Elderly patients who receive high doses of ciprofloxacin may be especially vulnerable.
In a handful of case reports, ciprofloxacin has been implicated as a cause of acute renal failure; an immune-mediated pathogenesis has been suggested. Now, authors in Italy present two cases of possible ciprofloxacin-induced crystal nephropathy.
In both cases, elderly patients with baseline serum creatinine around 1.0 mg/dL received 750 mg of oral ciprofloxacin twice daily. Serum creatinine peaked at 7.0 mg/dL in one patient and at 8.3 mg/dL in the other. Renal biopsy in both cases revealed needle-shaped stellate birefringent crystals within some renal tubules. The crystals, which stained negatively for calcium and phosphate, appeared identical to ciprofloxacin crystals described in previous reports. Both patients recovered after ciprofloxacin was withdrawn.
Comment: This report caught my eye because I recently cared for two patients hospitalized with acute renal failure superimposed on chronic mild renal insufficiency; both had been given ciprofloxacin during the previous week. Because these patients had several other plausible precipitants for renal failure, I did not consider ciprofloxacin as a possible contributing factor. Although this published report does not establish cause-and-effect with certainty, it suggests that ciprofloxacin crystal nephropathy should be considered as a potential cause of acute renal failure and that elderly patients who receive high doses may be especially vulnerable.
Published in Journal Watch General Medicine September 11, 2007
Stratta P et al. Ciprofloxacin crystal nephropathy. Am J Kidney Dis 2007
Aug; 50:330-5.