Association of duration of television viewing in early childhood with the subsequent development of asthma.

OBJECTIVE: To investigate whether duration of television (TV) viewing in young children is associated with subsequent development of asthma. METHODS: Children taking part in the Avon Longitudinal Study of Parents and Children (ALSPAC) with no wheeze up to the age of 3.5 years and follow-up data at 11.5 years of age took part in a prospective longitudinal cohort study. The main outcome measure was asthma, defined as doctor-diagnosed asthma by 7.5 years of age with symptoms and/or treatment in the previous 12 months at 11.5 years of age. Parental report of hours of TV viewing per day by the children was ascertained at 39 months. RESULTS: In children with no symptoms of wheeze at 3.5 years of age and follow-up data at 11.5 years of age, the prevalence of asthma was 6% (185/3065). Increased TV viewing at 3.5 years was associated with increased prevalence of asthma at 11.5 years of age (p for linear trend = 0.0003). Children who watched television for >2 h/day were almost twice as likely to develop asthma by 11.5 years of age as those watching TV for 1-2 h/day (adjusted odds ratio 1.8 (95% CI 1.2 to 2.6)). CONCLUSION: Longer duration of TV viewing in children with no symptoms of wheeze at 3.5 years of age was associated with the development of asthma in later childhood.

Definition, assessment and treatment of wheezing disorders in preschool children: an evidence-based approach.

There is poor agreement on definitions of different phenotypes of preschool wheezing disorders. The present Task Force proposes to use the terms episodic (viral) wheeze to describe children who wheeze intermittently and are well between episodes, and multiple-trigger wheeze for children who wheeze both during and outside discrete episodes. Investigations are only needed when in doubt about the diagnosis. Based on the limited evidence available, inhaled short-acting beta(2)-agonists by metered-dose inhaler/spacer combination are recommended for symptomatic relief. Educating parents regarding causative factors and treatment is useful. Exposure to tobacco smoke should be avoided; allergen avoidance may be considered when sensitisation has been established. Maintenance treatment with inhaled corticosteroids is recommended for multiple-trigger wheeze; benefits are often small. Montelukast is recommended for the treatment of episodic (viral) wheeze and can be started when symptoms of a viral cold develop. Given the large overlap in phenotypes, and the fact that patients can move from one phenotype to another, inhaled corticosteroids and montelukast may be considered on a trial basis in almost any preschool child with recurrent wheeze, but should be discontinued if there is no clear clinical benefit. Large well-designed randomised controlled trials with clear descriptions of patients are needed to improve the present recommendations on the treatment of these common syndromes.

Reversible chronic pulmonary fibrosis associated with MMF in a pediatric patient: a case report.

We describe a case of chronic mineralizing pulmonary elastosis in a seven-yr-old boy following DD renal transplantation for Wilms tumour. Fourteen months post-transplantation he developed respiratory symptoms with lung biopsy demonstrating chronic mineralizing pulmonary elastosis thought to be secondary to immunosuppression with MMF. Symptomatic resolution occurred following MMF cessation.

Standardizing lung function laboratories for multicenter trials.

Multi-center studies provide advantages in clinical research but differences between centers can introduce bias. Three specialist pediatric respiratory laboratories standardized their methodology and examined differences between centers. The specific aims were to (i) assess the variability of measurements on adults within and between centers and (ii) to exchange and cross-analyze data from children to assess the extent of agreement between centers. Each laboratory used identical equipment and software. Inter-laboratory visits were used to (i) standardize protocols for data collection and analysis and (ii) make spirometric and plethysmographic measurements on participating staff at each location. Staff also had repeat measurements in their home laboratories. Measurements from children in each laboratory were exchanged on disk, cross-analyzed, and data compared by ANOVA. There were no significant within-subject, between-center differences in FVC, FEV1, FEF50, FRCpleth, or VC. There was a slight trend for TLC and RV (P=0.07) to be higher at one center. The 95% limits of agreement within and between centers were similar for all parameters. There were no differences between centers in cross-analyzed data from 10 children. By standardizing hardware, software, and protocol, potential inter-laboratory differences can be minimized. We recommend that this approach be adopted prior to multi-center studies.

