Hyperkalemia is the medical term for a potassium level in the blood that's higher than is healthy. Potassium is a chemical that nerve and muscle cells need to work. This includes the nerve and muscle cells of the heart. The kidneys help control the amount of potassium in the blood.

A healthy blood potassium level is 3.6 to 5.2 millimoles per liter (mmol/L). Having a blood potassium level higher than 6.0 mmol/L can be a danger. It most often needs treatment right away.

The most common cause of true high potassium, also called hyperkalemia, is linked to the kidneys. Causes might include:

• Acute kidney injury
• Chronic kidney disease

Some medicines or supplements can cause of hyperkalemia, including:

• Angiotensin-converting enzyme (ACE) inhibitors
• Angiotensin II receptor blockers
• Beta blockers
• Too much potassium supplement

Other causes of hyperkalemia include these conditions:

• Addison's disease
• Dehydration — when the body doesn't have enough water and other fluids to work as it should.
• Destroyed red blood cells from severe injury or burns
• Type 1 diabetes

Seek immediate medical attention

If you have symptoms of hyperkalemia, call your healthcare professional right away. This is especially true if you have kidney disease or are taking medicines that raise your potassium level.

Sudden or severe hyperkalemia is serious. It can be life-threatening. Symptoms may include:

• Muscle weakness.
• Weakness, numbness and tingling in the arms and legs.
• Shortness of breath.
• Chest pain.
• Irregular heart rhythms, called arrhythmias.
• Nausea or vomiting.