A high potassium level has many causes, including kidney disorders, drugs 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 drugs that may cause hyperkalemia, and using drugs to increase potassium excretion.
(See also Overview of Electrolytes Overview of Electrolytes Well over half of the body's weight is made up of water. Doctors think about the body's water as being restricted to various spaces, called fluid compartments. The three main compartments are... read more and Overview of Potassium's Role in the Body 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. (See also Overview of Electrolytes.) Most of the body’s... read more .)
Potassium 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. (See also Overview of Electrolytes.) Most of the body’s... read more is one of the body's electrolytes, which are minerals Overview of Minerals Minerals are necessary for the normal functioning of the body’s cells. The body needs relatively large quantities of Calcium Chloride Magnesium Phosphate read more that carry an electric charge when dissolved in body fluids such as blood. The body needs potassium 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. (See also Overview of Electrolytes.) Most of the body’s... read more 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
Drugs that prevent the kidneys from excreting normal amounts of potassium (a common cause of mild hyperkalemia)
A diet high in potassium
Treatments that contain potassium
The most common cause of mild hyperkalemia is
The use of drugs that decrease blood flow to the kidneys or prevent the kidneys from excreting normal amounts of potassium
Kidney failure Overview of Kidney Failure This chapter includes a new section on COVID-19 and acute kidney injury (AKI). Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney... read more can cause severe hyperkalemia on its own. Addison disease Adrenal Insufficiency In adrenal insufficiency, the adrenal glands do not produce enough adrenal hormones. Adrenal insufficiency may be caused by a disorder of the adrenal glands, a disorder of the pituitary gland... read more 
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 intake of potassium does not often 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 Familial Periodic Paralysis Familial periodic paralysis is a rare inherited disorder that causes sudden attacks of weakness and paralysis. There are four different forms, which involve abnormalities in how electrolytes... read more , people have attacks of weakness that can progress to paralysis.
When hyperkalemia becomes more severe, it can cause abnormal heart rhythms Overview of Abnormal Heart Rhythms Abnormal heart rhythms (arrhythmias) are sequences of heartbeats that are irregular, too fast, too slow, or conducted via an abnormal electrical pathway through the heart. Heart disorders are... read more 
. If the level is very high, the heart can stop beating.
Diagnosis of Hyperkalemia
Measurement of potassium level in the blood
Usually, hyperkalemia is first detected when routine blood tests are done or when a doctor notices certain changes on an electrocardiogram Electrocardiography Electrocardiography (ECG) is a quick, simple, painless procedure in which the heart’s electrical impulses are amplified and recorded. This record, the electrocardiogram (also known as an ECG)... read more 
(ECG).
To identify the cause, doctors evaluate a person's medical history and routine laboratory test results, determine which drugs people have been taking, and do additional blood tests to check for evidence of diabetes mellitus Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more , acidosis Acidosis Acidosis is caused by an overproduction of acid that builds up in the blood or an excessive loss of bicarbonate from the blood (metabolic acidosis) or by a buildup of carbon dioxide in the blood... read more , muscle breakdown, or kidney disorders.
Treatment of Hyperkalemia
Drugs to increase potassium excretion
The disorder that is causing hyperkalemia is treated.
Mild hyperkalemia
For mild hyperkalemia, reducing consumption of potassium or stopping drugs 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.
If needed, a resin that absorbs potassium from the digestive tract and passes out of the body in the stool can be given by mouth or enema. Sodium polystyrene sulfonate is a potassium-absorbing resin that is effective but used only for short periods because it can cause excess sodium Hypernatremia (High Level of Sodium in the Blood) In hypernatremia, the level of sodium in blood is too high. Hypernatremia involves dehydration, which can have many causes, including not drinking enough fluids, diarrhea, kidney dysfunction... read more to be retained. Patiromer is a resin drug that can be used for longer periods. It is useful for people who require drugs that usually raise potassium levels, such as angiotensin-converting enzyme (ACE) inhibitors for treatment of heart or kidney disease. Sodium zirconium cyclosilicate also binds to potassium in the gastrointestinal tract. It decreases serum potassium over several hours.
Moderate to severe hyperkalemia
For moderate to severe hyperkalemia, the potassium level must be reduced immediately. Doctors monitor the heart continuously during treatment. Calcium is given intravenously to protect the heart, but calcium does not lower the potassium level. Then insulin and glucose are given, which move potassium from blood into cells, thus lowering the potassium level in blood. Albuterol (used mainly to treat asthma) may be given to help lower the potassium level. It is inhaled.
If these measures do not work or if people have kidney failure, dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more 
may be necessary to remove the excess potassium.
