a practical approach to urolithiasis in pediatrics

1. Approach to Pediatric
Urolithiasis
Mitra Basiratnia
Ped Nephrologist
SUMS
2021

2. INTRODUCTION
• The incidence of kidney stones is increasing
• The greatest increase in the incidence of NL was observed in the 15-
to 19-year-old adolescents, in whom the incidence increased 26%
over 5 years
• Even in colder countries like Iceland, the incidence has increased from
3.7/100,000 between 1995 and 1999 to 11.0/ 100,000 between 1999
and 2004

3. • About half of the pediatric patients with kidney stones have a
metabolic etiology (genetic or life style mediated)
• One quarter urinary tract infection
• 20% urinary tract obstruction and stasis
• Small proportion no reason can be found

4. • The most important role of the pediatric nephrologist is :
--diagnose and modify various metabolic and non-metabolic
risk factors
-- prevent long-term complications especially in the case of
recurrent urolithiasis

5. High chance of finding a metabolic risk
factor
• Presentation during the first years of life
• Positive family history or consanguinity
• Recurrent and multiple renal stones

6. Metabolic abnormalities
• Hypocitraturia may now account for 58% of metabolic causes
• Hypercalciuria (48.3%), hyperuricosuria (2.2%), and hyperoxaluria
(4.4%)
• Probably, dietary factors contribute to this shift owing to a low
consumption of potassium and magnesium

7. Inherited metabolic disorders

8. Diagnostic approach and
metabolic evaluation

9. A complete systematic diagnostic evaluation
Family and clinical history
Laboratory evaluation
Diagnostic imaging

10. Family and clinical history and P/E
• The presence of stones in a high percentage of first degree relatives
(22–75%) (genetic, diet, environment)
• Ask about risk factors
• Growth retardation, bone deformities characteristic of rickets (RTA),
photophobia owing to band keratopathy (hypercalcemia or
hyperoxaluria)

11. Metabolic evaluation
• Metabolic evaluation should be performed with patients on their
usual diet and fluid intake, and their usual activity routine
• Serum Na, K, calcium, phosphorus, uric acid, magnesium, alkaline
phosphatase, pH, bicarbonate and creatinine levels should be
measured in all patients
• In specific cases, further blood analysis can include measurements of
parathyroid hormone, vitamin D metabolites, and plasma oxalate

13. Flow chart for work-up of nephrolithiasis

14. Diagnostic imaging
• Both the AUA and the European Society for Pediatric Radiology
recommend ultrasound as the initial imaging modality
• Ultrasound was 66.7% (48.8– 80.8%) sensitive and 97.4% (86.8–
99.9%) specific for detecting stones.
• Aabdominal radiography is not used routinely in children anymore

15. • The most sensitive test for identifying stones in the urinary system
(especially for ureteric stones) is non-contrast helical CT scanning( low
dose protocols)
• Its use should be reserved for cases with non-informative US and/or
plain abdominal roentgenogram.
• Intravenous pyelography is rarely used in children, but may be needed
to delineate the caliceal anatomy prior to percutaneous or open
surgery.

16. Twinkling artifact
• The sensitivity of ultrasound can
be enhanced by the color Doppler
technique using the stone-
triggered artifact called twinkling
artifact
• The twinkling artifact is a mixture
of rapidly alternating red and blue
pixels behind a strongly reflective
object (e.g. calculus) resembling
turbulent blood flow.

17. Take home message
• Pediatric urolithiasis is a common health problem worldwide with
many causes, including environmental, dietary and genetic; the most
common disease has a metabolic etiology
• Metabolic risk factors include hypercalciuria, hyperuricosuria,
hyperoxaluria and cystinuria
• Diagnostic evaluation should aim to rule out anatomic obstruction,
determine the history of the patient (including familial risk factors)
and involve urine analysis