Total energy expenditure and physical activity in young Scottish children: mixed longitudinal study.

Childhood obesity has been attributed to a decline in total energy expenditure (TEE). We measured TEE, physical activity, and sedentary behaviour in a representative sample of young children from Glasgow, UK, at age 3 years (n=78), and we did a follow-up study at age 5 years (n=72). Mean physical activity level (TEE/resting energy expenditure) was 1.56 (SD 0.39) at age 3 years and 1.61 (0.22) at age 5 years. Median time in sedentary behaviour was 79% of monitored hours at age 3 years (IQR 74-84) and 76% (71-80) at age 5 years. Median time spent in moderate to vigorous physical activity represented only 2% of monitored hours at age 3 years (IQR 1-4) and 4% at age 5 years (2-6). Modern British children establish a sedentary lifestyle at an early age.

Low physical activity levels and high levels of sedentary behaviour are characteristic of rural Irish primary school children.

There is increasing public health concern that levels of physical activity in children are extremely low. This study aimed to describe objectively levels of physical activity and sedentary behaviour during the waking hours in a sample of 4-5 year old (median 5.4 years range 4.3, 6.0) rural Irish children (n=41) and to test for gender differences in patterns of physical activity and sedentary behaviour. There were significant gender differences in physical activity (Boys (median) 834 accelerometer counts per minute (cpm), girls (median) 628cpm; p = 0.0015), sedentary behaviour (Boys 74% of waking time, girls 81% of waking time, p=0.0011) and moderate-vigorous physical activity (Boys 4% of waking time, girls 2% of waking time; p=0.0175). This study that suggests young rural Irish children lead sedentary lifestyles.

Pilot study of objective cough monitoring in infants.

Cough is common in childhood, resulting in significant morbidity and frequent medical consultation. Despite this, little is known about the frequency or development of cough, particularly in infants and young children. Recent progress in monitoring has enabled cough to be measured objectively both day and night. However, to date, objective measurement has only been used in adults and older children. The aim of this study was to see whether such methods could be extended to allow objective cough monitoring in infants. Thirty infants were recruited: 13 with coughing illnesses (group 1), and 17 normal, healthy babies (group 2) born to nonatopic, nonsmoking parents. Group 2 infants were studied when well, several times in the first year of life. Coughs were recorded using an adapted commercial cough monitor (Logan Research LR100) and simultaneous infrared video and sound recording. Thirty-eight recordings with simultaneous cough monitor and video data were analyzed: 9 from group 1, and 29 from group 2. Overall, the sensitivity of the monitor when compared to video was 81%, with a positive predictive value of 0.8. There was good agreement between the two methods for infants with infrequent cough (<5 coughs per hour). Agreement in infants with more frequent cough was not as good, because more coughs were consistently identified by the cough monitor. The portability and small size of the cough monitor made it easy to use, although there were difficulties in keeping the leads attached in older, more mobile infants. In conclusion, objective assessment of cough is practical in infants, enabling the pattern of cough in illness and in health to be studied further.

Subcutaneous emphysema secondary to foreign-body aspiration.

Pneumomediastinum is uncommon in pediatric medical practice, outside the neonatal period. While asthma or respiratory infections are the most frequent underlying causes, it is important not to forget the possibility of foreign body aspiration, particularly after the clinical presentation.

Beta 2-agonists and running economy in prepubertal boys.

Asthmatic athletes (adults and junior) have competed successfully at the highest level for many years assisted by pre-event medication with beta 2-agonists. To examine the impact of beta 2-agonists upon submaximal running economy (oxygen consumption at a given submaximal work load), we studied 10 nonasthmatic boys (age, 10.4 +/- 0.48 years, mean +/- SD). They each completed submaximal (speeds, 7.2, 8.0 and 8.8 km/hr) and peak treadmill running protocols preceded by treatment with beta 2-agonist (terbutaline, 500 micrograms via nebuhaler) or placebo in a randomized, crossover single-blind study. No significant differences were found between running economy and heart rate during the submaximal exercise tests or between peak oxygen consumption (VO2), peak respiratory exchange ratio, peak heart rate (HR), or total running time during the peak VO2 test. Pretreatment with terbutaline did produce small but nonsignificant increases in aerobic fractional utilization (percent peak VO2 on drug: 65.9%, 72.6%, and 76.7% vs. placebo: 65.1%, 70%, and 75.5%), at the three submaximal work loads. Respiratory exchange ratio (RER) values were elevated throughout the submaximal tests (on drug: 0.94, 0.93, and 0.94 vs placebo: 0.91, 0.92, and 0.91, P < 0.05). No significant differences were found between drug and placebo for minute ventilation (VE) and ventilatory equivalent for oxygen (VE/VO2), at both submaximal and peak exercise intensities.(ABSTRACT TRUNCATED AT 250 WORDS)

