Renal consequences of immobilisation in children with fractured femurs

Parameters of renal function and calcium homeostasis were studied in 8 children, immobilised for 5-9 weeks with fractured femurs, weekly during immobilisation and fourth weekly following mobilisation until all parameters returned to normal. During immobilisation 1 patient became hypercalcaemic, but all showed an increase in serum calcium and all developed hypercalciuria. During immobilisation all showed diminished urine osomolality after a 12-hour fast (mean 591 +/- 133 mOsm/kg) which improved 4-39 weeks after mobilisation (mean 973 +/- 87 mOsm/kg). Serum creatinine, urinary beta-2-microglobulin and renal ultrasound appearances were all normal. An inverse relationship, R = -0.70, was demonstrated between serum calcium and fasting urine osmolality during immobilisation. Three patients showed diminished urinary concentrating ability beyond 4 weeks after mobilisation. For 1 patient this defect persisted for 8 months and glomerular filtration rate was diminished 9 months after mobilisation, raising the possibility of long term renal damage in immobilised patients.     

Renal function of children receiving long-term parenteral nutrition

Renal function was assessed in 13 children at a mean (+/- SD) age of 9 +/- 4.9 years who had been receiving total parenteral nutrition for 7.9 +/- 4.1 years. All children had normal blood pressure, urinary sediment, and serum creatinine concentrations (58.3 +/- 1.0 mumol/L). Glomerular filtration rate was measured by plasma clearance of diethylenetriaminepentaacetic acid labeled with indium 111. All 13 children had decreased glomerular filtration rate (65.5 +/- 11.9 ml/min per 1.73 m2; range 49.5 to 83.7). Creatinine clearance was 69.1 +/- 10.9 ml/min per 1.73 m2. No tubular damage, as assessed by beta 2-microglobulinuria, was detectable. Renal ultrasonography showed normal architecture with no evidence of nephrocalcinosis in all subjects. The kidney size was normal in seven children; six had reduced (less than -1 SD) size. No relationship was seen between the true glomerular filtration rate and diagnosis, number of episodes of infections, or antibiotics used. The duration of total parenteral nutrition was inversely correlated with the true glomerular filtration rate (r = -0.66, p less than 0.01). The decrease in glomerular filtration rate was not related to the underlying disease or to the nephrotoxic drugs used; the mechanism was not identified. We conclude that long-term total parenteral nutrition is associated with a decrease in glomerular filtration rate.     

Nonoliguric hyperkalemia in the premature infant weighing less than 1000 grams

Eighteen very low birth weight premature infants born before 28 weeks gestation and weighing less than 1000 gm were evaluated prospectively for disturbances in serum electrolyte concentrations and for renal glomerular and tubular functions. Clinically symptomatic hyperkalemia resulting in significant electrocardiographic dysrhythmias developed in eight of these infants; 10 babies remained normokalemic. Peak serum potassium concentration ranged from 6.9 to 9.2 mEq/L in the hyperkalemic group; all potassium values in the normokalemic group were less than 6.6 mEq/L. Indices of renal glomerular function and urine output were similar in both groups; no infant had oliguria. Serum creatinine concentrations were the same in both groups (1.04 +/- 0.16 SD mg/dl in normokalemic vs 1.19 +/- 0.24 mg/dl in hyperkalemic infants, beta less than 0.2 at alpha = 0.05), and glomerular filtration rates did not differ significantly (6.29 +/- 1.78 ml/min/1.73 m2 in normokalemic vs 5.70 +/- 1.94 ml/min/1.73 m2 in hyperkalemic infants, beta less than 0.2 at alpha = 0.05). In contrast, indicators of tubular function revealed a significantly larger fractional excretion of sodium in hyperkalemic infants: 13.9 +/- 5.4% versus 5.6 +/- 0.9% in normokalemic control subjects (p less than 0.001). Hyperkalemic infants also had a tendency toward lower urine concentrations of potassium, although there was no significant difference in their net potassium excretion in comparison with that in the normokalemic group. We speculate that hyperkalemia in the tiny baby is in part the result of immature distal tubule function with a compromise in ability to regulate potassium balance.     

