Potassium is one of the major electrolytes that your body carefully controls for proper heart and neuromuscular activity. A high potassium blood level, or hyperkalemia, is seen in a variety of medical conditions, including cancer and cancer treatment. Prompt recognition and treatment of hyperkalemia are important to avoid potentially life-threatening side effects.
Potassium is one of the body's major electrolytes, found in much higher concentrations inside your cells than in the surrounding fluids or blood. Nerves, muscles and the heart require carefully maintained blood potassium levels to function properly. Potassium is obtained through the diet, with excess amounts excreted primarily by the kidneys. According to Lab Tests Online, the most common cause of hyperkalemia is kidney disease, but certain medications, tissue injuries, dehydration, infection and diabetes can also lead to elevated blood potassium.
Hyperkalemia in Cancer
Cancer patients face additional risk factors for hyperkalemia, although kidney problems still commonly play a role. Side effects of chemotherapy, breakdown of tumor cells, hormones produced by certain types of tumors and extensive replacement of the adrenal glands by tumors can all result in high potassium blood levels, according to the "Manual of Clinical Oncology." In addition, very high white blood cell or blood platelet counts can cause an artificial increase in potassium in a test sample after the blood is drawn. This "pseudohyperkalemia" must be separated from true hyperkalemia occurring in the body.
Tumor Lysis Syndrome
Rapidly growing advanced cancers, especially certain types of lymphoma and leukemia, can respond dramatically to initial doses of chemotherapy. This results in extensive tumor cell death and breakdown and the release of large amounts of cellular material, including potassium, in a condition called tumor lysis syndrome. Tumor lysis syndrome usually occurs within hours or a few days of starting treatment, and if a patient is in a high-risk category, he will be monitored for increasing potassium levels as well as other blood and urine changes. Treatment is based on the severity of hyperkalemia and any complications that arise.
Symptoms of Hyperkalemia
Potassium levels are commonly monitored in cancer patients because mild or early hyperkalemia often shows no symptoms, according to MedHelp.org. As potassium levels worsen, symptoms can include muscle weakness, nausea and changes in heart function. The heart rate and pulse tend to become irregular and progressively slower, eventually leading to complete heart stoppage. Characteristic heart changes from hyperkalemia can be seen on an ECG, or electrocardiogram, and measuring potassium blood levels allows for a diagnosis.
Hyperkalemia treatment varies depending on the degree of potassium elevation and the symptoms present. Mild hyperkalemia can be treated with a low potassium diet or certain diuretic medications. Life-threatening potassium levels require more aggressive therapy, which could include intravenous glucose and insulin, intravenous calcium or methods to actively remove excess potassium such as dialysis or potassium-absorbing medications. The best long-term solution is successful treatment of the cancer or other underlying cause of hyperkalemia.