Risk factors associated with the development of chronic lung disease in children

Pulmonary outcomes in survivors of childhood cancer: a systematic review

BACKGROUND

The purpose of this article is to summarize the literature that documents the long-term impact of cancer treatment modalities on pulmonary function among survivors of cancer and to identify potential areas for further research.

METHODS

Systematic reviews of clinical trials, observational studies, case series, and review articles were conducted. Articles were limited to the studies that discussed pulmonary toxicity or late effects among pediatric cancer survivors and to follow-up investigations that were conducted a minimum of 2 years after completion of cancer-related treatment or 1 year after hematopoietic stem cell transplant.

RESULTS

Sixty publications (51 clinical studies/reports and nine reviews) published from January 1970 to June 2010 in PubMed met the inclusion criteria. Data showed an association between radiotherapy, alkylating agents, bleomycin, hematopoietic stem cell transplant, and thoracic surgery and pulmonary toxicity, as well as possible interactions among these modalities.

CONCLUSIONS

Pulmonary toxicity is a common long-term complication of exposure to certain anticancer therapies in childhood and can vary from subclinical to life threatening. Pulmonary function and associated loss of optimal exercise capacity may have adverse effects on long-term quality of life in survivors. Lung function diminishes as a function of normal aging, and the effects of early lung injury from cancer therapy may compound these changes. The information presented in this review is designed to provide a stimulus to promote both observational and interventional research that expands our knowledge and aids in the design of interventions to prevent or ameliorate pulmonary late effects among survivors of childhood cancer.

Parental and neonatal risk factors for atopy, airway hyper-responsiveness, and asthma

BACKGROUND

Previous studies have not resolved the importance of several potential risk factors for the development of childhood atopy, airway hyperresponsiveness, and wheezing, which would allow the rational selection of interventions to reduce morbidity from asthma. Risk factors for these disorders were examined in a birth cohort of 1037 New Zealand children.

METHODS

Responses to questions on respiratory symptoms and measurements of lung function and airway responsiveness were obtained every two to three years throughout childhood and adolescence, with over 85% cohort retention at age 18 years. Atopy was determined by skin prick tests at age 13 years. Relations between parental and neonatal factors, the development of atopy, and features of asthma were determined by comparison of proportions and logistic regression.

RESULTS

Male sex was a significant independent predictor for atopy, airway hyper-responsiveness, hay fever, and asthma. A positive family history, especially maternal, of asthma strongly predicted childhood atopy, airway hyperresponsiveness, asthma, and hay fever. Maternal smoking in the last trimester was correlated with the onset of childhood asthma by the age of 1 year. Birth in the winter season increased the risk of sensitisation to cats. Among those with a parental history of asthma or hay fever, birth in autumn and winter also increased the risk of sensitisation to house dust mites. The number of siblings, position in the family, socioeconomic status, and birth weight were not consistently predictive of any characteristic of asthma.

CONCLUSIONS

Male sex, parental atopy, and maternal smoking during pregnancy are risk factors for asthma in young children. Children born in winter exhibit a greater prevalence of sensitisation to cats and house dust mites. These data suggest possible areas for intervention in children at risk because of parental atopy.

The clinical impact of human respiratory virus infections

Acute respiratory infections are the most frequent illnesses of the human host. Most infections are caused by viruses and bacteria; the proportion caused by viruses is much greater. The viruses most frequently involved are adenoviruses, influenza viruses, parainfluenza viruses, respiratory syncytial viruses, and rhinoviruses. Acute respiratory infections are more common in young children, have rather specific seasonal occurrences, and some agents are associated with specific respiratory syndromes. Risk factors associated with increased incidence or severity of respiratory infections are occurrence in the very young or the elderly; crowding; being male; inhaled pollutants; anatomic, metabolic, genetic or immunologic disorders; and malnutrition, including vitamin or micronutrient deficiency. Respiratory infections are a much greater problem in developing countries than in developed countries and are the leading causes of death in children under 5 yr of age. The same agents cause infections, and the incidence of total respiratory infections is the same as in the developed countries. The precise causes of increased morbidity and mortality in the developing world are unclear, but crowding, inhaled pollutants, and malnutrition are likely candidates. The interactive role of viruses and bacteria is not clear but may play a role in increased severity of respiratory infections.

Lung function and exercise capacity in survivors of childhood leukaemia

The survival from acute lymphoblastic leukaemia in childhood is now approximately 60-70%, and from acute myeloid leukaemia, up to 50%. However, there is little information on the effects of intensive chemotherapy and radiotherapy used in the treatment of these conditions on lung function and exercise capacity in the long term. Severity survivors of acute leukaemia from one centre in the UK were studied. Measurements of lung volumes, spirometry and transfer factor were made. Each child also performed a standard, symptom-limited maximal exercise test on a cycle ergometer. Predictive equations for indices of lung function and exercise tolerance were calculated from 146 age- and sex-matched control subjects. The results of the survivors of leukaemia were compared to these. There was a significant reduction of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), total lung capacity (TLC), and transfer for carbon monoxide (DLCO; P < 0.05 for each measurement), in the survivors of leukemia when compared to the control subjects. In addition, there was a mild but significant reduction of both maximal and submaximal indices of exercise capacity in the leukaemic group. A multivariate analysis was carried out to identify those variables acting independently to reduce lung volumes. For FEV1, FVC and TLC, these were craniospinal irradiation, cyclophosphamide and chest complications during treatment. For a reduction in DLCO, the significant factors were administration of anthracyclines, craniospinal irradiation and bone marrow transplantation. Survivors of acute leukemia have impaired pulmonary function and exercise capacity. Long-term cardiopulmonary follow-up may be necessary and new regimens devised which reduce long-term toxicity without compromising survival rates.

