An uncommon but treatable etiology of acute respiratory failure is hypokalemia. A 36-year-old woman with previously undiagnosed distal renal tubular acidosis presented with foot and ankle swelling that was being treated with furosemide. She had been seen by three physicians within 24 hours and was diagnosed as having depression or hysterical conversion reaction. Her symptoms progressed to respiratory arrest. Initial treatment consisted of administering 40 mEq of KCl over one hour through a central venous line. The patient recovered rapidly and was weaned off a respirator within 24 hours of admission.