Comparison of stone size and response to analgesic treatment in predicting outcome of patients with renal colic.

The aim of this study was to compare the prognostic value of stone size and response to analgesic treatment in patients with renal colic. We reviewed the charts of patients treated for renal colic in our Emergency Department. The eligibility criteria were a radiological examination demonstrating direct or indirect signs of ureteral obstruction and/or a stone. The primary endpoint was the requirement for surgical treatment. The parameters considered as prognostic factors were pain relief with ketorolac (K) or ketorolac plus opiate treatment (KO), and stone size (>or= or <6 mm). Ninety-five patients were considered for analysis. Of these, 49 (52%) had a stone demonstrated radiologically. Four out of 27 patients (15%) in the KO group and six out of 68 patients (8.8%) in the K group required a surgical procedure to relieve the obstruction (NS). Four out of five patients (80%) with a stone >or=6 mm required a surgical procedure, compared with one out of 44 (2.2%) who had a stone smaller than 6 mm (P<0.001). In conclusion, stone size is a better prognostic factor than the response to analgesic treatment in predicting the clinical outcome of patients with renal colic. A stone >or=6 mm in patients with renal colic should alert the emergency physician that urological complications requiring surgical intervention may occur and that urological management may be warranted.