Low Potassium

Low Potassium Overview

Potassium is a mineral (electrolyte) in the body. Almost 98% of potassium is found inside the cells. Small changes in the level of potassium that is present outside the cells can have severe effects on the heart, nerves, and muscles.

Potassium is important to maintain several bodily functions:

* Muscles need potassium to contract.

* The heart muscle needs potassium to beat properly and regulate blood pressure.

The kidney is the main organ that controls the balance of potassium. It removes excess potassium into the urine.

When potassium levels are low (hypokalemia), you can become weak as cellular processes are impaired.

* The normal potassium level is 3.5-5.0 mEq/L (this is a measure used to evaluate the level). Low potassium is defined as a potassium level below 3.5 mEq/L.

* Almost one out of five people hospitalized in the United States has a low potassium level. Up to 14% of people otherwise seen in doctors' offices have slightly low potassium levels.

Low Potassium Causes

Low potassium can occur for many reasons. Use of water pills (diuretics), diarrhea, and chronic laxative abuse are the most common causes of low potassium.

Illness and other medications may also lower potassium levels. Other causes include:

Kidney losses

* Certain kidney disorders such as renal tubular acidosis (for example, chronic kidney failure and acute kidney failure)

* Magnesium deficiency

* Leukemia

Loss of potassium through stomach and intestines

* Vomiting

* Enemas or excessive laxative use

* Diarrhea

* After ileostomy operation

Effect of medicines

* Water pills (diuretics)

* Medicines used for asthma or emphysema (beta-adrenergic agonist type of drugs such as bronchodilators, steroids, or theophylline)

* Aminoglycosides (a type of antibiotic used for treating certain serious infections)

Shifting of potassium across cells can lower the concentration of potassium measured in the blood.

* Use of insulin

* Certain metabolic states (such as alkalosis)

Low Potassium Symptoms

Usually symptoms of low potassium are mild. At times they can be vague. You may have more than one symptom involving the gastrointestinal (GI) tract, kidneys, muscles, heart, and nerves.

* Weakness, tiredness, or cramping in arm or leg muscles, sometimes severe enough to cause inability to move arms or legs due to weakness (much like a paralysis)

* Tingling or numbness

* Nausea or vomiting

* Abdominal cramping, bloating

* Constipation

* Palpitations (feeling your heart beat irregularly)

* Passing large amounts of urine or feeling very thirsty most of the time

* Fainting due to low blood pressure

* Abnormal psychological behavior: depression, psychosis, delirium, confusion, or hallucinations.

Low Potassium Treatment

Self-Care at Home

If you are monitoring low potassium levels, avoid long, strenuous physical activities because of sweat loss of potassium.

If dietary supplements, herbal supplements, diuretics (water pills), or laxatives are causing the patient's low potassium symptoms, have the patient avoid taking these products and consult the doctor. Never stop taking a prescribed medication without first consulting your doctor.

Medical Treatment

Potassium replacement therapy will be directed by the type and severity of the patient's symptoms. Treatment begins after lab tests confirm the diagnosis.

People suspected of having severely low potassium need to be placed on a cardiac monitor and have an IV started.

Usually, those with mild or moderately low potassium levels (2.5-3.5 mEq/L), who have no symptoms, or who have only minor complaints only need to be treated with potassium given in pill or liquid form. This is preferred because it is easy to administer, safe, inexpensive, and readily absorbed from the gastrointestinal tract. Some preparations, or too high of a dose, may irritate the stomach and cause vomiting.

If cardiac arrhythmias or significant symptoms are present or if the potassium level is less than 2.5 mEq/L, IV potassium should be given. In this situation, admission or observation in the emergency department is indicated. Replacing potassium takes several hours as it must be administered very slowly intravenously to avoid heart problems.

For those with severely low potassium and symptoms, both IV potassium and oral medication are necessary.

Precautions:

* When potassium is used with medications such as ACE inhibitors, there is a risk of developing a high level of potassium.

* Potassium-sparing diuretics and potassium-containing salt substitutes can also result in high potassium levels.