Tracking and determinants of subcutaneous fat mass in early childhood: the Generation R Study

OBJECTIVES

To examine the development and tracking of subcutaneous fat mass in the first 2 years of life and to examine which parental, fetal and postnatal characteristics are associated with subcutaneous fat mass.

DESIGN

This study was embedded in the Generation R Study, a prospective cohort study from early fetal life onward. Subcutaneous fat mass was measured by skinfold thickness (biceps, triceps, suprailiacal, subscapular) at the ages of 1.5, 6 and 24 months in 1012 children. Information about parental, fetal and postnatal growth characteristics was collected by physical and fetal ultrasound examinations and questionnaires.

RESULTS

Normal values of subcutaneous fat mass are presented. Total subcutaneous fat mass was higher in girls than in boys at the age of 24 months (P=0.01). Subjects in the lowest and highest quartiles at the age of 6 months tended to keep their position in the same quartile at the age of 24 months (odds ratios 1.86 (95% confidence interval (CI) 1.3, 2.7)) and 1.84 (95% CI: 1.3, 2.6), respectively). Maternal height and weight, paternal weight, fetal weight at 30 weeks, birth weight and weight at the age of 6 weeks were each inversely associated with subcutaneous fat mass at the age of 24 months after adjustment for current weight at 24 months.

CONCLUSION

This study shows for the first time that subcutaneous fat mass tends to track in the first 2 years of life. Furthermore, the results suggest that an adverse fetal environment and growth are associated with increased subcutaneous fat mass at the age of 24 months. Further studies are needed to examine whether these associations persist in later life.

New charts for ultrasound dating of pregnancy and assessment of fetal growth: longitudinal data from a population-based cohort study

OBJECTIVES

Correct assessment of gestational age and fetal growth is essential for optimal obstetric management. The objectives of this study were, first, to develop charts for ultrasound dating of pregnancy based on crown-rump length and biparietal diameter and, second, to derive reference curves for normal fetal growth based on biparietal diameter, head circumference, transverse cerebellar diameter, abdominal circumference and femur length from 10 weeks of gestational age onwards.

METHODS

A total of 8313 pregnant women were included for analysis in this population-based prospective cohort study. All women had repeated ultrasound assessments to examine fetal growth.

RESULTS

Charts for ultrasound dating of pregnancy, based on crown-rump length and biparietal diameter, were derived. Internal validation with the actual date of delivery showed that ultrasound imaging provided reliable gestational age estimates. Up to 92% of deliveries took place within 37-42 weeks of gestation if gestational age was derived from ultrasound data, compared with 87% based on a reliable last menstrual period. The earlier the ultrasound assessment the more accurate the prediction of date of delivery. After 24 weeks of gestation a reliable last menstrual period provided better estimates of gestational age. Reference curves for normal fetal growth from 10 weeks of gestational age onwards were derived.

CONCLUSIONS

Charts for ultrasound dating of pregnancy and reference curves for fetal biometry are presented. The results indicate that, up to 24 weeks of pregnancy, dating by ultrasound examination provides a better prediction of the date of delivery than does last menstrual period. The earlier the ultrasound assessment in pregnancy, preferably between 10 and 12 weeks, the better the estimate of gestational age.

Quantitative differentiation between healthy and disordered brain matter in patients with neurofibromatosis type I using diffusion tensor imaging

BACKGROUND AND PURPOSE

Hyperintensities on T2-weighted images are seen in the brains of most patients with neurofibromatosis type I (NF-1), but the origin of these unidentified bright objects (UBOs) remains obscure. In the current study, we examined the diffusion characteristics of brain tissue in children with NF-1 to test the hypothesis that a microstructural abnormality is present in NF-1.

MATERIALS AND METHODS

Diffusion tensor imaging (DTI) was performed in 50 children with NF-1 and 8 controls. Circular regions of interest were manually placed in 7 standardized locations in both hemispheres, including UBO sites. Apparent diffusion coefficients (ADC), fractional anisotropy (FA), and axial anisotropy (A(m)) were used to differentiate quantitatively between healthy and disordered brain matter. Differences in eigenvalues (lambda(1), lambda(2), lambda(3)) were determined to examine parenchymal integrity.

RESULTS

We found higher ADC values for UBOs than for normal-appearing sites (P < .01) and higher ADC values for normal-appearing sites than for controls (P < .04 in 5 of 7 regions). In most regions, we found no differences in FA or A(m). Eigenvalues lambda(2) and lambda(3) were higher at UBO sites than in normal-appearing sites (P < .04).

CONCLUSION

With ADC, it was possible to differentiate quantitatively between normal- and abnormal-appearing brain matter in NF-1 and also between normal-appearing brain matter in NF-1 and healthy brain matter in controls, indicating subtle pathologic damage disrupting the tissue microstructure in the NF-1 brain. Higher diffusivity for lambda(1), lambda(2), and lambda(3) indicates that this disturbance of microstructure is caused by accumulation of fluid or vacuolation.

Perinatal stress influences lymphocyte subset counts in neonates. The generation R study

In the general population, it is unknown whether stress-related perinatal factors influence lymphocyte subset counts in neonates. The aim of this study was to assess the associations of perinatal factors related to stress and hypoxia (mode of delivery, Apgar scores, and umbilical cord blood pH) with absolute lymphocyte subset counts (T, B, NK, helper T, cytotoxic T, naïve, memory T) in cord blood of 571 neonates. This study was embedded in a population-based prospective cohort study from fetal life onwards. All models were adjusted for gestational age, birth weight, gender, maternal fever, and each of the other perinatal stress-relating factors. Our results showed that increasing stress-related mode of delivery was positively associated with NK and memory T-lymphocyte subset counts (all p < 0.01). Effects of Apgar scores on lymphocyte subsets were explained by umbilical cord blood pH. Lower umbilical cord blood pH was associated with higher B, NK, and memory T-lymphocyte counts (all p < 0.05). Effects of mode of delivery and umbilical cord blood pH on other lymphocyte subsets were not observed. We conclude that, in the general population, lymphocyte subset counts in neonates increase with increasing stress- and hypoxia-related perinatal factors.

Variation in the IGF1 gene and growth in foetal life and infancy. The Generation R Study

OBJECTIVE

The objective of this study was to examine whether variants of the IGF1 gene are associated with growth patterns from foetal life until infancy.

STUDY DESIGN AND MEASUREMENTS

This study was embedded in the Generation R Study, a population-based prospective cohort study of foetal life. Foetal growth (head circumference, abdominal circumference, femur length, estimated foetal weight) was assessed by ultrasound in early, mid- and late pregnancy. Growth in infancy was assessed at birth (weight) and at the ages of 6 weeks, 6 months and 14 months (head circumference, length, weight). The IGF1 promoter region genotype was determined in 738 children.

RESULTS

Eight alleles of the IGF1 promoter region were identified. In total, 43% of the subjects were homozygous for the most common 192-bp allele (wild-type), 45% were heterozygous, and 12% were noncarriers of the 192-bp allele. No differences were found in birthweight between the three groups. However, noncarriers had a lower estimated foetal weight in mid-pregnancy (P = 0.040), followed by an increased growth rate until 6 months (P < 0.005) in comparison to the 192-bp homozygotes. A similar difference in growth rate was found for length (P < 0.001).

CONCLUSIONS

Variants of the IGF1 promoter region are not associated with birthweight. However, noncarriers of the 192-bp allele tend to have a smaller foetal size, followed by an increased growth rate from mid-pregnancy to early infancy. Studies in larger cohorts are necessary to replicate our findings and to examine whether these effects persist throughout childhood.

