Renal tubular dysfunction in methylmalonic acidaemia

Renal tubular function was assessed in seven patients with methylmalonic acidaemia not responsive to vitamin B₁₂. Five patients failed to concentrate their urine normally and in these patients the glomerular filtration rate was also reduced. Fractional excretion of sodium was increased in four patients, fractional excretion of potassium in one patient and in three there was a decreased tubular reabsorption of phosphate. Although possibly representing primary tubular damage these findings were thought to be consistent with adaptive changes secondary to the reduced glomerular filtration rate. Two patients had evidence of a defect of urinary acidification and several had a degree of hyporeninaemic hypoaldosteronism suggesting type 4 renal tubular acidosis. In one patient with a mild variant no renal disease was detected. Decreased renal function and tubular abnormalities were common in patients with methylmalonic acidaemia. It is likely that they are linked and essentially secondary to the tubulo-interstitial nephritis that is histologically demonstrable on renal biopsy. The failure of urinary concentrating ability and the disturbed urine acidification will contribute to the metabolic derangement during episodes of decompensation.     

Cardiac enzyme levels in myocardial dysfunction in newborns with perinatal asphyxia

Objective  To study the usefulness of cardiac enzymes in evaluating myocardial damage in perinatal asphyxia. Methods  Thirty term babies with perinatal asphyxia and without any congenital malformations were selected as cases. They were compared with thirty healthy term babies without asphyxia. Myocardial dysfunction was evaluated using clinical, electrocardiography, echocardiography and cardiac enzymes i.e, troponin-T and CK-MB levels. Results  Among the 30 cases 23 had evidence of myocardial involvement while one baby in the control group had ECG evidence compatible with cardiac involvement. Cardiac enzymes were significantly increased in babies with perinatal asphyxia. The mean level of C-troponin-T among cases and controls were 0.22±0.28 and 0.003±0.018 while CK-MB levels were 121±77.4 IU/L and 28.8 ± 20.2 IU/L respectively. C-troponin-T had higher sensitivity and specificity compared to CK-MB levels. Moreover, C troponin-T levels correlated well with severity and outcome in babies with perinatal asphyxia. Conclusion  C-Tropopnin assay is useful in evaluating the severity of myocardial damage and outcome in perinatal asphyxia.     

Renal clearance of bilirubin conjugates in newborns of different gestational age

The renal excretion of bilirubin conjugates was analysed in 22 newborns. Bilirubin monoconjugate was the only metabolite detectable in urine samples and its renal excretion correlated with the creatinine excretion rate (r=0.91). The renal clearance of bilirubin mono-conjugates in newborns ranged between 380 and 2160 ml/1.73 m² per 24 h (median: 790). According to the present findings the renal function should be monitored in newborns and infants with conjugated hyperbilirubinaemia.     

Renal function in full-term newborns following neonatal asphyxia. A prospective study

A prospective study of full-term infants with neonatal asphyxia was performed to evaluate possible alterations in renal function. Twenty-one newborns with an Apgar score less than or equal to 3 at 1 minute after birth and a control group of 20 normal infants were included. Oliguria of 12 hours or more (less than 1 ml/Kg/h) during the first 24 hours after birth was considered indication for a volume challenge test and use of diuretic. The study of renal function was effected between 24 and 48 hours after birth for asphyxiated and control infants (Period I), and was repeated between 48 and 72 hours (Period II) for the asphyxiated group only. Intrinsic acute renal failure was diagnosed in two patients, one of whom died. In 10 cases, prerenal oliguria responded promptly to volume expansion with improvement of biochemical indices in Period II. In nine cases, urine volume was not altered, and all functional parameters were comparable with those of control.     