Bronchial responsiveness in children exposed to atmospheric pollution in Hong Kong

Bronchial responsiveness was studied by histamine challenge in 423 school children with mean (SEM) age of 10.85 (0.05) years living in two districts of Hong Kong with contrasting levels of air pollution. Differences between districts of residence were observed, with a higher prevalence of bronchial hyperreactivity (BHR) in children living in the more polluted district (chi 2 = 7.74, df = 3, p = 0.052). Bronchial hyperreactivity was defined as a 20 percent or greater drop in FEV1. The district effect remained after exclusion of children with a history of wheeze and those diagnosed asthmatic for prevalence of BHR (chi 2 = 8.93, df = 3, p = 0.030) and for degree of bronchial reactivity (BR) after adjustment for other socioeconomic factors and smoking in the home (z = 1.97, p = 0.049). Bronchial reactivity was defined as the percentage drop in FEV1 per cumulative histamine dose from postsaline to end dose. The results demonstrate that studies on bronchial responsiveness can be used to assess the effects of air quality on the respiratory health of children and will be employed to measure the impact of new air quality control measures in Hong Kong.

Pulmonary function of individuals with congenital cleft palate

Ventilatory pulmonary function was investigated in 160 children and adults with repaired or unrepaired congenital cleft palate in comparison with 130 normal children and adults. Pulmonary function tests included measurement of lung volumes, of maximal voluntary ventilation (MVV) and of forced spirometry parameters: forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio and mean forced expiratory flow during the middle half of FVC (FEF25-75). Patients with cleft palate demonstrated significant differences from normal individuals in some of the measurements made. Functional alterations were observed at higher frequency among adult patients with unrepaired clefts and mainly consisted of a reduction in expiratory flows and MVV. However, the deviations observed were usually discrete and probably of low physiopathologic significance. The results permit us to conclude that, in contrast to data reported by others, subjects with congenital cleft palate have little impairment of pulmonary ventilatory function.

Persistent or recurrent pneumonia in Saudi children seen at King Khalid University Hospital, Riyadh: clinical profile and some predisposing factors

Children with persistent or recurrent pneumonia without an apparent cause constitute an important clinical category with much morbidity and mortality and can be perplexing and frustrating to the treating physician and the parents. To identify the clinical profile and predisposing factors in this group of patients, 18 Saudi children were studied. Their ages ranged from 3 months to 12 years (mean age 5.7 years) with male preponderance--12 boys and 6 girls (M:F ratio 2:1). About 44.4% had immune and inherited metabolic disorders. Anatomical abnormalities were found in four (22.2%). Two had measles as a predisposing factor. None had tuberculosis or pertussis. One child each had pulmonary candidiasis and laryngeal papilloma, probably contracted from their mothers as congenital infections. Though the pattern seems to follow that found in developed countries, it is noteworthy that cystic fibrosis was not identified in any of our patients.

Long-term drug treatment of asthma in children

In this short review the pharmacologic and clinical effect of antiasthma drugs in children that is, beta 2-agonists, theophylline, anticholinergics, disodiumcromoglycate/nedocromil sodium, and inhaled corticosteroids are described. Furthermore, a medication plan for maintenance treatment is presented.

Domiodol treatment for bronchopulmonary diseases in the paediatric age group: a double-blind controlled clinical trial versus placebo

Thirty children (25 males, five females), mean age 9.33 +/- 2.57 years, with acute infectious pulmonary diseases or acute flare-ups of chronic bronchitis, were randomly treated with either domiodol or placebo. The study was conducted between November 1986 and February 1987. Domiodol was administered orally for 14 days in doses of 0.5 mg/kg three times daily. Subjective symptoms (cough, sputum viscosity, difficulty in raising sputum and sputum characteristics) were assessed semi-quantitatively. They were all reduced significantly in the group treated with domiodol compared to those given placebo. Spirometric measures of vital capacity and peak expiratory flow rate were also improved in patients given domiodol compared with placebo. Conversely, no differences were noted in forced expiratory volume in 1 s, Tiffenau index, or mid-expiratory flow. There were no clinical side-effects and no changes in any other parameters measured; in particular, levels of thyroid hormone and thyroid stimulating hormone were unchanged. Thus, domiodol proved effective in reducing the symptoms of infection of the lower respiratory tract and in improving the consistency of mucus in children.