Amniotic fluid peptides predict postnatal kidney survival in developmental kidney disease

Although a rare disease, bilateral congenital anomalies of the kidney and urinary tract (CAKUT) are the leading cause of end stage kidney disease in children. Ultrasound-based prenatal prediction of postnatal kidney survival in CAKUT pregnancies is far from accurate. To improve prediction, we conducted a prospective multicenter peptidome analysis of amniotic fluid spanning 140 evaluable fetuses with CAKUT. We identified a signature of 98 endogenous amniotic fluid peptides, mainly composed of fragments from extracellular matrix proteins and from the actin binding protein thymosin-β4. The peptide signature predicted postnatal kidney outcome with an area under the curve of 0.96 in the holdout validation set of patients with CAKUT with definite endpoint data. Additionally, this peptide signature was validated in a geographically independent sub-cohort of 12 patients (area under the curve 1.00) and displayed high specificity in non-CAKUT pregnancies (82 and 94% in 22 healthy fetuses and in 47 fetuses with congenital cytomegalovirus infection respectively). Change in amniotic fluid thymosin-β4 abundance was confirmed with ELISA. Knockout of thymosin-β4 in zebrafish altered proximal and distal tubule pronephros growth suggesting a possible role of thymosin β4 in fetal kidney development. Thus, recognition of the 98-peptide signature in amniotic fluid during diagnostic workup of prenatally detected fetuses with CAKUT can provide a long-sought evidence base for accurate management of the CAKUT disorder that is currently unavailable.

Clinical and Genetic Spectrum of Bartter Syndrome Type 3

Bartter syndrome type 3 is a clinically heterogeneous hereditary salt-losing tubulopathy caused by mutations of the chloride voltage-gated channel Kb gene (CLCNKB), which encodes the ClC-Kb chloride channel involved in NaCl reabsorption in the renal tubule. To study phenotype/genotype correlations, we performed genetic analyses by direct sequencing and multiplex ligation-dependent probe amplification and retrospectively analyzed medical charts for 115 patients with CLCNKB mutations. Functional analyses were performed in Xenopus laevis oocytes for eight missense and two nonsense mutations. We detected 60 mutations, including 27 previously unreported mutations. Among patients, 29.5% had a phenotype of ante/neonatal Bartter syndrome (polyhydramnios or diagnosis in the first month of life), 44.5% had classic Bartter syndrome (diagnosis during childhood, hypercalciuria, and/or polyuria), and 26.0% had Gitelman-like syndrome (fortuitous discovery of hypokalemia with hypomagnesemia and/or hypocalciuria in childhood or adulthood). Nine of the ten mutations expressed in vitro decreased or abolished chloride conductance. Severe (large deletions, frameshift, nonsense, and essential splicing) and missense mutations resulting in poor residual conductance were associated with younger age at diagnosis. Electrolyte supplements and indomethacin were used frequently to induce catch-up growth, with few adverse effects. After a median follow-up of 8 (range, 1-41) years in 77 patients, chronic renal failure was detected in 19 patients (25%): one required hemodialysis and four underwent renal transplant. In summary, we report a genotype/phenotype correlation for Bartter syndrome type 3: complete loss-of-function mutations associated with younger age at diagnosis, and CKD was observed in all phenotypes.

Mutation Update of the CLCN5 Gene Responsible for Dent Disease 1

Dent disease is a rare X-linked tubulopathy characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis and/or nephrolithiasis, progressive renal failure, and variable manifestations of other proximal tubule dysfunctions. It often progresses over a few decades to chronic renal insufficiency, and therefore molecular characterization is important to allow appropriate genetic counseling. Two genetic subtypes have been described to date: Dent disease 1 is caused by mutations of the CLCN5 gene, coding for the chloride/proton exchanger ClC-5; and Dent disease 2 by mutations of the OCRL gene, coding for the inositol polyphosphate 5-phosphatase OCRL-1. Herein, we review previously reported mutations (n = 192) and their associated phenotype in 377 male patients with Dent disease 1 and describe phenotype and novel (n = 42) and recurrent mutations (n = 24) in a large cohort of 117 Dent disease 1 patients belonging to 90 families. The novel missense and in-frame mutations described were mapped onto a three-dimensional homology model of the ClC-5 protein. This analysis suggests that these mutations affect the dimerization process, helix stability, or transport. The phenotype of our cohort patients supports and extends the phenotype that has been reported in smaller studies.

