Thr NEW ENGLAND JOURNAL f MEDICINE did not have stones)(table 3)Hematuria wa es (2 of 34).and leukocvturia in 2.9%d of 34).No child suspected to have stones had hematuria,and only 1of76(1.3%)had leukocyturia.Proteinuria was rare,and its frequency did not differ significant ly among of urir evidence of glomerular dysfunction.Among the children for whom these data were available glomerular dysfunction was found in 4 of the 41 children (9.8%)who had stones,12 of the 88 chil he th glomerular dysfunction amon children suspected to have stones as comnared with children whe did not have stones,was significantly increased (P=0.01).The incidence of renal tubular dystunc graphy in Two Children with Urolithiasis 41 anel A)anda l aminotransferase levels were measured in 56 chil- c punct dren-22 who had stones,21 suspected to have y0.3 stones,and 13 who did not have stones.All 50 0.92 cm sha at is row).dose to the lower pole of her right nes an wh stones (201 and 243 I per liter re had stones (overall prevalence,8.5%):112 were range,0 to 401).Neither of these two children had suspected to have urinary stones,and 427 had no received high-melamine formula,and neither had symptoms of infection such as fever and diarrhea gobbet-shapec ren 1968g obstructiononultrasonographyhoUghaGf of age.14:and 19 months to 078 these children had symptoms of obstruction.Most According to these values,62 of the children in of the children with stones did not have oliguria, our study had hypercalciuria:5 of 42(119%)who crying on urination,edema,or pas sing of stone had stones,13 of 88(14.8%)suspected to have The presence of symptoms d not dis inguish chil stones,and 44 of 274 (16.1%)who did not have ones from t did not P=0.34) FACTORS ASSOCIATED WITH URINARY STONES We considered age sex birth type melamine con LABORATORY EXAMINATIONS tent in the formula received,and use of the for- Urinalysis was performed in 372 children (34 ofmulalone inmbtion with breast milk as the 50 who ha suspected to have stones,and 262 of the 42 tion.Complete data were avail for 400 of th 1070 N ENGLJ MED 360:11 NEJM.ORG MARCH 12,2006 omaThe new england journal o f medicine 1070 n engl j med 360;11 nejm.org march 12, 2009 had stones (overall prevalence, 8.5%); 112 were suspected to have urinary stones, and 427 had no stones. Grossly, the stones were mainly grainy and gobbet-shaped (irregular and nubby) and did not cause shadowing on ultrasonography. Most were localized to the renal pelvis (Fig. 1). Four children who had stones also had evidence of urinary tract obstruction on ultrasonography, though none of these children had symptoms of obstruction. Most of the children with stones did not have oliguria, crying on urination, edema, or passing of stones. The presence of symptoms did not distinguish chil￾dren who had stones from those who were sus￾pected to have stones or those who did not have stones (Table 2). Laboratory Examinations Urinalysis was performed in 372 children (34 of the 50 who had stones, 76 of the 112 who were suspected to have stones, and 262 of the 427 who did not have stones) (Table 3). Hematuria was present in 5.9% of the children with stones (2 of 34), and leukocyturia in 2.9% (1 of 34). No child suspected to have stones had hematuria, and only 1 of 76 (1.3%) had leukocyturia. Proteinuria was rare, and its frequency did not differ significant￾ly among the groups. We considered the elevation of urinary micro￾albumin levels, transferrin levels, or both to be evidence of glomerular dysfunction. Among the children for whom these data were available, glomerular dysfunction was found in 4 of the 41 children (9.8%) who had stones, 12 of the 88 chil￾dren (13.6%) suspected to have stones, and 15 of the 269 (5.6%) who did not have stones (P=0.04 for the three-way comparison). The incidence of glomerular dysfunction among children suspected to have stones, as compared with children who did not have stones, was significantly increased (P=0.01). The incidence of renal tubular dysfunc￾tion, as indicated by elevation of the urinary β2- microglobulin level, did not differ significantly among the three groups (P=0.42) (Table 3). Serum creatinine, urea nitrogen, and alanine aminotransferase levels were measured in 56 chil￾dren — 22 who had stones, 21 suspected to have stones, and 13 who did not have stones. All 56 children had normal serum creatinine and urea nitrogen levels. In one child suspected to have stones and one child who did not have stones, alanine aminotransferase levels were increased (201 and 243 IU per liter, respectively [normal range, 0 to 40]). Neither of these two children had received high-melamine formula, and neither had symptoms of infection such as fever and diarrhea. The urinary calcium:creatinine ratio was mea￾sured in 404 children and compared with the published reference values for young children: 7 months of age or younger, 1.96; 8 to 18 months of age, 1.4; and 19 months to 6 years of age, 0.78.3 According to these values, 62 of the children in our study had hypercalciuria: 5 of 42 (11.9%) who had stones, 13 of 88 (14.8%) suspected to have stones, and 44 of 274 (16.1%) who did not have stones (P=0.34). Factors Associated with Urinary Stones We considered age, sex, birth type, melamine con￾tent in the formula received, and use of the for￾mula alone or in combination with breast milk as potential factors influencing urinary stone forma￾tion. Complete data were available for 400 of the 22p3 B A AUTHOR: FIGURE: JOB: 4-C H/T RETAKE SIZE ICM CASE EMail Line H/T Combo Revised AUTHOR, PLEASE NOTE: Figure has been redrawn and type has been reset. Please check carefully. REG F Enon 1st 2nd 3rd Ding 1 of 1 03-12-09 ARTIST: ts 36011 ISSUE: Figure 1. Results of Ultrasonography in Two Children with Urolithiasis Induced by Melamine-Tainted Formula. Ultrasonographic images of the abdomen are shown for a 2-year-old boy (Panel A) and a 1-year-old girl (Panel B). Both children had multiple and sporadic punctiform, bilateral hyperechoic areas in the renal sinus. The largest hyperechoic area in the boy (Panel A, arrowhead) is 0.25 cm by 0.31 cm, without any shadow. The girl has a hyperechoic conglomeration that is 0.92 cm by 0.74 cm by 0.33 cm (Panel B, arrowhead) with a shadow (ar￾row), close to the lower pole of her right renal sinus. The New England Journal of Medicine Downloaded from nejm.org on October 18, 2011. For personal use only. No other uses without permission. Copyright © 2009 Massachusetts Medical Society. All rights reserved