The Generation R Study Biobank: a resource for epidemiological studies in children and their parents

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health from fetal life until young adulthood. In total, 9,778 mothers were enrolled in the study. Prenatal and postnatal data collection is conducted by physical examinations, questionnaires, interviews, ultrasound examinations and biological samples. Major efforts have been conducted for collecting biological specimens including DNA, blood for phenotypes and urine samples. In this paper, the collection, processing and storage of these biological specimens are described. Together with detailed phenotype measurements, these biological specimens form a unique resource for epidemiological studies focused on environmental exposures, genetic determinants and their interactions in relation to growth, health and development from fetal life onwards.

Insulin gene variable number of tandem repeats is not associated with weight from fetal life until infancy: the Generation R Study

OBJECTIVE

The aim of this study was to examine whether the insulin gene variable number of tandem repeats (INS VNTR) is associated with growth patterns in fetal life and infancy.

DESIGN AND METHODS

This study was embedded in the Generation R Study, a population-based prospective cohort study from fetal life until young adulthood. Fetal growth was assessed by ultrasounds in early, mid-, and late pregnancy. Anthropometry in infancy was assessed at birth and at the ages of 6 weeks, 6 months, and 14 months. DNA for genotyping of the INS VNTR promoter region was available in 859 children.

RESULTS

The genotype distribution was I/I 50.8%, I/III 40.0%, and III/III 9.2%. III/III individuals had a shorter gestational age (P<0.005 versus I/I) and a lower birth weight (P<0.05 versus I/I). There were no differences in birth weight after adjusting for gestational age. Class III homozygotes had a smaller abdominal circumference/head circumference (HC) ratio (P<0.005 versus I/I) in mid-pregnancy, but not in late pregnancy. Also, III/III subjects had a relative decrease in HC (SDS) from mid-pregnancy to the age of 14 months (P<0.05 versus I/I). No other differences in pre- and postnatal growth characteristics and patterns were found.

CONCLUSIONS

Class III homozygotes were born at an earlier gestational age. No association was found between INS VNTR and birth weight adjusted for gestational age. Our data suggest that the III/III genotype may be associated with asymmetrical growth in mid-pregnancy, but not in late pregnancy.

Randomized trial of a clinical decision support system: impact on the management of children with fever without apparent source

OBJECTIVE

To assess compliance with a clinical decision support system (CDSS) for diagnostic management of children with fever without apparent source and to study the effects of application of the CDSS on time spent in the emergency department (ED) and number of laboratory tests.

DESIGN

The CDSS was used by ED nursing staff to register children presenting with fever. The CDSS identified children that met inclusion criteria (1-36 months and fever without apparent source (FWS)) and provided patient-specific diagnostic management advice. Children at high risk for serious bacterial infection were randomized for the 'intervention' (n = 74) or the 'control' (n = 90) group. In the intervention group, the CDSS provided the advice to immediately order laboratory tests and in the control group the ED physician first assessed the children and then decided on ordering laboratory tests.

RESULTS

Compliance with registration of febrile children was 50% (683/1,399). Adherence to the advice to order laboratory tests was 82% (61/74). Children in the intervention group had a median (25(th)-75(th) percentile) length of stay at the ED of 138 (104-181) minutes. The median length of stay at the ED in the control group was 123 (83-179) minutes. Laboratory tests were significantly more frequently ordered in the intervention group (82%) than in the control group (44%, p < 0.001, chi(2) test).

CONCLUSION

Implementation of a CDSS for diagnostic management of young children with fever without apparent source was successful regarding compliance and adherence to CDSS recommendations, but had unexpected effects on patient outcome in terms of ED length of stay and number of laboratory tests. The use of the current CDSS was discontinued.

Explaining differences in birthweight between ethnic populations. The Generation R Study

OBJECTIVE

To examine whether differences in birthweight of various ethnic groups residing in The Netherlands can be explained by determinants of birthweight.

DESIGN

Population-based birth cohort study.

SETTING

Data of pregnant women and their partners in Rotterdam, The Netherlands.

POPULATION

We examined data of 6044 pregnant women with a Dutch, Moroccan, Turkish, Capeverdean, Antillean, Surinamese-Creole, Surinamese-Hindustani and Surinamese-other ethnic background.

METHODS

Regression analyses were used to assess the impact of biomedical, socio-demographic and lifestyle-related determinants on birthweight differences.

MAIN OUTCOME MEASURE

Birthweight was established immediately after delivery in grams.

RESULTS

Compared with mean birthweight of offspring of Dutch women (3485 g, SD 555), the mean birthweight was lower in all non-Dutch populations, except in Moroccans. Differences ranged from an 88-g lower birthweight in offspring of the Turkish women to a 424-g lower birthweight in offspring of Surinamese-Hindustani women. Differences in gestational age, maternal and paternal height largely explained the lower birthweight in the Turkish, Antillean, Surinamese-Creole and Surinamese-other populations. Differences in birthweight between the Dutch and the Capeverdean and Surinamese-Hindustani populations could only partly be explained by the studied determinants.

CONCLUSIONS

These results confirm significant differences in birthweight between ethnic populations that can only partly be understood from established determinants of birthweight. The part that is understood points to the importance of determinants that cannot easily be modified, such as parental height. Further study is necessary to obtain a fuller understanding.

Fetal kidney volume and its association with growth and blood flow in fetal life: The Generation R Study

An adverse fetal environment may lead to smaller kidneys and subsequent hypertension with renal disease in adult life. The aim of our study was to examine whether maternal characteristics, fetal growth, fetal blood flow redistribution, or inadequate placental perfusion in different periods of fetal life affect kidney volume in late fetal life. We also determined if fetal kidney volume was linked to the amount of amniotic fluid. In a population-based prospective study from early fetal life, fetal growth characteristics and fetal blood flow parameters were assessed by ultrasound and Doppler examinations in 1215 women in mid- and late-pregnancy. Kidney volume was measured in late pregnancy. Maternal height and pre-pregnancy weight were associated with kidney volume. After adjustment for the same characteristics in late pregnancy, fetal growth and blood flow in mid-pregnancy were not associated with kidney volume in late pregnancy. In late pregnancy, however, all fetal growth parameters were positively linked with kidney volume. The largest effect on kidney volume was found for abdominal circumference. Signs of fetal blood flow redistribution and increased placental resistance were associated with decreased kidney volume in late pregnancy. Amniotic fluid volume was positively associated with kidney volume. Our study shows that maternal anthropometrics, fetal growth, fetal blood flow redistribution, and raised placental resistance all correlate with kidney volume.

The use of health economics to guide drug development decisions: Determining optimal values for an RSV-vaccine in a model-based scenario-analytic approach

Health-economic modelling is useful for assessing the clinical requirements and impact of new vaccines. In this study, we estimate the impact of potential vaccination for respiratory syncytial virus (RSV) of infants in the Netherlands. A decision analysis model was employed using seasonal data from a cohort of children (1996-1997 through 1999-2000) to assess hospitalisation, costs and impact of vaccination. Yearly, an estimated 3670 infants are hospitalised with RSV-infection in the Netherlands, vaccination protecting infants from 3 months of life onwards could prevent approximately 1000-3000 hospitalisations, depending on the effectiveness of the potential vaccine. Additionally, vaccination could prevent a major share of RSV-related costs. Comparison of the calculated break-even prices with the average price of recently introduced vaccines indicates that pricing for a potential RSV-vaccine most likely allows for only a single dose vaccination or several doses at a relatively low price per dose in order to achieve cost savings. However, if evidence on relevant RSV-related mortality would become available, higher pricing would be justified, while still remaining below accepted thresholds for cost-effectiveness.

Moderate alcohol consumption during pregnancy and the risk of low birth weight and preterm birth. The generation R study

PURPOSE

To examine the associations of alcohol consumption in different periods of pregnancy with the risks of low birth weight and preterm birth.

