Risk factors for renal insufficiency in children with urethral valves

Posterior urethral valves (PUV) associated with renal dysplasia are one of the most common causes of end stage kidney disease (ESKD) in childhood. In order to identify risk factors for the progression of this condition to early renal failure, we have retrospectively analyzed the clinical course, renal function, and first postnatal renal ultrasound in a sample of 42 young male patients with PUV, who were followed at a single center. Twelve (28.6%) were diagnosed with ESKD at a median age of 11.3 years. Our comparison of PUV patients without decreased estimated glomerular filtration rate (eGFR) (group A; K/DOQI CKD stage 0-1) with PUV patients showing a decreased eGFR (group B; K/DOQI CKD stage 2-5) revealed the following significant risk factors for loss of eGFR: renal volume <3rd percentile (P < 0.001), elevated echogenicity (P = 0.001), pathologic corticomedullary differentiation (P < 0.001), >3 febrile urinary tract infections (P = 0.012), and decreased eGFR at 1 year of age (P < 0.001). Receiver operating characteristic curve analysis in the cohort confirms that patients showing a renal volume >88.2 ml/m(2) body surface area (BSA) are not at risk to develop K/DOQI CKD stage 5 (sensitivity 75%, specificity 77.3%, positive/negative predictive value 37.5/94.4%). Ultrasound promises to be a valuable tool for identifying endangered patients.

Cluster of hemolytic-uremic syndrome caused by Shiga toxin-producing Escherichia coli O26:H11

BACKGROUND

The epidemiology and clinical characteristics of the hemolytic-uremic syndrome (HUS) caused by Escherichia coli O157:H7 are well-known, but HUS attributable to non-O157:H7 Shiga toxin (Stx)-producing E. coli (STEC) are less thoroughly described. Here we report a cluster of HUS cases caused by STEC O26:H11 the most common non-O157:H7 STEC isolated from sporadic cases of HUS in Europe.

METHODS

Three children between 13 and 17 months of age, living in the same small town, developed HUS within an interval of 5 days. We present clinical and microbiologic data on the patients and their infecting isolates.

RESULTS

The clinical course ranged from mild uncomplicated HUS to severe HUS complicated by multiorgan involvement. Microbiologic investigation demonstrated STEC of serotype O26:H11 in stools of all the patients. The phenotypic and molecular characterization of the STEC O26:H11 isolates demonstrated that these strains were identical and, unusual for STEC O26, they harbored the stx2 but not the stx1 gene. None of the patients had evidence of STEC O157:H7 infection either by culture or by E. coli O157 serology. The source of the STEC O26:H11 infection was undetermined.

CONCLUSIONS

Our results demonstrate that diagnostic procedures based on the detection of stx genes and/or Stx production and subsequent subtyping of the isolates using molecular methods are necessary to identify such outbreaks caused by non-O157:H7 STEC.

Novel paracellin-1 mutations in 25 families with familial hypomagnesemia with hypercalciuria and nephrocalcinosis

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis (FHHNC) is an autosomal recessive tubular disorder that is frequently associated with progressive renal failure. The primary defect is related to impaired tubular reabsorption of magnesium and calcium in the thick ascending limb of Henle's loop. Mutations in PCLN-1, which encodes the renal tight junction protein paracellin-1 (claudin-16), were identified as the underlying genetic defects. Comprehensive clinical data and the results of PCLN-1 mutation analysis of 25 FHHNC families with 33 affected individuals are presented. Patients presented mainly with urinary tract infections, polyuria, and hematuria at a median age of 3.5 yr. At the time of diagnosis, the GFR was already decreased to <60 ml/min per 1.73 m(2) for 11 patients. Twelve patients exhibited progression to end-stage renal disease, at a median age of 14.5 yr. Treatment with magnesium salts and thiazides seemed to have no effect on the progression of the disease. Genotype analysis revealed PCLN-1 mutations in all except three mutant alleles (94%). Fifteen different mutations were observed, including eight novel mutations. The accumulation of mutations affecting the first extracellular loop was striking, with 48% of all mutant alleles exhibiting a Leu151Phe exchange. Haplotype analysis strongly suggested a founder effect among patients with FHHNC who originated from Germany or eastern European countries. In 13 of 23 families, hypercalciuria and/or nephrolithiasis were observed in otherwise unaffected family members, indicating a possible role of heterozygous PCLN-1 mutations in yielding hypercalciuric stone-forming conditions.

Nephrocalcinosis in children: a retrospective survey. Members of the Arbeitsgemeinschaft für pädiatrische Nephrologie

We carried out a retrospective survey on 152 children and adolescents with nephrocalcinosis (NC) in 22 German centers of pediatric nephrology. Etiology, clinical manifestations, growth and development, sonographic appearance of NC and renal function were analyzed. The median age at the time of diagnosis was 3.3 (range 0.1-21) years and the median duration of follow-up was 4.1 years. In 34% of children NC was associated with idiopathic hypercalciuria (IHC) and in 32% with various hereditary tubular disorders. In 9% NC was observed subsequent to prophylactic bolus administration of vitamin D in infancy. A positive family history was found in 36%. Clinical manifestations were mainly failure to thrive during the 1st year of life (46%), psychomotor/mental retardation (28%) and urinary tract infection (34%). In 14% nephrolithiasis was associated. During the follow-up the proportion of patients with the most severe degree of NC (stages 2b or 3) increased from 40% to 55% and that of hypercalciuria decreased from 79% to 52%. Body height was <2 standard deviation scores (SDS) of normal in 41% at the time of diagnosis and in 32% at the last observation; the increase in relative height was significant only for IHC. Glomerular filtration rate (GFR) and urinary concentration capacity changed only slightly with time. At the last investigation GFR was <50 ml/min/1.73 m2 in 6% and concentration capacity <800 mosmol/kg in 48% of patients. The degree of NC was negatively correlated with GFR and concentration capacity.

