Hypokalemia: Causes, Symptoms, Diagnosis, Prevention and Treatment

Low levels of potassium in the blood.

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

Potassium is important to maintain various bodily functions:

  1. The muscles need potassium to contract and dilate.
  2. The heart muscle needs potassium to properly beat and regulate blood pressure.
  3. The kidney is the main organ that controls the balance of potassium eliminating excess potassium in the urine.
  4. When potassium levels are low (hypokalemia), the organism enters a state of weakness as cellular processes deteriorate.
  5. The normal potassium level is 3.5-5.0 mEq / L (mEq / L represents milliequivalents per liter of blood and this is a unit of measurement used to assess the level). Low potassium is defined as a potassium level below 3.5 mEq / L.

Nearly one in five people hospitalized in the United States has a low potassium level. People with eating disorders such as anorexia nervosa and bulimia, patients with AIDS, alcoholics and those who have had bariatric surgery have a higher incidence of hypokalemia than others.


Low potassium can occur for many reasons. The use of diuretic pills, diarrhea and chronic laxative abuse are the most common causes of low potassium levels.

Some diseases and other medications can also lower potassium levels. Women and African-Americans are at greater risk of developing hypokalemia.

Other causes of hypokalemia include:

  • Renal impairment.
  • Certain renal disorders such as renal tubular acidosis (eg, chronic renal failure and acute renal failure).
  • Magnesium deficiency
  • Leukemia.
  • Cushing’s disease (and other adrenal disorders).
  • Loss of potassium through the stomach and intestines.
  • Threw up.
  • Enemas or excessive use of laxatives.
  • Diarrhea.
  • After the ileostomy operation.
  • Side effect of medications.
  • Diuretic pills
  • Drugs used for asthma or emphysema (beta-adrenergic agonist drugs such as bronchodilators, steroids or theophylline).
  • Aminoglycosides (a type of antibiotic)
  • The change of potassium inside and outside the cells can decrease the concentration of potassium measured in the blood.
  • Use of insulin
  • Certain metabolic states (such as alkalosis).
  • Decrease in food intake or malnutrition.
  • Anorexia.
  • Bulimia.
  • Bariatric surgery.
  • Alcoholism.


Usually, the symptoms of low potassium content are mild. Sometimes the effects of low potassium content can be vague. There may be more than one symptom that involves the gastrointestinal tract, kidneys, muscles, heart and nerves.

Weakness, tiredness or cramping in the arm or leg muscles, sometimes severe enough to cause inability to move the arms or legs due to weakness (such as paralysis).

  1. Tingling or numbness
  2. Nausea or vomiting
  3. Abdominal cramps, swelling.
  4. Constipation.
  5. Palpitations (feeling that your heart beats irregularly).
  6. Spend large amounts of urine or thirsty most of the time.
  7. Fainting due to low blood pressure.
  8. Abnormal psychological behavior: depression, psychosis, delirium, confusion or hallucinations.

When to seek medical attention for hypokalemia

If you have symptoms of low potassium, call your doctor. If you have muscle cramps, weakness, palpitations or feel weak and are taking a diuretic, contact your healthcare professional or go immediately to an urgent care center or to the emergency department of the hospital.

Without symptoms, you will not know that you have low potassium levels until you have a routine blood test or an electrocardiogram.

Diagnosis of low levels of Potassium in the body

Sometimes the cause of low potassium content is unclear. Your doctor may perform certain tests to rule out other conditions such as renal tubular acidosis, Cushing’s syndrome, and hypocalcemia.

If an electrolyte imbalance is suspected, blood tests will be ordered to monitor potassium levels, renal function (creatinine), glucose, magnesium, calcium and phosphorus if an electrolyte imbalance is suspected.

Because it is known that low potassium content affects cardiac rhythms (arrhythmias), a doctor may order a level of Digoxin (Lanoxin).

An electrocardiogram or cardiac scan is performed to detect electrical changes in the heart and certain types of irregular heart rhythms that can be caused by low potassium content.

Monitoring of potassium levels from home

If you are monitoring low levels of potassium, avoid long and strenuous physical activities because the loss of potassium occurs with sweating.

If dietary supplements, herbal supplements, diuretics or laxatives are causing symptoms of low potassium, avoid taking these products and consult a doctor.

Never stop taking a prescription without first talking to your doctor.

Medical treatment

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

People suspected of having a low potassium level should be placed on a cardiac monitor.

Normally, those patients with low or moderately low potassium levels (2.5-3.5 mEq / L), who have no symptoms or who have only minor complaints need only be treated with given potassium in the form of a pill or liquid.

This is preferred because it is easy to administer, safe, inexpensive and easily absorbed from the gastrointestinal tract. Some preparations, or a dose too high, can irritate the stomach and cause vomiting.

If there are cardiac arrhythmias or significant symptoms or if the potassium level is less than 2.5 mEq / L, potassium should be administered. In this situation, admission or observation in the emergency service is indicated.

Potassium replacement takes several hours, since it must be administered very slowly intravenously to avoid serious heart problems and avoid irritating the blood vessel where the line is placed.

For those with potassium levels and very low symptoms, both potassium and oral medication are necessary.


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 levels of potassium.

Follow-up of Hypokalemia

Usually, doctors recommend a certain dose of potassium supplements to have a level of blood monitoring taken 2-3 days later.