Long-term outcome of idiopathic steroid-resistant nephrotic syndrome: a multicenter study

Long-term outcome of idiopathic steroid-resistant nephrotic syndrome was retrospectively studied in 78 children in eight centers for the past 20 years. Median age at onset was 4.4 years (1.1-15.0 years) and the gender ratio was 1.4. Median follow-up period was 7.7 years (1.0-19.7 years). The disease in 45 patients (58%) was initially not steroid-responsive and in 33 (42%) it was later non-responsive. The main therapeutic strategies included administration of ciclosporine (CsA) alone (n = 29; 37%) and CsA + mycophenolate mofetil (n = 18; 23%). Actuarial patient survival rate after 15 years was 97%. Renal survival rate after 5 years, 10 years and 15 years was 75%, 58% and 53%, respectively. An age at onset of nephrotic syndrome (NS) > 10 years was the only independent predictor of end-stage renal disease (ESRD) in a multivariate analysis using a Cox regression model (P < 0.001). Twenty patients (26%) received transplants; ten showed recurrence of the NS: seven within 2 days, one within 2 weeks, and two within 3-5 months. Seven patients lost their grafts, four from recurrence. Owing to better management, kidney survival in idiopathic steroid-resistant nephrotic syndrome (SRNS) has improved during the past 20 years. Further prospective controlled trials will delineate the potential benefit of new immunosuppressive treatment.

Prognosis of lupus membranous nephropathy in children

The occurrence of membranous nephropathy in pediatric series of systemic lupus erythematosus has been reported only rarely, probably due to a very low frequency. One hundred fifty-four children who were seen in 100 French pediatric centers between January 2002 and April 2005 were included. Fifteen (12 girls and three boys) out of the 81 (18.5 %) children with renal involvement presented histological features of membranous nephropathy. Their ages ranged from six to 15 years old (mean=11.3) at the age of SLE diagnosis and 8/15 children were of African origin. Isolated membranous nephropathy was observed in nine patients, of whom five patients displayed a complete recovery following immunosuppressive treatment. Associated proliferative lesions were observed on the first kidney specimen in two patients and in a further renal biopsy in four other patients, leading to a less favorable course of lupus nephropathy.

[Botulism in a neonate]

Botulism was suspected in a 17-day-old breastfed infant who developed over 2 days progressive muscular weakness and hypoventilation. The patient also presented with pupil dilation and light unresponsiveness. The electroencephalogram was normal. Full recovery was obtained after 85 days of artificial ventilation. Diagnosis was confirmed by the presence of the botulin toxin B in the patient serum. The source of the infection was not identified.

[Prenatal Bartter's syndrome. Report of two cases]

Antenatal Bartter Syndrome (ABS) is a rare autosomic recessive tubulopathy characterized by idiopathic hydramnios, fetal polyuria and elevated levels of amniotic chloride. It is related to mutations affecting several transporters in the loop of Henle e.g. the Na-K-2Cl cotransporter, the chloride channel CLC-NKB and the potassium channel ROMK. We report two cases of ABS in siblings born to consanguineous parents (first cousins). The first pregnancy showed hydramnios of unknown etiology at week 23. Two amnio drains were performed at weeks 26 and 27. The baby was born in week 29 and developed polyuria with hyponatremia, hypokalemia and hyperaldosteronism. After eliminating diabetes insipidus and adrenal insufficiency, ABS was diagnosed. The baby was treated with 0.5 mg/kg/d indomethacine, which controlled the polyuria and the hydroelectrolytic disorder. The second pregnancy showed idiopathic hydramnios at week 24. The elevated amniotic chloride level (above 112 mmole/l) led to the antenatal diagnosis of ABS. The mother was treated with 1 mg/kg/d indomethacine until week 31 in order to stabilize the hydramnios. Two amnio drains at weeks 31 and 33 allowed the pregnancy to be prolonged until week 34. A genetic study of the family showed homozygosity of the NKCC2 gene marker suggesting its implication in the disease.

