This document provides an overview of pediatric urinary stones, including epidemiology, etiology, clinical presentation, diagnosis, and management. Some key points: - Urinary stones are relatively uncommon in children but can indicate underlying metabolic or anatomical issues. - Evaluation involves imaging like ultrasound or CT to identify stones as well as metabolic testing of urine and serum. - Treatment depends on stone characteristics and includes conservative management, extracorporeal shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. - Long-term follow-up is important due to risk of recurrence from untreated metabolic abnormalities or anatomical anomalies.

1. Saleamlak T.( MD, Pediatric surgery resident)
September, 2019

2. OUTLINES
 Introduction
 Epidemiology
 Etiology
 Pathophysiology of stone formation
 Clinical presentation and Diagnosis
 Management options
 Recurrence and prevention
 SUMMARY
 REFERENCES

3. Introduction
 Urinary stones
 Relatively uncommon in the pediatric age group
 Significant long-term complications include possible
progression of renal dysfunction
 May herald systemic metabolic disorder or underlying
anatomical anomalies
 The clinical features are often vague and nonspecific
 so a high index of suspicion is usually required for diagnosis
 The standard procedures
 To treat urinary stone disease in children are the same as those used in
an adult population

4. Epidemiology
 Incidence
 2-3% of all patients with stone disease
 Age
 Mean: 8-10yrs
 Infected stones tend to occur more frequently in children under
4 years of age
 Sex
 Equal
 Recurrence
 4-70%
 The highest for children with underlying metabolic risk factors

5. Etiology
 Metabolic Causes- 40%
 Hypercalciuria
 Cystinuria
 Hyperoxaluria
 Hyperuricosuria
 Hypocitric aciduria
 Hyperxanthinuria and others
 Congenital Abnormalities-25%
 PUV, bladder exstrophy, VUR, meatal stenosis, medullary
sponge kidney, and PUJO , Neuropathic bladders
 Urinary Tract Infection- 10%
 Diet
 Idiopathic

7. Pathophysiology of stone formation

8.  INHIBITORS
 Inhibits crystal Growth
 Citrate
 Magnesium
 Pyrophosphate
 Zinc
 Inhibits crystal Aggregation
 Glycosaminoglycans
 Tamm- Horsfall Protein
 PROMOTERS
 Bacterial Infection
 Anatomic Abnormalities
 Altered Ca and oxalate
transport in renal epithelium
 Prolonged immobilisation
 Increased uric acid levels
 Taking increased purine subs–
promotes crystalisation of Ca
and oxalate

9. Clinical presentation
 The clinical manifestations of pediatric urinary
stones are dependent upon a number of factors:
 Age of the patient
 Size of the stone
 Location of the stone
 Degree of obstruction to the flow of urine
 Presence of infection
 Presence or absence of a normal contralateral renal unit

10.  h

11. Investigations for Urolithiasis
 The role of diagnostic imaging can be considered at two
levels
 Initial screening for possible calculi
 Ultrasound
 Abdominal X-ray
 Unenhanced spiral computed tomography
 Evaluation prior to treatment of proven stone disease
 DMSA
 Intravenous urography
 Additional investigations
• Micturating cystography
• Dynamic renography
• Computed tomography
• Metabolic investigations
• Stone screening

12. Ultrasound
 A sensitive modality
 For the detection of renal
calculi
 Directly visualized
 An ‘acoustic shadow’
• serves to distinguish calculi
from other echogenic lesions
within the renal collecting
 NB.
 Ureteric calculi and small bladder
calculi
 May sometimes be difficult to detect on
ultrasound

13. Plain X-ray KUB
 Disadvantage
 Radioluscent stone
 Stone <4mm
 Lies over sacrum/bony
structures
 Bowel gas can obscure its
efficacy
 Cannot differentiate
 Stones
 Calcified LN
 Sensitivity: 50-70%

14. Unenhanced spiral CT
 Best diagnostic modality
 Provides an accurate diagnosis
within minutes
 Avoids the potential risk of
adverse reaction to contrast
media
 Will positively demonstrate the
presence of radiolucent calculi
 That cannot be directly visualized
by conventional radiology