Digital clubbing and pulmonary function abnormalities in children with lung disease.

Digital clubbing and pulmonary function tests were measured in children, adolescents, and adults with chronic lung diseases to determine pulmonary function correlates with a quantitative measure of clubbing. The group had a mean age of 13.8 +/- 6.0 (SD) years, mean PaO2 of 81 +/- 21 mm Hg, and mean FEV1 of 60% +/- 26% predicted. Digital clubbing was diagnosed in 43 cases when the distal phalangeal depth to interphalangeal depth (DPD/IPD) ratio, measured on a finger cast, was greater than or equal to 1 (greater than 3 SD above mean from 85 controls; no history of pulmonary disease; mean age, 14.8 +/- 7.6). The PaO2 of patients with digital clubbing was 69.4 +/- 2.1 (SEM) mm Hg compared with 88.3 +/- 1.3 mm Hg in those without digital clubbing (P less than 0.0001). Digital clubbing was present in 39 of the 84 (46%) hypoxic patients (PaO2 less than or equal to 88) but only four of the 78 (5%) normoxic patients (P less than 0.0001). The DPD/IPD ratio was negatively correlated with PaO2 in subjects with cystic fibrosis and interstitial fibrosis. Weak negative correlations were seen for all other subjects except asthmatics. Overall, the DPD/IPD ratio was significantly correlated with PaO2 (r = -0.53; P less than 0.0001). The DPD/IPD ratio was correlated with other lung function abnormalities (increased RV, decreased FEV1, and FEF25%-75%) only for the subjects with cystic fibrosis. We conclude that digital clubbing is associated with hypoxemia and airway obstruction. The relation is seen most clearly in subjects with cystic fibrosis, possibly reflecting the prolonged duration of hypoxemia. Digital clubbing is rarely seen in normoxic subjects.

Flexible bronchoscopy under 10 kg.

We report 35 bronchoscopies performed in 27 post-neonatal subjects weighing less than 10 kg using an Olympus BC3F20 (3.5 mm diameter) bronchoscope. Twenty-three procedures were performed primarily for investigation of airway anatomy and 12 primarily for broncho-alveolar lavage. Mild oxygen desaturation responsive to increased O2 administration was common. Major complications were infrequent with two children developing lower respiratory tract infection and one patient requiring ventilation overnight. The diagnostic yield was high with 76% of studies in children suspected of airway anomalies proving positive. We conclude that bronchoscopy in this age group is well tolerated and identifies a significant number of abnormalities.

Resting heart rate definition and its effect on apparent levels of physical activity in young children.

PURPOSE: Heart rate monitoring is widely used to measure physical activity in children, but it may be dependent on the definition of resting heart rate used and the protocol used to measure or derive resting heart rate (RHR). The aim of this study was to determine the effect of RHR definition on activity levels assessed by PAHR-25 (% time at >25% of RHR), PAHR-50 (% time at >50% of RHR), and activity heart rate (AHR; mean HR minus RHR). METHODS: Minute-to-minute heart rates were measured over 3 d in 20 healthy preschool children aged 3-4 yr. Resting heart rate was measured for 5 min after a 10-min rest and was also derived from the following different but commonly used protocols: 1) mean of lowest heart rate plus all heart rates within three beats; 2) mean of lowest 5; 3) lowest 10; 4) lowest 50. This gave five different definitions of RHR. Differences in RHR and in the derived indices of activity among definitions were tested for agreement using a Bland-Altman analysis, and by rank order correlation. RESULTS: Differences in RHR among all definitions were statistically significant. These resulted in significant differences in apparent physical activity levels: PAHR-25 varied 10-50% depending on the protocol used to define RHR; PAHR-50 varied by 16-65% as a function of the protocol used to define RHR. However, the different definitions of RHR had no significant influence on physical activity level when children were rank ordered. CONCLUSION: Choice of method for defining RHR has a profound effect on the apparent level of activity of children. This does not alter the relative assessment of activity by rank order. A consensus definition of RHR is desirable if comparisons of activity levels between samples or populations are to be made and if the adequacy of physical activity levels is to be assessed using heart rate.