Autonomic cardiac control of very preterm newborns: a prolonged dysfunction

BACKGROUND: Autonomic nervous system (ANS) activity is fundamental to infant health. ANS activity of preterm newborns seems to be reduced at term equivalent age, but follow-up of ANS activity has rarely been performed in that population during the weeks after birth. The aim of the study was to perform such a follow-up in preterm newborns of different gestational ages, up to their term equivalent ages. METHODS: Prolonged electrocardiographic recordings were prospectively performed in a group of 39 premature newborns, each week, up to term equivalent age before discharge. Control values were obtained from a group of 19 full-term newborns, recorded at the first week of their life. ANS indices were calculated from recordings during quiet sleep periods by spectral-domain analysis (Fourier transform): Ptot (total power), VLF (very low-frequencies), LF (low-frequencies), HF (high-frequencies), LF/HF ratio, LFnu (normalized low-frequencies) and HFnu (normalized high-frequencies) values. RESULTS: Ptot, VLF, LF and HF were significantly lower in the preterm group at birth compared to the control group, while LFnu, HFnu and LF/HF ratio were not significantly different. The results were similar when comparing the control group to any ANS values at a given post-natal corrected age of preterm newborns. Furthermore, preterm newborns did not demonstrate any significant increase in ANS values from birth to theoretical term. CONCLUSION: The finding of substantial reduced ANS activity and failure of maturation in preterm infants up to term equivalent age needs confirming by other research groups, and mechanisms and implications for infant health explored.     

Renal tubular dysfunction following treatment with anti-epileptic drugs

To evaluate renal side-effects of anti-epileptic medication in children, we performed a cross-sectional study of various aspects of renal function. We studied 59 patients from our outpatient clinic. They had been on anti-epileptic monotherapy for at least 3 months. None had a history of renal disease. Twenty-three healthy children of the same age group served as controls. After collecting 24-h urine samples, glomerular function was derived from creatinine clearance and from the excretion of albumin. Proximal tubular function was investigated by the urinary excretion of 1-microglobulin and of the tubular enzymes N-acetyl-ß-D-glucosaminidase, alamine-amino-peptidase and fructose-1,6-di-phosphatase. Distal tubular function was examined by the 24-h excretion of Tamm-Horsfall protein. On treatment with carbamazepine (n=27) and phenytoin (n=8), the excretion of 1-microglobulin was significantly increased, as compared with the healthy controls. On valproate (n=20), ethosuximide (n=9) and phenytoin (n=8), therapies significantly increased excretion of N-acetyl-ß-D-glucosaminidase. This must be interpreted as an indication of a functional disturbance of the proximal tubulus. The other parameters, indicating function of the glomerulus, loop of Henle and distal tubules did not differ from normal.Patients on anti-epileptic treatment with therapeutic drug levels may demonstrate minor signs of tubular dysfunction. These are probably insignificant from a clinical standpoint, but they should be considered in drug overdose.     

Renal tubular dysfunction in children living in the Aral Sea Region

Background: The Aral Sea region is a natural area seriously polluted by human activities. Recent surveillance revealed the increased prevalence of diverse chronic diseases in children. Aims: To investigate the function of renal tubules, which are most at risk of damage as a result of heavy metal intoxication, in children of the Aral Sea region. Methods: A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were examined by means of random urine samples. Both urinary N-acetyl-ß-D-glucosaminidase (NAG; U/mmol Cr) and ß₂ microglobulin (BMG; µg/mmol Cr) were calculated for each subject. Results: Mean urinary NAG and BMG were both significantly higher in Kazalinsk than in Zhanakorgan (NAG: 0.77 (0.58) and 0.62 (0.37) U/mmol Cr; BMG: 41.8 (54.8) and 22.5 (20.4) µg/mmol Cr, respectively; mean (SD), p < 0.01). The number of children with abnormal values of NAG (>1.5 U/mmol Cr) was significantly more prevalent in Kazalinsk than in Zhanakorgan (7.9% and 2.6%, respectively, p < 0.05). Conclusion: Renal tubular function of children around the Aral Sea region is profoundly impaired. This should be taken into account when considering the health problems of this area.     

Renal dysfunction in the pediatric surgical patient: When to intervene

Renal dysfunction is very common in the pediatric surgical critical care patient, with an estimated incidence of up to 35% in the PICU population. It impacts multiple other organ systems, particularly ventilation, and adds to the morbidity and mortality in children with multisystem organ dysfunction. In this article, we review the definitions and stages of renal failure in the pediatric population, identify which of these are more likely to require renal replacement therapy, and identify the indications for the different types of intervention. In addition, the complications of each form of therapy, along with management options, will be discussed. Finally, we will discuss the immediate and long-term outcomes for pediatric patients from neonates to adolescents.     

Renal tubular dysfunction in children living in the Aral Sea Region.