METHODS

This study was based on 7141 subjects participating in a population-based prospective cohort study from early pregnancy. Alcohol consumption was assessed in early, mid, and late pregnancy. Birth outcomes were birth weight in grams, low birth weight (<2500 g), small size for gestational age at birth (< -2 standard deviation scores) and preterm birth (gestational age <37 weeks).

RESULTS

Overall, alcohol consumption during pregnancy was not associated with adverse birth outcomes. However, dose-response analyses showed tendencies toward adverse effects of average consumption of 1 or more alcoholic drinks per day in early pregnancy on birth weight (difference -129 g [95% confidence interval (CI): -271, 12]), low birth weight (adjusted odds ratio [aOR] 4.81 [95% CI: 1.10, 21.08]), small size for gestational age at birth (aOR 1.45 [95% CI: 0.33, 6.44]) and preterm birth (aOR 2.51 [95% CI: 0.92, 6.81]). Similar effects were found in late pregnancy.

CONCLUSION

Average consumption of one or more but not less than one alcoholic drink per day in early or late pregnancy seems to be associated with adverse birth outcomes in the offspring.

Maternal smoking and fetal growth characteristics in different periods of pregnancy: the generation R study

The authors examined the associations of maternal smoking in pregnancy with various fetal growth characteristics among 7,098 pregnant women participating in the Generation R Study (2002-2006), a population-based prospective cohort study of pregnant women and their children in Rotterdam, the Netherlands. Maternal smoking was assessed by questionnaires administered in early, mid-, and late pregnancy. Fetal growth characteristics evaluated included head circumference, abdominal circumference, and femur length measured repeatedly in mid- and late pregnancy. Maternal smoking during pregnancy was associated with reduced growth in head circumference (-0.56 mm/week; 95% confidence interval (CI): -0.73, -0.40), abdominal circumference (-0.58 mm/week; 95% CI: -0.81, -0.34), and femur length (-0.19 mm/week; 95% CI: -0.23, -0.14). This reduced growth resulted in a smaller femur length from midpregnancy (gestational age 18-24 weeks) onwards and smaller head and abdominal circumferences from late pregnancy (gestational age > or =25 weeks) onwards. Analyses using standard deviation scores for the growth characteristics demonstrated the largest effect estimates for femur length. The authors concluded that maternal smoking during pregnancy is associated with reduced growth in fetal head circumference, abdominal circumference, and femur length. The larger effect on femur length suggests that smoking during pregnancy affects primarily peripheral tissues.

Reliability and validity of the Infant and Toddler Quality of Life Questionnaire (ITQOL) in a general population and respiratory disease sample

OBJECTIVE

To evaluate feasibility, internal consistency, test-retest reliability, and concurrent and discriminative validity of the Infant and Toddler Quality of Life Questionnaire (ITQOL) for parents of pre-school children with 12 scales (103-items) covering physical and psychosocial domains and impact of child health on parents, in comparison with the TNO-AZL Pre-school Children Quality of Life Questionnaire (TAPQOL).

METHODS

Parents of children from a random general population sample (2 months-4 years old; n = 500) and of an outpatient clinic sample of children with respiratory disease (5 months-[Formula: see text] years old; n = 217) were mailed ITQOL and TAPQOL questionnaires; a retest was sent after two weeks.

RESULTS

Feasibility: The response was >or=80% with few missing and non-unique ITQOL-answers (<2%) in both study populations. Some ITQOL-scales (3-4 scales) showed a ceiling effect (>25% at maximum score). Internal consistency: All Cronbach's alpha >0.70. Test-retest Intraclass Correlation Coefficients (ICCs) were moderate or adequate (>or=0.50; p < 0.01) for 10 ITQOL-scales.

VALIDITY

ITQOL-scales, with a few exceptions, correlated better with predefined parallel TAPQOL scales than with non-parallel scales. Five to eight ITQOL-scales discriminated clearly between children with few and with many parent-reported chronic conditions, between children with and without doctor-diagnosed respiratory disease and with a low and a high parent-reported medical consumption (p < 0.05).

CONCLUSIONS

This study supported the evidence that the ITQOL is a feasible instrument with adequate psychometric properties. The study provided reference ITQOL scores for gender/age subgroups. We recommend repeated evaluations of the ITQOL in varied populations, especially among very young children, including repeated assessments of test-retest characteristics and evaluations of responsiveness to change. We recommend developing and evaluating a shortened ITQOL version.

Food questionnaire for assessment of infant gluten consumption

BACKGROUND

In light of the possibly preventive role of timing and amount of gluten in celiac disease, it would be helpful to have a questionnaire to assess the gluten intake in infants.

AIMS

Development and validation of a food questionnaire to assess gluten consumption in healthy infants aged 0-12 months (FQ-gluten).

METHODS

A food frequency questionnaire, previously developed for the Generation R study, was adapted for the assessment of gluten intake. The results of a 2-day food record (FR) were compared with the results of this FQ-gluten.

RESULTS

Eighty-seven parents filled in the FR and the FQ-gluten. The number of children who consume gluten and who are breast-fed is higher, reported in the FQ-gluten. The amount of gluten is comparable from the age of 3 up to 10 months, but at 11 and 12 months a higher gluten intake is reported using the FR, probably due to a larger variety of food products not detectable by the FQ-gluten. However, there is a high agreement in the food groups (Cohens' kappa=0.6-0.8).

CONCLUSIONS

This new, short, standardized, validated and easy to use FQ-gluten may be a useful instrument to assess gluten intake in infants, both at the individual and at the population level. The use of this method by investigators in other countries provides the opportunity for a better comparison of the results of gluten consumption in (co-operative) studies throughout different countries.

The Generation R Study: Design and cohort profile

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health from fetal life until young adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioral and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. Of all eligible children at birth, 61% participate in the study. Data collection in the prenatal phase included physical examinations, questionnaires, fetal ultrasound examinations and biological samples. In addition, more detailed assessments are conducted in a subgroup of 1232 pregnant women and their children. The children form a prenatally recruited birth-cohort that will be followed until young adulthood. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

Validating and updating a prediction rule for serious bacterial infection in patients with fever without source

AIM

To externally validate and update a previously developed rule for predicting the presence of serious bacterial infections in children with fever without apparent source.

METHODS

Patients, 1-36 mo, presenting with fever without source, were prospectively enrolled. Serious bacterial infection included bacterial meningitis, sepsis, bacteraemia, pneumonia, urinary tract infection, bacterial gastroenteritis, osteomyelitis/ethmoiditis. The generalizability of the original rule was determined. Subsequently, the prediction rule was updated using all available data of the patients with fever without source (1996-1998 and 2000-2001, n = 381) using multivariable logistic regression.

RESULTS

the generalizability of the rule appeared insufficient in the new patients (n = 150). In the updated rule, independent predictors from history and examination were duration of fever, vomiting, ill clinical appearance, chest-wall retractions and poor peripheral circulation (ROC area (95%CI): 0.69 (0.63-0.75)). Additional independent predictors from laboratory were serum white blood cell count and C-reactive protein, and in urinalysis > or = 70 white bloods (ROC area (95%CI): 0.83 (0.78-0.88).

CONCLUSIONS

A previously developed prediction rule for predicting the presence of serious bacterial infection in children with fever without apparent source was updated. Its clinical score can be used as a first screening tool. Additional laboratory testing may specify the individual risk estimate (range: 4-54%) further.

Validity of the Manchester Triage System in paediatric emergency care

OBJECTIVE

To assess the validity of the Manchester Triage System (MTS) in paediatric emergency care, using information on vital signs, resource utilisation and hospitalisation.

METHODS

Patients were eligible if they had attended the emergency department of a large inner-city hospital in The Netherlands from August 2003 to November 2004 and were <16 years of age. A representative sample of 1065 patients was drawn from 18,469 eligible patients. The originally assigned MTS urgency levels were compared with resource utilisation, hospitalisation and a predefined reference classification for true urgency, based on vital signs, resource utilisation and follow-up. Sensitivity, specificity and percentage of overtriage and undertriage of the MTS were calculated.