The rapid diagnosis and clinical features of human herpesvirus 6.

Since human herpesvirus 6 (HHV6) was first linked with exanthem subitum in 1988 there has been increasing evidence that the morbidity associated with acute HHV6 infection may be more significant and variable. However, the clinical appreciation of HHV6 infection has been hampered by the lack of rapid and clinically useful diagnostic methods. In this prospective study of hospitalized febrile children under 3 years of age we compared three rapid viral diagnostic methods, (polymerase chain reaction assay (PCR), IgM serology and direct antigen detection), with conventional serology on paired serum samples. In addition, we documented the range of clinical features associated with acute HHV6 infection. Of 67 children recruited, 11 (16%) had evidence of acute HHV6 infection: six had detectable, specific, IgM; four were PCR positive; and one was PCR positive with IgM. Direct antigen testing on batched frozen samples detected no infections. Apart from high fever (median peak 38.5 degrees C), common features were non-specific. Two children had febrile convulsions and only one child had a non-specific rash. We conclude that rapid microbiological diagnosis at present requires two tests (IgM and PCR). HHV6 is a common cause of febrile illness in hospitalized infants with no rash and should be considered in their diagnosis.

Submaximal running economy in run-trained pre-pubertal boys.

There is an increasing tendency for young children to participate in training and competitive running. The impact long-term training has upon stimulating functional physiological adaptation has yet to be fully understood. In this study cardio-respiratory and kinematic differences were assessed at submaximal and maximal exercise intensities in run-trained and non-run-trained boys. Thirty three pre-pubertal boys volunteered to take part in the study. The subjects were in two groups: 15 run-trained subjects [age 11.7 +/- 1.06 yrs, mean +/- SD] and 18 non-run-trained (control) subjects [age 11.3 +/- 0.90 yrs]. Two separate (4 x 3 min) submaximal protocols were used for the trained and non-run-trained groups, with two of the speeds overlapping for comparison purposes. In addition, all boys also performed a maximal oxygen consumption test. Mean VO2max value for the run trained group was 60.5 +/- 3.3 ml/kg/min and for the control group 51.1 +/- 4.3 ml/kg/min, (p < 0.001). No significant differences were found for submaximal running economy at either comparison speed. In addition, no significant (p > 0.05) differences were noted between the groups for any of the kinematic variables at the two comparison speeds. However, selected physiological differences did exist at the submaximal running speeds. The source of the differences that did exist between the two groups may be the result of training, genetic pre-selection or developmental differences between the groups.

Current status of long term ventilation of children in the United Kingdom: questionnaire survey.

OBJECTIVES: To identify the number and current location of children, aged 0 to 16 years, requiring long term ventilation in the United Kingdom, and to establish their underlying diagnoses and ventilatory needs. DESIGN: Postal questionnaires sent to consultant respiratory paediatricians and all lead clinicians of intensive care and special care baby units in the United Kingdom. SUBJECTS: All children in the United Kingdom who, when medically stable, continue to need a mechanical aid for breathing. RESULTS: 141 children requiring long term ventilation were identified from the initial questionnaire. Detailed information was then obtained on 136 children from 30 units. Thirty three children (24%) required continuous positive pressure ventilation by tracheostomy over 24 hours, and 103 received ventilation when asleep by a non-invasive mask (n=62; 46%), tracheostomy (n=32; 24%), or negative pressure ventilation (n=9; 7%). Underlying conditions included neuromuscular disease (n=62; 46%), congenital central hypoventilation syndrome (n=18; 13%), spinal injury (n=16; 12%), craniofacial syndromes (n=9; 7%), bronchopulmonary dysplasia (n=6; 4%), and others (n=25; 18%). 93 children were cared for at home. 43 children remained in hospital because of home circumstances, inadequate funding, or lack of provision of home carers. 96 children were of school age and 43 were attending mainstream school. CONCLUSIONS: A significant increase in the number of children requiring long term ventilation in the United Kingdom has occurred over the past decade. Contributing factors include improved technology, developments in paediatric non-invasive ventilatory support, and a change in attitude towards home care. Successful discharge home and return to school is occurring even for severely disabled patients. Funding and home carers are common obstacles to discharge.