BACKGROUND: The Aral Sea region is a natural area seriously polluted by human activities. Recent surveillance revealed the increased prevalence of diverse chronic diseases in children. AIMS: To investigate the function of renal tubules, which are most at risk of damage as a result of heavy metal intoxication, in children of the Aral Sea region. METHODS: A group of 205 children living in Kazalinsk, close to the Aral Sea, and a group of 187 children living in Zhanakorgan, far from the Aral Sea, were examined by means of random urine samples. Both urinary N-acetyl-beta-D-glucosaminidase (NAG; U/mmol Cr) and beta2 microglobulin (BMG; microg/mmol Cr) were calculated for each subject. RESULTS: Mean urinary NAG and BMG were both significantly higher in Kazalinsk than in Zhanakorgan (NAG: 0.77 (0.58) and 0.62 (0.37) U/mmol Cr; BMG: 41.8 (54.8) and 22.5 (20.4) microg/mmol Cr, respectively; mean (SD), p < 0.01). The number of children with abnormal values of NAG (>1.5 U/mmol Cr) was significantly more prevalent in Kazalinsk than in Zhanakorgan (7.9% and 2.6%, respectively, p < 0.05). CONCLUSION: Renal tubular function of children around the Aral Sea region is profoundly impaired. This should be taken into account when considering the health problems of this area.     

Hemostatic profile in septicemic neonates with and without bleeding

Hemostatic profile was studied in 25 full term, non-asphyxiated neonates with blood culture-proven septicemia. Nine (36%) of these neonates manifested bleeding. Detailed coagulation tests and platelet studies were deranged in 24 (96%) of neonates with septicemia. Abnormalities in coagulation tests did not differ in those with and without bleeding. Only platelet aggregation with ADP was deranged to a significantly greater extent in those with bleeding as compared with those without bleeding.     

Renal functional maturation: renal handling of proteins by mature and immature newborns

Renal clearance of creatinine (C_cr), total protein excterion, urinary protein composition and renal clearance of albumin (C_alb) were measured and calculated in male premature and mature infants of gestational age 29–41 weeks and in mature infants 1 and 3 months of age. Total protein excretion decreased slightly but not significantly during maturation. The urinary protein composition changed significantly as the fraction of low molecular weight proteins decreased from 38% at a gestational age of 29–33 weeks to 24% in mature infants aged 3 months, the albumin fraction increased from 39%–46% and the proportion of higher molecular weight proteins increased from 12%–29%, respectively. C_alb decreased from 2.73–0.80 l/min/1.73 m² in the presence of a rise in C_cr, resulting in a significant fall of the ratio C_alb/C_cr from 0.0137 in the youngest prematures to 0.00147 in 3-month-old mature infants.Abbreviations C_cr clearance of craatinine - C_alb clearance of albumin - GA gestational age - GFR glomerular filtration rate - HMW high molecular weight - LMW low molecular weight - A albumin     

Renal preservation in children with neurogenic bladder-sphincter dysfunction followed in a national program

PurposeNeurogenic bladder–sphincter dysfunction (NBSD) constitutes the major reason for morbidity in children with spina bifida. The aim of this study was to identify risk factors for renal damage in children with NBSD followed according to the Swedish national guidelines.Materials and MethodsRecords and cystometries from 6 to 16 years (median 11) follow up of 41 consecutive children born 1993–2003 with NBSD were evaluated. The children were divided into a high pressure group (baseline pressure above 30 cmH₂O at maximal clean intermittent catheterization volume in at least two cystometries) and a low pressure group. Most children (34/41) were followed from birth.ResultsAlthough renal scarring on DMSA-scintigraphy was found in 5/41 children, all but one had normal renal function. Two already had renal scars on entering the follow-up program at age 2.5 and 3 years. Renal scarring was more frequent in the high pressure group (P < 0.01). Most children with renal scars (4/5) had a combination of low compliant bladder and insufficient compliance with treatment and follow up.ConclusionHigh baseline pressure is confirmed as a risk factor that, in combination with complex social issues, creates a demanding situation for families and professionals. A structured early follow up with treatment compliance effectively prevents renal damage.     

Transient tricuspid insufficiency of the newborn: a form of myocardial dysfunction in stressed newborns.