Beta 2 microglobulin. Index of glomerular filtration in children

121 assays for plasma Beta 2 microglobulin (B2M) levels were carried out with an immuno-enzymatic technique in 94 children whose ages ranged from 13 months to 18 years and whose renal functions showed various levels of renal impairment. In the 37 children with normal glomerular filtration rate, plasma B2M level was 1.58 +/- 0.48 mg/l (mean +/- 1 SD) and no significant differences were found according to sex, ages or heights. In the 29 children with glomerular filtration rate (GFR) ranging from 20 to 100 ml/min/1.73 m2, there was a significant correlation between B2M and the inulin clearance, plasma creatinine level and creatinine clearance (p less than 0.001). In 28 patients presenting with terminal renal failure, plasma B2M levels were significantly higher in children undergoing hemodialysis than in those under chronic peritoneal dialysis. These results indicate that B2M levels are as good an index of glomerular filtration rate as serum creatinine whereas its assay uses a long and difficult technique.     

Evaluation of renal functions in asphyxiated newborns

Renal injury due to perinatal asphyxia has not been systematically evaluated. The available studies have used variable definitions, incomplete investigations and none had a control group. The aim of this study was to evaluate systematically the renal functions in severely asphyxiated newborns and to find if abnormal renal function tests can predict adverse outcome (death or neurologic abnormality at discharge). In a prospective case-control design, 25 inborn babies>or=34 weeks gestation having asphyxia (5 min Apgaror=5 min) were enrolled as 'cases'. Simultaneously 25 gestation and weight matched babies with no asphyxia were enrolled as 'controls'. Renal function tests, calculated renal indices using timed urine collections and excretion of beta2-microglobulin and N-acetyl-beta-D-glucosaminidase (NAG) were monitored in both the groups for first 4 days of life. Fourteen (56 per cent) asphyxiated babies had acute renal failure (ARF) as compared to 1 (4 per cent) control (p=0.002). Blood urea and serum creatinine values were significantly higher in asphyxiated babies on day 4 but not on day 2. Renal failure index and FeNa were higher in asphyxiated babies on both day 2 and day 4, but creatinine clearance was not different. Urinary excretion of both beta2-microglobulin and NAG was higher in the asphyxiated babies on day 2 as well as day 4. Five minute Apgar1.5 mg/dl alone had the best specificity and positive predictive value. The renal parameters were however poorer predictors of adverse outcome in comparison to clinical markers like 5 min Apgar相似文献   

Serum concentration and urinary excretion of beta 2-microglobulin and microalbuminuria in familial Mediterranean fever.

Familial Mediterranean fever is characterised by recurrent and self limited attacks of fever and polyserositis and its devastating complication is the development of renal amyloidosis. In order to detect the presence of early glomerular and tubular damage in patients with familial Mediterranean fever and to assess the possible role of beta 2-microglobulin in the inflammatory attacks of this disease, serum and urine beta 2-microglobulin concentrations and microalbuminuria were evaluated in these patients. A total of 20 patients with familial Mediterranean fever were studied on and off colchicine treatment; seven of these patients developed a familial Mediterranean fever attack when they were off treatment. During the familial Mediterranean fever attacks serum beta 2-microglobulin concentrations decreased, whereas fractional excretion of beta 2-microglobulin, urine beta 2-microglobulin creatinine, and urine albumin/creatinine ratios increased. We conclude that glomerular and tubular functions deteriorate during the attacks. Further studies are needed to discover the effector(s) causing these transient glomerular and tubular disorders.     