RESULTS

The number of patients who used more than two resources increased with a higher level of MTS urgency. The percentage of hospital admissions increased with the increase in level of urgency, from 1% in the non-urgent patients to 54% in emergent patients. According to the reference classification, the sensitivity of the MTS to detect emergent/very urgent cases was 63%, and the specificity was 78%. Undertriage occurred in 15% of patients, of which 96% were by one urgency category lower than the reference classification. Overtriage occurred in 40%, mostly in lower MTS categories. In 36% of these cases, the MTS classified two or more urgency categories higher than the reference classification.

CONCLUSIONS

The MTS has moderate sensitivity and specificity in paediatric emergency care. Specific modifications of the MTS should be considered in paediatric emergency care to reduce overtriage, while maintaining sensitivity in the highest urgency categories.

Health-related quality of life of pre-school children with wheezing illness

Pre-school children are frequently affected by wheezing illness, with substantial influences on their health-related quality of life (HRQL). The Infant/Toddler Quality of Life Questionnaire (ITQOL) is the only generic health status measure for children aged 2 months up to 5 years. In this present study we evaluated the impact of wheezing illness in pre-school children on the HRQL, using the ITQOL. A questionnaire including the ITQOL and ISAAC questions on frequency and severity of respiratory complaints were sent to parents of patients aged 6 months-5 years visiting the outpatient department with wheezing illness. Scale scores of ITQOL of the included children were compared with general population scores. Using multivariate analysis, the influence of general and clinical characteristics on ITQOL scale scores was evaluated. Results are based on 138 children, 59% male, mean age 34 months. Children with wheezing illness scored differently to the general population sample on 8 of the 11 ITQOL scales. Age, comorbidity and employment of the respondent affected scales on child's physical and emotional functioning and parental functioning. Severity of dyspnoea and wheezing, presence of cough, corticosteroid use, and number of GP visits negatively affected scales on the child's physical and emotional functioning. In conclusion, the HRQL as measured by the ITQOL was lower in a group of Dutch pre-school children with wheezing illness compared to a general population sample. The scale scores were sensitive to age, co morbidity, socio-economic situation, and disease severity.

Structured data entry for narrative data in a broad specialty: patient history and physical examination in pediatrics

Background

Whereas an electronic medical record (EMR) system can partly address the limitations, of paper-based documentation, such as fragmentation of patient data, physical paper records missing and poor legibility, structured data entry (SDE, i.e. data entry based on selection of predefined medical concepts) is essential for uniformity of data, easier reporting, decision support, quality assessment, and patient-oriented clinical research. The aim of this project was to explore whether a previously developed generic (i.e. content independent) SDE application to support the structured documentation of narrative data (called OpenSDE) can be used to model data obtained at history taking and physical examination of a broad specialty.

Methods

OpenSDE was customized for the broad domain of general pediatrics: medical concepts and its descriptors from history taking and physical examination were modeled into a tree structure.

Results

An EMR system allowing structured recording (OpenSDE) of pediatric narrative data was developed. Patient history is described by 20 main concepts and physical examination by 11. In total, the thesaurus consists of about 1800 items, used in 8648 nodes in the tree with a maximum depth of 9 levels. Patient history contained 6312 nodes, and physical examination 2336. User-defined entry forms can be composed according to individual needs, without affecting the underlying data representation. The content of the tree can be adjusted easily and sharing records among different disciplines is possible. Data that are relevant in more than one context can be accessed from multiple branches of the tree without duplication or ambiguity of data entry via "shortcuts".

Conclusion

An expandable EMR system with structured data entry (OpenSDE) for pediatrics was developed, allowing structured documentation of patient history and physical examination. For further evaluation in other environments, the tree structure for general pediatrics is available at the Erasmus MC Web site (in Dutch, translation into English in progress) [1]. The generic OpenSDE application is available at the OpenSDE Web site [2].

The Generation R Study: Design and cohort profile

The Generation R Study is a population-based prospective cohort study from fetal life until young adulthood. The study is designed to identify early environmental and genetic causes of normal and abnormal growth, development and health from fetal life until young adulthood. The study focuses on four primary areas of research: (1) growth and physical development; (2) behavioral and cognitive development; (3) diseases in childhood; and (4) health and healthcare for pregnant women and children. In total, 9778 mothers with a delivery date from April 2002 until January 2006 were enrolled in the study. Of all eligible children at birth, 61% participate in the study. Data collection in the prenatal phase included physical examinations, questionnaires, fetal ultrasound examinations and biological samples. In addition, more detailed assessments are conducted in a subgroup of 1232 pregnant women and their children. The children form a prenatally recruited birth-cohort that will be followed until young adulthood. Eventually, results forthcoming from the Generation R Study have to contribute to the development of strategies for optimizing health and healthcare for pregnant women and children.

Hospitalization for respiratory syncytial virus infection in young children: development of a clinical prediction rule

BACKGROUND

Because passive immunization against respiratory syncytial virus (RSV) is costly, its use should be restricted to well-defined groups of high risk children. We aimed to develop a clinical prediction rule that estimates the individual monthly risk of hospitalization for RSV infection in young children.

METHODS

A retrospective cohort study was conducted in the southwestern part of The Netherlands. We included children born between January 1, 1996 and December 31, 1998. Children hospitalized for proven RSV infection were compared with children not hospitalized for RSV infection. The monthly risk was estimated with a logistic regression model including 5 clinical predictors (gender, gestational age, birth weight, presence of bronchopulmonary dysplasia and age) and the mean seasonal monthly pattern of RSV infections. We compared the predictive performance of the prediction rule with the guidelines of the American Academy of Pediatrics (AAP).

FINDINGS

Information was collected on 2469 hospitalized children and 140,661 children who were 1,181,790 months at risk. All predictors were statistically significant, with age and the seasonal monthly RSV pattern having the strongest effects. The clinical prediction rule that included these predictors could better discriminate between high and low risk children than the AAP guidelines and would potentially reduce the number of immunizations by 20%.

INTERPRETATION

The prediction rule reliably estimates individual monthly risks of hospitalization for RSV infection in the population studied. It provides an improved index for passive immunization but further validation in other populations is required.

Health-related Quality of Life in Preschool Children with Wheezing and Dyspnea: Preliminary Results from a Random General Population Sample

Respiratory symptoms have a high prevalence among preschool children (5-20%). This study evaluated the impact of parent-reported respiratory symptoms on health-related quality of life (HRQOL) using the TNO-AZL Preschool Children Quality of Life (TAPQOL) questionnaire. A random general population sample of 500 parents of 3-46-month old children was mailed a questionnaire containing the TAPQOL and questions on the prevalence of respiratory symptoms. The impact of respiratory symptoms on HRQOL was analysed using the Mann-Whitney test and linear regression analysis. Response rate was 83%. The prevalence of combined "wheezing and dyspnea" during the past 4 weeks was 10%. For the sleeping, appetite, lung problems, skin problems, communication, and positive mood TAPQOL scales, HRQOL was significantly lower in the subgroup with "wheezing and dyspnea" (n = 41) than in the subgroup without symptoms (n = 321); large effect sizes were observed for lung problems (2.06) and sleeping (0.80). In multivariate analysis, adjusted for age and gender of the child, "wheezing and dyspnea" were associated with the scales sleeping, appetite, lung problems, communication, and positive mood (p < 0.05). In conclusion, decreases in HRQOL among preschoolers with parent-reported respiratory symptoms are measurable with the TAPQOL. We recommend studying the impact of doctor-diagnosed respiratory symptoms on HRQOL in future studies.

