(Pediatrics in Review. 1999;20:280-283. doi:10.1542/10.1542/pir.20-8-280)
© 1999 American Academy of Pediatrics
Renal Stones
Donna Elliott, MD, MSEd*
Lawrence M. Opas, MD
*
Associate Professor of Clinical Pediatrics,
University of Southern California School of
Medicine; Associate Director of Pediatric
Nephrology, LAC+USC Medical Center.
Professor of Clinical Pediatrics, University
of Southern California School of Medicine;
Chief of Pediatric Services, Director of
Pediatric Nephrology, LAC+USC Medical
Center, Los Angeles, CA.
 |
Introduction
|
|---|
Renal stone disease is a frequent consideration in
the evaluation of many kidney diseases of childhood, but the diagnosis
rarely is confirmed. The true incidence is unknown; only 1 in
3,000 to 7,500 pediatric hospital admissions are attributed to
renal stones. There is a bimodal peak incidence at 4 years of age and
in mid-adolescence, with an equal gender prevalence. Stones are rare in
African-American children. Although most renal stones in the United
States have a metabolic etiology, hereditary, infectious, and dietary
causes should be considered in the evaluation of affected children.
|
Pathogenesis
|
|---|
Crystallization is influenced by urinary tract anatomy, flow, ion
concentration, pH, and select organic and inorganic molecules. Low
urinary flow rates resulting from obstruction or hypovolemia, damaged
uroepithelial cells, foreign bodies, and increased ion concentration
favor stone formation. Acidic urine decreases the solubility of uric
acid and cystine, which promotes crystallization; an alkaline pH is
conducive to the formation of struvite and calcium-containing stones.
Increased urinary concentrations of citrate, pyrophosphate,
glycosaminoglycans, and proteinaceous substances such as Tamm-Horsfall
protein and beta2 microglobulin inhibit stone
formation. Nephrocalcin, which normally is found in the urine and is
known to inhibit crystal formation, frequently is absent in the urine
of children who have renal stone disease.
|
Infective Stones
|
|---|
Renal stones formed as a result of infection consist of an organic
matrix of Tamm-Horsfall glycoprotein, struvite
(Mg-NH4-PO4), and apatite
(CaPO4). Urease-producing organisms such as
Proteus and more rarely Pseudomonas, Klebsiella,
Serratia, Staphylococcus, and Candida cause the
hydrolysis of urinary urea to ammonia and carbon dioxide, creating an
alkaline environment that favors crystallization.
Infective stones are more common among males and usually are detected
before age 5 years; 93% of children have active infection at the time
of diagnosis. Only one third of children have primary obstructive
uropathy, such as posterior urethral valves, . . . [Full Text of this Article]
CiteULike 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
Copyright © 1999 by the American Academy of Pediatrics.
