In hyperkalemia, the level of potassium in blood is too high.
A high potassium level has many causes, including kidney disorders, medications that affect kidney function, and consumption of too much supplemental potassium.
Usually, hyperkalemia must be severe before it causes symptoms, mainly abnormal heart rhythms.
Doctors usually detect hyperkalemia when blood tests or electrocardiography is done for other reasons.
Treatment includes reducing consumption of potassium, stopping medications that may cause hyperkalemia, and using medications to increase potassium excretion.
(See also Overview of Electrolytes and Overview of Potassium's Role in the Body.)
Potassium is one of the body's electrolytes, which are minerals that carry an electric charge when dissolved in body fluids such as blood. The body needs potassium for nerve and muscle cells to function, but too much potassium can also interfere with function.
Causes of Hyperkalemia
Usually, hyperkalemia results from several simultaneous problems, including the following:
Kidney disorders that prevent the kidneys from excreting enough potassium
Medications that prevent the kidneys from excreting normal amounts of potassium (a common cause of mild hyperkalemia)
A diet very high in potassium
Treatments that contain potassium
The most common cause of mild hyperkalemia is
The use of medications that decrease blood flow to the kidneys or prevent the kidneys from excreting normal amounts of potassium
Kidney failure can cause severe hyperkalemia on its own. Addison disease can also cause hyperkalemia.
Hyperkalemia can develop after a large amount of potassium is released from the cells. The rapid movement of potassium from cells into blood can overwhelm the kidneys and result in life-threatening hyperkalemia.
By itself, increased potassium in a person's diet does not usually cause hyperkalemia because normal kidneys do a good job in excreting any extra potassium.
Symptoms of Hyperkalemia
Mild hyperkalemia causes few, if any, symptoms. Sometimes, people may develop muscle weakness. In a rare disorder called hyperkalemic familial periodic paralysis, people have attacks of weakness that can progress to paralysis.
When hyperkalemia becomes more severe, it can cause abnormal heart rhythms. If the level is very high, the heart can stop beating.
Diagnosis of Hyperkalemia
Measurement of the level of potassium in the blood
Usually, hyperkalemia is first detected when routine blood tests are done or when a doctor notices certain changes on an electrocardiogram (ECG).
To identify the cause, doctors evaluate a person's medical history and routine laboratory test results, determine which medications people have been taking, and do additional blood tests to check for evidence of diabetes mellitus, acidosis, muscle breakdown, or kidney disorders.
Treatment of Hyperkalemia
Medications to increase potassium excretion
The disorder that is causing hyperkalemia is treated.
Mild hyperkalemia
For mild hyperkalemia, reducing consumption of potassium or stopping medications that prevent the kidneys from excreting potassium may be all that is needed. If the kidneys are functioning, a diuretic that increases potassium excretion may be given.
Moderate to severe hyperkalemia
If these measures do not work or if people have kidney failure, dialysis may be necessary to remove the excess potassium.