Ethnic differences in prenatal growth and the association with maternal and fetal characteristics

OBJECTIVES

The objectives of this study were to determine ethnic differences in prenatal growth and to examine their association with differences in maternal and fetal characteristics such as maternal height, weight, age, parity and fetal gender.

METHODS

A total of 1494 women from Rotterdam, The Netherlands, with a low-risk pregnancy who participated in a population-based cohort study, the Generation R Study, were offered three ultrasound examinations during pregnancy. Multilevel modeling was applied to determine ethnic differences in (estimated) fetal weight (including birth weight) and in the separate biometric variables that were used to calculate the estimated fetal weight (abdominal circumference, head circumference and femur length). Additionally the association of ethnic differences with maternal and fetal characteristics (i.e. maternal weight, height, age, parity and fetal gender) was studied.

RESULTS

Turkish, Cape Verdian, Surinamese-Creole and Surinamese-Hindustani women had on average smaller fetuses than the native Dutch women. The differences became more pronounced towards term. In the Turkish group the differences were no longer statistically significant when adjusted for maternal weight, height, age, parity and fetal gender. In the Cape Verdian, Surinamese-Creole and Surinamese-Hindustani groups the differences decreased after adjustment (31%, 16% and 39%, respectively).

CONCLUSIONS

This study shows that there are ethnic differences in fetal growth, which to a large extent may be attributed to differences in maternal weight, height, age and parity. For some ethnic groups, however, additional factors are involved, as differences remain significant after correction for fetal and maternal characteristics.

Reliability and validity of health status measurement by the TAPQOL

BACKGROUND

In addition to clinical measures in the evaluation of paediatric interventions, health related quality of life (HRQoL) is an important outcome. The TAPQOL (TNO-AZL Preschool children Quality of Life) was developed to measure HRQoL in preschool children. It is a generic instrument consisting of 12 scales that cover the domains physical, social, cognitive, and emotional functioning.

AIMS

To evaluate the feasibility, score distribution, internal consistency, test-retest reliability, and discriminative and concurrent validity of the TAPQOL multi-item scales in preschool children, aged 2-48 months. Also to evaluate the feasibility, reliability, and validity separately for infants (2-12 months old) and toddlers (12-48 months old).

METHODS

Parents of a random general population sample of 500 preschool children were sent a questionnaire by mail. A random subgroup of 159 parents who participated received a retest after two weeks.

RESULTS

The response rate was 83% at the test and 75% at the retest. There were few missing answers. Six scales showed ceiling effects. Nine scales had Cronbach's alphas >0.70. In general, score distributions and Cronbach's alphas were comparable for infants and toddlers. Test-retest showed no significant differences in mean scale scores; two scales had intra-class correlations <0.50. Five scales showed significant differences between children with no conditions versus children with two or more parent reported chronic conditions.

CONCLUSION

Results showed that the TAPQOL is a feasible instrument to measure HRQoL and support the reliability and discriminative validity of the majority of its scales for infants as well as toddlers.

Anticipated costs of hospitalization for respiratory syncytial virus infection in young children at risk

BACKGROUND

Reliable estimates of hospitalization costs for severe respiratory syncytial virus (RSV) infection are necessary to perform economic analyses of preventive strategies of severe RSV disease. We aimed to develop a model that predicts anticipated mean RSV hospitalization costs of groups of young children at risk for hospitalization, but not yet hospitalized, based on readily available child characteristics.

METHODS

We determined real direct medical costs of RSV hospitalization from a societal perspective, using a bottom-up strategy, in 3458 infants and young children hospitalized for severe RSV disease during the RSV seasons 1996-1997 to 1999-2000 in the Southwest of the Netherlands. We used a linear regression model to predict anticipated mean RSV hospitalization costs of groups of children at risk, based on 4 child characteristics [age, gestational age, birth weight and bronchopulmonary dysplasia (BPD)], expressed in EC Euros as of the year 2000.

FINDINGS

The mean RSV hospitalization costs of all patients were 3110 Euros. RSV hospitalization costs were higher for patients with lower gestational age (5555 Euros; gestational age, </=28 weeks), lower birth weight (3895 Euros; birth weight </=2500 g), BPD (5785 Euros; with BPD) and young age (4730 Euros; first month of life). The linear regression model had an adjusted R of 0.08. This indicates a low explanatory ability for hospitalization costs of individual children. However, the model could accurately estimate the anticipated mean hospitalization costs of groups of children with the same characteristics.

INTERPRETATION

RSV hospitalization costs were substantial, especially of specific high risk groups. Anticipated mean hospitalization costs of groups of children at risk for RSV hospitalization, but not yet hospitalized, could well be estimated with 4 child characteristics (age, gestational age, birth weight and BPD). These estimated costs can be used for economic analyses of preventive strategies for severe RSV disease.

Application of a diagnostic decision rule in children with meningeal signs: a cost-minimization study

OBJECTIVES

Recently, we developed a diagnostic rule for the diagnosis and treatment of children with meningeal signs. This rule may provide the physician with a rationale to decide on the use of diagnostic and treatment procedures in these children and to improve their care. In this study, we estimated cost savings of the rule compared with current practice.

METHODS

Routine care data of 360 children visiting the emergency department of the Sophia Children's Hospital with meningeal signs between 1988 and 1998 were used. Costs of diagnostic tests and treatment were estimated by using financial accounts of an academic and a general pediatric hospital. The number of procedures actually performed and the resulting cost estimates (i.e. unit costs x volume) were compared with the estimated figures after application of the decision rule.

RESULTS

The population of children with meningeal signs comprised 99 with bacterial meningitis (27%), 36 with another serious bacterial infection (10%), and 225 with a self-limiting disease (63%). Application of the rule would reduce lumbar punctures by 12% and hospitalizations for empirical treatment by 15% with the same diagnostic accuracy as current practice. Cost savings were estimated at Euro292 per patient (relative reduction 10%) and were mainly achieved in the treatment course (Euro259).

CONCLUSIONS

A diagnostic decision rule for children with meningeal signs has the potential to improve the appropriate use of medical resources, to be cost-effective, and to ascertain the absence of bacterial meningitis earlier.

External validation is necessary in prediction research:

BACKGROUND AND OBJECTIVES

Prediction models tend to perform better on data on which the model was constructed than on new data. This difference in performance is an indication of the optimism in the apparent performance in the derivation set. For internal model validation, bootstrapping methods are recommended to provide bias-corrected estimates of model performance. Results are often accepted without sufficient regard to the importance of external validation. This report illustrates the limitations of internal validation to determine generalizability of a diagnostic prediction model to future settings.

METHODS

A prediction model for the presence of serious bacterial infections in children with fever without source was derived and validated internally using bootstrap resampling techniques. Subsequently, the model was validated externally.

RESULTS

In the derivation set (n=376), nine predictors were identified. The apparent area under the receiver operating characteristic curve (95% confidence interval) of the model was 0.83 (0.78-0.87) and 0.76 (0.67-0.85) after bootstrap correction. In the validation set (n=179) the performance was 0.57 (0.47-0.67).

CONCLUSION

For relatively small data sets, internal validation of prediction models by bootstrap techniques may not be sufficient and indicative for the model's performance in future patients. External validation is essential before implementing prediction models in clinical practice.

[A diagnostic decision rule for managing children with signs of meningeal irritation]

OBJECTIVE

To develop a diagnostic decision rule based on clinical features to predict the risk of bacterial meningitis in children with signs of meningeal irritation.

DESIGN

Retrospective and prospective.

METHOD

Predictors for bacterial meningitis were identified by collecting clinical data from the records of 360 patients (aged 1 month to 15 years) who consulted the Casualty Department, Sophia Children's Hospital, Rotterdam, the Netherlands, with signs of meningeal irritation during the period 1988-1998. The diagnostic decision rule derived was prospectively validated on 226 similar children who consulted the casualty departments of four hospitals in the Netherlands during the period 1999-2001.

RESULTS

Predictors for bacterial meningitis were the main complaint and vomiting (in the history) persisting for a long time, the presence of meningeal irritation, cyanosis, petechiae, disturbed consciousness (during physical examination), and a high serum concentration of C-reactive protein. Liquor analysis parameters with an added diagnostic value were the total polymorphonuclear cell count in the liquor and the liquor/blood glucose ratio. The use of these patient characteristics in a decision rule accurately predicted the chance of bacterial meningitis. The rule can also be used to refine the indication for lumbar puncture and empirical antibiotic treatment.

Diagnostic research on routine care data: prospects and problems

A diagnosis in practice is a sequential process starting with a patient with a particular set of signs and symptoms. To serve practice, diagnostic research should aim to quantify the added value of a test to clinical information that is commonly available before the test will be applied. Routine care databases commonly include all documented patient information, and therefore seem to be suitable to quantify a tests' added value to prior information. It is well known, however, that retrospective use of routine care data in diagnostic research may cause various methodologic problems. But, given the increased attention of electronic patient records including data from routine patient care, we believe it is time to reconsider these problems. We discuss four problems related to routine care databases. First, most databases do not label patients by their symptoms or signs but by their final diagnosis. Second, in routine care the diagnostic workup of a patient is by definition determined by previous diagnostic (test) results. Therefore, routinely documented data are subject to so-called workup bias. Third, in practice, the reference test is always interpreted with knowledge of the preceding test information, such that in scientific studies using routine data the diagnostic value of a test under evaluation is commonly overestimated. Fourth, routinely documented databases are likely to suffer from missing data. Per problem we discuss methods that are presently available and may (partly) overcome each problem. All this could contribute to more frequent and appropriate use of routine care data in diagnostic research. The discussed methods to overcome the above problems may well be similarly useful to prospective diagnostic studies.

Sequelae after bacterial meningitis in childhood

The neurological outcome of bacterial meningitis in children was evaluated retrospectively. Data were obtained from a large study on children aged between 1 month and 15 y who initially visited the emergency department of Sophia Children's Hospital, Rotterdam, The Netherlands with meningeal signs. This study presents data from 103 patients in whom bacterial meningitis was diagnosed. Neisseria meningitidis was the dominant pathogen of meningitis. We found a 2% case-fatality rate in children with bacterial meningitis and a 13% rate of sequelae among survivors: 7% hearing impairment and 7% neurological sequelae. Children with bacterial meningitis caused by Streptococcus pneumoniae and those with acute focal neurological symptoms tended to have the worst prognosis.

Early prediction of neurological sequelae or death after bacterial meningitis

This study determined independent predictors of the occurrence of permanent neurological sequelae or death after childhood bacterial meningitis. Data were used from a large study on children (aged 1 mo to 15 y) initially presenting with meningeal irritation. A nested case-control study was performed on children with (n = 23) and without (n = 70) permanent neurological sequelae (hearing impairment, locomotor dysfunction, mental retardation or epilepsy) or death after bacterial meningitis. Predictors obtained from clinical evaluation and laboratory tests at presentation and during the clinical course were identified by multivariate logistic regression and receiver operating characteristic (ROC) curve analyses. The study population comprised 23 cases and 70 controls (52% boys, median age 2.8 y). Independent predictors for an adverse outcome after bacterial meningitis were male gender, atypical convulsions in history, low body temperature at admission and the pathogen Streptococcus pneumoniae. The area under the ROC curve of this prediction rule was 0.87 (95% confidence interval: 0.78-0.96), which was not improved by adding other characteristics. A score including these independent predictors could classify patients into categories with increasing risk for an adverse outcome.

CONCLUSION

Clinical characteristics available early in the clinical course, such as gender, atypical convulsions in history, low body temperature at admission and the pathogen, are predictive for the occurrence of permanent neurological sequelae or death after bacterial meningitis in childhood. The pathogen type, in particular, is the main prognostic determinant of childhood bacterial meningitis.

Cost-utility analysis of patient care in children with meningeal signs

OBJECTIVES

We designed a model of diagnostic and therapeutic interventions applied in children with meningeal signs. Using this model, we determined in a cost-utility analysis the consequences for society of different diagnostic strategies in terms of quality-adjusted life-years (QALYs) and costs.

METHODS

Data were used from 360 children (0.1-15 years) visiting the pediatric emergency department of the Sophia Children's Hospital Rotterdam, The Netherlands (1988-98) with meningeal signs. Model inputs included probabilities of meningitis and adverse outcome, QALYs for years lived with long-term sequelae, and costs of tests and treatments. Mean outcome measures were costs and effects of diagnostic and therapeutic interventions in children suspected of bacterial meningitis, key determinants of the model outcomes, and evaluation of alternative diagnostic strategies and two vaccination programs in an analysis.

RESULTS

The population comprised 99 children with bacterial meningitis (adverse outcome in 10), 36 with serious other bacterial infections, and 225 with self-limiting diseases. Key determinants were the risk of bacterial meningitis or sequelae, costs of treatment, and long-term morbidity. Minimizing lumbar punctures and empirical treatments using a diagnostic decision rule, without missing a single case of meningitis, was a dominant strategy to actual practice. Vaccination strategies of Streptococcus pneumoniae and Neisseria meningitidis resulted in our model in incremental cost-utility ratios of 401,965 Euro dollar ([symbol: see text])/QALY and [symbol: see text]22,635/QALY, respectively.

CONCLUSIONS

Costs of long-term morbidity of bacterial meningitis largely outweigh diagnostic and treatment costs. Modeling interventions in children at risk of bacterial meningitis should include long-term consequences in terms of costs and QALYs.

Prediction of duration of hospitalization in respiratory syncytial virus infection

Identification of variables that predict duration of RSV-associated hospitalization may be useful in the identification of preventive and therapeutic strategies. A recently published prediction model (Michigan model) for the duration of hospitalization in RSV infection demonstrated good discrimination between children with and without an increased likelihood of a hospital stay >or= 7 days, based on variables such as log weight, congenital heart disease, failure to thrive, premature birth, bronchopulmonary dysplasia, other pulmonary diseases, miscellaneous conditions, early mechanical ventilation, and early ribavirin treatment (receiver operating characteristic (ROC) area, 0.89). Validation of this model is of particular interest for Europe, since the mean duration of hospitalization in The Netherlands is approximately twice that in the USA. The objective of the current study was 1) to validate the Michigan model for RSV hospitalized patients in a large university hospital in The Netherlands, and 2) to develop our own prediction model for a prolonged hospital stay. Data from 177 children younger than 12 months of age admitted with confirmed RSV infection to the Sophia Children's Hospital Rotterdam between 1992-1995, were used for valiation of the Michigan model and derivation of the Rotterdam model. Mean duration of hospitalization for the Rotterdam database was 10.3 (+/-6.3) days, with a median of 9 days; 138 (78%) patients had a hospital stay >or= 7 days. The Michigan model performed poorly when applied to the Rotterdam database, with an ROC area of 0.65 (95% CI, 0.57-0.73). The Rotterdam prediction model (hospital stay >or= 9 days, the median in our database) considered weight and need for oxygen supplementation. The ROC area was 0.65 (95% CI, 0.57-0.73). When using data from patients for the 1995-1996 season, the ROC area was 0.52 (95% CI, 0.34-0.72). The Michigan and the Rotterdam models failed to identify a considerable number of patients who had a prolonged hospital stay, with a low false-positive rate. We conclude that neither the Michigan, nor the Rotterdam model reliably predicted the duration of hospitalization based on demographic and clinical variables.