Measured bronchodilator use in preschool children with asthma.

OBJECTIVE: To investigate how parents use bronchodilator treatment for relief of symptoms when treating their asthmatic preschool children. DESIGN: A commercial electromechanical timer device was attached to a large volume spacer to record the time and date of each use of inhaled bronchodilator over two months. The recorded time and dates were compared with symptoms noted in an asthma diary card. SETTING: Large paediatric teaching hospital in Glasgow. SUBJECTS: 29 preschool children with moderately severe asthma attending a specialist paediatric asthma clinic. MAIN OUTCOME MEASURES: Inhaler use measured by the timer device; symptoms and inhaler use recorded by parents in a daily asthma diary. RESULTS: Satisfactory data were obtained in 22 of the 29 children; the median number of study days was 53 (range 18-77). Asthmatic symptoms were recorded on a median of 30 (3-77) days. Bronchodilator was used on a median of 19 (2-73) days, or on 63% (7-100%) of days when symptoms occurred. The median number of puffs used in a day was 1 (range 0-100) and was significantly related to symptom severity in only 14 of the 22 children. In only two of the 22 children was bronchodilator given more frequently than four hourly, and only five children ever used more than 12 puffs a day. CONCLUSIONS: The frequency of parental administration of bronchodilator treatment was variable and not closely related to the parent's record of symptom severity. Parents often recorded symptoms in their children but did not treat them.

Home nebuliser use in children with asthma in two Scottish Health Board Areas.

OBJECTIVE: To audit the use of home nebulisers in children with asthma. DESIGN: Postal questionnaire. SETTING: Two Health Board Areas in Central Scotland--one large industrialised city, one mixed urban and rural. SUBJECTS: 297 children with asthma. MEASURES EVALUATED: Initial supply and technical support for the compressor. EDUCATION: Pattern of drug usage. SYMPTOM CONTROL: Monitoring and treatment of acute attacks. RESULTS: The full burden of the home nebulised therapy is not being met by the NHS. Supply and servicing arrangements for home nebuliser therapy were poorly organised. Chronic asthma symptoms did not appear to be optimally controlled on present medication, with 61% reporting sleep disturbance in the previous three months. About 20% of parents admitted that they would give nebulised bronchodilator therapy more frequently than the recommended 3 to 4 hourly. CONCLUSION: Re-organisation of resources and arrangements could improve the service and bring it in line with recognised standards of care.

Management of paediatric tuberculosis in leading UK centres: unveiling consensus and discrepancies.

SETTING: Large specialist paediatric TB clinics in the UK. OBJECTIVE: To evaluate clinical practice and compare with national and international guidelines. DESIGN: A survey based on an electronic questionnaire on the management of latent tuberculous infection (LTBI) and tuberculosis (TB) disease was conducted in 13 specialist paediatric TB clinics. The consensus and discrepancies were evaluated by descriptive analysis. RESULTS: Practice was reportedly different when choosing age limits for preventive treatment for TB contacts with initially negative tuberculin skin tests (TSTs), interpretation of TST results and use of interferon-gamma release assays (IGRAs) in the context of LTBI. In relation to management of children with TB disease, practices varied for duration of treatment of osteoarticular TB, monitoring for ethambutol ocular toxicity and use of pyridoxine. There was limited experience with multidrug-resistant TB (MDR-TB), and over half of the clinics monitored MDR-TB contacts without giving preventive treatment. CONCLUSIONS: The survey showed heterogeneity in several aspects of clinical care for children with TB. Available paediatric TB guidelines differ substantially, explaining the wide variations in management of childhood TB. Prospective paediatric studies are urgently required to inform and standardise clinical practice, especially in the context of evolving drug resistance.