Increased potassium, or hyperkalemia, interferes with the electrical currents of the body. The cells of the body rely on the flow of electrolytes such as sodium and potassium into and out of cells in order to function properly. Electrolyte imbalances such as high potassium interfere with this functioning and can affect the heart, causing arrhythmias. It is important to consult a physician regarding the diagnosis and treatment of high potassium levels.
Symptoms and Signs
Increased potassium frequently causes no symptoms. The more slowly the potassium rises, the less likely symptoms are to develop. If symptoms do appear, they tend to affect nerve and muscle the most. In addition, many symptoms are nonspecific, such as fatigue and malaise. Other symptoms may include nausea, muscle weakness and tingling. If the heart is affected, it can develop an arrhythmia, felt as a palpitation, or fluttering in the chest. Arrhythmias may go unnoticed as well. They can also cause chest pain or shortness of breath.
Causes
Potassium enters the body through the gastrointestinal tract. It is found in the blood, stored in high concentration inside of cells and excreted by the kidneys. Problems in these areas can result in hyperkalemia. It is unlikely, but possible, to overdose on oral potassium from the diet or potassium pills. It is unlikely because the intestinal tract absorbs potassium slowly, and healthy kidneys are able to excrete potassium into the urine relatively quickly. Potassium delivered by I.V., however, goes straight to the blood bypassing the intestine, and can rapidly cause high blood potassium. In addition, damage to cells, such as from chemotherapy or a crush injury to muscle can release potassium into the blood; a build up of acid in the blood also causes cellular release of potassium. Kidney issues, such as medications or kidney disease, will also cause potassium to build up. The excessive potassium interferes with electrical conduction of the heart, which leads to arrhythmias and can even stop the heart.
Diagnosis
Diagnosis of hyperkalemia is made from blood tests. The cause can be established from a medical history that is positive for symptoms of high blood potassium or risk factors such as kidney disease, a physical exam and other laboratory tests. The diagnosis of arrhythmias is similar. Arrhythmias can be diagnosed by a history of typical symptoms, a physical exam demonstrating an abnormal pulse, blood pressure and heart sounds, and other tests such as an ECG. The ECG measures the electrical currents in the heart through painless electrodes on the skin.
Treatment
The treatment of high potassium depends on the cause. Treatment is aimed at immediately bringing down the potassium while addressing the underlying cause. Certain drugs can cause cells to take up potassium, can bind potassium in the intestine, or increase kidney output. While the potassium is being lowered by these drugs, a physician can work on treating the underlying cause of high potassium. This can be done, for example, by eliminating a medication that is increasing the potassium, or giving antibiotics to treat an infection that is acidifying the blood and causing high potassium.
In addition, if there is an arrhythmia, calcium can be given intravenously to stabilize the heart muscle. Once the potassium is lowered, the arrhythmia should disappear. If a dangerous arrhythmia occurs, it will be necessary to give an anti-arrhythmia medication or deliver an electrical shock to the heart through a defibrillator or pacemaker according to "Harrison's Principles of Internal Medicine" by Anthony S. Fauci, M.D.
References
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci, et al.; 17th Ed 2008
- "Physiology"; Linda S.Costanzo; 4th Ed 2008
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