Nephrolithiasis

Etiology in neonates: diuretics
Etiology beyond neonates: calcium oxalate most common, idiopathic in 30%, chronic urinary tract infection, urinary stasis, proximal renal tubular acidosis, interrupted enteropathic circulation, dehydration
Imaging: primarily radioopaque on AXR

Cases of Nephrolithiasis

CT of ureteral stone — Axial (left) and coronal (right) CT without contrast of the abdomen shows a dense calcification at the right ureteovesical junction. There is mild associated enlargement of the right kidney with mild inflammatory fat stranding around the right kidney.

AXR and US of bladder stone — AXR AP (above) shows two irregularly-shaped calcified objects projecting over the pelvis. Spinal dysraphism is noted in the sacrum. There is a cecostomy tube in the right lower quadrant. Sagittal US of the bladder (below) shows an echogenic mass within the inferior aspect of the bladder (to the right of the image) that has posterior shadowing.