Causes and Clinical Features of Metabolic Alkalosis

Introduction

Metabolic alkalosis is a condition characterized by elevated blood pH due to excess bicarbonate or loss of hydrogen ions. Understanding its causes, clinical features, and compensatory mechanisms is essential for effective diagnosis and management.

Causes of Metabolic Alkalosis

• Loss of Acid: Excessive vomiting leads to loss of gastric acid.
• Diuretic Therapy: Loop and thiazide diuretics increase bicarbonate reabsorption.
• Hyperaldosteronism: Aldosterone excess enhances renal hydrogen ion excretion.
• Excessive Bicarbonate Administration: Intake of sodium bicarbonate or citrate-containing solutions.
• Renal Dysfunction: Impaired bicarbonate excretion due to kidney disease.

Clinical Features of Metabolic Alkalosis

Patients may present with:

• Muscle cramps, tetany, and paresthesia due to hypocalcemia.
• Weakness and confusion resulting from electrolyte imbalances.
• Respiratory compensation leading to hypoventilation.
• Cardiac arrhythmias due to potassium depletion.

Compensatory Mechanisms

The body attempts to restore acid-base balance through:

• Respiratory Compensation: Hypoventilation increases CO2 levels.
• Renal Compensation: Reduced bicarbonate reabsorption and increased hydrogen ion retention.

Conclusion

Metabolic alkalosis arises from acid loss or bicarbonate excess and presents with neuromuscular and respiratory symptoms. Timely identification and appropriate management are crucial for preventing complications.