[Predictive factors of severe Henoch-Schonlein nephritis in children: report of 34 cases]. / Les facteurs préédictifs des atteintes rénales sévères du purpura rhumatoïde chez l'enfant: a propos de 34 cas.

BACKGROUND: Henoch Schonlein Purpura is the most frequent vasculitis in children. Renal involvement is variable. Renal manifestations vary from isolated microscopic hematuria to the association on nephrotic syndrome to nephritic syndrome. AIM: To determine the predictors of severe Henoch - Schönlein nephritis. METHODS: Retrospective study over 15 years (1996-2010) of 34 chidren, with henoch-schonlein nephritis. RESULTS: Renal involvement was determined in 68.7%. Mean age was 7.23 years (3-14 years). Renal manifestations were variable. Moderate renal manifestations were noted in 15 cases. Microscopic hematuria was observed in 23.5% of cases and moderate proteinuria with or without hematuria is noted in 20.5% of cases. Severe nephritis was noted in 18 cases: nephrotic syndrome in 29.5 % and nephrotic syndrome associated to nephritic syndrome in 23.5%. Hypertension without urinary anomalies was observed in one case. In univariate analysis, factor predictive of severe nephritis were: male sex, macroscopic hematuria, biologic inflammatory syndrome and leukocytosis. In multivariate analysis, only the leukocytosis was predictor of severity. CONCLUSION: In our study, only leukocytosis was predictor of severity in henoch-schönlein nephritis.

Severe pneumococcal hemolytic uremic syndrome in an 8-month-old girl.

The hemolytic uremic syndrome (HUS), characterized by microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure, represents one of the major causes of acute renal failure in infancy and childhood. The typical form occurring after an episode of diarrhea caused by Escherichia coli is the most frequent in children. Other microorganisms also may be responsible for HUS, such as Streptococcus pneumoniae, which causes more severe forms of the disease. We report an 8-month-old girl who presented with pneumonia and subsequently developed HUS. Renal biopsy showed characteristic lesion of thrombotic microangiopathy and extensive cortical necrosis. She was managed with peritoneal dialysis but did not improve and developed severe sepsis due to staphylococcal peritonitis, resulting in the death of the patient. Streptococcus pneumoniae-induced HUS is uncommon, but results in severe disease in the young. There is a high risk of these patients developing end-stage kidney disease in the long term.

Primary hyperoxaluria type 1 in Tunisian children.

To determine the clinical, biological, and radiological futures of primary hyper-oxaluria type 1 in Tunisian children, we retrospectively studied 44 children with primary hyper-oxaluria type 1 who were treated in our center from 1995 to 2009. The diagnosis was established by quantitative urinary oxalate excretion. In patients with renal impairment, the diagnosis was made by infrared spectroscopy of stones or kidney biopsies. The male-to-female ratio was 1:2. The median age at diagnosis was 5.75 years. About 43% of the patients were diagnosed before the age of five years with initial symptoms dominated by uremia. Four patients were asymptomatic and diagnosed by sibling screenings of known patients. Nephrocalcinosis was present in all the patients; it was cortical in 34%, medullary in 32%, and global in 34%. At diagnosis, 12 (27%) children were in end-stage renal disease. Pyridoxine response, which is defined by a reduction in urine oxalate excretion of 60% or more, was obtained in 27% of the cases. In the majority of patients, the clinical expression of primary hyperoxaluria type 1 was characterized by nephrocalcinosis, urolithiasis, and renal failure; pyridoxine sensitivity was associated with better outcome.

Vascular complications after pediatric kidney transplantation.

BACKGROUND: Vascular complications, especially those including the renal vein, remain a major cause of lost graft. AIMS: To evaluate retrospectively the incidence and management of vascular complications after pediatric renal transplantation and to assess possible risk factors and their effects on patient and graft. METHODS: A total of 82 consecutive renal transplants were performed in 79 patients at a single institution. The diagnosis of vascular complications was suspected in the presence of suggestive symptoms and confirmed by Doppler ultrasound and if necessary by a computed tomographic angiography. Urgent exploration was performed in all suspected cases. RESULTS: There were seven vascular complications (8,5%), including renal vein thrombosis in four patients, renal artery stenosis in one, and sural thrombophlebitis in two. The thrombosis of the graft vein which is the main complication occurred at mean 24 hours after renal transplantation. All these patients needed transplant nephrectomy after thrombosis event. In the remaining cases, the outcome was favorable even for the patient with transplant renal artery stenosis. CONCLUSIONS: Vascular complications are common and serious events affecting patient and graft survivals. A perfect surgical technique and rigorous radiological monitoring may result in decreased incidence and severity of these complications.

Histopathological spectrum of childhood idiopathic steroid-resistant nephrotic syndrome in Tunisia.

