kidneys and cause AKI. These include:
NSAIDs (non-steroidal anti-inflammatory drugs):
- Ibuprofen
- Naproxen
- Diclofenac
Blood pressure medication:
- Lisinopril
- Ramipril
- Enalapril
- Perindopril
- Losartan
- Candesartan
- Valsartan
Diuretics (water tablets): - Bendroflumethiazide
- Furosemide
- Spironolactone
- Bumetanide
Some medicines are processed in the body by the kidneys and therefore can make AKI worse or some might not work as well if your kidneys are not working.
In the hospital, your doctor or pharmacist will review your prescription and they might change or stop some of the medicines, this is because the medication have caused the AKI, worsened the AKI or the risk of side effects is heightened with AKI. There are some medicines you will be advised to stop in the future if you are unwell or become dehydrated. These are called “sick days rules/guidance” and your doctor or pharmacists will discuss this with you. Sick day rule/guidance is an aid to help you understanding which medicines you should stop taking temporarily during illness which can result in dehydration.
What happens after you go home?
Sometimes medications taken for other reasons can affect the kidneys and cause AKI. These include:
NSAIDs (non-steroidal anti-inflammatory drugs):
- Ibuprofen
- Naproxen
- Diclofenac
Blood pressure medication:
- Lisinopril
- Ramipril
- Enalapril
- Perindopril
- Losartan
- Candesartan
- Valsartan
Diuretics (water tablets): - Bendroflumethiazide
- Furosemide
- Spironolactone
- Bumetanide
Some medicines are processed in the body by the kidneys and therefore can make AKI worse or some might not work as well if your kidneys are not working.
In the hospital, your doctor or pharmacist will review your prescription and they might change or stop some of the medicines, this is because the medication have caused the AKI, worsened the AKI or the risk of side effects is heightened with AKI. There are some medicines you will be advised to stop in the future if you are unwell or become dehydrated. These are called “sick days rules/guidance” and your doctor or pharmacists will discuss this with you. Sick day rule/guidance is an aid to help you understanding which medicines you should stop taking temporarily during illness which can result in dehydration.
References/Further Reading
- British Medical Journal (2020) Best Practice-Patient Information- Acute Kidney Injury. BMJ Publishing Group Limited accessed 27/10/22 Acute kidney injury- Patient Leaflet | BMJ Best Practice
- Kidney Care UK (2020) Acute Kidney Injury Patient Leaflet accessed 27/10/22 Acute Kidney Injury | Kidney Care UK
- Tidy C (2016) Acute Kidney Injury, Patient UK accessed 27/10/22 Acute Kidney Injury and Kidney Pain. Kidney pain causes | Patient
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This leaflet has been produced in partnership with patients and carers. All patient leaflets are regularly reviewed, and any suggestions you have as to how it may be improved are extremely valuable. Please write to the Clinical Governance team, North Tees and Hartlepool NHS Foundation Trust, University Hospital of North Tees, TS19 8PE or:
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Leaflet Reference: PIL1421
Date for Review: 27/02/2026