Immediate versus deferred radiological investigation after acute renal colic: a prospective randomized study

The timing of radiological assessment after acute renal colic is controversial. The aim of this study was to investigate the value of immediate versus deferred radiological imaging and to compare morbidity rates after an attack of acute renal colic.Between September 2001 and December 2002 all 686 patients with acute renal colic attending our university hospital were registered. Of these, 172 patients rendered pain-free after analgesic injection were randomized to either immediate or deferred radiological investigation. All patients received a questionnaire encompassing questions on consumption of analgesics, impact of symptoms on normal daily activity (including working ability), need for additional emergency department visits and hospitalization. Stone treatments were registered.The incidence of renal colic was 0.9/1,000 inhabitants per year. In total, 74% of all patients became pain-free after analgesic injection. Morbidity was low among the randomized patients, and did not differ between the immediate or deferred radiological investigation groups. In both groups, the duration of impairment of normal daily activities and analgesic consumption was a median of 2 days. In the immediate group, 14% needed another emergency visit and 4% were hospitalized. Corresponding figures for the deferred group were 15% and 7%. In the immediate group, 17% had stone treatment, compared with 8% in the deferred group.For most patients with acute renal colic, parenteral analgesia resulted in complete symptom resolution. When initial medical treatment was successful, patient morbidity was low. In these patients, immediate radiological imaging did not lead to reduced morbidity compared with radiological imaging after 2-3 weeks.