Potassium is the main mineral inside cells and is essential for the electrical activity of muscle and heart. The normal blood level is about 3.5 to 5.0 mmol/L. Hypokalaemia means a low level and hyperkalaemia a high level.
Both matter chiefly because of the heart: marked changes in either direction can trigger dangerous rhythm disturbances, sometimes with little warning. Mild changes are common and often linked to medication.
Symptoms
- Muscle weakness, heaviness in the legs or cramps
- Tiredness
- Constipation and bloating with low potassium
- Palpitations or skipped beats
- Tingling or numbness
- Passing large amounts of urine with prolonged low potassium
- Frequently no symptoms even at dangerous levels, particularly with high potassium
Causes and risk factors
Low potassium usually results from losses: diuretics, vomiting, diarrhoea, laxative misuse, or hormone excess such as primary aldosteronism and Cushing syndrome. Low magnesium, rare tubular disorders (Gitelman, Bartter) and insulin or salbutamol treatment also lower it. High potassium is most often due to reduced kidney excretion in acute or chronic kidney disease, combined with drugs such as ACE inhibitors, ARBs, spironolactone, trimethoprim or NSAIDs. Adrenal insufficiency, uncontrolled diabetes, tissue breakdown and potassium supplements or salt substitutes contribute. A falsely high result from a damaged blood sample is common.
How it is diagnosed
- Repeat blood potassium: Confirms the result and excludes a sample artefact.
- ECG: Looks for the rhythm changes that determine how urgent treatment is.
- Kidney function, magnesium, glucose and bicarbonate: Identify the commonest underlying causes.
- Urine potassium: Shows whether the kidneys are wasting or retaining potassium.
- Renin, aldosterone and cortisol: Requested when blood pressure is high with low potassium, or when adrenal failure is suspected.
Treatment options
- Medication review: Reducing, stopping or switching the responsible drug often solves the problem.
- Potassium replacement: Tablets or liquid for mild deficits; slow intravenous infusion with heart monitoring when severe. Magnesium is corrected at the same time.
- Emergency treatment of high potassium: Intravenous calcium to protect the heart, insulin with glucose and nebulised salbutamol to shift potassium into cells, then measures to remove it.
- Potassium binders: Patiromer or sodium zirconium cyclosilicate allow some people with kidney or heart disease to stay on protective medicines.
- Dietary advice: Guidance from a renal dietitian on high-potassium foods and salt substitutes in kidney disease.
- Dialysis: For severe hyperkalaemia with kidney failure.
When it is urgent
A potassium above about 6.0 or below 2.5 mmol/L, or any abnormal level with palpitations, chest pain, fainting or marked weakness, is an emergency. Go to the nearest hospital; do not fly.
Travelling to Türkiye for treatment
Potassium problems are handled locally and quickly. A visit is only sensible for investigating a recurrent, unexplained abnormality once you are stable, for example testing for primary aldosteronism, including adrenal vein sampling, or for a hereditary tubular disorder. Follow-up blood tests then continue with your own doctor.
Send your reports, scans and a short history and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Should I eat bananas for low potassium?
Food helps maintain potassium but rarely corrects a real deficit, which usually needs supplements and treatment of the cause.
Do I have to stop my heart or kidney tablets because of high potassium?
Not necessarily. Diet changes, diuretics or a potassium binder may allow you to continue medicines that protect your heart and kidneys. Decide this with your doctor.
Are salt substitutes safe?
Many contain potassium chloride. They can be dangerous if you have kidney disease or take potassium-retaining drugs.