C-reactive protein to predict the need for surgical intervention in acute renal colic

Abstract

Objectives: C-reactive protein (CRP) is a serum marker of systemic inflammation which has been suggested to predict need for emergent surgical intervention in patients with acute renal colic at a value of > 28 mg/l on admission.1 We aimed to determine if this applied to our patients. Patients and methods: We prospectively collected data from all patients admitted with symptomatic urolithiasis, confirmed by CT-KUB, over three months. Fifty-nine patients were included; however, four were excluded because of co-morbidites which could influence CRP, or recent urological surgery, giving N = 55, age 50.0±14.6 years (mean±SD), M:F 40:15. The decision to proceed to intervention was made by each patient’s clinical team and not by the authors; however, there was no blinding to CRP. Results: A total of 24 of 55 patients required intervention on their index admission (22 retrograde ureteric stent, one nephrostomy, one ureteroscopic stone extraction), and 31 were managed conservatively. Those undergoing intervention had higher CRP on admission (mean 16.3 vs 9.4 mg/l, p = 0.06) and higher maximum CRP (mean 94.7 vs 25.7 mg/l, p < 0.001) than those managed conservatively. Nineteen (79%) of those requiring intervention had CRP < 28 mg/l on admission. There were no deaths, no intensive care admissions and all were discharged to outpatient follow-up. Conclusion: Rising CRP during admission is a strong predictor of the need for emergency surgical intervention in patients with acute renal colic; however, CRP at admission is less useful.