A 60-year-old woman presents with a maculopapular rash, fever, and fatigue and reports decreased urine output. Laboratory tests reveal a serum creatinine level of 3.5 mg/dL (baseline, 1.0 mg/dL). She has peripheral eosinophilia, and urine eosinophils are detected.
Her history is notable for recent antibiotic exposure beginning two weeks previously for refractory sinusitis. What is the next best step for managing this patient? *This Case Challenge is from the Editorial Team of Docplexus and is meant for educational purposes only.
