High Potassium (Hyperkalemia): Symptoms, Causes and Testing

What it involves

MedlinePlus explains that potassium is an electrolyte, an electrically charged mineral that helps control fluid and acid-base balance and the activity of muscles and nerves. Your cells, nerves, heart and muscles need it to work properly. Your kidneys remove extra potassium in urine, and too much in the blood is called hyperkalemia.

Who this is for

• Adults whose blood work showed a high potassium level and who want to know what it means.
• Patients with kidney disease, diabetes or adrenal gland disorders who need regular monitoring.
• People who take water pills or other medicines that can change potassium levels.
• Anyone with muscle weakness, tingling, nausea or palpitations and no clear cause.

What to expect

• Questions about symptoms, kidney problems, diabetes, medicines, supplements, salt substitutes and diet
• A review of earlier results and a blood pressure and heart rate check
• Repeat blood work, which the practice offers, and an EKG at the Loxahatchee and West Palm Beach offices when rhythm is a concern
• A plan for the cause, and a referral to a kidney or heart specialist when needed

Why potassium matters

Potassium helps keep the heartbeat steady and the muscles working. MedlinePlus says levels that are too high or too low may be a sign of a medical condition and may cause serious health issues. Most of the body's potassium sits inside cells, with only a small amount in the blood, and the kidneys keep that amount in range. The opposite problem is covered in the low potassium guide, and a related electrolyte problem in the low sodium guide.

What it can feel like

MedlinePlus names arrhythmia, fatigue, muscle weakness, nausea and numbness or tingling as possible symptoms of high potassium. These are vague and shared by many conditions, which is why the level is usually found by testing rather than by symptoms. A fluttering or skipping heartbeat is described in the heart palpitations guide, and tingling in the numbness and tingling guide. Weakness that keeps getting worse is covered in the muscle weakness guide.

Common causes

The lab test page says high potassium is often the result of two or more causes. It lists kidney disease, because weak kidneys may not clear potassium, Addison disease, injuries, burns or surgery that release potassium from cells, and poorly controlled type 1 diabetes. Certain medicines, including water pills and some antibiotics, can raise levels, and so can potassium supplements or very large amounts of potassium-rich food. The adrenal insufficiency guide and the chronic kidney disease guide describe two of these.

How it is tested

A potassium blood test measures the amount in a blood sample drawn from a vein, and MedlinePlus says it is often part of a routine electrolyte panel. No special preparation is needed unless other tests are on the same sample. Clenching and relaxing the fist before or during the draw can temporarily raise the level and give a wrong reading, so a repeat test is common. The basic metabolic panel guide and the kidney function tests guide show how the result fits with other numbers.

What happens after a high result

A single abnormal result does not always mean a condition needs treatment, according to MedlinePlus, because some medicines and supplements can raise levels and a blood draw can be affected. A provider usually repeats the test, reviews medicines and kidney function, and may check an EKG for rhythm changes. Treatment depends on the cause and how high the level is. Do not stop a prescribed medicine on your own, and avoid potassium supplements or salt substitutes unless a provider says they are safe for you.

When to get urgent help

Very high potassium can affect the heart. Call 911 or go to the ER for chest pain, fainting, a very slow or irregular heartbeat, severe weakness or trouble breathing, and do the same if a lab calls with a critically high value and tells you to go in. For a mildly high result with no symptoms, call the office, bring a list of medicines and supplements and plan repeat blood work. The sick visit versus urgent care or ER guide can help you decide where to go.

Sources

• MedlinePlus: Potassium Blood Test