Potassium is an electrolyte normally found inside cells and is essential for proper functioning of the heart, muscles and nervous system. A high level of potassium in the blood, also known as hyperkalemia, can be caused by a variety of conditions, and the symptoms can be difficult to diagnose. A normal level of potassium for an adult varies from 3.5 to 5.0 milli-equivalents per litre (mEq/L).
You may not experience any symptoms until the potassium in your blood reaches a significant level. Initially, a high level of potassium in the blood can cause nausea, fatigue, paralysis, muscle weakness or tingling in the extremities and tongue. As the level continues to rise, it can cause the heartbeat to slow or become arrhythmic and, in the most extreme cases, actually stop. Overly high potassium levels can also cause confusion, shallow breathing, seizure or convulsions, uneven heartbeat, heavy feeling in your arms or legs, or feeling faint.
If this condition is not diagnosed immediately it can have long-term effects on the heart, kidneys, nerves and muscle function, leading to atherosclerosis, blood pressure problems, heart arrhythmia and digestive system complications. Since the digestive system and kidneys are what the body uses to process potassium, this can aggravate the problem.
One of the most common causes of an increased potassium level is problems with kidney function. It can also be caused by lupus nephritis, diabetes, Addison's disease or tissue trauma. Some medications can cause the blood potassium levels to increase because they interfere with the body's ability to filter the potassium from the blood. These include ACE inhibitors, NSAIDs, potassium-sparing diuretics and potassium supplements.
Treatment for a high level of potassium includes insulin, beta-agonists or sodium bicarbonate. These promote the movement of potassium from the blood back into the cells. Diuretics can be given to help the kidneys excrete potassium, and binding resins can help the digestive system with the exchange of potassium and sodium. Long-term treatment often involves changes to the diet to decrease potassium intake.
A high potassium level should be taken seriously, as it can cause the heart to stop if untreated for too long. This can be difficult to diagnose because symptoms do not necessarily appear until the level is high enough to cause significant problems. Severe hyperkalemia is present when the level of potassium in the blood reaches 7.0 mEq/L and has approximately a 67 per cent mortality rate. Medical attention should be sought immediately if any of these primary symptoms are experienced.