The normal blood level of potassium, a mineral critical to the function of nerve and muscles cells, is 3.6 to 4.8 milliequivalents per liter, or mEq/L, according to MayoClinic.com. A potassium level higher than 6.0 mEq/L can be dangerous and requires immediate treatment. The causes of high potassium levels, or hyperkalemia, include kidney problems that reduce the amount of potassium excreted by the body, drug or alcohol abuse, certain medications, type 1 diabetes, excessive potassium intake, burns and injury. The patient may be unaware of the problem until a blood test identifies hyperkalemia, according to the National Institutes of Health.
Cardiac Arrhythmias
Potassium regulates muscle and nerve functions, including those of the heart. Often, the patient has no symptoms until the blood potassium level is high enough to cause an irregular heartbeat that can be seen on an ECG or electrocardiogram, according to the Merck Manual. Severe hyperkalemia may cause a complete heart block or ventricular fibrillation, either of which is life threatening and requires immediate treatment, according to the National Institutes of Health. Treatment may include intravenous calcium to protect the heart, followed by medication to reduce the amount of potassium in the body, according to the Merck Manual. Dialysis may be needed if the patient's kidney function is not adequate.
Cardiac Arrest
Cardiac arrest or an absent heartbeat may occur at any time in a patient with hyperkalemia, so the patient should be monitored in the hospital if the potassium level is high, according to the National Institutes of Health. The patient may have bradycardia---a slow pulse, at first. The pulse continues to slow until it eventually stops. An irregular heartbeat or arrhythmia can also develop into a cardiac arrest. Treatment includes medication to remove potassium from the body, intravenous glucose and insulin to reverse symptoms, and dialysis if kidney function is compromised.
Muscle Weakness
Potassium is involved in regulating nerve and muscle function in the body so hyperkalemia can cause varying degrees of muscle fatigue and weakness until the problem is corrected. Patients with mild hyperkalemia may have no muscle or nerve symptoms, but those with moderate to severe hyperkalemia may complain of weakness, according to the Merck Manual. Patients with a rare genetic disorder called hyperkalemic familial periodic paralysis, which raises the level of potassium in the blood during attacks, may experience weakness and sometimes paralysis.
