COST-EFFECTIVE EMERGENCY DIAGNOSIS PLAN FOR URINARY STONE PATIENTS PRESENTING WITH URETERAL COLIC

Objective: To develop a cost-effective plan for the accurate diagnosis of urinary stone patients presenting with ureteric colic based on an assortment of investigations which are less invasive and more economic al than intravenous urography (IVU). Patients and Methods: 143 consecu tive emergency patients presenting with ureteric colic were admitted t o hospital and prospectively studied by history recording, physical ex amination, laboratory tests and imaging procedures according to a pres et format. Significant association of the final diagnosis of urinary s tones (which was made by actual stone retrieval) with various diagnost ic variables obtained from the results of investigation (including IVU ) was statistically studied using bivariate correlation and multivaria te logistic regression analysis. Algorithms for reaching an accurate d iagnosis of urinary tract stones were formulated using the most signif icant diagnostic variables and the accuracy of each of those plans was compared with that of emergency IVU. Results: 18 patients were exclud ed for various reasons. Of the remaining 125 patients 82 (66%) were co nfirmed as having urinary stones. A positive IVU had the strongest cor relation with the final diagnosis of urinary tract stones. Other findi ngs associated with eventual stone retrieval in a descending order of significance were: calcular sonographic features; radio-opacities on a plain abdominal film of the kidney, ureter and bladder (KUB), and mic rohaematuria. Based on these findings two algorithms could be formulat ed to reach as accurate a diagnosis as possible. Algorithm A in which an initial ultrasound is mandatory had a sensitivity of 89%, a specifi city of 88% and an overall accuracy of 88% for urinary stone detection compared with 91, 77, and 86%, respectively, for algorithm B in which ultrasonography was employed selectively after initial KUB and urinal ysis for microhaematuria. This compares with 94, 79, and 89%, respecti vely, for IVU. Conclusion: Both plans are viable alternatives which co uld replace routine emergency IVU.