[Therapy of iodine deficiency goiter in adolescents with iodine or a combination of iodine and levothyroxine with special reference to lipid parameters]

The are various opinions about the optimal therapy of endemic goiter in adolescents. From 106 patients (75 girls) suffering from endemic goiter 50 patients (group A) were treated with 300 micrograms iodine per day and 56 patients (group B) with 100 micrograms iodine plus 100 micrograms levothyroxine per day. Before therapy and after 172 days of therapy on average the thyroid volume, the thyroid hormones (TSH, T3, T4) and the lipidparameters (cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides) were measured. Within the period of treatment the thyroid volume (measured by ultrasound) decreased by 11.3% in group A and by 23% in group B. The iodine deficiency was corrected completely in both groups. However, investigations in both groups proved that patients undergoing combined therapy excrete the iodine administered additionally. Analogously to studies of the intrathyreoidal iodine metabolism it can be concluded that combined therapy on the basis of the dose mentioned above does either not result in an increase in the intrathyreoidal iodine contents or in a minor increase only. Iodine treatment as well as combined treatment cause a decrease in TSH-levels and an increase in T4-levels. The changes are only significant in group B. In the total group the percentage of T3-increases was reduced from 45% to 33% during treatment. The initially elevated plasma concentration of cholesterol, LDL-cholesterol and triglycerides - compared to the control group - decreased significantly in both groups during therapy. Both groups does not differ significantly with respect to the decrease in lipids. It is to be concluded that combination therapy is preferable to iodine therapy with respect to the SD-volume reduction as well as the lipid metabolism. The primary cause of endemic goiter, i.e. the intrathyreoidal iodine deficiency, can presumably not be eliminated by means of the dose of 100 micrograms iodine combined with 100 micrograms LT4.

[Euthyroid goiter in puberty--a harmless illness?]

An investigation was carried out in to thyroid hormones (TSH, T3, T4) and lipid parameters (total cholesterol, LDL cholesterol, HDL cholesterol, triglyceride) in 136 adolescents (94 femals, average age 13 years). An iodine deficiency (grade II-II) with respect to the daily urine excretion per 1,73 m2 BSA was found in 75%. With few exceptions the serum levels of TSH and T4 were in the normal range. In 36% of the patients we noticed compensatory elevated T3 levels. Correlations between thyroid hormones TSH, T4, renal iodine excretion and the volume of thyroid glands were not detectable, only T3 showed a dignificant positive correlation to the thyroid gland volume. The average values of lipids in patients were found to be higher than in normals. We consider the changed lipids as a sign of a disturbed efficacy of thyroid hormones. The regional insufficient iodine supply causes goiters and to a high degree the observed hyperchole-sterolemia, too. Our results underline the necessity of a common iodine salt prophylaxis as well as the treatment of "harmless" goiters in puberty.

[Effect of organized general preventive administration of iodized salt on struma incidence and ioduria in 11-16-year-old children in the Jena endemic area]

In 1988 and in 1991, i.e. two and five years after the introduction of a general iod salt supply (32 mg KJO2/kg salt) in our region, we investigated the frequency of goiters and the level of iodine excretion in urine in 504 and 336 school children of 11 to 16 years of age. In 1988 the assessment of goiter size was made by inspection and palpation according to the recommendation of WHO. 36% of the school children were found to have goiters of type I b or II. The average urine excretion of iodine amounted to 46.2 +/- 37.2 micrograms Iod/g creatinine (n = 353). In 1991 we selected school children with goiters by the same criteria and found frequency (34%) to be nearly unchanged compared to 1988. Furthermore we investigated these goiters with ultrasound and confirmed the diagnosis in 100 from 107 children. The average daily urine excretion of iodine was significantly higher in 1991 (57.7 +/- 24.8 micrograms/Iod/g creatinine, n = 328) than in 1988. However this value is below the level recommended by the WHO (minimum 75 micrograms Iod/g creatinine). Despite the increase of the iodine intake over the last years, the frequency of goiters in pubertal school children in the Jena region is endemic. This fact supports the demand for a general and sufficient iodine supply.

[Contamination of breast milk with organochlorine compounds in comparison with cow's milk and selected milk products in the new federal districts]

400 human milk, 280 cowmilk, 56 milkpowder and 305 butter samples were examined concerning there content of chloroorganic compounds. In human milk the highest concentration had DDE, followed by PCB, DDT and HCB, the lowest values were measured for HCH. Only total DDT in human milk but no compound in the milk product samples was above the maximal tolerated limit. There is a strong reduction in comparison to the values measured in 1979 (ten times for total HCH, one half for total DDT and to one sixth for HCB) but the PCB concentration didn't change.