eAJKD: You present a case of acute kidney injury in a patient with recurrent pulmonary infections following solid-organ transplantation. While on multiple medications, he developed rhabdomyolysis after ciprofloxacin administration. With so many potential offenders, please describe your differential diagnosis going into the kidney biopsy?
QQ: The patient had a history of a1-antitrypsin deficiency, which was the reason for double lung transplant. Immunosuppression included tacrolimus, so calcineurin inhibitor toxicity was a consideration even trough levels had not been elevated. He had chronic bronchiectasis and recurrent pulmonary infections, so we considered infection-related decreased kidney function but repeated evaluation of urinary sediment was bland. On further questioning, the patient described previous reactions to ciprofloxacin which lead us to consider this as a possible cause. Acute allergic interstitial nephritis was in the differential despite the patient being on chronic steroids.
eAJKD: How essential was biopsy in determining the cause of acute kidney injury?
QQ: On light microscopy, crystals were noted. Stains were strongly positive for myoglobin. We were surprised. Without the biopsy, it would have been difficult to make a firm diagnosis in this case.
eAJKD: In your review of the literature, you have identified at least forty cases of rhabdomyolysis induced by a fluoroquinolone. Is this the first case of biopsy-proven kidney injury as a result?
QQ: Yes, this is the first biopsy-proven case report of myoglobin-induced kidney injury. Most reports are associations, reported only with elevated serum creatinine kinase levels in the setting of fluoroquinolone use.
eAJKD: Interestingly, the patient your describe had previously reported ankle pain as an adverse reaction to ciprofloxacin. We are now aware of the risk of tendon rupture as a complication of fluoroquinolone use, particularly in older patients receiving long-term steroid therapy and recipients of organ transplants. Do you believe there is a common link between the risk of fluoroquinolone-induced musculoskeletal complications and rhabdomyolysis?
QQ: I believe that rhabdomyolysis in our patients was a multifactorial event. He was certainly on a few medications that have been described to cause myotoxicity. His advanced age and chronic immunosuppression may have contributed to deconditioning, making him particularly susceptible to further myotoxic injury. I think the take-home point that this case makes is to not assume a diagnosis, particularly in patients on such complex pharmacologic regimens.
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