BACKGROUND: In children, renal biopsy is routinely required in the management of idiopathic steroid-resistant nephrotic syndrome particularly prior to starting nephrotoxic immunosuppressive agents. AIM: To investigate the correlations between the results of initial renal biopsy in Tunisian children with idiopathic steroid-resistant nephrotic syndrome and the subsequent response to cyclosporineprednisolone combination. METHODS: We conducted a retrospective study of children with idiopathic steroid-resistant nephrotic syndrome over the period 2002- 2009. Data on clinico-biological features, histological diagnosis and response to cyclosporine-prednisolone were collected. RESULTS: Thirty patients were enrolled, of whom 16 had focal segmental glomerulosclerosis, eight had minimal change disease and six had diffuse mesangial proliferation. Complete Remission was achieved in 15 patients (50%). Nine patients (30%) went into partial remission. Only six patients presented no response (20%). No statistically significant relationship between the different pathological types and the response to CsA-prednisone was found. CONCLUSION: In our study, two important facts were noted: 1) the predominant histopathological subtype was the focal segmental glomerulosclerosis; 2) a high remission rate was achieved in our patients using a combined cyclosporine-prednisolone treatment regimen. This response is not dependent on the histological type.

Primary hyperoxaluria type 1 in Tunisian children.

BACKGROUND: Primary hyperoxaliuria type 1 is an autosomal recessive disorder characterized by increasing urinary excretion of calcium oxalate, recurrent urolithiasis, nephrocalcinosis, and accumulation of insoluble oxalate throughout the body. This inborn error of metabolism appears to be a common cause of end stage renal disease in Tunisia. AIMS: To review the clinical, biological and radiological futures of primary hyperoxaluria type 1 and to correlate these aspects with the development of end-stage renal disease. METHODS: we retrospectively reviewed 44 children with Primary hyperoxaliuria type I who were treated in our department during a period of 15 years between 1995 and 2009. The diagnosis was established by quantitative urinary oxalate excretion. In patient with renal impairment, the diagnosis was made by infrared spectroscopy of stone or by renal biopsy. RESULTS: Male to female ratio was 1.2. The median age at diagnosis was 5.75 years. About 43 % of those were diagnosed before the age of 5 years. Initial symptoms were dominated by uraemia. Four patients were asymptomatic and diagnosed by sibling screening of known patients. Nephrocalcinosis was present in all patients. It is cortical in 34%, medullary in 32% and global in 34%. At diagnosis, twelve children were in end-stage renal disease (27%). Pyridoxine response, which is defined by a reduction in urine oxalate excretion of 60% or more, was found in 27%. CONCLUSION: In the majority of patients, the clinical expression of Primary hyperoxaliuria type 1 is characterized by nephrocalcinosis, urolithiasis and renal failure. Pyridoxine sensitivity is associated with better outcome.

Mycophenolate mofetil in treatment of childhood steroid-resistant nephrotic syndrome.

INTRODUCTION: The literature on the clinical effectiveness of treatments for steroid-resistant nephrotic syndrome (SRNS) is very limited. The available evidence suggests a beneficial effect of cyclosporine on remission rates. Mycophenolate mofetil (MMF) represents a promising therapeutic alternative without nephrotoxicity. The purpose of the present study was to evaluate the efficacy and tolerance of MMF therapy in children with SRNS. METHODS: Six patients with SRNS were treated with MMF combined with oral prednisolone at a dosage of 1 mg/kg per day. The initial dosage of MMF was 600 mg/m² per 12 hours, adjusted to maintain levels of mycophenolic acid at 2.5-5 µg/mL. The planned duration of study to assess treatment efficacy was 12 weeks. All patients had a pathological renal study. RESULTS: The treatment with MMF was started at a median age of 11 years (range 9-13). Pathological patterns were 4 patients with focal segmental glomerulosclerosis (FSGS), 1 patient with minimal change disease (MCD) and 1 patient with diffuse mesangial proliferation glomerulonephritis (DMP). Only 1 patient, who had MCD, achieved complete remission. One patient went into partial remission. However, the subgroup with no response to MMF appeared to have a reduction in proteinuria and an increase of serum albumin. There were no significant beneficial effects on the level of glomerular filtration. CONCLUSIONS: In this small, single-center study, a therapeutic response to MMF was obtained only in one third of patients. This response rate, though it is low, encourages us to use MMF in some patients who are resistant to conventional therapy for SRNS.

[Uropathies and nephropathies of Bardet-Biedl syndrome in children]. / Uropathies et Nephropathies Dans Le Syndrome De Bardet-Biedl Chez L'enfant.

