Metabolic alkalosis is an acid-base disorder in which blood becomes too alkaline because bicarbonate has increased or acid has been lost. It often occurs together with changes in chloride, potassium and body-fluid volume.

Common causes

Prolonged vomiting or stomach drainage can remove acid. Diuretic medicines, severe potassium depletion, excess alkali intake and certain hormone or inherited disorders can also contribute. Kidney function affects whether the alkalosis persists.

Symptoms and diagnosis

Mild cases may cause few symptoms. More significant electrolyte and pH changes can cause weakness, cramps, tingling, confusion or an abnormal heart rhythm. Diagnosis uses blood electrolyte and acid-base measurements, often including an arterial blood gas, together with medical and medicine history.

Treatment

The underlying cause determines treatment. A clinician may replace fluid, chloride or potassium, address vomiting, or adjust a contributing medicine. Diuretics and supplements should not be stopped or started without advice. Severe alkalosis or a dangerous rhythm disturbance requires monitored hospital treatment.

Persistent vomiting, confusion, fainting, marked weakness or palpitations warrants prompt assessment.