An elevated potassium level is referred to as hyperkalemia. For the most part, people with hyperkalemia do not have symptoms until the blood or serum level becomes very high. The normal serum potassium level ranges from 3.5 to 5.3 milli-equivalents per liter. Health care providers consider a serum level greater than 7.0 mEq/l a critical value. An elevated potassium level can indicate a disease process, an adverse drug reaction or a metabolic imbalance.
Etiology
An elevated potassium level indicates a condition that causes an imbalance in the metabolic system. Sometimes medications like potassium sparing diuretics, penicillin and cephalosporin antibiotics, histamine, the anti-tuberculosis drug isoniazid and the blood thinner heparin cause the potassium imbalance. Hyperkalemia may also indicate kidney disease, the presence of Addison's disease or dehydration. Patients who suffer severe burns or trauma may develop hyperkalemia. This indicates the need for careful fluid volume control and maintenance of adequate kidney function to prevent worsening hyperkalemia.
Effects
Potassium plays an important role in the transmission of nerve impulses and electrical impulses through heart tissue. A patient who presents with nausea, abdominal cramping, muscle twitching, numbness and tingling to the extremities and an irregular heart rate indicates possible hyperkalemia.
Significance
Hyperkalemia may cause a dangerous life-threatening heart arrhythmia called heart block. High potassium levels interfere with heart impulse transmission. A heart block results, creating a very slow pulse. Another serious complication is ventricular fibrillation. When the heart rate becomes too slow the ventricles respond in an attempt to maintain blood pressure and circulation. Without normal potassium levels the response becomes erratic and the ventricles may only quiver rather than produce a sustainable regular heartbeat. The pulse can stop altogether.
Treatment
Because an elevated potassium level indicates the potential for cardiac arrest, medical treatment is necessary. Patients require hospitalization and heart monitoring. Physicians initiate emergency medical care to lower the potassium level until the underlying cause is corrected. Medications called cation-exchange resins increase the removal of potassium from the gastrointestinal tract. Diuretics increase the excretion of potassium in the urine. Intravenous calcium, glucose and insulin help control irregular heart rates until the potassium level is stabilized. In acute conditions, especially when kidney function is impaired, dialysis removes excess potassium from the body.
Considerations
Patients whose elevated potassium level is caused by kidney failure require long-term treatment with a low-potassium diet, avoidance of salt substitutes in a low-salt diet and the use of diuretics to promote potassium excretion. These patients also require periodic lab work to check serum potassium levels.
References
- Scott and White Healthcare: Hyperkalemia
- "Laboratory and Diagnostic Tests, 6th ed."; Joyce LeFever Kee; 2009
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