Renal Consequences of Immobilisation in Children with Fractured Femurs

Abstract. Parameters of renal function and calcium homeostasis were studied in 8 children, immobilised for 5-9 weeks with fractured femurs, weekly during immobilisation and fourth weekly following mobilisation until all parameters returned to normal. During immobilisation 1 patient became hypercalcaemic, but all showed an increase in serum calcium and all developed hypercalciuria. During immobilisation all showed diminished urine osomolality after a 12-hour fast (mean 591·133 mOsm/kg) which improved 4-39 weeks after mobilisation (mean 973·87 mOsm/kg). Serum creatinine, urinary beta-2-microglobulin and renal ultrasound appearances were all normal. An inverse relationship, R= -0.70, was demonstrated between serum calcium and fasting urine osmolality during immobilisation. Three patients showed diminished urinary concentrating ability beyond 4 weeks after mobilisation. For 1 patient this defect persisted for 8 months and glomerular filtration rate was diminished 9 months after mobilisation, raising the possibility of long term renal damage in immobilised patients.     

Value of blood creatinine in children

Non-standardized values of serum creatinine are studied in 205 children aged 3 months to 12 years. Data are collected from paediatric patients hospitalised for mild illness without previous renal impairment; these values are quite comparable to those related in the literature based or standardised methods. The normal age-dependent serum creatinine values (mean +/- 2 SD) are shown in a graphic curve, which confirms that serum creatinine increases with age and that it is a faithful parameter to estimate the glomerular filtration rate in children.     

Renal function of neonates during gentamicin treatment.

Thirteen newborn infants, 8 term and 5 preterm (gestational age 31 to 36 weeks), were treated for between 3 and 7 days with gentamicin and ampicillin or cloxacillin because of suspected bacterial infection. The dosage of gentamicin was carefully monitored by serum concentration assays. Urinary alanine aminopeptidase, urinary beta 2-microglobulin, serum urea, and serum beta 2-microglobulin were measured during and after the end of treatment to detect signs of renal toxicity. Levels of urinary aminopeptidase increased in 12 of them, indicating damage to the cells of the proximal tubuli. Changes in urinary beta 2-microglobulin followed the normal physiological course seen in neonates after birth. Serum levels of urea and beta 2-microglobulin did not indicate any drug-associated depression of glomerular filtration rate.     

Bone gamma-carboxyglutamic acid containing protein in the perinatal period

We measured bone gamma-carboxyglutamic acid-containing protein (BGP), calcium (Ca), phosphorus (P), and alkaline phosphatase (Al-P) in paired maternal and cord sera, and urinary gamma-carboxyglutamic acid (gamma-Gla) in neonates. The circulating BGP was 41.21 +/- 2.47 ng/ml and 7.44 +/- 0.87 ng/ml in the cord (n = 15) and the maternal (n = 14) sera, respectively. The urinary gamma-Gla in the neonates was 147.68 +/- 10.75 mumol/g creatinine (n = 15). The cord serum BGP was significantly higher than the normal adult level. The maternal serum BGP was at the same level as in other adults. It is conceivable that the fetus may produce BGP during gestation, as the cord serum BGP level was significantly higher than the maternal level and there was no correlation between the cord and maternal serum BGP concentrations. The reason for the elevated circulating BGP level in the cord serum is not known, but increased bone turnover may be a factor. The cord serum BGP may include not only carboxylated but also non-gamma-carboxylated GP because of fetal vitamin K deficiency.     

Renal injury in sick newborn infants: a prospective evaluation using urinary beta 2-microglobulin concentrations

