Low blood potassium may also be referred to as hypokalemia. It occurs when there is not enough potassium in your body. Potassium helps the nerves and muscles in your body, and particularly the heart, to function normally. Eating a healthy, balanced diet helps your body get enough potassium.
Low blood potassium is usually caused by a condition other than poor diet, however. Treating low blood potassium can typically restore the mineral balance in the body and prevent any lasting problems.
Causes of Low Blood Potassium
Low blood potassium is usually caused by the body excreting too much potassium or being unable to absorb enough potassium from food and diet. This may happen due to:
- excessive sweating
- eating disorders
- laxative abuse
- use of diuretics (water pills)
- antibiotic use
- magnesium deficiency
- primary aldosteronism: a condition that is caused by problems with your adrenal glands
- diabetic ketoacidosis: when your body uses fat for fuel instead of sugar because it does not have enough insulin
- kidney disease or failure
- thyroid problems
Symptoms of Low Blood Potassium
Symptoms of low blood potassium tend to progress the longer the condition is left untreated. Symptoms may include:
- muscle spasms
- muscle weakness and damage
- dysrhythmia (abnormal heart rhythms)
- paralysis: when part of your body can no longer move or feel sensation
Rarely, serious cases of low blood potassium can cause life-threatening dysrhythmias and kidney damage.
Tests for Low Blood Potassium
Blood tests are done to check the level of potassium. These are usually done in a lab. A phlebotomist (a healthcare professional who takes blood) will tie an elastic band around your upper arm and ask you to make a fist. This helps your veins to pop out. He or she will then insert a needle into your vein to begin collecting blood in a tube. This may feel like a small pinch.
You will be able to relax your arm and the elastic tie will be removed while the blood is being drawn. The amount of blood taken depends on the number of tests your doctor ordered. When the phlebotomist is finished drawing blood, he or she will apply pressure to the wound to prevent bruising. A bandage will then be applied.
Along with checking the level of potassium in your blood, your doctor may wish to test the levels of other minerals in your body, including magnesium,calcium, sodium, and phosphorus. This will help your doctor determine if you have other mineral deficiencies.
Your blood may also be tested for:
- glucose (which can identify diabetes)
- thyroxine (which can determine a thyroid problem)
- aldosterone (which can indicate primary aldosteronism)
If your doctor suspects that low blood potassium is causing paralysis in your lungs, he or she may wish to have your blood gases tested. This involves measuring the amount of oxygen and carbon dioxide in your blood, which will give your doctor information about how well your lungs are working.
An electrocardiogram (ECG), a test that measures electricity in your heart, may be done to check for dysrhythmias.
Restoring Your Blood Potassium Levels to Normal
The goal of treatment for low blood potassium is to restore your potassium level to normal. This can be done by taking potassium supplements. Your doctor will tell you how much you need to take depending on your potassium level.
If your blood potassium is very low, your doctor may order potassium to be given intravenously (IV). This allows your potassium level to increase more quickly, which may be necessary with more severe symptoms. Your doctor will monitor your potassium level throughout treatment.
If you are on diuretic medication, your doctor may wish to change your medication to prevent too much potassium from being lost in your urine. Your doctor will also wish to treat any conditions that are causing your low blood potassium such as:
Primary Aldosteronism (PA)
When you have PA, your adrenal glands (on top of your kidneys) produce too much of the hormone aldosterone, which balances sodium and potassium in your body. Excess aldosterone causes your body to retain sodium, so potassium is low in comparison. Treatment for PA depends on its cause. These include overactive adrenal glands (most common) or a noncancerous tumour in one gland. Rarely, the condition is the result of an inherited disorder or a cancerous tumor. Treatments include medication, lifestyle changes, and surgery for tumours.
Diabetic Ketoacidosis (DK)
This condition occurs when your body does not have enough insulin to fuel itself. When insulin is too low, levels of electrolytes (such as potassium) can also fall. An episode of DK can result from illness or infection, including pneumonia and urinary tract infections. The condition can also occur because of a problem with insulin therapy, such as a missed dose, in someone who has diabetes. DK is treated with insulin and fluids.
Thyroxitic Periodic Paralysis
This is a genetic thyroid disorder in which too much thyroid hormone levels cause episodes of muscle weakness. During these episodes, your potassium level drops. Controlling thyroid hormone levels through medication and lifestyle modifications may treat this condition.
Hypokalemic Periodic Paralysis
This condition is similar to thyroxitic periodic paralysis, but it does not involve the thyroid. Low potassium occurs during an attack of muscle weakness because potassium moves abnormally from the blood to the muscle cells. Treatment to prevent these attacks includes medication and dietary changes.
Eating a diet that is rich in potassium can help prevent and treat low blood potassium. If you are taking potassium supplements, discuss your diet with your doctor to make sure you are not taking too much potassium. Good sources of potassium include: