Idiopathic hypercalciuria is a common metabolic abnormality in children of all ages. There is evidence of an association of idiopathic hypercalciuria with nephrolithiasis, hematuria, and osteoporosis. However, much of this evidence is anecdotal and the precise role of hypercalciuria in the pathogenesis of these conditions is far from clear. Furthermore, the precise definition of idiopathic hypercalciuria has not yet been established. The methodologies for quantitating urinary calcium excretion have also not been standardized, adding another potential confounding factor to the accurate interpretation of urinary calcium excretion. Long-term studies on the natural history of unselected children with idiopathic hypercalciuria are needed to establish the true clinical significance of this condition. The focus of this review is to critically evaluate the methods currently being used to measure urinary calcium excretion in children and to assess the validity of existing criteria for diagnosing idiopathic hypercalciuria.
Individuals with focal segmental glomerulosclerosis (FSGS) are at risk for recurrence of disease following renal transplantation. The rate of recurrence has been estimated to range from 20% to 30%. The factors associated with an increased probability of recurrence are not known, although the rapidity of progression of disease, age at onset, and the presence of diffuse mesangial proliferation in the native kidney have all been implicated. We analyzed the data from 35 patients with FSGS who received 37 renal transplants at this institution between October 1968 and December 1997. Recurrence was diagnosed by the development of nephrotic-range proteinuria and a transplant biopsy compatible with the diagnosis. Sixteen recurrences were noted, with an overall recurrence rate of 43%. The risk of recurrence was associated with the use of antilymphocytic serum (ALS) for initial induction therapy; being 11% in those who received no induction therapy versus 53% in those who received ALS. Furthermore, in the latter group, the rate of recurrence was 88% in those who received antithymocyte globulin (ATGAM) versus 40% in those who received Minnesota antilymphocytic globulin. Factors such as race, sex, age at time of diagnosis, rapidity of progression to end-stage renal disease (ESRD), response to alkylating agents and/or cyclosporin therapy prior to ESRD, age at time of transplant, donor source, and triple or double immunosuppressive therapy did not appear to have an effect on the rate of recurrence. We conclude that induction therapy with ALS at time of transplantation increases the risk of recurrence of FSGS following renal transplantation.
We investigated the phenomenon of secondary resistance to cyclosporin (CsA) in children with steroid dependent (SD) or steroid resistant (SR) nephrotic syndrome. Secondary resistance was defined as an initial response to CsA with relapse on withdrawal of therapy and absent or diminished response on reinstitution of the drug. Thirty-two children with nephrotic syndrome who were treated with CsA were included in the study. Twenty-two of the children (15 of 15 SD and 7 of 17 SR) responded while ten demonstrated primary CsA resistance. Of these 22 responders, 20 relapsed when therapy was tapered or discontinued. Cyclosporin was reinstituted in 19. Ten responded, demonstrating CsA dependence, and nine exhibited secondary CsA resistance. Focal segmental glomerular sclerosis (FSGS) was present in one patient with CsA dependence on the initial biopsy and in two of six on a subsequent biopsy. In comparison, seven of nine patients with secondary CsA resistance and ten of ten with primary CsA resistance had FSGS on the initial or subsequent biopsy ( P=0.03). C4 and/or C1q were present on the initial biopsy in one patient with CsA dependence as compared to six of nine with secondary CsA resistance ( P=0.02). Four patients with secondary CsA resistance had an accelerated progression to end-stage renal disease (ESRD). We conclude that the presence of FSGS, or of C4 and/or C1q, appears to increase the risk of secondary CsA resistance and some of these children rapidly progress to ESRD.
A 2.8-year-old girl with focal segmental glomerulosclerosis had recurrence of nephrotic syndrome within 3 days of renal transplantation and the serum creatinine increased. Renal biopsy showed cellular rejection and also complete effacement of the epithelial cell foot processes. The rejection responded to methylprednisolone therapy but massive proteinuria persisted. An increase in the dose of cyclosporine A to 14 mg/kg per day was followed by immediate remission of the proteinuria. One month later, a second renal biopsy showed only focal fusion of foot processes. She remains free of proteinuria 2 years later. We propose that the higher dose of cyclosporine caused remission of the nephrotic syndrome.
Idiopathic carpal tarsal osteolysis (ICTO) is a rare congenital disorder that results in the destruction and resorption of bone, leading to severe functional deficits and cosmetic deformities. This report includes a literature review describing the orthopedic and renal manifestations of ICTO. An additional case report of ICTO with atypical features is included.
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