[Varicella complicated with necrotizing fasciitis caused by group A hemolytic Streptococcus]

Chickenpox has a high risk of invasive group A streptococcal disease and necroziting fasciitis.

CASE REPORT

A five-year-old girl, during chickenpox treated with ibuprofen, developed sepsis and edematous and necrotic lesions of the pelvis and the abdominal wall. The child improved with surgical treatment and adjunction of clindamycin to the antibiotic therapy.

CONCLUSION

We review the optimal medical and surgical treatment of necrotizing fasciitis and discuss the role of chickenpox and non steroidal antiinflammatory agents in this disease.

[Intestinal volvulus in extremely premature infants]

Volvulus with or without malrotation are infrequent in the extremely premature newborn.

CASE REPORTS

Intestinal volvulus in seven premature newborns are reported with abdominal distention, bright and tense skin without visible bowel loops and spiraled bowel loops on the abdominal X-ray. Intestinal resection was avoided due to early diagnosis. We identified abdominal wall massages as a risk factor, because no new cases have occurred since interdiction of these practices.

CONCLUSIONS

Symptoms and radiologic findings are relatively specific for excluding the diagnosis of necrotizing enterocolitis in premature newborns. Abdominal nursing could be the incriminating factor.

[Thrombocytopenia due to materno-fetal allo-immunization. Report of a familial case]

The diagnosis of fetomaternal alloimmune thrombocytopenia (FMAT) was made in a newborn with thrombocytopenia and intracranial hemorrhage. The first child of the family was severely affected with neurodevelopmental sequelae secondary to intracranial hemorrhage. According to the maternal HPA phenotype, close to 100% of subsequent pregnancies could be expected to be affected as the homozygous state was observed in both platelet systems. Another infant was born after a poorly followed pregnancy and was affected as was his elder brother. Prednisolone was given during another pregnancy. A thrombocytic newborn without intracranial hemorrhage was delivered by prudent cesarian section. The infant received platelet transfusion (maternal platelets). We present case histories of FMAT, and stress the conditions for prenatal diagnosis and management.

The importance of 99Tcm-DMSA renal scintigraphy in the follow-up of acute pyelonephritis in children: comparison with urographic data

At present, 99Tcm-dimercaptosuccinic acid (DMSA) renal scintigraphy is the most sensitive examination for the detection of parenchymal damage during acute pyelonephritis (APN) in children. This prospective study had three aims: (1) to evaluate the medium-term evolution of the scintigraphic abnormalities, to find a prognostic criterion of scintigraphic evolution; (2) to assess the correlation between the severity of early or late scintigraphic damage and selected clinical factors; and (3) to compare the permanent scintigraphic renal scars with intravenous urography (IVU) 2 years after the acute infection. Seventy-four children (mean age 32 months), presenting with a first clinical episode of pyelonephritis and an initial scintigraphic abnormality, were included in the study. Patients with a history of urinary tract infection (UTI), uropathy other than vesico-ureteral reflux (VUR) and a relapse of acute pyelonephritis were excluded. All children underwent control scintigraphy (mean 9 months after APN) and 43 had an IVU (mean 26 months after APN). Fifty-seven children (77%) still have scintigraphic abnormalities of varying severity (7 atrophic kidneys). Initial relative DMSA uptake of less than 45% results in a worse scintigraphic prognosis. The age of the child has no bearing on the severity of the initial renal involvement or on the evolution of the scintigraphic abnormalities. The rapid introduction of antibiotics (< 12 h) significantly improves the scintigraphic prognosis (P < 0.01). The presence of reflux (n = 39) leads to more serious initial damage, but we did not find any effect on later evolution in this study, in which all reflux was low grade in nature. Among the 43 children who had an IVU, 5 showed typical urographic and scintigraphic renal scars in the corresponding region and 38 showed a normal IVU with 28 cases of scintigraphic abnormalities. A DMSA scan is more sensitive than IVU for the detection of renal scarring after a first episode of APN.

