Information about kidneys and kidney disease

What the kidneys do:

• Most people have two kidneys; each kidney is about the size of a clenched fist.
• The kidneys clean and filter the blood. Waste products and excess water leave the body in urine. The kidneys filter about 180 litres of blood every day.
• Kidneys control the level of water and different minerals needed for health such as sodium (salt) and potassium.
• Kidneys make hormones to control blood pressure and Kidneys have some control over your red blood cells – if your kidneys are not getting enough oxygen they send a signal to your body to make more red blood cells and prevent you from becoming anaemic (deficiency of red blood cells).
• Kidneys keep the acid base (pH) balance of the blood constant
• Kidneys convert Vitamin D into its active form and control the body’s calcium levels to keep our bones healthy.

Acute Kidney Injury:

Acute kidney injury (AKI) is a sudden and recent reduction in a person’s kidney function. Kidney function is measured by blood tests and acute kidney injury is identified in the same way. Acute kidney injury can be caused by a number of things. It might be because of stress on the kidneys, due to other illnesses or infection. It might be due to severe dehydration or it could be the result of the side effects of some drugs, when you are unwell. Sometimes it’s due to a combination of factors. Acute kidney injury can get better in a few days or weeks, but sometimes it causes ongoing problems.

Who is at risk of Acute Kidney Injury?

We are all at risk of Acute Kidney Injury. It is very common when people become seriously unwell, and affects 1 in 5 people admitted as an emergency to hospital. The kidneys require an adequate blood pressure to function. If blood pressure drops a lot then cells in the kidneys are damaged and they may not function properly again, even when blood pressure returns to normal. 

Some people are more at risk than others, for example those people who already have abnormal kidney structure or function. This may be related to other long term conditions such as diabetes or high blood pressure.  

What are the symptoms of acute kidney injury?

Sometimes there are no real symptoms or signs, a blood test is needed to detect it. Acute kidney injury can have the following symptoms:

• Changes to urine output, particularly a major reduction in the amount of urine passed.
•  Nausea, vomiting.
• Abdominal pains and feeling generally unwell, similar to a hangover.
• Dehydration or thirst.

What is Chronic Kidney Disease?

Chronic kidney disease (CKD) is a long-term condition where the kidneys don't work as well as they should. It is quite a common condition and often associated with getting older, it is found to be more common in black people and people of south Asian origin.  CKD can range from a mild condition with no or few symptoms, to a very serious condition where the kidneys stop working, ‘kidney failure’. 

Most people with CKD will be able to control their condition with medication and regular check-ups with their family GP.  CKD only progresses to kidney failure in around 1 in 50 people with the condition.

Symptoms of CKD

There are usually no symptoms of kidney disease in the early stages; it is often referred to as a ‘silent disease’. It may only be picked up if blood or urine tests carried out and detect a possible problem with your kidneys.

When it reaches a more advanced stage, symptoms can include:

• tiredness
• swollen ankles, feet or hands
• shortness of breath
• blood in your urine
• feeling sick

Common causes of CKD

Kidney disease is usually caused by other conditions that put a strain on the kidneys. Often it's the result of a combination of different problems.

CKD can be caused by:

• High blood pressure– over time, this can put strain on the small blood vessels in the kidneys and stop the kidneys working properly
• Diabetes– too much glucose in your blood can damage the tiny filters in the kidneys
• Kidney infections
• A condition known as Glomerulonephritis (kidney inflammation)
• Polycystic Kidney Disease– an inherited condition where growths called cysts develop in the kidneys
• blockages in the flow of urine – for example, from enlarged prostate or kidney stones
• long-term, regular use of certain medicines – for example NSAIDs ( Ibuprofen or Diclofenac).

Healthy lifestyle changes and ensuring any underlying conditions are well controlled may prevent or delay CKD.

Treatments for CKD

There's no cure for CKD, but treatment can help relieve the symptoms and stop or delay it from getting worse.

Your treatment will depend on how severe your kidney disease is.

The main treatments are:

• lifestyle changes to ensure you remain as healthy as possible
• medication to control associated problems such as high blood pressure and high cholesterol
• Dialysis is a treatment that replaces the kidney's function of cleaning and filtering the blood; this may be necessary in advanced CKD.
• Kidney Transplant is another form of replacing kidney function.

For more information about Acute Kidney Injury and Chronic Kidney Disease (CKD), the treatment and management of CKD and links to further useful websites and resources.

Useful Link:

www.thinkkidneys.nhs.uk