Fourteen term newborn infants have been recognized as having transient tricuspid insufficiency associated with significant perinatal stress. Five of these infants underwent cardiac catheterization for presumed congenital heart disease, but had only massive tricuspid valve insufficiency. The other nine infants were diagnosed on the basis of a murmur characteristic of tricuspid valve insufficiency and on other clinical grounds. All had a history of significant perinatal stress in the form of asphyxia with or without hypoglycemia. Frequently, congestive heart failure, persistent cyanosis, and ECG evidence of myocardial ischemia were present. Twelve of the 14 survived, and in each of them all cardiac signs and symptoms, including the murmur, spontaneously resolved. The two patients who died had histopathologic evidence of necrosis in the anterior papillary muscle of the tricuspid valve. The constant features of perinatal stress, ST-T wave abnormalities on the ECG, and spontaneous resolution of the transient tricuspid insufficiency strongly suggest that this syndrome is secondary to a reversible form of myocardial dysfunction, perhaps by affecting papillary muscle specifically. We believe that hypoxia with or without hypoglycemia precipitates the events leading to this clinical syndrome which is distinguishable from other cardiac abnormalities in the newborn by the history, distinctive murmur, and the ECG abnormalities.     

血清γ-痕迹蛋白对新生儿ABO溶血症肾功能损害的诊断价值

目的 探讨ABO溶血症(ABO-HDN)新生儿血清γ-痕迹蛋白(cystatin-C,Cys-C)水平变化及其在判断新生儿肾功能损伤状况中的临床价值.方法 将入选新生儿分为2组:对照组20例,观察组40例.后者根据血清胆红素水平分为轻度组(18例)和中重度组(22例).测定血清BUN、SCr、β2-MG及Cys-C,并计算肌酐清除率(CCr),比较各组间各指标的差异及相关性,行ROC曲线分析.结果 轻度组血清Cys-C、β2-MG、CCr值与对照组比较,差异无统计学意义(P均＞ 0.05);中重度组血清Cys-C、β2-MG值较对照组及轻度组显著升高(P均＜ 0.05),CCr值较对照组及轻度组显著降低(P均＜ 0.05).各组BUN、SCr比较差异无统计学意义(P均＞ 0.05).血清1/Cys-C、1/β2-MG水平与CCr呈显著相关(r ＝ 0.524、0.463,P均＜ 0.05).血清Cys-C 最佳截断点为1.83 mg/L,敏感度为90.3%,特异度为89.5%;β2-MG 最佳截断点为4.87 mg/L,敏感度为85.2%,特异度为87.1%.血清Cys-C、β2-MG ROC曲线下面积分别为0.892、0.805,差异有统计学意义(P ＜ 0.05).结论 血清Cys-C比β2-MG更能反映新生儿肾小球滤过功能的损害,可作为ABO-HDN新生儿肾功能损害的敏感诊断指标.     

Exchange transfusion in neutropenic septicemic neonates: effect on granulocyte functions

Depletion neutropenia caused by overwhelming bacterial infection is associated with fatal outcome and is an objective indicator of the severity of sepsis. Studies on controlled evaluation of exchange transfusion in the management of severe neonatal sepsis have not considered neutropenia as an inclusion critcrion, and randomized, controlled trials on evaluation of ncutrophil functions after exchange transfusion are scarce. This prompted us to carry out the present study. Septicemic neonates were enrolled if they had neutropenia and were randomized to undergo exchange transfusion (study group, n = 20) or not (controls, n= 10). Granulocyte functions were assessed using the nitro blue tetrazolium (NBT) reduction test and the staphylococcicidal index. Blood was drawn for granulocyte function tests once from controls and donors, and before, immediately after and 6 h after exchange transfusion in the study group. Mortality was 35% in the study group and 70% in controls. Gram-negative organisms accounted for 80%, in the study group and 90% in controls. Mean total leukocyte count and neutrophil count increased significantly immediately after exchange transfusion and 6 h later. Absolute band count decreased significantly immediately after exchange transfusion and incrcased 6 h later. NBT reduction in septicemic neonates in the study group, as wclras in controls. was significantly decreascd as compared to donor cells. NBT reduction improved significantly immediately after exchange transfusion and 6 h later. The valucs of the perccntage of viable staphylococci recovered from neutrophils also improved significantly immediately after exchange transfusion and 6 h later. We conclude that exchange transfusion with fresh whole blood in severe neonatal septicemia with neutropenia improves survival, increases the neutrophil count and cnhances neutrophil function.