Urinary concentrations of beta 2-microglobulin and creatinine were measured serially in 140 sick infants, of whom 109 were asphyxiated, and in 35 healthy preterm and term infants. First voided urines and samples from days 3 and 7 postpartum were studied. Urinary beta 2-microglobulin concentrations in healthy infants averaged 1.34 +/- 1.34 mg/L (mean +/- SD) in first voided specimens and 1.32 +/- 0.98 mg/L in day 3 samples; the calculated upper limit of normal (95% confidence limit) was 4.00 mg/L. Elevated values (those exceeding the 95% confidence limit) occurred most often in the sick asphyxiated patients (56%); the first voided sample value in these patients was 10.0 +/- 10.4 mg/L. The equivalent value in the sick nonasphyxiated infants was 8.32 +/- 7.27 mg/L. Values were significantly and persistently elevated in the sick infants on days 3 and 7. Factoring beta 2-microglobulin levels by urinary creatinine concentration did not affect the significance of the findings. The increased urinary beta 2-microglobulin levels were not (1) related to gestational age; low beta 2-microglobulin values occurred at all gestational ages for both healthy and sick infants; (2) a consequence of urine flow rate; urinary beta 2-microglobulin did not correlate with urinary creatinine concentration or with urine to plasma creatinine ratio; and (3) a consequence of increased production of beta 2-microglobulin; urinary and serum beta 2-microglobulin values did not correlate (r = .03). Thus, we propose that the elevated levels of urinary beta 2-microglobulin in the sick infants were the consequence of tubular injury. This was associated with hematuria but not with a high incidence of azotemia or oliguria.(ABSTRACT TRUNCATED AT 250 WORDS)     

Impaired tubular excretory function as a late renal side effect of chemotherapy in children

PURPOSE: Renal drug excretion is variously influenced by nephrotoxic drugs. This study was designed to evaluate renal function as a late renal side effects in children receiving combination chemotherapy for malignancy. PATIENTS AND METHODS: Follow-up studies of 30 newly diagnosed patients were performed a median of 12 months after completion of chemotherapy. The glomerular filtration rate (GFR) was measured using sodium thiosulfate. The following were also assessed: urinary high-molecular-weight fraction (urinary albumin/urinary creatinine ratio); para-aminohippurate (PAH) clearance; urinary low-molecular-weight fraction (urinary beta2-microglobulin/urinary creatinine ratio); and routine serum and urinary parameters. RESULTS: Serum and urinary electrolytes were normal in most patients. GFR was low in four patients (13%). Urinary high-molecular-weight fraction was elevated in two patients. Urinary low-molecular-weight fraction was elevated in one patient. PAH clearance was below the referenced normal value in 73% of the patients. CONCLUSIONS: This report demonstrates decreased PAH clearance as a late renal side effect of chemotherapy and suggests disturbed function of the organic anion transport system. The unexpected high serum concentration of drugs excreted through the organic anion transport system may induce severe side effects. Elucidation of the mechanism and clinical relevance of decreased PAH clearance is warranted.     

Pretreatment cystatin C in children with malignancy: can it predict chemotherapy-induced glomerular filtration rate reduction during the induction phase?

BACKGROUND: Monitoring of kidney function is essential during chemotherapy. Serum creatinine is of limited value in early detection of renal insufficiency. The cystatin C level has been proved to be a good marker for detection of mild reduction in glomerular filtration rate. PURPOSE: To evaluate the validity of the pretreatment serum cystatin C level in predicting significant reduction of the glomerular filtration rate during the induction phase of chemotherapy. PATIENTS AND METHODS: Serum levels of cystatin C and creatinine and corrected creatinine clearance were assessed in 34 children with different types of malignancy just before the start of chemotherapy and again in 33 of them 1 month later. Patients were compared with 14 healthy controls of matched age and sex. RESULTS: Before chemotherapy, all patients when compared with controls had normal levels of cystatin C (P = 0.1) and creatinine (P = 0.62) and normal corrected creatinine clearance (P = 0.76). One month after chemotherapy, patients showed a significant increase in their cystatin C levels (P < 0.001) and a significant decrease in their corrected creatinine clearance (P < 0.001). However, creatinine levels did not change significantly (P = 0.65). Corrected creatinine clearance negatively correlated significantly with both cystatin C and creatinine levels (r = -0.622, P < 0.001; r = -0.346, P = 0.045, respectively) before chemotherapy and also 1 month after chemotherapy (r = -0.577, P < 0.001; r = -0.45, P = 0.009, respectively). When pretreatment levels of cystatin C and creatinine were used to predict patients who developed a reduction in corrected creatinine clearance of more than 20% after therapy, only the cystatin C level was statistically significant (P = 0.03). A cutoff point of 0.57 mg/L with sensitivity of 77.8%, specificity of 63%, and overall accuracy of 74% was suggested. CONCLUSIONS: Children with malignant diseases develop significant reduction in their glomerular filtration rate during the induction phase of chemotherapy, although their serum creatinine level may not change significantly. Cystatin C, as a more sensitive marker than creatinine for the assessment of glomerular filtration rate, can be used to predict patients who would have a higher risk of renal impairment during the induction phase of chemotherapy and who thus would require more frequent renal function assessment to consider adjustment of the chemotherapy dose if indicated.     

Increased fractional excretion of phosphate and beta 2-microglobulin in unilateral renal disease

Following progressive nephron loss tubular reabsorption in the remaining nephrons will fall to preserve solute and electrolyte excretion. We have examined the fractional excretion (FE) of phosphate, sodium, beta 2-microglobulin (beta 2M) and tubular glucose reabsorption (T glucose) in children with unilateral renal disease to find 1) the threshold for this response and 2) whether intrinsic renal mechanisms can elicit this response. Separate renal function studies were performed using unilateral ureteral compression. Total glomerular filtration rate (GFR) was 93.7 +/- 2.99 ml/1.73(m2)-1 X min-1, and 110.25 +/- 5.40 in control children. GFR in the scarred kidney (SK) was 22.4 +/- 2.46 and in the contralateral kidney (CIK) 67.2 +/- 4.60 ml X 1.73 (m2)-1 X min-1. The kidney area was reduced in proportion to GFR in SK. FE phosphate and beta 2M were significantly higher in SK than in CIK (sign test), but absolute values for FE phosphate and beta 2M were not higher in SK than in control kidneys. FE sodium and T glucose were the same in SK and CIK. Conclusion: Following moderate unilateral reduction of GFR selective depression of tubular reabsorption can occur without extrarenal impulses.     

Serum osteocalcin concentrations in children with chronic renal insufficiency who are not undergoing dialysis. Growth Failure in Children with Renal Diseases Study

This report describes the serum osteocalcin values in children with mild to moderate, but relatively stable, renal dysfunction followed in the Growth Failure in Children With Renal Diseases Study. This report is derived from data obtained during the control period (6 months) before the initiation of vitamin D therapy. Up to three measurements per patient were obtained. Serum osteocalcin concentration was compared with creatinine clearance (glomerular filtration rate) calculated by the Schwartz formula; with serum concentrations of alkaline phosphatase, parathyroid hormone, and bicarbonate; and with the percentages of the recommended dietary allowances of calories and protein ingested. By standard correlation techniques, there appeared to be an inverse correlation between calculated creatinine clearance and serum osteocalcin concentration, and a direct correlation between serum osteocalcin and parathyroid hormone values. However, when we employed a statistical technique that takes into account repeated measures in the same patient, no correlation was found between calculated glomerular filtration rate and serum osteocalcin concentration, and no direct correlation was found between serum osteocalcin and parathyroid hormone values. The lack of a correlation between calculated glomerular filtration rate and serum osteocalcin values may be due to large fluctuations in the serum osteocalcin concentration, even though renal function is relatively stable.     

血清胱抑素C浓度测定对病毒性脑炎患儿肾功能损害的诊断价值

目的：探讨血清胱抑素C(Cyst C)浓度在评估病毒性脑炎患儿肾小球滤过功能中的价值。方法：92例病毒性脑炎患儿为病例组,50例健康儿童为对照组,又根据肾小球滤过率（GFR）将病例组分成肾功能正常组、代偿组、失代偿组和衰竭及终末期组。检测各组血清Cyst C、尿素氮(BUN)、肌酐(Cr)浓度。结果：① 与对照组比较,病例组BUN、Cr及Cyst C均显著增高(P0.05）,在其余各病例亚组间差异有统计学意义（P<0.01）。③Cyst C与BUN、Cr呈显著正相关,与GFR呈显著负相关。结论：病毒性脑炎患儿存在不同程度的肾功能损害;Cyst C是一种比BUN和Cr更好地反映肾小球滤过功能的指标,检测血清Cyst C对病毒性脑炎患儿肾脏功能的监测有重要的临床应用价值。     

