Acute Kidney Injury AKI

What do the kidneys do?

Most people have two kidneys that lie on either side of the backbone just below the ribs.

The kidneys maintain the balance in the body by:

• Removing waste and extra fluid
• Controlling your blood pressure
• Keeping the right amount of fluid in your body
• Kidneys produce a hormone which stimulates the bone marrow to produce new red cells when needed
• Control the minerals in your body like potassium and phosphate.

What is acute kidney injury (AKI)?

Acute Kidney Injury or AKI is a sudden reduction in a person’s kidney function. Kidney function is measured by blood tests. It does not mean that the kidneys have been physically injured. Up to one in five people admitted to hospital in the UK have AKI. AKI often gets better in a few days or weeks, but sometimes it doesn’t resolve fully and can cause long term problems. AKI is not to be confused with chronic kidney disease (CKD) which is used to describe long-term kidney dysfunction that can be the result of various kidney and systemic diseases.

What causes AKI?

AKI can be caused by several factors. Such as dehydration, systemic illnesses or infections, major surgery and trauma or by side effect of drugs that pass through the kidney. AKI may also be caused when the drainage system of the kidneys (the ureters or bladder) is blocked. The risk of having an AKI increases with age. Those with CKD, diabetes, heart or liver failure, are also at a higher risk.

What are the symptoms of AKI?

You may not feel unwell until kidney function has deteriorated significantly, sometime to less than ten percent. AKI can have the following symptoms:

• Changes in urine output, particularly a reduction in amount passed.

• Nausea and vomiting.

• Abdominal pains and feeling generally unwell.

• Dehydration with thirst.

• Later symptoms can include confusion and drowsiness.

How is AKI diagnosed?

Clinicians measure the blood level of a substance called creatinine. This is produced by the muscles and is removed by the kidneys. If there is a reduction in kidney function the creatinine levels will rise.

What makes an AKI episode a risk to your health?

• Although AKI can be mild, in more serious forms the loss of kidney function may cause

• An increase in potassium levels in the blood that can subsequently affect the heart.

• Blood may become acidic which can lend to further complications.

• Salt and water build up may lead to swelling to legs, hands or face.

• In some cases, fluid can build up in the lungs.

What is the treatment for AKI?

• Once the cause of the AKI is identified, treatment is directed at the underlying cause.

• Hydration is assessed and intravenous fluids may be given.

• Some medications may be stopped while others require a dose adjustment.

• Kidney function is monitored by measuring the volume of urine produced and to do this may require a small tube called a catheter placed into the bladder if you have urinary retention or very unwell with low blood pressure.

• Frequent blood tests until the AKI improves

• An ultrasound scan of the kidneys may be needed in certain circumstances

• Your blood pressure, pulse and oxygen levels will be checked frequently

• Your weight may be assessed daily

What are the long-term effects?

• AKI is usually treated successfully. You may need to be followed up by the hospital medical team or your family doctor (GP) to monitor your kidney function.

• In some patient’s, kidney function doesn’t fully recover after AKI. In a very small minority of AKI patients there is significant damage to the kidneys, and they need on-going dialysis under the care of the Nephrology (Kidney) team.

• Whilst in hospital your doctor will keep you informed of your progress. Once discharged your GP should receive information regarding your hospital stay including diagnosis of AKI and medications that have been changed or temporarily held

How can I avoid AKI in the future?

You must follow the healthy kidney guidance below, when you are unwell with any of the following:

• Vomiting where you are unable to keep fluids down.

• Diarrhoea where you lose more water in stools than you manage to drink.

• Fevers and high temperature, making you feel lethargic or dizzy

• Any of the above illness please contact your GP/Nurse for a review

Caring for your kidneys (how to prevent kidney injury)

Pause:

If you are losing fluid through persistent vomiting and diarrhoea, or seriously unwell with low blood pressure: You will need a review of your medication by your doctor or nurse

• Seek advice if you are taking medication (called antihypertensives) and your blood pressure has recorded low.
• Seek advice if you are on water tablets (called diuretics) and losing fluid through diarrhoea/vomiting. (Example Furosemide, bumetanide, thiazide, Spironolactone, Eplerenone, Finerenone).
• Seek advice if you are taking specific medication like SGLT2 inhibitor and losing fluid through diarrhoea/vomiting (Example- Dapagliflozin, Empagliflozin).

Review:

Make sure you remain hydrated. Drink small sips of fluids regularly.

• Contact your GP/ Nurse requesting review immediately if you feel dizzy, your Blood Pressure is low, or you are not passing usual amounts of urine
• Medication to pause following medical advice

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Restart:

• If your doctor/clinical team has paused any of the above medications, please contact your GP/Nurse about when to restart the medications. Usually once you feel well and you can eat and drink.

• Your clinical team should inform you of any medications that have been reduced or temporarily held whilst your kidneys are recovering.

• These should be reviewed with you before discharge with a plan if appropriate of when to restart them. Please check your discharge letter for medications that have been stopped or those needing to be restarted

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