A hidden cause of hypokalemia

A hidden cause of hypokalemiaA 21-year-old-man presented to the emergency department with increasing fatigue and psychosis symptoms.He had experienced no nausea, vomiting, diarrhea, chest pain, dyspnea, or urinary symptoms.He was not on any prescribed or over-the-counter medications or herbal supplements, and he denied smoking and alcohol consumption.Recently, he observed a 20-lb weight gain over 6 weeks.On examination, the patient was alert and oriented, with clear lungs on auscultation.His temperature was 37.0°C (98.6°F), heart rate 60 beats per minute, respiratory rate 11 breaths per minute, oxygen saturation 98% on room air, blood pressure 153/92 mm Hg, and body mass index 34 kg/m2.Cardiovascular and gastrointestinal fi ndings were unremarkable, and there were no focal neurologic abnormalities.Striae were noted over his abdomen and back.Initial laboratory test results are listed in Table 1. ■ EVALUATION OF THE METABOLIC DISORDER1 What is the most appropriate next step in investi- gating this patient's acid-base disorder?□ Random urine potassium □ Random urine chloride □ Random urine sodium □ Random urine urea