Pediatr Nephrol (1994) 8:756-761 9 IPNA 1994 Pediatric Nephrology Practical pediatric nephrology Hematuria associated with hypercalciuria and hyperuricosuria: a practical approach F. Bruder Stapleton Department of Pediatrics, State Universityof New York at Buffalo and Children's Hospital of Buffalo, 219 Bryant Street, Buffalo, New York 14222, USA Received May 23, 1994; received in revised form July 25, 1994; accepted August 1, 1994 Abstract. Hematuria is one of the most common urinary abnormalities found in children. When hypercalciuria was identified as a potential etiology of painless hematuria, many questions arose concerning the general importance of this observation. Subsequently, increased uric acid excre- tion also has been purported to cause hematuria in children. This review traces the history of these observations and describes the clinical characteristics of the clinical syn- drome of hematuria associated with hypercalciuria and hyperuricosuria. Diagnostic criteria of excessive urinary excretion of calcium and uric acid are reviewed; differences in urinary calcium and uric acid excretion between infants and older children are emphasized. Aside from urolithiasis, few long-term consequences from hypercalciuria or hy- pemricosuria have been identified, although some debate exists concerning the effect of chronic hypercalciuria upon bone mineralization. Key words: Hematuria - Hypercalciuria - Hyperurico- suria - Urolithiasis Introduction Since antiquity hematuria has been a sign of genitourinary tract pathology. Approaches to hematuria in children were calculated to uncover the underlying glomerular or tubu- lointerstitial disorders, neoplasms, infections, or anatomical abnormalities [1, 2]. Perhaps it was litaki and West [3] who first suggested the possibility of metabolic causes of he- maturia when they described six children with "exercise- induced" hematuria that was associated with, or preceded, unsuspected renal calculi. The association of hematuria with hypercalciuria was first proposed in a review of hy- percalciuria by Moore in 1981 [4]. This observation was corroborated by two simultaneous reports from Galveston, Texas and Memphis, Tennessee [5, 6]. Kalia et al. [5] re- ported seven children in whom hypercalciuria was asso- 'ciated with gross hematuria; the hematuria resolved with hydrochlorothiazide and returned when the anticalciuric drug was discontinued. Roy et al. [6] noted that hematuria prededed overt calcium oxalate urolithiasis formation in five children with hypercalciuria and suggested that hy- percalciuria may independently produce hematuria. Subse- quently, hypercalciuria has been accepted as one cause of hematuria in children. Increased urinary excretion of uric acid also has been identified in children with hematuria, albeit to a lesser extent than has hypercalciuria [7, 8]. Per- rone et al. [1] identified urinary uric acid hyperexcretion in 10 of 250 children (4%) evaluated for hematuria. In this report, the association of hematuria and hypercalciuria and hyperuricosuria is reviewed, and a practical approach to this relatively new clinical problem is proposed. Clinical manifestations In a prospective study of 83 consecutive children in Mem- phis, Tennessee, with hematuria but without proteinuria, urinary infection, or previous calculi, hypercalciuria (>4 mg/kg per day) was discovered in 22 (27%) [9]. Macroscopic hematuria and a family history of urolithiasis were found more frequently in hypercalciuric children than in hematuric children with normal calcium excretion. Hy- percalciuria was not associated with abdominal or flank pain in this group of children, although others have occasionally noted pain as an associated symptom [10]. Boys and girls were represented equally in the hypercalciuric group. When urinary calcium was reduced by hydrochlorothiazide or di- etary calcium restriction, hematuria resolved in most chil- dren. Water diuresis did not lessen hematuria [9]. These findings were subsequently confirmed by additional studies in the United States, Brazil, and Spain [7, 10, 11]. The clinical presentation of painless microscopic or macroscopic hematuria, often with a family history of urolithiasis, has been a consistent finding. Urinary calcium oxalate crystals are frequently observed in children with hypercalciuria and hematuria [10, 1l]. The association of hypercalciuria and hematuria appears to be uncommon in African-American children and has been reported only occasionally in Asian