What are the complications of severe hypokalemia (low potassium levels)?

From the Guidelines

Severe hypokalemia (potassium level <2.5 mEq/L) can lead to life-threatening complications, including cardiac arrhythmias, neuromuscular weakness, and respiratory failure, emphasizing the need for prompt recognition and treatment. The most dangerous complications of severe hypokalemia include cardiac arrhythmias such as ventricular tachycardia, ventricular fibrillation, and torsades de pointes, which can be life-threatening 1. Patients may develop ECG changes including flattened T waves, ST depression, and prominent U waves before progressing to more serious rhythm disturbances.

Key Complications

• Cardiac arrhythmias: ventricular tachycardia, ventricular fibrillation, and torsades de pointes
• Neuromuscular complications: muscle weakness, cramps, ascending paralysis, and respiratory failure
• Rhabdomyolysis: potentially leading to acute kidney injury
• Gastrointestinal complications: ileus, constipation, and decreased gut motility
• Metabolic complications: glucose intolerance and metabolic alkalosis
• Renal complications: polyuria, polydipsia, and decreased concentrating ability of the kidneys

These complications occur because potassium is essential for normal cell membrane function, particularly in electrically excitable tissues like the heart and muscles, as noted in the context of hypokalemia definition and management 2. Potassium maintains the resting membrane potential and is crucial for action potential generation, explaining why cardiac and neuromuscular systems are particularly vulnerable to hypokalemia. Prompt recognition and treatment of severe hypokalemia are critical to prevent these complications and improve patient outcomes.

From the FDA Drug Label

The dose and rate of administration are dependent upon the specific condition of each patient... In urgent cases where the serum potassium level is less than 2 mEq/liter or where severe hypokalemia is a threat (serum potassium level less than 2 mEq/liter and electrocardiographic changes and/or muscle paralysis) EKG abnormalities serve as a clinical reflection of the seriousness of changes in serum potassium concentrations: peaked T waves and prolonged P-R intervals usually occur with modest elevations above the upper limit of normal potassium concentrations; P waves disappear, the QRS complex widens, and eventual asystole usually occurs with higher elevations

The complications of severe hypokalemia include electrocardiographic changes and/or muscle paralysis. Other potential complications may be inferred from the symptoms of hyperkalemia, which include paresthesia of the extremities, areflexia, muscular or respiratory paralysis, mental confusion, weakness, hypotension, cardiac arrhythmia, heart block, electrographic abnormalities, and cardiac arrest [3] [4].

From the Research

Complications of Severe Hypokalemia

• Severe hypokalemia, defined as a serum potassium level of 2.5 mEq per L or less, can lead to life-threatening cardiac conduction disturbances and neuromuscular dysfunction 5, 6, 7.
• Common symptoms of severe hypokalemia include cardiac arrhythmias, muscle weakness, and paralysis 8, 6, 9.
• Electrocardiography abnormalities, such as changes in the QT interval and T-wave flattening, can occur in patients with severe hypokalemia 5, 8, 6.
• Severe hypokalemia can also cause respiratory muscle weakness, leading to respiratory failure 7.
• The management of severe hypokalemia requires urgent treatment, including potassium replacement and addressing the underlying cause of the disorder 5, 8, 6, 7, 9.

Risk Factors for Severe Hypokalemia

• Diuretic use, particularly in elderly patients, can increase the risk of severe hypokalemia 8, 7, 9.
• Malnutrition and gastrointestinal losses can also contribute to the development of severe hypokalemia 9.
• Patients with cardiovascular conditions, such as heart failure, are at increased risk of severe hypokalemia 8.
• The use of certain medications, such as indapamide, can increase the risk of severe hypokalemia 7.

Treatment of Severe Hypokalemia

• Intravenous potassium replacement is often necessary in patients with severe hypokalemia, particularly those with cardiac arrhythmias or neuromuscular symptoms 5, 8, 6, 7.
• Oral potassium replacement can be used in patients with less severe hypokalemia or those who are asymptomatic 5, 8.
• Addressing the underlying cause of the disorder, such as discontinuing diuretic therapy or treating gastrointestinal losses, is also crucial in the management of severe hypokalemia 5, 8, 6, 7, 9.