View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Kidney International, Vol. 39 (1991), pp. 707—710 Metabolic disturbance as a cause of recurrent hematuria in children HELOISA CATTINI PERRONE, HoRAclo AJZEN, JULIO ToPoRovsKI, and NESTOR SCHOR Nephrology Division, Facu/dade de Cjéncias Médicas da Santa Casa de São Paulo and Escola Paulista de Medicina, São Paulo, Brazil Metabolic disturbance as a cause of recurrent hematuria in children. be distinguished utilizing an oral calcium load test [9]. The To evaluate metabolic disturbance as a cause of hematuria, 250 chil- characterization of these groups of IH have been reported to be dren, aged eight months to fourteen years, with recurrent hematuria were studied. In the present series, metabolic disturbance was mainly of clinical value in formulating a rational therapeutic regimen due to idiopathic hypercalciuria (IH), the most common etiology of for children with IH associated with hematuria and/or urolithi- hematuria without proteinuria in childhood. Sixty-seven (27%) of the asis [10]. This paper therefore, was undertaken to analyze children had IH, ten children (4%) had hyperuricosuria, and 27 (11%) metabolic disturbances associated with hematuria and to assess had nephrolithiasis. To better characterize the IH into renal (RH) or the clinical value of the oral calcium load test in characterizing absorptive hypercalciuria (AH) subtypes, 45 of the 67 children (ranging age from six to twelve years) were further submitted to an oral calcium IH subtypes in children. Furthermore, we examined the clinical load test. Eighteen patients (40%) had AH, 7(15.5%) RH and 20(44.4%) evolution of children with IH, who were submitted to different could not be classified as having AH or RH [indeterminant (ID)therapeutic approaches based upon classification by the oral idiopathic hypercalciuria group]. Intravenous pyelography or ultra- calcium test. sound were normal in all children. The oral calcium load test may be useful in characterizing the subtype of IH in some children; however, a great number of the IH children were characterized as indeterminant. Methods Also hyperuricosuria, recently described as another metabolic distur- During the last five years (1984 to 1989), 250 children with bance associated with hematuria, may be an important cause of recurrent hematuria in children. recurrent hematuria (more than 5 red blood cells per high powered field), aged 8 months to 14 years old were evaluated in our nephrology department. Twenty-seven percent of those children had only hypercalciuria as a cause of the hematuria Idiopathic hypercalciuria (IH), a disorder characterized by anwithout proteinuria. The presenting symptom was microscopic increase of calcium urinary excretion higher than 4 mg/kg/day,in 18% and gross hematuria in 82%. Among them, we studied is a frequent metabolic disorder in childhood and has beenthe first 45 of a total of 67 children with IH with oral calcium associated with clinical findings such as urolithiasis [I], hema-load test. Ten healthy children, aged 5 to 9 years, without tuna [2], and juvenile rheumatoid arthritis [3]. Recently, anhistory of renal disease were used as controls. After an Ethical association between asymptomatic hematuria and hypercalci-Committee approval and a consent obtained from parents of the uria prior to clinical or roentgenographic evidence of urolithia-patients and control group, each child was submitted to an oral sis has been emphasized [2, 4, 5]. In 1981, Moore [51 reportedcalcium load test similar to that described for Pak Ct al which that hematuria without urolithiasis was the initial clinical man-was adapted to children by Stapleton Ct al [9, 11]. On their ifestation in eight of twenty-three children with IH. Recently,habitual diets, the patients fasted from 8 p.m. of the preceding hyperuricosuria has also been associated with hematuria [6]. evening to 8 a.m. the next morning, except for 200 ml of However, evaluation of urinary calcium and uric acid excre-distilled water at 8p.m., 10p.m. and 6a.m. Urine was collected tion has not been routinely carried out in children with macro-for two hours and, after a light breakfast, an oral calcium load scopic or intermittent hematuria, and the prevalence of IH as(1 g/l.73 m2 of body surface area) was administered. An well as hyperuricosuria (HU) in a population of children withequilibration period of 30 minutes was followed and a new hematuria remains unknown in most pediatric centers. In viewcollection of urine was obtained over the next 210 minutes. of the reported familial incidence of IH [3, 7, 8], it was alsoBlood samples were collected just before calcium administra- interesting to find that in 86% of children studied with grosstion. Serum calcium, uric acid and phosphorus were measured, hematuria and a family