This document discusses the approach to pediatric urolithiasis or kidney stones. It notes that the incidence of kidney stones is increasing, especially in adolescents. About half of pediatric kidney stone cases have a metabolic cause, such as hypercalciuria, while others are due to urinary tract infections or obstructions. The role of the pediatric nephrologist is to diagnose and modify metabolic and non-metabolic risk factors to prevent long-term complications. A complete evaluation involves taking a family history, medical tests to check for metabolic abnormalities, diagnostic imaging like ultrasound, and identifying inherited disorders.

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