15. Intravenous urography
 Roles
 Visualization of nonopaque stones and
 The matrix component of infective
staghorn calculi
 Information on calyceal anatomy
 Important in planning percutaneous nephrolithotomy (PCNL)
and external shockwave lithotripsy (ESWL)
 Ureteric calculi
 Are best localised by intravenous urography
 Underlying anatomical abnormality

16. Investigation
 URINE
 Ph
 Routine analysis(including & specific gravity)
 Culture
 Spot specimen:
 Ca, protein, uric acid, oxalate, citrate ,Mg, creatinine.
 24hr urine:
 Volume, protein, creatinine, Na, Ca, Mg, oxalate,
phosphorus, uric acid, citrate, cystine.
 Stone analysis
 Metabolic work up

17. Urine analysis:

18. Normal urinary excretion of important constituents

19. Treatment
 Four main factors affect initial treatment
decisions:
 The clinical scenario
 The stone composition
 The stone size, and
 The stone location

20. Management options
Clinical scenario
 Bilateral obstruction
 Obstruction of a solitary kidney
 Fever/UTI with potential obstruction
 Intractable pain
URGENT intervention
Stent or
Nephrostomy
Stone composition
Uric acid
Struvite
Cystine
Calcium oxalate
 Stone size
 <4 mm
 90% chance of spontaneous passage
 4-6 mm
 50% chance of spontaneous passage
 >6 mm
 10%chance of spontaneous passage Stone location
 Renal
 ESWL or PCNL, or RIRS
 Proximal ureteral
 Ureteroscopic extraction (antegrade) or ESWL
 Distal ureteral
 Ureteroscopic extraction (retrograde) or ESWL
 Bladder
 Cystolithotomy or cystolitholapaxy

21. Initial Management
 Pain control
 NSAIDS (renal function)
 Oral/rectal/IV
 Acetaminophen
 Narcotics
 Oral/IM/IV
 Decompression or removal
 Anti-emetics
 IV hydration
 IF FEVER – antibiotic
 Alpha-blockers as medical
expulsive therapy (MET)

22. Conservative management
 Spontaneous stone passage depends on:
 Location: Proximal vs. distal (distal stones more likely to pass)
 Size: ~90% of stones <5mm will pass
 Time since onset: Most stones pass by ~40 days

24. Probability of passage:
 <4mm- ~90%
 4-7mm- ~50%
 >7mm- <10%

25.  h

26.  h

27.  h

28.  A recent meta-analysis (MA) of five
trials(406 patients)
 Adrenergic a-antagonists are effective for MET increasing SFR
compared to control (OR = 2.7, p = 0.001) without significantly
increasing the treatment-emergent adverse events (OR = 2.01, p
= 0.17)
• Tamsulosin - 0.2-0.4 mg/day and
• Doxazosin - 0.03/mg/kg/day)

29. Definitive Treatment
 Extracorporeal shock wave lithotripsy (SWL)
 Ureteral stones <1cm or
 Renal stones <2cm
 Ureteroscopic laser lithotripsy (URS)
 Ureteral stones or
 SWL failures
 Percutaneous nephrolithotomy (PCNL)
 Large >2cm renal stones
 Open surgery /laparoscopic

30. Extracorporeal Shockwave Lithotripsy
(SWL)
 First described in the early 1980s
 Noninvasive and well-tolerated
 GA
 Conscious sedation
 The first-line treatment for most
ureteral and renal stones in children

31.  Absolute Contra-indications
 Bleeding Disorder/anticoagulation
(NSAIDS pre-op)
 Febrile UTI
 Obstruction Distal to the stone
being treated
 Relative Contra-indications
 Radiolucent stones
 Pacemaker
 Calcified renal artery/AAA
 Severe orthopedic deformities
When do we not use SWL?
 Stone Burden
 >2cm in largest diameter or multiple
stones
 Stone composition
 Particularly cystine or brushite
stones
 Patient habitus
 skin-to-stone distance >10cm)
 Failed SWL
 2nd treatment reasonable
 Diminishing returns of 3 or
more treatments
• Hematuria
• Hematochezia
• Ureteral obstruction - 5-30%
• Sepsis - 1%
• Perinephric Hematoma - <1%