[Young child with fever of unknown origin in the 'post Haemophilus influenzae era']

A 2.5-year-old boy and a 2-month-old girl presented with fever without an apparent source. Additional laboratory tests were requested due to alarming signs for the presence of a serious bacterial infection. Pneumonia and viral meningitis respectively were diagnosed, and adequate therapy led to a quick and complete recovery. Due to changing prospects following the near eradication of invasive Haemophilus influenzae type b (Hib) infections by vaccination, there are no suitable guidelines at present concerning fever without an apparent source in children. A selection of patients at risk can first of all be made based on patient history and a physical examination and secondly by carrying out additional laboratory tests. Furthermore, careful evaluation, clinical acumen, well-informed parents and observation are all important elements in the treatment of these patients.

Predicting serious bacterial infection in young children with fever without apparent source

The aim of this study was to design a clinical rule to predict the presence of a serious bacterial infection in children with fever without apparent source. Information was collected from the records of children aged 1-36 mo who attended the paediatric emergency department because of fever without source (temperature > or = 38 degrees C and no apparent source found after evaluation by a general practitioner or history by a paediatrician). Serious bacterial infection included bacterial meningitis, sepsis, bacteraemia, pneumonia, urinary tract infection, bacterial gastroenteritis, osteomyelitis and ethmoiditis. Using multivariate logistic regression and the area under the receiver operating characteristic curve (ROC area), the diagnostic value of predictors for serious bacterial infection was judged, resulting in a risk stratification. Twenty-five percent of the 231 patients enrolled in the study (mean age 1.1 y) had a serious bacterial infection. Independent predictors from history and examination included duration of fever, poor micturition, vomiting, age, temperature < 36.7 degrees C or > or = 40 degrees C at examination, chest-wall retractions and poor peripheral circulation (ROC area: 0.75). Independent predictors from laboratory tests were white blood cell count, serum C-reactive protein and the presence of >70 white blood cells in urinalysis (ROC area: 0.83). The risk stratification for serious bacterial infection ranged from 6% to 92%.

CONCLUSION

The probability of a serious bacterial infection in the individual patient with fever without source can be estimated more precisely by using a limited number of symptoms, signs and laboratory tests.

[Few ethnic differences in acute pediatric problems: 10 years of acute care in the Sophia Children's Hospital in Rotterdam]]

OBJECTIVE

To evaluate whether there are differences in acute general paediatric problems and their severity between children with different ethnic backgrounds.

DESIGN

Descriptive.

METHOD

The following information was registered for patients who visited the paediatric emergency department at the Sophia Children's Hospital in Rotterdam, the Netherlands (1988 through to 1997): demographics, reason for encounter, diagnoses, diagnostics performed and follow-up. Ethnicity was determined by patient's surname. Analyses were performed using the chi 2 test, non-parametric Kruskal-Wallis test and multiple logistic regression.

RESULTS

Fifty-one percent of all patients belonged to one of the ethnic minority groups. Infection-related problems were seen more often in Turkish (45%) and Moroccan (46%) children than in Dutch children (41%). Of those children with infection-related problems, the Turkish children were less likely to need X-rays (odds ratio: 0.73), laboratory diagnostics (0.72), an outpatient follow-up (0.79) or hospital admission (0.74). On the other hand, Moroccan paediatric patients were admitted slightly more frequently (to the intensive care department) and were more likely to have a lower respiratory tract infection (1.65).

CONCLUSIONS

There were some differences between Dutch children and ethnic minorities in terms of the reasons for encounter and the severity of the problem. Compared with Dutch children, Turkish children presented with less severe infection-related problems, while Moroccan children had more severe infection problems.

Respiratory tract infections by Mycoplasma pneumoniae in children: a review of diagnostic and therapeutic measures

This review discusses the current knowledge on laboratory tests and treatment of respiratory tract infections caused by Mycoplasma pneumoniae (MP) in children. MP infection is endemic in most areas of the world. The highest incidence is seen in children aged between 3 and 14 years. Most infections are mild and non-pneumonic. Parapneumonic complications of MP pneumonia are rare. Complications are described affecting the skin, central nervous system, kidneys, heart, muscles and the eyes. To diagnose an acute MP infection in children, a combination of PCR and IgM serology is sensitive and convenient. In both tests it is possible to obtain a result in 1 to 2 days. As a consequence, adequate antibiotic treatment can be prescribed to the child. Macrolides are the first choice in treatment of MP infection in children.

CONCLUSION

The most sensitive and rapid test to diagnose a Mycoplasma pneumoniae infection in children is a combination of nasopharyngeal polymerase chain reaction and IgM enzyme immunoassay. The treatment of choice in children is a macrolide.

Prediction of bacterial meningitis in children with meningeal signs: reduction of lumbar punctures

Physicians often have to perform a lumbar puncture to ascertain the diagnosis in patients with meningeal signs, because of the serious consequences of missing bacterial meningitis. The aim of this study was to derive and validate a clinical rule to predict bacterial meningitis in children with meningeal signs, to guide decisions on the performance of lumbar punctures. Information was collected from records of patients (aged 1 mo to 15 y) consulting the emergency department of the Sophia Children's Hospital between 1988 and 1998 with meningeal signs. Bacterial meningitis was defined as cerebrospinal fluid (CSF) leucocyte count >5 cells microl(-1) with a positive bacterial culture of CSF or blood. The diagnostic value of predictors was judged using multivariate logistic modelling and area under the receiver operating characteristic curves (ROC area). In the derivation set (286 patients, years 1988-1995) the duration of the main complaint, vomiting, meningeal irritation, cyanosis, petechiae and disturbed consciousness were independent clinical predictors of bacterial meningitis. The ROC area of this model was 0.92. The only independent predictor from subsequent laboratory tests was the serum C-reactive protein concentration, increasing the ROC area to 0.95. Without missing a single case, this final model identified 99 patients (35%) without bacterial meningitis. Validation on 74 consecutive patients in 3 subsequent years (1996-1998) yielded similar results.

CONCLUSION

This prediction rule identifies about 35% of the patients with meningeal signs in whom a lumbar puncture can be withheld without missing a single case of bacterial meningitis. For the individual patient this prediction rule is valuable in deciding whether or not to perform a lumbar puncture.

Signs of meningeal irritation at the emergency department: how often bacterial meningitis?

OBJECTIVE

Although signs of meningeal irritation are highly indicative of meningitis, they are not pathognomonic. In this study, we described the final diagnoses in children with signs of meningeal irritation, and we assessed the frequency of bacterial meningitis related to specific signs of meningeal irritation.

METHODS

Information was collected from records of 326 patients (aged 1 month to 15 years) who visited the emergency department of the Sophia Children's Hospital between 1988 and 1998 with signs of meningeal irritation, assessed by either the general practitioner or the pediatrician.

RESULTS

Bacterial meningitis was diagnosed in 99 patients (30%), viral or aseptic meningitis in 43 (13%). Other diagnoses were pneumonia (8%), other serious bacterial infections (2%), and upper respiratory tract infections or other self-limiting diseases (46 %). Presence of one of the signs of meningeal irritation assessed by the pediatrician was related to bacterial meningitis in 39%. Specific tests eliciting meningeal irritation, such as Brudzinski's and Kernig's signs, were not related to a higher frequency of bacterial meningitis than neck stiffness and the tripod phenomenon. In children < or =1 year, bacterial meningitis is more frequently related to presence of irritability and a bulging fontanel.

CONCLUSION

Bacterial meningitis is present in 30% of children with signs of meningeal irritation. Presence of meningeal irritation as assessed by the pediatrician is related to bacterial meningitis in 39%. A better prediction of bacterial meningitis was not achieved by using more specific tests for signs of meningeal irritation.

