January 27, 2011

Epidemiology 1/685 pediatric admissions Lower incidence than adults Higher crystal formation inhibitors in urine M>F Most common stones Calcium oxalate Calcium phosphate Struvite Cystine Uric Acid

Risk Factors Present in 75-85% of children Urinary metabolic abnormality Hypercalciuria* Hyperoxaluria Hyperuricosuria Hypocitraturia UTI Structural renal or urinary tract abnormality

Nephrolithiasis Presentation Abdominal or flank pain Wide variability Gross hematuria Dysuria Urgency Nausea/vomiting 15-20% asymptomatic Younger patients

Other History Previous history Family history Underlying renal and urinary tract structural abnormalities Underlying metabolic conditions Medication use History of UTI Especially with urease-producing organisms Proteus or Klebsiella

Physical Exam Growth parameters Congenital or chronic condition Temperature UTI Blood pressure Glomerular disease Edema Abdomen Tenderness Mass Obstruction

Lab Evaluation UA Sediment Cystine crystals Calcium oxalate Calcium phosphate Uric acid Phosphate Urine Culture

Diagnosis Confirmation Imaging Non-contrast helical CT Ultrasonography Stones >5mm Location Plain abdominal radiography Radiopaque only Not good for small stones Retrieval

Treatment Hospitalization Nausea/vomiting Severe pain Urinary obstruction Solitary kidney Infection

Treatment Pain control NSAIDs Opiod therapy Combination may be superior Passage <5 mm Hydration Strain urine Stone analysis

Treatment Urologic intervention Unremitting severe pain Urinary obstruction Infection Renal insufficiency >5mm stone Struvite calculi >2 weeks of conservative treatment

Treatment Urological intervention Extracorporeal shock wave lithotripsy Small <1cm Percutaneous nephrostolithotomy >2cm Structural abnormalities Harder stones Ureteroscopy

Prevention Recurrent stone disease frequently occurs in children >50% of children with nephrolithiasis will have an underlying metabolic abnormality Reduce Pain School absenteeism Loss of work for parents Clinical costs

Prevention Stone analysis Focus metabolic evaluation Metabolic evaluation At home Fully ambulatory Regular diet Free of infection

Prevention Serum testing Calcium Phosphorus Bicarbonate Creatinine Magnesium Uric Acid

Prevention UA SpGr pH Crystals Urine solute excretion 24h vs single Volume and creatinine

Prevention Fluid intake Metabolic interventions Targeted to correct the specific abnormality Infants>750ml/day <5y>1L/day 5-10y>1.5L/day >10y>2L

Monitoring Imaging New formation or increasing size of previous stones U/S Frequency depends on risk Lab eval Assess response to preventative therapy 6-8 weeks, 6 months, yearly