Shockwaves and the Rolling Stones: An Overview of Pediatric Stone Disease

Abstract

Urinary stone disease is a common problem in adults, with an estimated 10% to 20% lifetime risk of developing a stone and an annual incidence of almost 1%. In contrast, in children, even though the incidence appears to be increasing, urinary tract stones are a rare problem, with an estimated incidence of approximately 5 to 36 per 100,000 children. Consequently, typical complications of rare diseases, such as delayed diagnosis, lack of awareness, and specialist knowledge, as well as difficulties accessing specific treatments also affect children with stone disease. Indeed, because stone disease is such a common problem in adults, frequently, it is adult practitioners who will first be asked to manage affected children. Yet, there are unique aspects to pediatric urolithiasis such that treatment practices common in adults cannot necessarily be transferred to children. Here, we review the epidemiology, etiology, presentation, investigation, and management of pediatric stone disease; we highlight those aspects that separate its management from that in adults and make a case for a specialized, multidisciplinary approach to pediatric stone disease.

Keywords: children; lithotripsy; stone prevention; stone surgery; urolithiasis.

Figure 1

Xanthogranulomatous kidney secondary to UTI and urolithiasis. The external surface had been inked by the Pathology department.

Figure 2

Examples of imaging in pediatric stone disease. (a) Ultrasound of the urinary tract. Note the echogenic focus (arrow) within the proximal ureter which demonstrates posterior acoustic shadowing, suggesting a stone. (b) Same patient, but now color Doppler applied. Note the “twinkle” artifact (arrow), a focus of alternating colors behind a reflective object. (c) Ultrasound of the right kidney in a patient with primary hyperoxaluria. Note the dense medullary nephrocalcinosis (arrows), some with acoustic shadowing, consistent with stone formation. (d) Ultrasound of the right kidney with a Staghorn calculus (arrow) occupying the renal pelvis and upper pole calyceal system. (e) Example of a large calculus (arrow) in the left pelviureteric junction, as seen on computed tomography. (f) Dimercaptosuccinic acid imaging of the same patient as in (e) shows associated focal scarring in the left upper and lower pole.

Figure 3

Child receiving extracorporeal shock wave lithotripsy under general anesthesia on a Piezolith Lithotripser: in-line ultrasound enables real-time monitoring of effectiveness and for complications (modified from⁸¹). Arrow indicates the shock-wavegenerator with the in-line ultrasound.

Figure 4

Image of an encrusted stent. Dimercaptosuccinic acid-SPECT showing reduced left-sided function in a “stretched” kidney and gross encrustation of a “forgotten” JJ stent after pyeloplasty surgery for a pelvi-ureteric junction obstruction. A combination of extracorporeal shock wave lithotripsy, cysto-ureteroscopy, and percutaneous nephrolithotomy were required for extraction. SPECT, single-photon emission computerized tomography.

Figure 5

Extraction of cystine stones by percutaneous nephrolithotomy. Nephroscopy view through the percutaneous access into the pelvicalyceal system: stone grasping forceps have been deployed to lift out stones, which have the classical appearance of cystine stones.