Urinary Tract Stone Disease - Nephrolithiasis
(Lith - Gr. for stone or rock)
Sx: Renal Colic (impacted or moving stone)
Stones hangup at ureteropelvic junction (UPJ), where ureter crosses the iliac vessels, ureterovesicle junction.

Regarding the stones:
90% have Ca++
About 60% visible on plain film
Virtually ALL visible on CT - and may be precisely localized

Evaluation:
Plain Film - good first step to screen for other disease
IVP/IVU - evaluates possible obstruction (stone in ureter)
CT - Best Exam, but highest radiation dose to patient

CT Evaluation:
Rapid - some scans < 5 min.
Plain (unenhanced CT) otherwise contrast may mask stone
May detect other coexistent pathology:
- Appendicitis
- Diverticulitis
- Adnexal Disease (in women)

Localization of Stones:
- 22% proximal ureter (-> ESWL)
- 71% distal (extraction or ESWL)

Size of Stones:
< 5mm likely to pass
> 5mm » Get a Urology Consult
> 7mm unlikely to pass

CT Findings:
- Dilated Ureter
- Perinephric/periureteral stranding
- Ca++ density in ureter w/rim of soft-tissue

TREATMENT:
ESWL (Extra-Corporeal Shockwave Lithotripsy) is effective for most stones < 2cm in the renal pelvis and < 1 cm in the ureter. NOTE: NSAIDS are a contraindication prior to ESWL because of possible perinephric bleeding.

Larger stones in the renal pelvis may be extracted by ureteroendoscopy or percutaneous nephrolithotomy.


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