What is it?
Hyperkalaemia is the medical term for higher than normal potassium levels in the blood. (It should not be confused with hypokalaemia, which is the medical term for lower than normal potassium levels).
Potassium is a key mineral in the human body. We get potassium from the food we eat (including meat, vegetables, fruit and milk) and almost all of it is stored in our cells. However, the levels of potassium in the bloodstream are very important. Potassium levels control the electrical impulses in nerves and muscles. Minor changes in the potassium level in the blood can affect muscle contraction and heart rhythms. Extreme changes can cause the heart to stop, sometimes with very little warning.
What are the causes
Our kidneys are responsible for keeping blood potassium levels normal (known as ‘regulating’), no matter how much potassium we have in our diets. But kidney disease can reduce their ability to regulate potassium levels, particularly when kidney function drops below around 20%. This means that having a diet high in potassium can cause dangerous hyperkalaemia for people with advanced chronic kidney disease.
If you have kidney disease, other factors can also help to raise potassium levels:
- Taking certain drugs, for example:
- Tablets often prescribed to control blood pressure or for heart failure e.g., ACE inhibitors, angiotensin receptor blockers, and some diuretics (such as spironolactone, epleronone, triamterene and amiloride)
- Non-steroidal anti-inflammatory drugs e.g., Diclofenac, Ibuprofen and Naproxen
- Some beta-blockers
- Digoxin (a drug often prescribed for heart issues)
- Becoming dehydrated, for instance due to diarrhoea or vomiting
- Having blood transfusions
- Developing acidosis (Where reduced kidney function results in the kidneys being unable to excrete acids into the urine and causes the blood to become acidic)
Hyperkalaemia can alter the function of your nerves and muscles and can cause:
- muscle weakness
- a slow heart beat, and, in severe hyperkalaemia, the heart stopping altogether.
The danger with hyperkalaemia is that it often causes very few symptoms, even in patients at high risk of the heart stopping.
Your kidney doctors will do regular blood tests to check your potassium levels. The most common group of tests is known as ‘U&Es’, which stands for ‘urea and electrolytes’ (potassium is an ‘electrolyte’). Hyperkalaemia would be suspected if your blood test showed high levels of potassium. In blood test reports, potassium levels are listed as ‘K’, which is the chemical symbol for potassium.
However, sometimes the way your blood is taken or handled may lead to a falsely high potassium concentration, so a second test may be required.
- Don’t panic if you get an ‘abnormal’ test result; but don’t ignore it either. Speak to your kidney doctor or nurse if you are concerned and always go to A&E if you’re told to do so – even if you feel perfectly fine.
Treatments for hyperkalaemia will differ, depending on the severity of the condition.
If you have severe hyperkalaemia you will usually be admitted to hospital as an in-patient and given treatments including:
- Nebulised salbutamol via a face mask or T piece tube in your nostrils (this is a treatment usually given for asthma, but it helps to push down the potassium level as well)
- Intravenous glucose and insulin (this also helps to push down the potassium level)
- Dialysis (to remove potassium from the body)
If your hyperkalaemia is less severe your treatments may include:
- Changing the drugs you take to ensure you avoid taking any that could raise your potassium level
- Taking additional drugs such as diuretics to increase your production of urine, potassium binders to prevent absorption of potassium through the gut and sodium bicarbonate to regulate blood acid levels
- Changing your diet to control the intake of foods and drinks containing potassium. But you should only restrict your diet if advised to do so by a kidney healthcare professional.
Help for you
Don’t hesitate to speak to your kidney specialist or dialysis unit if you have any concerns about hyperkalaemia – or if you need help with any other aspects of your illness.
- You can also find lots of helpful tips, advice and information about exercise, diet, mental wellbeing and peer support in our our How can I help myself? section.
- Kidney Care UK web page on diet, fluids and exercise: https://www.kidneycareuk.org/about-kidney-health/living-kidney-disease/lifestyle
- Potassium fact sheet – National Kidney Federation: https://kidney.org.uk/help-and-info/medical-information-from-the-nkf-/medical-info-factsheets-potassium/
- Potassium Test – Lab Tests Online: https://labtestsonline.org.uk/tests/potassium-test
Reviewed April 2019
Why we need more research
New treatments have recently been developed that bind potassium in the gut, without some of the side effects of the older ‘potassium binders’. However we still need a lot more research about how to use these new drugs safely.
If you have kidney problems and are interested in research, one way in which you can help is to join our Kidney Voices for Research network. Through this network you can hear exciting updates on the latest research and share your insights into being involved in research.
Join our research network
Join our Kidney Voices for Research network and get involved in the latest research into the causes and treatments of kidney disease.
Our life-saving research is only possible with your support.