Bladder Stones

Transverse ultrasound image of the urinary bladder shows a 5-cm mobile hyperechoic lesion (between arrows) with posterior acoustic shadowing within the bladder lumen.

Facts:

• Risk factors: urinary stasis (voiding dysfunction i.e., urethral stricture, benign prostatic hyperplasia, bladder neck contracture, neurogenic bladder), infection, bladder diverticula, foreign body (Foley catheter balloon, suture material, etc)
• Common compositions: uric acid, ammonium urate, calcium oxalate
• Uric acid stones predominate in a setting of bladder outlet obstruction
• Magnesium ammonium phosphate and apatite stones predominate in a setting of urinary tract infection (UTI)
• Patient presentation: hematuria, suprapubic pain, interruption of urine stream

Imaging

• If sufficiently calcified, bladder stones may be visible on radiography
• Tends to locate in the midline when the patient is supine
• If calcification is located laterally, think of a stone in the diverticulum or ureterocele
• Key to confirm that the abnormality is a stone = mobility (either on radiography or ultrasound)

Reference:

1. Zagoria RJ. Genitourinary Radiology: the Requisites, 2004.

2. Tanagho EA, McAninch JW. Smith's General Urology, 2004.