Hypokalemia is a drop in the amount of potassium in the blood. It can cause muscle weakness, cramps, and changes in heart rhythm.
Low potassium can happen after frequent vomiting, with laxative use, or as a side effect of certain medications. Potassium is an electrolyte found in many foods, including bananas, pumpkin seeds, orange juice, and carrots.
It is essential for proper muscle function and for sending nerve signals throughout the body. Treatment for hypokalemia should be guided by a healthcare provider and usually involves an oral potassium supplement or, in more severe cases, potassium given directly into a vein.
Hypokalemia symptoms
The main symptoms of hypokalemia are:
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Cramps
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Involuntary muscle contractions
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Persistent weakness
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Difficulty breathing
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Changes in heart rhythm
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Paralysis, in more severe cases
Symptom severity depends on how low potassium levels are in the blood. In general, the lower the potassium level, the more intense the symptoms may be.
Hypokalemia should be identified and treated properly, as very low potassium levels can lead to muscle paralysis and kidney failure, for example. This condition can be especially serious for people with heart problems.
Confirming a diagnosis
Hypokalemia is diagnosed based on blood potassium levels and the symptoms a person has. Normal blood potassium levels are usually between 3.5 mEq/L and 5.0 to 5.5 mEq/L, although this range may vary slightly between laboratories.
Therefore, potassium levels below 3.5 mEq/L indicate hypokalemia.
The doctor may also order an electrocardiogram, especially in moderate to severe cases, as hypokalemia can cause changes in heart rhythm.
Main causes
The main causes of low potassium in the blood are:
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Vomiting and diarrhea, which are the most common causes of low potassium in the blood due to potassium loss through the gastrointestinal tract.
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Use of certain medications, such as insulin, albuterol, and theophylline, for example, as these can move potassium into the cells and lower its concentration in the blood.
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Hyperthyroidism, which can also cause potassium to shift into the cells.
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Changes in the adrenal glands, leading to increased aldosterone production. Aldosterone is a hormone that regulates the balance between sodium and potassium, and when levels are high, it can increase potassium loss in the urine, resulting in hypokalemia.
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Regular use of laxatives, as this can lead to electrolyte loss and, over time, may cause kidney and heart problems.
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Cushing syndrome, which occurs due to increased cortisol levels in the blood. As a result, more potassium is eliminated in the urine, causing hypokalemia.
Low potassium in the blood is rarely related to diet, since most foods eaten day to day contain adequate amounts of potassium.
Treatment options
Treatment for low potassium, or hypokalemia, depends on the underlying cause, the severity of symptoms, and the level of potassium in the blood.
In most cases, a primary care doctor may recommend an oral potassium supplement. This is usually taken in divided doses with meals to help prevent irritation of the gastrointestinal tract.
In more severe cases, potassium may be given directly into a vein to restore potassium levels more quickly. According to the American Academy of Family Physicians, urgent treatment may be needed when serum potassium is 2.5 mEq/L or lower, or when there are ECG abnormalities or neuromuscular symptoms.
IV potassium may also be recommended when potassium levels continue to drop even with oral supplements.