Young patients with suspected uncomplicated renal colic are unlikely to have dangerous alternative diagnoses or need emergent intervention.

INTRODUCTION: In the United States there is debate regarding the appropriate first test for new-onset renal colic, with non-contrast helical computed tomography (CT) receiving the highest ratings from both Agency for Healthcare Research and Quality and the American Urological Association. This is based not only on its accuracy for the diagnosis of renal colic, but also its ability to diagnose other surgical emergencies, which have been thought to occur in 10-15% of patients with suspected renal colic, based on previous studies. In younger patients, it may be reasonable to attempt to avoid immediate CT if concern for dangerous alternative diagnosis is low, based on the risks of radiation from CTs, and particularly in light of evidence that patients with renal colic have a very high likelihood of having multiple CTs in their lifetimes. The objective is to determine the proportion of patients with a dangerous alternative diagnosis in adult patients age 50 and under presenting with uncomplicated (non-infected) suspected renal colic, and also to determine what proportion of these patients undergo emergent urologic intervention.

METHODS: Retrospective chart review of 12 months of patients age 18-50 presenting with "flank pain," excluding patients with end stage renal disease, urinary tract infection, pregnancy and trauma. Dangerous alternative diagnosis was determined by CT.

RESULTS: Two hundred and ninety-one patients met inclusion criteria. One hundred and fifteen patients had renal protocol CTs, and zero alternative emergent or urgent diagnoses were identified (one-sided 95% CI [0-2.7%]). Of the 291 encounters, there were 7 urologic procedures performed upon first admission (2.4%, 95% CI [1.0-4.9%]). The prevalence of kidney stone by final diagnosis was 58.8%.

CONCLUSION: This small sample suggests that in younger patients with uncomplicated renal colic, the benefit of immediate CT for suspected renal colic should be questioned. Further studies are needed to determine which patients benefit from immediate CT for suspected renal colic, and which patients could undergo alternate imaging such as ultrasound.