A 50-year-old woman presents to the outpatient clinic with complaints of muscle cramps, fatigue, and occasional dizziness. She has a history of gastroesophageal reflux disease (GERD) and has been taking high doses of over-the-counter antacids containing aluminium hydroxide and magnesium hydroxide for the past month to manage her symptoms. She also reports increased urination over the same period.

On examination, she appears well-nourished but slightly dehydrated. Vital signs reveal a blood pressure of 120/75 mmHg, a heart rate of 80 beats per minute, and a respiratory rate of 16 breaths per minute. Laboratory tests show a serum bicarbonate level of 34 mEq/L, a pH of 7.48, and a low serum potassium level of 3.2 mEq/L. A urinalysis reveals a urinary pH of 8.0.

Given her clinical presentation and laboratory findings, the patient is diagnosed with metabolic alkalosis, likely due to excessive antacid use leading to increased bicarbonate levels and hypokalaemia. She is advised to discontinue the over-the-counter antacids and is started on potassium supplementation to address her hypokalaemia. The patient is educated about the appropriate use of medications for GERD and is referred for dietary counselling. Follow-up appointments are scheduled to monitor her electrolyte levels and overall health.