A 28-year-old woman with systemic lupus erythematosus presents to the clinic with a 3-week history of progressive muscle weakness, polyuria, and polydipsia. She has been on prednisone 20 mg daily for the past 6 months. Vital signs are stable (BP 118/76 mmHg, HR 88 bpm, RR 14 breaths/min, temperature 37°C). Laboratory studies show serum potassium 3.1 mEq/L (normal 3.5-5.0), serum chloride 92 mEq/L (normal 96-106), serum HCO3− 28 mEq/L (normal 22-26). Arterial blood gas: pH 7.45, PCO2 38 mmHg, HCO3− 28 mEq/L. Urinalysis shows no glycosuria, ketonuria, or proteinuria. Which of the following best explains her acid-base status?
- A)Respiratory alkalosis with appropriate metabolic compensation
- B)Metabolic acidosis with appropriate respiratory compensation
- C)Metabolic alkalosis with concurrent hypokalemic hypochloremiaGABARITO
- D)Mixed respiratory and metabolic acidosis
- E)Normal acid-base balance with isolated hypokalemia
Explicação
The patient has metabolic alkalosis with concurrent hypokalemic hypochloremia. Key findings: (1) pH 7.45 indicates alkalemia; (2) HCO3− 28 is elevated, indicating metabolic alkalosis as the primary disorder; (3) PCO2 38 is appropriate for metabolic alkalosis (... Ver explicação completa e trilha adaptativa →