Hypokalemia

Definition

Hypokalemia is an abnormally low concentration of potassium in the bloodstream, impairing muscle function and cardiac rhythm.

How it works

Hypokalemia occurs when serum potassium falls below 3.5 mEq/L, disrupting the electrical gradient essential for muscle contraction and nerve impulse transmission. Potassium is the primary intracellular cation maintaining cellular osmolarity and resting membrane potential; deficiency causes muscle weakness, fatigue, and potentially life-threatening cardiac arrhythmias including premature ventricular contractions and torsades de pointes. Symptoms progress from subtle weakness to severe manifestations including paralysis and cardiac instability. Common causes include diarrhea, vomiting, diuretic medications, amphotericin B, and inadequate dietary intake. Hypokalemia is particularly concerning in individuals taking cardiac medications or with existing arrhythmias, as it increases sudden cardiac death risk.

Role

Hypokalemia impairs muscle contraction and electrical heart function, potentially causing life-threatening arrhythmias.

Examples

• Diuretic medications
• Diarrhea or vomiting
• Inadequate fruit and vegetable intake
• Alcohol abuse
• Amphotericin B
• Laxative abuse
• Excessive sweating

Recommendations

Increase dietary potassium through fruits, vegetables, legumes, and fish, aiming for 2,600-3,400 mg daily. Monitor potassium levels carefully if taking diuretics or have gastrointestinal losses. Seek medical care immediately if experiencing muscle weakness, palpitations, or shortness of breath, as these may indicate dangerous arrhythmias.

Key takeaway

Hypokalemia is a medical emergency that impairs cardiac function and requires prompt treatment of underlying causes and potassium replacement.

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