A Comparison between Clinical and Metabolic Features of Renal Calyceal Microlithiasis and Overt Urolithiasis in Different Pediatric Age Groups.
BACKGROUND
This study assesses the differences in the presentations, complications and metabolic abnormalities of children with renal calyceal microlithiasis (RCM) and overt urolithiasis in different pediatric ages.


METHODS
A total of 465 children with urolithiasis were investigated retrospectively. Patients were categorized based on their ages to infancy, early childhood, middle childhood and adolescence. When the hyperechogenic spots on ultrasound imaging were <3 mm, they were considered RCM, and if they were ≥3 mm, they were considered overt urolithiasis.


RESULTS
Metabolic abnormalities were detected in 71%; hyperuricosuria in infants, hyperoxaluria in younger children and hypocitraturia in older children were the most common metabolic abnormalities. Hypercalciuria was the only metabolic abnormality that was significantly associated with overt urolithiasis in all pediatric ages (OR 2.25, 95% CI 1.21-4.19). The clinical presentations were not significantly different between RCM and overt urolithiasis; however, complications such as urinary tract infection was significantly higher with overt urolithiasis in infancy (p = 0.01), early childhood (p = 0.02), middle childhood (p = 0.007) and adolescence (p = 0.01). Also, growth retardation was significantly higher with overt urolithiasis in infancy and early childhood (p = 0.02).


CONCLUSIONS
Most children with urolithiasis have underlying urinary metabolic abnormalities that differ according to the child's age. Despite these differences, hypercalciuria is significantly associated with overt urolithiasis in all pediatric ages. Clinical and laboratory features cannot differentiate RCM and overt urolithiasis; however, complications are significantly higher with overt urolithiasis.
Department of Pediatric Nephrology, Bahrami Children Hospital, Tehran, Iran.
Daryoosh
D
Fahimi
Mojdeh
M
Habibi Zoham
Mahdi
M
Sheikh
Mirataollah
M
Salabati
Arash
A
Ghazanfari
Mojdeh
M
Firouzi
Malektaj
M
Honarmand
D000293:Adolescent; D000367:Age Factors; D002114:Calcinosis / Q000652:urine; D002118:Calcium / Q000652:urine; D002648:Child; D002675:Child, Preschool; D019343:Citric Acid / Q000652:urine; D005260:Female; D006801:Humans; D007223:Infant; D007670:Kidney Calices / Q000473:pathology; D008297:Male; D009398:Nephrology / Q000379:methods; D010070:Oxalates / Q000652:urine; D010372:Pediatrics / Q000379:methods; D012189:Retrospective Studies; D012307:Risk Factors; D014527:Uric Acid / Q000652:urine; D014552:Urinary Tract Infections / Q000150:complications; D052878:Urolithiasis / Q000150:complications* / Q000652:urine*
D010070:Oxalates; D014527:Uric Acid; D019343:Citric Acid; D002118:Calcium