| Background and ObjectiveThe urinary stones are very common in adults,but rare in infants,and most are sporadic cases,cover 1%～3%of the total urinary calculi incidence.The present study has shown that male urolithiasis was more than that of females(male vs. female,3:1),the infant patients diagnosed increased dramatically since it was reported on 9th September 2008 that infants who had been fed on infant formula contaminated by melamine were prone to urolithiasis.Melamine is of low toxicity itself;however,according to the research,long-term intake or repeated intake in large amount of melamine may produce negative effects on the kidney and urinary bladder,that is formation of urolithiasis.Animal testing indicates that long-term melamine-feeding could lead to renal failure and even urinary bladder cancer.At the present time,there are scant reports relevant to effects of melamine on human body,especially on infants.The infant generally fail to name their suffering for they have limited language competence.As a consequence,many infants are detected till renal failure appears and it is of key importance to realize early diagnosis and early application of proper therapy,so it is also of vital importance to have an utter understanding of its pothogenesy,clinical characteristics and methods of diagnosis and treatment.Our objectives are as follows:Analysis of pothogenesy,clinical characteristics and methods of diagnosis and treatment of the disease:Collection and analysis of its imaging manifestations,summarization of the diagnosis and treatment of renal failure so as to provide references for the diagnosis, treatment and prevention of the disease.Materials and Methods1.Clinical data:Retrospective analysis was performed on clinical data of 128 cases of infant patients,the first group admitted to hospital,with urolithiasis and a melamine-contaminated milk-fed history,meanwhile.10 cases of urolithiasis patients fed merely on breast milk served as urolithiasis control group,and another 20 cases of hospital babies with no melamine-contaminated milk-fed history or urolithiasis served as normal control group.2.Method:All cases were treated according to the Diagnosis and Treatment Guideline from the Chinese Ministry of Health.Ultrasonic examination is of the first choice,and examinations of blood biochemistry,liver and kidney functions,and routine urine test are necessary.Infants diagnosed should undergo medical therapy. Relevant parameters should be recorded so as to facilitate further grouping according to shape,location,size,number,patient's condition,and treatment therapy.Alterations of these parameters among different groups should be analyzed.The standards for determining treatment effectiveness are as follows:1.Recovery:urinary stones and clinical symptoms disappear;2.validness:clinical symptoms disappear and part of stones are discharged or stone shadows shrink illustrated by ultrasonic scan.3. Invalidness:stones remain unchanged or even increase in number or size.3.Statistical analyses were carried out using the Statistical Package for Social Sciences(SPSS),for Windows.Values were expressed as mean±SD,and the t test was used to evaluate the difference.P values of＜0.05 were considered to be statistically significant.Result1.Clinical characteristicsUrinary melamine calculi occurred most often in children less than 2 years old (88.3%),78.1%between 6 months to 18 months of age.Upper urinary tract calculus occurred in 124 cases(96.9%),and renal calculus in 100 cases(78.1%).The infants with no obvious symptoms were diagnosed at the time of physical examination;Different clinical symptoms including including dysuria,abdominal pain or unexplained crying,and oliguria or anuria.Ultrasonographic appearance:In renal melamine calculi,sporadic spot or hyper-echo mass with different size and shape exists in the collecting system,partly without acoustic shadow has been found;Ureteral calculi showed a dense echo and luminous belt with obscuration acoustic shadow under a band without echo.Middle ureteral stones shows oval or round granular strong echo.End ureteral stones shows bladder wall with a strong echo in the light of the strong echo,with acoustic shadow. In the bladder calculi,irregular strong echo mass or small spot with thick acoustic shadows without side lobe artifact in the liquid dark areas was presented.2.Comparisons of Relevant parameters between different groupsComparison between melamine-calculi and non-melamine-calculi group shows urine pH value and calculi size in melamine urinary calculi group were significant decreased compared with non-melamine-calculi group(P＜0.05).The multiple and sand-like calculi seen more frequently in MS than NMS(P＜0.05).Urine pH value was significant decreased in experimental group compared with normal-control group(P＜0.05).BUN,Scr and potassium levels increased markedly in severe experimental group compared to mild,moderate subgroup and normal-control group(P＜0.05),the age of children were younger than those of other groups(P＜0.05).3.TreatmentAfter hospital treatment,the clinical symptoms in all patients disappeared and none died.The calculi disappeared in 65,diminished in size in 53 and had no change in 10,the cure rate is 50.8%,and effective rate was 92.2%.The calculi expelling rate in mild group was 85%,in moderate 46.8%and in severe 28.6%.The maximum diameter of calculi expelled was 6mm.The urine pH value of response and partial response group was decreased significantly compared to invalid group(P＜0.05).In response group,the calculi size reduced in size markedly compared to those in partial response group(P＜0.05).Eighteen melamine-calculi patients suffered from renal acute failure who received conservative treatment including urethral catheterization and urine alkalinization to dispel calculis in hospital.Hemodialysis was performed in 8 with severe renal failure. All severe renal failure cases gradually recovered after 1 to 3 hemodialysis treatments. Sand-like calculi s were expelled.The calculi were partially,expelled,the clinical symptom disappeared;calculi size was less than 4mm at discharge in 2 cases.4.Features of the calculiThe calculi expelled from 12 cases were analyzed by using combined liquid phase chromatography-mass spectrum method and the main contents of the calculi were identified to be uric acid and melamine.Conclusions1.The MUS occurred most often in infants aged 6 months to 12 months old:mainly male,the incidence of bilateral kidney stone is high.2.Ultrasonography is an reliable and accurate method of diagnosis of melamine urinary calculus.3.The analysis of calculi that expelled from the infants shows the main contents of the calculi were uric acid and melamine.That is the reason for urine alkalinization.4.Noninvasive management had a good treatment response to the MUS children. Efficacy of treatment is associated with the size of urinary stones and PH value, and not with age.5.Blood purification dialysis is suggested to treat life-threatening acute renal failure. |
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