32.  Retrospective study
 64 patients
 58(90.6%)– treated with ESWL
 54 (84.4%) were successfully treated
within three ESWL sessions
 Success rate
 Stone -free status or
 Clinically insignificant residual
fragments (CIRFs)
• Asymptomatic noninfectious and
nonobstructive fragments smaller than 3
mm
Multiplicity
Size of the stone

33. Ureteroscopy (URS) Lithotripsy
 Typically for ureteral calculi
and SWL failures
 Advantages:
 Near 100% stone free rate
 Low retreatment rates
 Treatment available in most
centres
 SWL tends to be in specific
centers only
 Disadvantages:
• General anesthesia
• Ureteral stent
• The size in pediatrics
Ureteroscopic Equipment
Complications
Ureteral perforation
Ureteral stricture
Reflux
Proximal migration of the stone
Loss of the stone through
a perforated ureter

34.  Thirty-four studies
(2758 children)
overall stone-free rate
(SFR)
 90.4% (range 58–100).
Medium-volume centres
reported - 94.1% (range
87.5–100)
High -volume centres-
88.1% (range 58–98.5)
 The overall complication rate was
11.1%

35. Percutaneous Nephrolithotripsy
 Typically for large (>2cm) renal calculi
 Advantages:
 Ability to remove large or multiple stone
burden with high success rate (>95%)
 Disadvantages:
 General anesthesia
 More invasive than URS
 Risk of bleeding
 <5% require transfusion
 Injury to surrounding organs
 Risk of hydropneumothorax

36.  Complications
Sepsis or SIRS
Bleeding requiring transfusion or selective
angioembolization.
Perforation of the renal pelvis
Stricture
UPJ or infundibulum
Residual stone fragments
Hemothorax/pleural effusion (<10%)
Adjacent organ injury (colon perforation)

37. Open Surgery
 Open surgical treatment
 Is still required in up to 17% of patients
 Which may result in decreased renal function in up to 45%
 Anatomic abnormalities
 Ureteropelvic junction obstruction or
 Obstructed megaureter
• May be addressed concurrently with stone treatment and
• Must be dealt with eventually to prevent recurrence and optimize renal function
 In developing countries
 Due to the limited availability of endoscopic equipment
 Procedures

38.  gb

40. Recurrence and prevention
 Recurrence
 Children are at risk for recurrence for a longer time than adults
 Thus the cumulative likelihood of recurrent stone disease is higher in
children
 Metabolic evaluation
 Is strongly encouraged in children after their first presentation with
urolithiasis
 A 24-hour urinalysis
 Prevention
 Treat metabolic abnormalities
 Control urinary infection
 Correct anatomic anomalies

41. Summary
 Urinary stones are relatively uncommon in children
 In a majority of patients
 An identifiable predisposing cause can be found, and more than one factor may be
responsible in the same patient
 Presentation may be acute or nonspecific and varied
 Thus , diagnosis is often difficult or delayed
 A wide range of imaging techniques as well as urine and
serum biochemical analysis are needed for evaluation
 Helical noncontrast CT is useful in confirming the presence of a stone and also in
detecting abnormalities of the urinary tract
 Treatment should be directed towards
 Removing the underlying cause(s) of the stone, where this is identified
 As well as dealing with the pathological effects of the stone
 Long-term follow-up of children with urinary stones is
necessary to detect recurrence

42. References
 Coran Pediatric Surgery, 7th ed
 The Kelalis-King-Belman Textbook of Clinical Pediatric Urology
Informa 2007.
 Principles and practice of pediatrics surgery, 4th ed
 Essentials of pediatric urology 2nd, 2008
 Pediatric surgery :a comprehensive text for Africa(volume II)
 American Urology Association Guideline
 EUA guideline
 Journals

43. We have to advance our practice
on pediatrics endourology!

44. 4
4
Thank You