Ultrasonography is an Adequate Initial Screening Test for Urinary Calculi

Opposing Views Ultrasonography is an Adequate Initial Screening Test for Urinary Calculi PRO M ORE than 3,600 emergency department (ED) visits related to nephrolithiasis occur daily in the United States. 1 Whether computerized tomography (CT) or ultrasonography is the best initial screening test for acute renal colic has been debated. A recent prag- matic, comparative effectiveness trial was per- formed at 15 centers with 2,759 participants followed for 2 years to determine whether the initial imaging method for patients with suspected neph- rolithiasis should undergo CT, ultrasonography as performed by a radiologist or point-of-care ultraso- nography as performed by an ED physician. 2 Notably, the study excluded individuals the physi- cian considered to be at high risk for serious alter- native diagnoses, including acute cholecystitis, appendicitis, aortic aneurysm or bowel disorders. As part of the pragmatic design, after the initial imag- ing was assigned by randomization, the provider determined subsequent medical care, including the potential need for additional imaging. The average cumulative radiation exposures were significantly lower in both ultrasonography groups compared to those assigned to CT. There was no difference in the rate of high risk diagnoses with complications related to misdiagnoses. Among the secondary outcomes, there were no significant dif- ferences in serious adverse events, pain scores, rate of return ED visits or hospitalizations. As such, this study supports ultrasonography for the initial eval- uation of acute renal colic. As urologists, we think we evaluate all stone for- mers. In reality, we only see the tip of the iceberg. A secondary analysis of the trial data revealed that 14.5% of participants had a urology consultation at presentation. 3 Most patients are given appointments to return to the ED or to their primary care pro- viders, and they are not specifically referred to a urologist. Patients diagnosed with stones at one ED often present to a different ED for persistent symp- toms without accompanying documents or images, and additional CT scans are obtained. It is not THE JOURNAL OF UROLOGY ® O 2016 by A MERICAN U ROLOGICAL A SSOCIATION E DUCATION AND R ESEARCH , I NC . infrequent for urologists to see new patients who have undergone multiple CT studies for the same acute renal colic episode (despite this fact, often the urologist is often unable to personally review these studies). Therefore, these multiple ED settings represent multiple initial visits at which there were opportunities for ultrasonography to be per- formed first. Proponents of CT will point to the availability of low dose protocols that maintain the high sensitivity and specificity for stone detection. However, while we routinely request these scans, in practice many patients still receive regular dose CT (frequently young women of childbearing age) and often there are questionable incidental findings 4 that may lead to additional investigations and treatments with their associated risks. The widespread dissemina- tion of reduced dose CT has not happened. In a study of renal colic protocol CT from 93 institutions the reduced dose protocol (3 mSv or less) was used only in 2% of all studies. 5 Urologists bear the burden to advocate for reduced dose protocols at their institutions. Combining ultrasonography with a thorough his- tory, physical examination and urinalysis allows for an obstructing stone to be diagnosed with reasonable confidence. Notably in this study 42% of patients had a history of kidney stones, and so they recognize stone pain. Ultrasonography can consistently iden- tify hydronephrosis, yet it is unreliable to defini- tively visualize mid ureteral stones. In this study the diagnostic accuracy for nephrolithiasis was deter- mined by comparing the initial diagnosis to patient observation of stone passage or at the time of sur- gery. Using this criterion, ultrasonography had lower sensitivity than CT, as expected. However, on intention-to-treat analysis there was no difference in sensitivity or specificity. The majority of patients in the point-of-care ultrasonography group still avoided a subsequent CT. In other words, although ultraso- nography is less sensitive for stone detection, man- agement of a suspected stone does not require http://dx.doi.org/10.1016/j.juro.2016.06.019 Vol. 196, 645-647, September 2016 Printed in U.S.A. www.jurology.com j