A 55-Year-Old Woman Presented to the Clinic Complaining of Fever

A 55-year-old woman presented to the clinic complaining of fever and skin rash of 3 days duration. She does not complain of cough, dyspnea, angina, vomiting, or dysuria. The patient was recently diagnosed with gastroesophageal reflux disease and has been taking omeprazole for the last two weeks. Temperature is 38.1 C (100.6 F) , blood pressure is 135/95 mm Hg, and pulse is 88/min. Examination shows a diffuse, maculopapular skin rash. No mucosal lesions are found on examination. There are no cardiopulmonary deficits on physical examination. Costovertebral angle tenderness is absent. Serum creatinine is 2.5 mg/dL (baseline 1.2 mg/dL, 2 weeks ago) . Urinalysis shows numerous white blood cells/hpf. Which of the following is the most likely cause of this patient's acute renal dysfunction?

A) Interstitial nephritis
B) Pyelonephritis
C) Renal tubular necrosis
D) Stevens-Johnson syndrome
E) Uric acid nephropathy