Woman With Right-Sided Flank Pain
Article Outline
A 26-year-old woman presented to the emergency department with 2 weeks of intermittent right-sided flank pain, nausea, and vomiting. She reported several days of hematuria but denied dysuria, fever, or chills. Vital signs were unremarkable, and physical examination demonstrated moderate right costovertebral angle tenderness. Urine studies showed RBCs and WBCs too numerous to count, few bacteria, and a negative pregnancy test result. After emergency ultrasonography was performed (Figure 1, Figure 2, Figure 3), a urology consultation and computed tomography (CT) of the abdomen and pelvis were obtained (Figure 4). Real time ultrasonographic images are available for viewing at http://www.annemergmed.com.
Figure 1.
The longitudinal (LT) image shows large renal calculi (black arrows) within the right kidney (RK). The transverse view (TV) depicts a calculus (black arrow) and the dilated proximal ureter (*). These images were obtained with a large curvilinear probe positioned over the right midaxillary line, just posterior to the ribs.
Figure 2.
B-mode ultrasonography (left) shows a large stone (black arrow) within the dilated ureter, with shadowing over the right common iliac artery (RCIA). The same structures are visualized with duplex color Doppler (right). A comet tail–shaped twinkling artifact (thick black arrow) is shown running with the stone shadow through and posterior to the RCIA (white arrow). These images were obtained with the transducer placed over the right lower abdomen.
Figure 3.
The right ureteral stone (black arrow) is now shown with a linear transducer in B-mode (left). The ureter appears 3 layered (*) and is found directly over the RCIA. The color Doppler image (right) shows a classic “twinkling” deep to the calculus (black arrow).
Figure 4.
Coronal CT image. Used with permission of Tiffany C. Fong, MD, Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
Diagnosis
Obstructing midureteral calculus with moderate hydronephrosis. Transabdominal B-mode sonography of the right flank demonstrated 2 large intrarenal calculi, moderate hydronephrosis, and a dilated proximal ureter (Figure 1). Given these findings, an additional source of obstruction was suspected distally. Indeed, a calculus with shadowing and color Doppler “twinkling artifact” was detected midureter (Figures 2 and 3). Subsequent CT revealed multiple large stones in the lower kidney pole and one 8-mm midureteral stone with moderate hydronephrosis (Figure 4).
The sonographic twinkling artifact is generated when color Doppler is applied to a strongly reflecting medium with a rough interface.1 The Doppler waves create a random, rapidly changing color artifact in place of the stone's shadow. This phenomenon is well documented in sonography of urolithiasis, observed in up to 86% of cases.2, 3 The twinkling artifact may be considered an additional sonographic feature of urinary stones because of the frequent observation of its presence and its utility in identifying calculi in cases in which no abnormality is detected in B-mode.4
Supplementary data
Supplementary data.
References
- Color Doppler twinkling artifact in hyperechoic regions. Radiology. 1996;199:269–271
- Evaluation of patients with suspected renal calculi using sonography as an initial diagnostic tool: how can we improve diagnostic accuracy?. J Ultrasound Med. 2008;27:1441–1450
- Color and power Doppler twinkling artifacts from urinary stones: clinical observations and phantom studies. Am J Roentgenol. 2001;176:1441–1445
- Diagnostic value of colour Doppler twinkling artifact in sites negative for stones on B mode renal sonography. Urol Res. 2007;35:313–317
For the diagnosis and teaching points, see page 188.
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PII: S0196-0644(10)00039-9
doi:10.1016/j.annemergmed.2010.01.016
© 2009 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.
