Renal colic: Streamlining investigations to improve patient outcomes in emergency medicine

In Australian EDs, patients experience long waits for imaging, particularly for presentations such as renal colic. Computed tomography (CT) imaging is the gold-standard for renal stones, although ultrasonography is recommended for young patients and those susceptible to radiation, an approach supported by The Canberra Hospital (TCH) ED guidelines for renal colic. This audit aims to not only assess how well these guidelines are adhered to, but also to discuss possible methods of improving flow through ED and thus patient outcomes.

A retrospective audit was conducted using 100 attendances to TCH ED between the dates of 02/04/2022 and 15/06/2022 with the diagnosis of renal colic or calculus. Data were collected on biochemical and radiographic results and patient outcomes with the associations between these datasets statistically analysed.

Blood tests demonstrating abnormal renal function, white cell count and C-reactive protein (CRP) together with haematuria on urine analysis conferred high positive and negative predictive values (83.3% and 100%, respectively) for renal stones. Larger renal stones were associated with higher creatinine and CRP levels and a lower estimated glomerular filtration rate (P = 0.0145, P = 0.0062 and P = 0.0022, respectively).

We propose that patients with significant clinical and biochemical features of renal stones could be referred to urology earlier to await CT as an inpatient and those without be referred to their general practitioner for outpatient imaging and medical management. This could improve flow through the department and improve patient outcomes through reduced waiting times and radiation burden.