Hypokalemia: when potassium levels are below normality

Hypokalemia is an electrolytic disorder characterized by low potassium levels in the blood. It is commonly caused by excessive potassium loss through urine or the gastrointestinal tract, but it can also result from a reduced intake of this essential electrolyte.

Potassium losses in the gastrointestinal tract are often due to:

• Chronic diarrhea
• Clay ingestion, which binds potassium and hinders its absorption
• Rarely, a villous adenoma in the colon, which can lead to massive potassium loss

Additionally, hypokalemia may be caused by an increase in potassium movement into cells, which can occur in situations such as:

• After insulin administration
• Stimulation of the sympathetic nervous system, such as with beta-2 adrenergic agonists
• Glycogenesis during parenteral nutrition

Certain diseases, including Cushing's syndrome and Bartter syndrome, as well as specific medications, can also cause excessive potassium loss through urine.

A mild decrease in blood potassium levels may cause no symptoms or very mild ones, such as:

• Constipation
• Irregular or pounding heartbeats (palpitations)
• Fatigue
• Muscle damage
• Muscle spasms or weakness
• Tingling and numbness

Severely low potassium levels can cause abnormal heart rhythms, especially in people with heart disease.

This can lead to dizziness or fainting. Extremely low potassium levels may result in heart failure.

The main risk factors for hypokalemia include:

• Taking certain medications (beta-2 adrenergic agonists, laxatives, or diuretics)
• Advanced age
• Certain diseases that affect potassium reabsorption at the renal level (e.g., Liddle syndrome or Bartter syndrome)
• Anorexia nervosa and/or bulimia
• Certain infectious or tumor-related diseases
• Conditions that cause vomiting and/or diarrhea

Measuring blood potassium levels is typically used to diagnose hypokalemia. Additional tests may be conducted to determine its causes and effects, including:

• Blood tests for glucose, magnesium, calcium, sodium, and phosphorus
• Thyroid hormones, such as free triiodothyronine (free T3) and free thyroxine (free T4)
• Aldosterone levels
• An electrocardiogram (ECG) to assess the heart

For mild cases, treatment involves prescribing oral or intravenous potassium supplements. In certain situations, diuretics may also be prescribed.

Dietary adjustments can also be made to include potassium-rich foods while maintaining a varied diet to restore potassium levels.

Hypokalemia can be prevented by following a balanced diet that includes potassium-rich foods or, if necessary, taking dietary potassium supplements. Proper management of underlying conditions that may cause hypokalemia can also help prevent it.