BACKGROUND: The Bardet-Biedl syndrome is an autosomal recessive disease, characterised by obesity, retinal degeneration, hypogenitalism in men, polydactylism and an often moderate mental retardation. With these cardinal features, others clinical findings (secondary features) including diabetes, congenital heart defects, hypertension or syndactyly can be seen. Renal involvement is almost constant, but varies from a moderate impairment of the tubular functions to chronic renal failure caused by malformative uropathy or glomerulopathy. AIM: Report a new cases. METHODS: We report 6 patients with Bardet-Biedel syndrome who had renal involvement. RESULTS: Three patients had cystic dysplasia, one patient an increased fractional sodium excretion, one other a vesico-ureteral reflux and the last patient developed end-stage renal failure following acute post streptococcal glomerulonephritis. We insist on precocious diagnosis and multidisciplinary treatment of these renal lesions, to ovoid or, at least, to slow down the evolution to the terminal renal failure, essential prognosis factor. CONCLUSION: Renal involvement, is considered as a major criteria predicting high morbidity and mortality during Bardet-Biedl disease.

[Interest of mycophenolate mofetil in children with membranous lupus nephritis]. / Place du mycophénolate mofétil dans la néphropathie lupique proliférative de l'enfant.

The management of lupus nephritis remains a clinical problem in children as in adults. Corticosteroids, cyclophosphamide and azathioprine have been used with satisfactory response, but the most important problems are their potential toxicities. Therefore, we evaluate the use of mycophenolate mofetil (MMF) as a new agent for treatment of lupus nephritis in children. Five children with biopsy-proven proliferative glomerulonephritis with active lesions received MMF, combined with corticosteroids during the induction phase and alone during the maintenance phase. We retrospectively studied the efficacy and safety of this therapeutic regimen. All patients had proteinuria and renal failure. Four patients from five presented nephrotic syndrome. During the induction phase, three patients achieved complete remission of their nephrotic syndrome with normalization of renal function. One patient achieved partial remission and kept moderate renal failure. One patient died at 50 days by severe sepsis secondary to leucopenia. During the maintenance phase, three patients had complete remission. One patient was kept proteinuria with a creatinine clearance of 55 mL/min/1,73 m². The growth of these patients is not affected. In childhood lupus proliferative glomerulonephritis, MMF was well tolerated, and most of the patients achieved remission and improvement of their renal functions.

[Urinary tract infections in children following renal transplantation: a single-center experience]. / Infections urinaires de l'enfant transplante rénal: expérience d'un centre de néphro-pédiatrie.

BACKGROUND: Urinary tract infection (UTI) is the most common complication after kidney transplantation and represents a potential life-threatening risk for the immunocompromised child. AIM: The aim of this report is to determinate incidence, risk factors, microbiologic features and evaluate the impact of this complication on graft outcome and patient mortality. METHODS: We performed a retrospective cohort study reviewing the medical records of 17 children from 38 who received a renal transplant in our center between January 1992 and june 2008 and who present an urinary tract infection. RESULTS: All patients received Lich-Gregoire implantation and insertion of double-J stunt. Antibioprophylaxis was not systematic. After a mean period of 6 years, 9 children (5+4) developed early UTI (during the first month after transplantation) and 5 (3+2) had late UTI. Three patients (2+1) with an indeterminate nephropathy developed early and late UTI. Causal agents are: E. Coli, Klebsiella Pneumoniae and Candida albicans. The further voiding cystourethrography showed a vesico-ureteral reflux on graft in 5 cases. Among the 17 patients, 4 lost their graft and are actually on haemodialysis. CONCLUSION: The urinary tract infection represents the major complication after renal transplantation. Diagnosis ant treatment must be made early to avoid the loss of the graft.

Xanthine urolithiasis.

Hereditary xanthinuria type I, a defect of purine metabolism, results from a genetic deficiency of xanthine oxidase. It is an uncommon cause of stone formation in children. We report here two children with xanthine urolithiasis. The first patient was an 8-year-old boy who presented with repeated episodes of hematuria evaluated with excretory urography, which demonstrated radio-lucent pelvic stone in the right kidney, causing hydronephrosis. He had pyelolithotomy, and the extracted stone consisted of pure xanthine. Family study revealed an asymptomatic xanthinuria in younger brother. The second patient was a 5-year-old boy who had a 2-week history of abdominal pain and gross hematuria. Conventional excretory intravenous urography showed a non-functioning right kidney. Nephrectomy was performed, and histology revealed end-stage pyelonephritis. The calculi consisted of pure xanthine. In both patients, plasma and urinary concentrations of uric acid were low but xanthine and hypoxanthine concentrations were markedly elevated. Xanthine urolithiasis is usually a benign condition, easy to prevent or cure by appropriate alkalinization, forced hydration and restriction of dietary purines. However asymptomatic, and therefore undiagnosed, stones may invade the kidney and urinary tract, resulting in destruction of parenchyma, nephrectomy and renal failure.