1. Nephrolithiasis Patrick Carter MPAS, PA-C Clinical Medicine I March 14, 2011

2. Objectives For nephrolithiasis, describe the: Etiology Epidemiology Pathophysiology Risk factors Signs and symptoms Diagnostic work-up Treatment

3. Nephrolithiasis

4. Nephrolithiasis One of the most common urological problems in the US ~13% of American men ~7% of American women Prevalence is increasing throughout the industrialized world

5. Nephrolithiasis Constituents of renal stones Uric acid Cystine Struvite (MgNH4PO4) Calcium oxalate and calcium phosphate stones make up 75–85%

6. Nephrolithiasis Calcium stones More common in men Average age of onset is in the 20’s or 30’s 50% of patients will form another within the next 10 years, usually one every 2-3 years

7. Nephrolithiasis Uric acid stones 5–10% of kidney stones Also more common in men Half of patients also have gout Usually familial Cystine stones Uncommon, only ~1% of cases

8. Nephrolithiasis Struvite stones Common and potentially dangerous Mainly in women or patients who require chronic bladder catheterization Result from UTI’s with urease-producing bacteria (Proteus species) Can produce a large stone with a "staghorn" appearance

9. Staghorn Stones

10. Nephrolithiasis Epidemiology Third most common type of renal disease after UTI and prostate disease 240,000–720,000 Americans per year Men > women 3-4:1 More common in areas of high humidity and elevated temperatures More common in the summer

11. Nephrolithiasis Risk factors Gout Chronic UTI’s Family history Medications Antacids Loop diuretics Vitamin C in large doses EtOH

12. Acute Nephrolithiasis Signs and symptoms May be asymptomatic Flank pain with radiation to testicle or vulva Pain is often severe and patient cannot stay in one position Hematuria Frequency, urgency +/- dysuria CVA tenderness

13. Acute Nephrolithiasis Diagnostic studies Stone analysis if any stones recovered Urinalysis for hematuria, pyuria, crystals, altered pH pH < 5 correlated with uric acid or cystine stones pH > 7.5 is suggestive of struvite stones KUB x-ray will show calcium, struvite and cystine stones Renal ultrasound CT Scan is imaging is 1st line

14. KUB X-Ray

15. IV Pyelogram

16. CT Scan

17. Acute Nephrolithiasis Treatment Initial management  fluids and analgesics Most stones < 5 mm will pass spontaneously Strain urine for stones

18. Acute Nephrolithiasis Treatment Indications for stone removal Intractable pain Severe obstruction Serious bleeding Infection Stones > 10 mm

19. Acute Nephrolithiasis Treatment Methods of stone removal Retrograde passage of a flexible basket Pyelolithotomy and ureterolithotomy Lithotripsy Extracorporeal Percutaneous Endoscopic

20. Specific Treatments Calcium stones Hypercalciuria Low-sodium and low-protein diet Thiazide diuretic Hyperuricosuria Low-purine diet Allopurinol 100 mg PO twice daily Primary hyperparathyroidism  parathyroidectomy

21. Specific Treatments Calcium stones Hyperoxaluria Low-oxalate diet Cholestyramine – binds oxalate Uric acid stones Potassium citrate to raise urine pH Low-purine diet Allopurinol

22. Specific Treatments Cystine stones High fluid intake > 3 L per day Low-salt diet Raising urine pH > 7.5 Struvite stones Complete removal of the stone followed by sterilization of the urinary tract If cannot tolerate surgery, acetohydroxamic acid Limited by side effects Headache tremor, thrombophlebitis

23. Questions?