Urinary protein profiles in ketorolac-associated acute kidney injury in patients undergoing orthopedic day surgery

Background: Parenteral administration of ketorolac is very effective in controlling postoperative pain for orthopedic surgery. Ketorolac can induce clinically relevant renal alterations in elderly patients, whereas its short course is considered safe for young adults with normal preoperative renal function. In this study, of a cohort of young adults undergoing elective orthopedic day surgery, we sought cases complicated by readmission due to acute kidney injury (AKI). Patients and methods: Among 1397 young adults, aged 18-32 years who were admitted to undergo orthopedic day surgery from 2013 to 2015, four patients (0.29%, three males/one female) treated in postprocedure with ketorolac (from 60 to 90 mg/day for 1-2 days) were readmitted for suspected severe AKI. We evaluated functional outcome, urinary protein profiles and kidney biopsy (1 patient). Results: After day surgery discharge, they experienced gastrointestinal disturbances, flank pain and fever. Readmitted on post-surgery days 3-4, they presented with oliguric AKI (creatinine range 158.4-466.4 µmol/L) and frank proteinuria (albumin range 2.1-6.0 g/L). Urine protein profiles demonstrated a nonselective glomerular proteinuria, with a significant 9.4-fold increase in glomerular/tubular index on day 6. Kidney biopsy on day 19 showed normal glomeruli and minimal tubular alterations and negative immunofluorescence. All patients recovered their renal function, and after 20 days proteinuria disappeared. Conclusion: AKI can ensue even in young adults who have undergone a short course of ketorolac, when they suffered from relative dehydration, abdominal disturbances, flank pain and oliguria after discharge. Urine findings were characterized by a marked nonselective glomerular proteinuria disappearing in 2-3 weeks.