Hyperkalemia
(High Blood Potassium)

Medical Author: Melissa C. Stoppler, MD
Medical Editors: Dennis Lee, MD and William C. Shiel Jr., MD, FACP, FACR

• What is hyperkalemia?
• How does hyperkalemia affect the body?
• What causes hyperkalemia?
• Kidney dysfunction
• Diseases of the adrenal gland
• Potassium shifts
• Medications
• What are the symptoms of hyperkalemia?
• How is hyperkalemia diagnosed?
• How is hyperkalemia treated?
• Related hyperkalemia (high sodium blood levels) article:
  Hyperkalemia - on eMedicineHealth
• Patient Discussions: Hyperkalemia - How Was Diagnosis Established

Featured hyperkalemia patient discussions on established diagnosis "was diagnosed with Cushing's syndrome in 2006. I had my left adrenal gland removed and felt better for two months. I then started having Cushing’s syndrome symptoms again and had my right adrenal removed in February of 2008. Since surgery, I have been hospitalized three times with hyperkalemia. My potassium levels were 10, 8.8 and 8.0. I had to have dialysis five times and the last time I was hospitalized, I crashed twice. Since then, my endocrinologist can't figure out what level of prednisone to put me on, and I feel like there is no end to feeling sick. " "My potassium level reached 7.5 (severe), and I had almost constant weakness in my legs. I could barely walk. I had a recurring nauseated feeling in my stomach. I had no energy accompanied by an overall exhausted feeling. I had no appetite. Hyperkalemia was detected through a blood test. " "I had been taking several medications for high blood pressure, including a diuretic, Norvasc 10 mg, metoprolol, and an ACE inhibitor. I had a second episode of irregular heartbeat and went to hospital where I was found to have hyperkalemia. My symptoms were/are tingling/numbness in lower extremities, sweating, and a slight shortness of breath." Read All Comments on Hyperkalemia » Top Searched Hyperkalemia Terms: symptoms, treatment, ecg, thrombocytosis, chronic renal failure, diabetic ketoacidosis, diet, definition, insulin, drug induced, arrhythmia Patient Discussions are not a substitute for professional medical advice, or treatment. See the disclaimer at the bottom of the comments page.

What is hyperkalemia?

Hyperkalemia is common; it is diagnosed in up to 8% of hospitalized patients in the U.S. Fortunately, most patients have mild hyperkalemia (which is usually well tolerated). However, any condition causing even mild hyperkalemia should be treated to prevent progression into more severe hyperkalemia. Extremely high levels of potassium in the blood (severe hyperkalemia) can lead to cardiac arrest and death. When not recognized and treated properly, severe hyperkalemia results in a mortality rate of about 67%.

Technically, hyperkalemia means an abnormally elevated level of potassium in the blood. The normal potassium level in the blood is 3.5-5.0 milliequivalents per liter (mEq/L). Potassium levels between 5.1 mEq/L to 6.0 mEq/L reflect mild hyperkalemia. Potassium levels of 6.1 mEq/L to 7.0 mEq/L are moderate hyperkalemia, and levels above 7 mEq/L are severe hyperkalemia.

How does hyperkalemia affect the body?

Potassium is critical for the normal functioning of the muscles, heart, and nerves. It plays an important role in controlling activity of smooth muscle (such as the muscle found in the digestive tract) and skeletal muscle (muscles of the extremities and torso), as well as the muscles of the heart. It is also important for normal transmission of electrical signals throughout the nervous system within the body.

Normal blood levels of potassium are critical for maintaining normal heart electrical rhythm. Both low blood potassium levels (hypokalemia) and high blood potassium levels (hyperkalemia) can lead to abnormal heart rhythms.

The most important clinical effect of hyperkalemia is related to electrical rhythm of the heart. While mild hyperkalemia probably has a limited effect on the heart, moderate hyperkalemia can produce EKG changes (EKG is an electrical reading of the heart muscles), and severe hyperkalemia can cause suppression of electrical activity of the heart and can cause the heart to stop beating.

Another important effect of hyperkalemia is interference with functioning of the skeletal muscles. Hyperkalemic periodic paralysis is a rare inherited disorder in which patients can develop sudden onset of hyperkalemia which in turn causes muscle paralysis. The reason for the muscle paralysis is not clearly understood, but it is probably due to hyperkalemia suppressing the electrical activity of the muscle.

Hyperkalemia - How Was Diagnosis Established

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