1. RENAL STONE IN CHILDREN
Ali Derakhshan MD
Shiraz university of Medical Sciences
Shiraz-Iran
بهمن 9626

2. Case1 8 mo old baby presented with irritability, an US →19 mm stone in LP of LT kidney,since his older brother was a case of cystine stone , urine sample →+nitroprusside test for cystine
Urologic consult →can wait on medical Rx since non-obstructive
Combination Rx with polycitra-K+ captopril+ vit. B6+
D-penicillamine, 6 weeks later stone size  to 12 mm
and Rx continued with a 3mo F up
At this time US was entirely NL.

3. CASE 2 3yrs old♀, fever and abdominal pain,active UA,UC to follow,
Past Hx:open surgery for a Lt.pelvic stone 1yr ago with composition85% cystine but no follow up Rx.
US 8mm stone in lt proximal ureter +hydronephrosis +2other 6mm and 5 mm stone in lt U and Lower pole.

4. Case 3
45days old♂ with colicky pain,an US revealed a few gravel mm in each kidney
NL UA

5. Urinary tract obstruction
Common cause of acute and chronic renal failure
Potentially curable form of kidney disease

6. Our ESRD children 1990-1999 116 children on hemodialysis
Major causes of ESRD in order of frequency were glomerulopathies 23 (19.83%), reflux 15 (12.93%), chronic pyelonephritis without reflux 11 (9.5%), cystic diseases 10 (8.62%),
neurogenic bladder 10 (8.62%)
stone disease 9 (7.75%),
posterior urethral valve 7 (6.03%)
ureteropelvic junction obstruction 7 (6.03%)=
total obst:29%UTO

7. Epidemiology
Rate of symptomatic stone formation was 7.9/10000 in 1996, increased to 18.5/10000 in 2007.
Adult rate :
Asia 1-5%
Europe 5-9%
North America 13%
Saudi Arabia 20%

8. Causes of increase incidence:
The causes of increase incidence is unknown but obesity, higher salt intake, lower water intake, low Ca diet and high rate of using antibiotics may be considered.

9. Predisposig Factors
1. Peak Age ( yr),Adolescents 10 times more symptomatic stone than< 3 yr
2. Sex (M>F)
3. Race
4. Environmental and Socioeconomic Factors
5. Genetic Factors, Obesity
6. Dietary Habits

10. Renal stone Composition
Ca is found in 90%
Ca-oxalate(40-60%)
ca-phosphate(15-25%)
Ca-oxalate + Ca-phosphate(10-25%)
Struvite(17-30%)
Uric acid(2-10%)
Cystine(6-8%)
xanthin, Hypoxanthin, Drugs,……

11. Stone Composition With increasing age :
Ca-oxalate stone increases while P and struvite stones decrease.

12. Mechanism of stone formation
Supersaturation
Infection
- crystals(formation, growth, aggregation, adherence to epithelial cells), presence of matrix & absence of inhibitors.
Foreign body or urinary stasis
Urine PH

13. Why stones form… Acidic urine: Uric acid, Cystine, Ca Oxalate
1. Decreased urine volume…
Urine concentrates, supersaturates & crystals precipitate.
2. Urine pH affects solubility…
Acidic urine: Uric acid, Cystine, Ca Oxalate
Alkaline urine: Ca phosphate, struvite
Promotes precipitation of:

14. Why stones form… 3. Absence of inhibitors
Citrate, glycosaminoglycans and Tam Horsfall proteins,Zn and Mg.
4. Infection:
Urea-splitting organisms (Proteus, Klebsiella, E.coli,….) generate ammonia and alkalinize urine
Proteus
Urease
Staghorn calculi (struvite)

15. Underlying Causes(75%) Hypocitraturia(15-63%) Primary
Secondary (acidosis, ↑protein intake, severe exercise, ↑Na intake, ↓urine Mg, UTI, chronic diarrhea, thiazides, hypokalemia)
Structural abnormalities(32%)
Hyperoxaluria, Cystinuria, RTA Hyperuricosuria, Hypercalciuria(the most common 50%),other rare causes

16. Management of renal stone
Paraclinical evalution indicated in all children since:
Once stone always stone
24 hrs. urine for Ca, Cr, Uric acid, Mg, Cystine, citrate and oxalate,urine PH
- VBG
-BUN,Cr,Na,K,Ca,P,UA,Mg,AG
- Stone analysis if any
-Some may need genetic evaluation for primary hyperoxaluria

18. Treatment Pain control
Alpha adrenergic blockers (Tamsulosin) ,Ca Channel Blockers
Hydration
Control of UTI
Medical, surgical or ESWL
Prevention

19. Medical treatment Non-pharmacological medical therapy in all children
Pharmacological therapy in children with multiple stones at presentation or recurrence of stone during one year.

20. Renal stone Rate of another stone formation >50% in 5yrs
How long to continue medical Rx
Depends on the cause
for cystine it is mentioned lifelong ??
for other causes 3-6 mo after clearance but at least 5 yrs. FUP

21. Special indications for drug therapy
Hypercalciuria (the most common)
RTA
Cystinuria
Hyperuricosuria
Hypocitraturia
Hyperoxaluria
Hypomagnesuria
Citrate compounds HCTZ…………
Citrate is recommended for all types of stone except for phosphate & infectious stone

22. Non-pharmacological Non-surgical therapy
↑Water intake
Prevention of heavy exercise
↓Na intake
↓Protein intake (↓urine Ca, ↑Urine PH, ↓Urine uric acid, Effect on urine citrate)
Ca-intake (regular or even ↑)
↓Lipid intake
↓Intake of oxalate containing drinks or foods.

23. Recurrence of renal stone
Rcurrence occurs frequently
It is higher in children with metabolic abnormalities
It is about 5-10% each year
So, long term FU and periodic reassessment is indicated
Frequency of imaging depends on type, number of stones, severity of metabolic abnormalities, UTI and symptoms.

24. Sarv
Abarkooh
Gonbade Ali
Abarkooh 24

25. Results of study in Shiraz
153 children <18 Yr (M/F=1.1)
<2 Yr: 37%, 2-6 Yr: 36.6%, >7 Yr: 26%
F HX: about 50% positive
Stone size <5 mm: 70%, >10 mm: 2.5%.
Stone No: 40.5% =1 stone, 42.5%= 2-3 & 17%>3 stones.
Bilateral in 37%

26. 24 Hr. Urinary Findings 90.8% had at least one metabolic abnormality
Hypomagnesuria 60.8%
Hypocitraturia %
Hypercalciuria %
Hyperuricosuria 37.3%
Hyperoxaluria 17%
Cystinuria 2%