Ultrasound First for Renal Colic
Renal colic affects nearly 1.2 million people each year and accounts for approximately 1 percent of hospital admissions.1 Diagnosing kidney stones in patients who present with renal colic is often performed with computed tomography (CT) and, less commonly, with intravenous urography (IVU).2 While CT and IVU are accurate diagnostic tests and define clearly the size, shape, and position of uric acid stones, they also present a number of factors that would discourage use,3 including the potential risks of exposing patients to repeated doses of ionizing radiation. In fact, the Joint Commission recently issued a Sentinel Event Alert4 about the radiation risks of diagnostic imaging. It reports that over the last 20 years, Americans' exposure to ionizing radiation has nearly doubled. It states, "…any physician can order tests involving exposure to radiation at any frequency, with no knowledge of when the patient was irradiated or how much radiation the patient received."
Berrington de Gonzales, et al., combined risk-based models with scan frequencies for the United States in 2007 and estimated that 29,000 future cancers might be related to CT scans, with the largest proportion from scans of the abdomen and pelvis.5 Medicare data from 2006 and 2009 show that CT scans were used nearly 80 percent of the time when diagnosing renal colic. Given the fact that renal colic is often a recurrent condition, this magnifies the patient's radiation-related risk.
Meanwhile, point-of-care ultrasound results are immediately available and do not expose patients to ionizing radiation. In its Sentinel Event Alert, one of the Joint Commission's recommendations to reduce exposure to ionizing radiation is to use other imaging techniques, such as ultrasound or MRI, "…when such tests will produce the required diagnostic information at a similar quality level." Studies have found that ultrasound provides reliable and noninvasive diagnoses of renal colic in the majority of cases.6,7
The European Association of Urology in its 2011 Guidelines on Urolithiasis advises that for patients with renal stone disease, imaging procedures should follow clinical examination. Its first imaging choice is ultrasound: "Ultrasonography should be used as the primary procedure. It is a safe (no risk of radiation), reproducible and inexpensive method of urinary stone detection." Ultrasound scans can identify stones in the calices, pelvis, pyelo-ureteric junction and vesicoureteric junction, as well as dilatation of the upper urinary tract.8
In addition to the clinical efficacy of ultrasound for renal colic, it is significantly less expensive than CT. A report by KNG Health Consulting, LLC9, found that if ultrasound was used first in a diagnostic algorithm, our nation's healthcare system and your patients could realize significant cost savings. KNG's examination of 2009 Medicare data showed that if ultrasound was substituted for CT in 30 percent of renal colic diagnoses, the savings to Medicare would have been $21.6 million. Had it been substituted 70 percent of the time, the savings would have jumped to more than $50 million. In summary, ultrasound not only provides a safe and effective first line approach for many patients with renal colic, it is significantly more cost-effective for the patient and the health system.
1Wolf JS. Nephrolithiasis: Acute renal colic. Medscape Reference, 2011. Available at: http://emedicine.medscape.com/article/437096-overview
2Renal colic is a condition that begins as pain in the kidney area or below and radiates through the flank until reaching the bladder. Renal colic pain tends to remain constant and may come in two varieties: dull or acute. Koenig L, Ruiz D, Cornejo A. Potential cost savings from the use of diagnostic ultrasound in the Medicare population. KNG Health Consulting LLC, 2011. Prepared for SonoSite, Inc.
3Wolf JS. Nephrolithiasis: Acute renal colic. Medscape Reference, 2011. http://emedicine.medscape.com/article/437096-overview
4The Joint Comission Sentinal Event Alert, issue 47, August 24, 2011. http://www.jointcommission.org/assets/1/18/SEA_471.PDF
5Berrington de Gonzales A, Mahesh M, Kim K, Bhargavan M, Lewis R, Mettler F, et al. Projected cancers risks from computed Tomographic scans performed in the United States in 2007. Arch Intern Med. 2009;169(22):2071-77.
6Erwin B, Carroll B, Sommer G. Renal Colic: The role of ultrasound in initial evaluation. Radiology. 1984;(152)147-50.
7Perven A, Ammar A. Role of ultrasound in evaluation of renal colic and assessment of risk factor for renal calculi. Gomal Journal of Medical Sciences, Jan. - June, 2007;5(1).
8Turk C, Knoll T, Petrik A, et. al. Guidelines on Urolithiasis, European Association of Urology, 2011.
9Renal colic is a condition that begins as pain in the kidney area or below and radiates through the flank until reaching the bladder. Renal colic pain tends to remain constant and may come in two varieties: dull or acute. Koenig L, Ruiz D, Cornejo A. Potential cost savings from the use of diagnostic ultrasound in the Medicare population. KNG Health Consulting LLC, 2011. Prepared for SonoSite, Inc.
Selected Additional References
Katz SI, Saluja S, Brink JA, et al. Radiation dose associated with unenhanced ct for suspected renal colic: Impact of repetitive studies. Am J Roentgenol. 2006;186(4):1120-4.
Chauhan V, Eskin B, Allegra JR, Cochrane DG. Effect of season, age, and gender on renal colic incidence. Am J Emerg Med. 2004;22(7):560-3
Brenner DJ, Hall EJ. Computed tomography - An increasing source of radiation exposure. New Eng J Med. 2007;357:2277-84.