Predictors of a normal chest x-ray in respiratory syncytial virus infection

Respiratory syncytial virus (RSV) accounts for the majority of lower respiratory tract infections (LRTI) in infants and young children. A chest x-ray is frequently performed in infants with LRTI caused by RSV. The aim of this study was to develop and validate a prediction model to estimate the probability for a normal chest x-ray in children with RSV infection. For this purpose, easy obtainable diagnostic parameters were used. This prediction model may be applied to decide which patients do not require a chest x-ray. The data of 287 children admitted with RSV infection or diagnosed as such in the outpatient department of the Sophia Children's Hospital between 1992-1996 were studied. The derivation set comprised 232 patients (1992-1995), and the validation set contained 55 patients (1995-1996). A chest x-ray was designated as normal when atelectasis, hyperinflation, or pulmonary infiltrates were absent. In order to develop a prediction model, patient history and clinical and laboratory variables were consecutively entered into a logistic regression model according to the diagnostic workup that was practiced at the time. Variables with P < or = 0.10 were retained in the model. The predictive accuracy of the multivariable models was examined using the area under receiver operating curve (ROC-area). In 202 (87%) patients from the derivation set, a chest x-ray was performed. A normal chest x-ray could be predicted by increasing age, increasing birth weight, presence of rhinitis, absence of retractions, and increasing arterial oxygen saturation. The ROC-area was 0.80 in the derivation and validation sets. This prediction model was transformed into a score chart. In conclusion, a normal chest x-ray can accurately be predicted, using a model including easily obtainable patient characteristics, and clinical and laboratory variables. This model may be a useful tool in deciding whether or not to perform a chest x-ray in patients with RSV infections.

Efficacy, safety and tolerability of 3 day azithromycin versus 10 day co-amoxiclav in the treatment of children with acute lower respiratory tract infections

To compare the efficacy, safety and tolerability of a 3 day course of azithromycin with a 10 day course of co-amoxiclav in the treatment of children with acute lower respiratory tract infection (LRTI), 118 patients with community-acquired LRTI were included in a multicentre randomized double-blind, double-dummy study. The diagnosis of LRTI was based on the presence of respiratory signs and symptoms in combination with consolidation on a chest radiograph or clinical evidence of LRTI. Patients received oral azithromycin suspension (10 mg/kg/24 h) or placebo in one dose for 3 days and co-amoxiclav (45/11.25 mg/kg/24 h) or placebo in three doses for 10 days. Of 110 eligible patients, 56 and 54 patients, respectively, were treated with azithromycin or co-amoxiclav. The percentage of patients cured or clinically improved at days 10-13 (primary endpoint) was 91% for azithromycin and 87% for co-amoxiclav. This difference of 4% (90% confidence interval: -6%, +14%) was not statistically significant (P= 0.55). Significantly (P = 0.01) more related adverse events were found in the co-amoxiclav group. This was largely due to a higher percentage (43% versus 19%) of gastrointestinal complaints. A 3 day course of azithromycin (three doses) is as effective in the treatment of LRTI in children as a 10 day course of co-amoxiclav (30 doses). The azithromycin group had fewer adverse events. We conclude that azithromycin is an effective, safe and well-tolerated drug in the treatment of children with LRTI. An additional advantage is the easy administration and short duration of therapy.

Type 1-like immune response is found in children with respiratory syncytial virus infection regardless of clinical severity

The immunological response of infants younger than six months to infection with respiratory syncytial virus (RSV) was studied in relation to clinical severity. IL-6 and IL-8 were found more frequently and at higher levels in the plasma samples of more severely ill patients and no significant differences were found in the levels of cytokines differentiating between Type 1 and Type 2 responses. Cellular infiltrates in nasopharyngeal washings consisted mainly of polymorphonuclear granulocytes and monocytes. Eosinophils, IgE positive cells and tryptase positive cells were found sporadically. Analyses of RSV stimulated T cell cultures established from peripheral blood mononuclear cells, for intracellular and secreted cytokines showed that, irrespective of clinical severity, the responses were dominated by the production of IFN-gamma, and that only low levels of IL-4 and IL-10 were detectable. Collectively these data do not indicate an association between clinical severity and a Type 2-like T cell response.

G protein variation in respiratory syncytial virus group A does not correlate with clinical severity

Respiratory syncytial virus group A strain variations of 28 isolates from The Netherlands collected during three consecutive seasons were studied by analyzing G protein sequences. Several lineages circulated repeatedly and simultaneously during the respective seasons. No relationships were found between lineages on the one hand and clinical severity or age on the other.

Prediction of vesico-ureteric reflux in childhood urinary tract infection: a multivariate approach

In this study, independent predictors obtained from patient history, physical examination and laboratory results for vesico-ureteric reflux (VUR) in children of 0-5 y with a first urinary tract infection (UTI) were assessed and the added value of renal ultrasound (US) investigated. Information was collected from children visiting the paediatric outpatient department with a first proven UTI, defined as a urine monoculture with > or = 10(5) organism/ml, with clinical symptoms and possible white cell count > or = 20 per high-power field of spun fresh urine. Children with neurologic bladder dysfunction were excluded. VUR was determined by voiding cystourethrography (VCUG) and graded from I to V. The diagnostic value of predictors was judged using multivariate logistic modelling with the area under the receiver operating characteristic (ROC area). A risk score was derived based on the regression coefficients of the independent predictors in the logistic model. In 140 children (51 boys and 89 girls) VUR was diagnosed in 37. Independent predictors for VUR were male gender, age, family history for uropathology, serum C-reactive protein level (CRP) and dilatation of the urinary tract on US. The ROC area of this model was 0.78 (95% CI: 0.69-0.87). This prediction model identified 12% (95% CI: 7-18) of the patients without VUR without missing one case of VUR. If we used VUR > or = grade 3 as a threshold, the model assessed VUR to be absent in 34% (95% CI: 26-42).

CONCLUSION

A prediction rule based on age, gender, family history, CRP and US results is useful in assessing the probability of VUR in the individual child with a first UTI and may help the physician to make decisions about performing additional imaging techniques. Prospective validation of the model in future patients, however, will be necessary before applying the rule in practice.

Long-term effects of respiratory syncytial virus (RSV) bronchiolitis in infants and young children: a quantitative review

One of the major questions regarding long-term side effects of bronchiolitis by respiratory syncytial virus (RSV) is whether or not it induces asthma in later life. In this quantitative review, the data of 10 controlled studies are analysed.

METHODS

Follow-up studies of RSV bronchiolitis published between January 1978 and December 1998 were identified through a MEDLINE search. Studies were selected if (i) postnatal age at the time of the initial illness was below 12 mo, (ii) all children were hospitalized for RSV bronchiolitis, (iii) the diagnosis RSV was virologically confirmed in all cases, and (iv) a control group was used.

RESULTS

Six studies met all selection criteria. Up to 5 y of follow-up after RSV bronchiolitis in infancy, 40% of children reported wheezing as compared to only 11% in the control group (p <0.001). Between 5 and 10 y of follow-up 22% of the bronchiolitis group reported wheezing against 10% of the control group (p = 0.19). The incidence of recurrent wheezing as defined by three or more wheezing episodes also decreased with increasing years of follow-up: at 5 or more years of follow-up the difference between the RSV group and the control group was no longer significant. Furthermore, the presence of either a personal and/or a family history of either atopy and/or asthma did not differ between the two groups.

CONCLUSIONS

Wheezing is common after RSV bronchiolitis in infancy. It may persist for > or = 5 y of follow-up. However, no significant difference between the RSV bronchiolitis and the control group was observed regarding recurrent wheezing by 5 y of follow-up. No significant difference between the RSV bronchiolitis and the control group were found regarding a personal history of atopy, a family history of atopy and/or asthma. Therefore it seems unlikely that RSV bronchiolitis is a cause of atopic asthma in later life.