Review Question - QID 214559

A 44-year-old man presents to the clinic complaining of painful burning penile lesions that appeared a few days ago. The affected area bothers him so much that he has limited his water intake to decrease how many times he urinates. The patient has a history of diabetes mellitus. He has multiple sexual partners and inconsistently uses barrier protection. On examination, there are multiple lesions appreciated on the penile shaft, as shown in Figure A. The appropriate medication is prescribed to treat the patient’s diagnosis. Two days later the patient arrives at the emergency department complaining of nausea and flank pain. Labs are obtained, as shown below:

Serum:
Na+: 138 mEq/L
Cl-: 103 mEq/L
K+: 4.3 mEq/L
HCO3-: 27 mEq/L
Urea nitrogen: 56 mg/dL
Glucose: 110 mg/dL
Creatinine: 3.4 mg/dL

His baseline serum creatinine is 1.2 mg/dL. A urinalysis is pending. Which of the following is the most likely cause of the patient’s symptoms?