history of urolithiasis, hypercalciuriaa creatinine clearance was calculated and urinary cyclic AMP was present [2]. On the basis of the pathogenic mechanisms two(cAMP) determined. Three 24-hour urinary collections, with a 7 major subtypes of IH, renal and absorptive hypercalciuria, canto 10 day interval, were analyzed for uric acid, creatinine and calcium excretion in each child. Three 24-hour samples of urine were collected as there was a variability in the daily UCa Received for publication February 26, 1990 excretion, and the highest value was chosen for the IH diagno- and in revised form October 23, 1990 sis because of its relationship with a high risk of nucleation. Accepted for publication October 26, 1990 Cyclic AMP was measured by the method of Broadus [12], © 1991 by the International Society of Nephrology calcium by atomic absorption technique (290-B Perkin Elmer, 707 708 Perrone et al: Hematuria by hypercalciuria and hyperuricosuria Atomic Spectrophotometer model; Perkin-Elmer, Norwalk, Table 1. Recurrent hematuria in children: Etiology Connecticut, USA); uric acid by Follin and Denis' technique Mean age [13]; phosphorus by Fishe and Subbarrow method [141 and Number Percent years creatinine by Jaffé technique [15]. All patients were submitted Hypercalciuria 67 27 8.7 0.5k' to intravenous pyelogram and/or ultrasound examinations. Pa-Uric acid hyperexcretion 10 4 8.6 1.0 tients with RH were submitted to a prospective treatment withNephrolithiasis 27 11 9.1 0.2 hydrochlorothiazide (0.5 mg/kg/day), and those with AH were Glomerulopathies treated with rice bran or calcium restricted diet (400 to 500 mg Berger 15 6 10.5 0.8 Alport 19 7 7.70.6 of calcium/day) for three to twelve months. Children with HU Others 45 18 9.8 0.9 were treated with allopurinol and/or purine restricted diet for 1Urinary tract infection 14 6 7.5 1.1 to 3 months. For indeterminant IH potassium citrate wasRenal malformation 8 3 6.3 0.5 administered (0.5 mEq/kg'day). Urinary excretion of calcium,After renal trauma 2 I 11.0 0.7 Without diagnosis 43 17 9.3 1,7 uric acid, urinalysis and urine culture were performed monthly.Total 250 100 The patients have been followed in our outpatient clinic. a X SE Laboratory criteria The diagnosis of HI was established by an urinary calcium excretion > 4 mg/kg/day in one or more of the three 24-hour The incidence of urolithiasis in the control group was null. urinary collections, with normal serum calcium concentrationHowever, the IH group had positive family history in 16 of 45 while ingesting an habitual diet [16]. The data provided bychildren (35.5%); the RH group had positive family history in 4 Stapleton et al [3] is similar to that observed in previousof 7 children (57%), the AH group had positive family history in research with 140 Brazilian children: mean urinary calcium9 of 18 (50%), the ID group had positive family history in 8 of 20 excretion was 1.60,1 mg/kg/day (XSE) in children aged 2children (40%), and the HU group had positive family history in to 7 years; 1.90.1 mg/kg/day in children aged 7 to 12 years5 of 10 children (50%). and 1.20.2mg/kg/day in children aged 12 to 18 years. Hence No statistical differences were observed in serum concentra- 4 mg/kg/day (X 2 SD) was considered to be the upper limit fortions of calcium, uric acid or phosphorus serum concentrations 24-hour urinary calcium excretion. Renal hypercalciuria (RH)among the five groups. Also, no alterations in glomerular was defined as a fasting Uca/Ur concentration ratio greaterfiltration rate, as estimated by creatinine clearance, were found. than 0.21 [9]. Absorptive hypercalciuria (AH) was defined as aThe higher 24-hour urinary calcium excretion in children in the fasting UCa/UCr concentration rate less than 0.21 and a urinaryrenal, absorptive and ID groups was significant, especially Ca/Cr index greater than 0.27 after calcium administration [10].when compared with the control group (P < 0.0005; Table 2). Finally, a third group of children with IH was characterized byThe mean urinary calcium was 1.6 0.3 mg/kg/day in the 24-hour urinary calcium excretion greater than 4 mg/kg/day, butcontrol group, .6.8 1.0 mg/kg/day in children with RH, 6.6 the oral calcium load test was not able to define if the children0.6 mg/kg/day in the AH group and 6.0 0.3 mg/kg/day in the had an AH or RH subtype. Those children had Ua/Ur fastingID. Urinary cyclic AMP excretion was normal in all children ratio less than 0.21 and loading less than 0.27. Therefore they(Table 2). were characterized as the indeterminant (ID) IH group. According to their responses, children were classified as Uric acid hyperexcretion is considered to be excessive ifhaving renal hypercalciuria, absorptive hypercalciuria or inde- greater than X 2 SD for age per 24 hours [171, similar to theterminant IH (ID).