Imaging of pyelonephritis

OBJECTIVE

Accurate diagnosis of pyelonephritis using clinical and laboratory parameters is often difficult, especially in children. The main aims of this prospective study were to compare the value of different imaging techniques [renal sonography, cortical scintigraphy with technetium-99m dimercaptosuccinic acid (99mTc DMSA) and computed tomography (CT)] in detecting renal involvement in acute urinary tract infections and to determine the sensitivity of DMSA scans for permanent renal scars 6 months later.

MATERIALS AND METHODS

Between February 1992 and January 1993, 55 children admitted to our pediatric unit with febrile symptomatic urinary tract infections were eligible for analysis. Ultrasonography (US), DMSA scanning and micturating cystourethrography were performed in every case. Only 18 children underwent CT. A second DMSA scan was performed in 48 children a mean of 7.5 months after the first.

RESULTS

US abnormalities were found in 25 children (45 %). The first DMSA scan showed a parenchymal aspect suggestive of pyelonephritis in 51 patients (93 %). Among the 18 patients studied by CT, 14 had abnormalities. Normal US findings did not rule out renal parenchymal involvement. Scintigraphy appeared to be more sensitive than CT for renal involvement. The frequency and degree of initial renal parenchymal damage seemed to correlate with vesicoureteral reflux, but the most severe initial parenchymal defects were not associated with marked clinical or laboratory manifestations. Repeat DMSA scans, performed on 45 kidneys with abnormalities at the first examination, showed resolution in 19, improvement in 16, persistence in 8 and deterioration in 2. The prevalence of vesicoureteral reflux was not higher in patients with renal scarring on the second DMSA scan than in patients whose scans showed an improvement.

CONCLUSION

DMSA scans should be considered as a reference in the detection and follow-up of renal scarring associated with acute urinary tract infection as this technique is more sensitive than US and CT, the latter being unsuitable because it entails radiation exposure and sedation of patients.

Outcome of cadaver kidney transplantation in small children

Small children have often been reported to have poor outcome after kidney transplantation (KT). Recent reports from North America have shown that the use of living-related donors improves patient and graft survival. We report the experience in one centre of primary cadaveric KT using sequential immunosuppression in nine children aged 8-30 months and weighing 5.4-9.8 kg; donors were 0.7-12.3 years old. Four patients had pre-emptive KT and the other five were on peritoneal dialysis; the mean +/- SD waiting time was 2.0 +/- 2.4 months. Perioperative care has been published previously. The surgical approach was intraperitoneal if the aorta and vena cava were used (n = 7) and extraperitoneal for common iliac vessels anastomosis (n = 2); the duration of surgery was 3.5 +/- 0.9 h and the time for vascular anastomosis was 32 +/- 6 min. The recipients received ATG, azathioprine, prednisone and delayed administration of cyclosporin A. The patients were followed for 12-98 (median 41) months and showed good graft function (inulin clearance 63-100 ml/min/1.73 m2); only one child with recurrent haemolytic uraemic syndrome lost his graft three months post-transplantation and died after he had received a second graft. None of the recipients required post-transplant dialysis; arterial hypertension involved four children and was related to graft artery stenosis in two. Growth improved by 0.24 +/- 0.48 SD score of height per year.(ABSTRACT TRUNCATED AT 250 WORDS)

[Urothorax caused by traumatic rupture of the subpyelic ureter. Apropos of a case in a 5-year-old]

The authors report the observation of a five years old boy who presents after a polytraumatism a chronic pleural effusion who stop only after decortication and which is caused by a ruptur of sub-pyelic uretere. Echography is a good procedure for diagnosis. Laboratory studies of pleural fluid (protein, urea nitrogen, creatinine) could give information for diagnosis.