Renal toxicity of cisplatin in children

We measured renal function in 22 children receiving cisplatin as initial treatment for neuroblastoma or malignant germ cell tumors. Glomerular filtration rates were estimated from the plasma clearance of 51Cr-EDTA and were compared with measurements of plasma creatinine concentration and creatinine clearance. The degree of cisplatin-induced renal damage varied widely, and plasma creatinine measurements and creatinine clearances were not reliable guides to glomerular filtration rate. Renal function in children receiving cisplatin should be monitored by measurement of glomerular filtration rate with an isotope clearance technique.     

Chronic renal failure in methylmalonic acidaemia

The renal function of 12 patients with non vitamin B₁₂ responsive methylmalonic acidaemia has been investigated. Eight patients had reduced glomerular filtration rates, but the plasma creatinine concentration was only raised in those with values of less than 40ml/min per 1.73m² surface area. The reduction in glomerular filtration was a function of the age and the severity of the disease. Plasma urate concentrations were increased in four patients but this may be secondary to the renal disease rather than its cause.Abbreviations 51 Cr-EDTA 51-chromium ethylenediamine tetraacetic acid - GFR glomerular filtration rate - MMA methylmalonic acidaemia - SA surface area - TRP tubular reabsorption of phosphate - Ua/Uc urinary albumin/creatinine concentration ratio - Ul/Uc urinary lysozyme/creatinine concentration ratio     

Theophylline for renal function in term neonates with perinatal asphyxia: a randomized, placebo-controlled trial

OBJECTIVE: To study whether prophylactic theophylline can reduce the incidence and/or severity of renal failure in term infants with perinatal asphyxia. STUDY DESIGN: Term neonates with severe perinatal asphyxia were randomized to receive a single dose of either theophylline (study group, n = 40) or placebo (control group, n = 30) during the first hour of life. Daily weight, output/input ratio, 24-hour fluid intake, and urine volumes were recorded during the first 5 days of life. Those infants with asphyxial renal failure were followed up for 1 year. RESULTS: The incidence of severe renal dysfunction was increased in the control group. Creatinine clearance was higher and excretion of beta 2 microglobulin (beta2M) was lower in the theophylline group. Conversely, the glomerular filtration rate was lower in the control group. In infants with renal failure, serum creatinine and creatinine clearance returned to normal in the neonatal period, and the increased beta2M excretion normalized by age 6 weeks. CONCLUSIONS: A single dose of theophylline within the first hour of birth in term neonates with perinatal asphyxia results in a significant decrease in serum creatinine level and urinary excretion of beta2M, along with an increase in creatinine clearance.     

The relationship between serum creatinine,serum cystatin C and glomerular filtration rate in pediatric renal transplant recipients: a pilot study

Serum cystatin C more accurately reflects glomerular filtration rate (GFR) in pediatric renal transplant recipients than serum creatinine. Nineteen pediatric renal transplant recipients, 15 male and 4 female, ranging in age from 8.35 yr to 19.06 yr (median 13.52 yr), were enrolled in the study over an 18-month period. Twenty-eight measurements of 99mTc-DTPA GFR were compared with simultaneous measurements of serum cystatin C and Cr. Linear regression analysis, Pearson correlation coefficients and analysis of variance (anova) were used to determine the relationship between creatinine, cystatin C and GFR. The correlation coefficients (R2) for the relationship of 1/Cr to DTPA-GFR and for 1/cystatin C to DTPA-GFR were 0.63 and 0.58, respectively. There was no significant difference between serum cystatin C and serum creatinine as markers of GFR. Serum cystatin C, which costs more to measure than serum creatinine, offers no advantage in monitoring the renal function of pediatric renal transplant recipients.