Hyperkalemia, or high potassium, means the level of potassium in your blood is higher than normal. Severe hyperkalemia usually occurs when kidneys are damaged and can't remove enough potassium from the bloodstream, but certain medications can also contribute to high potassium. Hyperkalemia is defined as a serum potassium level greater than 5.5 mill equivalents per liter (mEq/L); levels greater than 6 mEq/L may be life threatening, according to Margaret Roberson, M.D. at Virginia Commonwealth University.
Cardiac Symptoms
Cardiac changes are the most important symptom of severe hyperkalemia, and the most dangerous. Hyperkalemia can cause a weak or irregular heartbeat or arrhythmias. The heartbeat may be bradycardic, which means slow. Changes may be seen on an EKG, which should be done whenever a patient has high serum potassium levels. Complete heart block can occur, according to the National Library of Medicine, which means the electrical signals that tell the ventricles when to contract are slowed, and the heart rate drops to a very slow rate.
Lethal cardiac changes like ventricular fibrillation may occur in severe cases of hyperkalemia. Ventricular fibrillation can only be treated by cardiac defibrillation. Asystole, which means the heart is no longer beating, can also occur in hyperkalemia. In a 1998 article in "Lancet," M.L. Halperin and K.S. Kamel mention that asystole is often the first sign of hyperkalemia, meaning that the first recognizable symptom may be sudden death.
Because many symptoms of hyperkalemia are non specific, hyperkalemia may go undiagnosed until it's too late.
Skeletal Muscle Symptoms
People with hyperkalemia may feel weak and fatigued. In severe cases, a person with hyperkalemia may be completely limp and paralyzed. According to Jennifer Best, M.D. of Harborview Medical Center, symptoms as severe as paralysis don't occur until potassium levels are greater than 7 mEq/L. Potassium levels can be lowered by giving diuretics or kayexalate, a drug that binds to potassium and can be given in pill form or as an enema. Calcium or insulin may be infused; dialysis can also be used to lower very high potassium levels.
Other Symptoms
Severe hyperkalemia can cause paresthesias, or feelings of tingling and numbness. Respiratory distress and abdominal distention and nausea are also potential symptoms of severe hyperkalemia, according to the U.S. National Library of Medicine.
