Understanding Nephrolithiasis: Stones, Evaluation, and Management

1. NEPHROLITHIASIS SCOPE OF THE PROBLEM • Incidence 0.10 – 0.5% population/yr • High cost in yearly health care dollars • High morbidity: pain, obstruction, bleeding, infection, loss of work • Males >>Females except for infection related stones

2. COMMON STONES • Calcium oxalate • Calcium phosphate • Struvite-apatite • Cystine • Uric acid

3. STONE EVALUATION • Stone History • Family History • Medications • Dietary Considerations • Urologic Procedures • Radiologic Studies • Urinalysis • Stone Analysis • Metabolic Evaluation

4. STONE HISTORY • Total number of stones • Frequency of analgesic use • Time off work • Symptoms: renal colic, renal ache • History of UTI, gout, diarrhea, malabsorption, myeloproliferative disorders

5. STONE EVALUATION • Stone History • Family History • Medications • Dietary Considerations • Urologic Procedures • Radiologic Studies • Urinalysis • Stone Analysis • Metabolic Evaluation

6. STONE-PROVOKING MEDICATIONS

7. DIETARY CONSIDERATIONS IN NEPHROLITHIASIS • Fluids • Dairy products • Salt • Protein Animal Vegetable • Oxalate • Alcohol

8. STONE EVALUATION • Stone History • Family History • Medications • Dietary Considerations • Urologic Procedures • Radiologic Studies • Urinalysis • Stone Analysis • Metabolic Evaluation

9. UROLOGIC PROCEDURES • Anatrophic Nephrolithotomy • Percutaneus Nephrolithotomy • Extracorporeal shock lithotripsy • Ureteroscopy (laser)

10. RADIOLOGIC APPEARANCE OF CALCULI Radiopaque Calculi Radiolucent Calculi Calcium Oxalate Uric Acid Calcium Phosphate Struvite-Apatite Cystine

11. STONE EVALUATION • Stone History • Family History • Medications • Dietary Considerations • Urologic Procedures • Radiologic Studies • Urinalysis • Stone Analysis • Metabolic Evaluation

12. URINALYSISCRYSTALLURIA • Calcium Oxalate • Calcium Phosphate-Apatite, Brushite • Struvite—Magnesium Ammonium Phosphate • Uric Acid • Cystine

15. STONE EVALUATION • Stone History • Family History • Medications • Dietary Considerations • Urologic Procedures • Radiologic Studies • Urinalysis • Stone Analysis • Metabolic Evaluation

16. STONE ANALYSISRADIOPAQUE STONES

17. STONE EVALUATION • Stone History • Family History • Medications • Dietary Considerations • Urologic Procedures • Radiologic Studies • Urinalysis • Stone Analysis • Metabolic Evaluation

18. METABOLIC CLASSIFICATION OF NEPHROLITHIASIS • Hypercalciuria • Hyperuricosuria • Hyperoxaluria • Hypocitraturia • Hypomagnesiuria • Altered urinary pH • Cystinuria • Low urinary volume

19. METABOLIC EVALUATION OF NEPHROLITHIASIS • Blood Chemistries CBC PTH • Urine Urianalysis Culture & Sensitivity Cystine • 24-Hour Urine Collections Random Diet Restricted Diet • Fast and Calcium Load Test

20. 24 HOUR URINE COLLECTIONS

21. NEPHROLITHIASISCOEXISTENCE OF METABOLIC DERANGEMENTSN=1270

22. CYSTINE STONES • Decreased renal tubule absorption of cystine, ornithine, lysine and arginine (COLA) • Autosomal recessive • Large, radiopaque, often staghorn • Rx: thiola, D-penicillamine, captopril

23. INFECTION – STRUVITE STONES • Urea CO2 + NH3 NH4+ • NH4 + Mg2 + PO4 Struvite • Carbonate + PO4 carbonate apatite urease

24. INFECTION – STRUVITE STONES • Radiopaque, staghorn • Women > men • Associated with chronic infection with urease producing organisms • Poor prognosis: Rx: surgery, lithotripsy, antibiotics, acetohydroxamic acid

25. URIC ACID STONES • Associated with gout, GI disease, neoplasm • Radiolucent • Fluids, diet, alkali, allopurinol

26. DEFINITIONS OF HYPERCALCIURIA • 24 hour Urinary Calcium Excretion > 200 mg/day 1 week on Ca and Na restricted diet (40 mg Ca, 10 mEg Na) • 24 hour Urinary Calcium Excretion > 4 mg/kg/day • 24 hour Urinary Calcium Excretion > 250 mg/day-females, > 300 mg/day--males

27. FAST AND CALCIUM LOAD TEST • Normal fasting value <0.11 mg Ca/mg Cr (GFR) • Normal postload value <0.20 mg Ca/mg Cr

29. ABSORPTIVE HYPERCALCIURIA • Primary Defect – increased intestinal absorption of Ca • Location of Lesion – Jejunum • Inheritance – autosomal dominant • Animal Model – genetically Hypercalciuric rat • Skeletal Status – normal to increased cortical bone density • Calcium Balance - normal

30. ABSORPTIVE HYPERCALCIURIA • Sodium Cellulose Phosphate • Urinary Ca > 350 mg/day • Side effects – hyperoxaluria, hypomagnesiuria • Thiazide + Potassium Citrate • Amiloride

32. RENAL HYPERCALCIURIA • Primary Defect – impaired tubular reasborption of Ca • Location of Lesion - ? Proximal tubule • No effect of Diet on Calcium Excretion • 1,25-(OH)2D3 – increased • Skeletal Status – decreased cortical bone density • Calcium Balance - negative

33. RENAL HYPERCALCIURIA • Thiazide • Potassium Citrate

35. PRIMARY HYPERPARATHYROIDISM • Primary Defect – parathyroid glad adenoma or hyperplasia • 1,25-(OH)2D3 – PTH- dependent increased renal synthesis • Skeletal Status – decreased cortical bone density

36. PRIMARY HYPERPARATHYROIDISM • Surgical Management • Medical Management Estrogen Orthophosphates

38. RENAL PHOSPHATE LEAKABSORPTIVE HYPERCALCIURIA TYPE III • Primary Defect – increased urinary phosphate • 1,25-(OH)2D3 – increased • Skeletal Status – decreased bone density • Calcium Balance – negative • Role of Diet

39. RENAL PHOSPHATE LEAK TREATMENT • Orthophosphates

40. MANIFESTATIONS OF THE HYPERCALCIURIAS

41. TREATMENT OF NEPHROLITHIASISCONSERVATIVE MANAGEMENT • Fluids to maintain 3-8 L Urinary Volume/Day • Diet No Calcium Restriction Sodium Restriction Limited Purine Intake Oxalate Restriction