Risk Factors for Respiratory Syncytial Virus Bronchiolitis Admissions

Aim Determine the seasonal incidence of hospital Respiratory Syncytial Virus (RSV) bronchiolitis and explore the variables associated with admission to ward versus the Paediatric Intensive Care Unit (PICU). Method Retrospective case-control study. Children, aged ≤2 years, between November and March, over a 3 year period with a positive RSV nasopharyngeal aspirate test. Results A total of 557 children were included; 19% (n=106) required PICU admission. Children admitted to the PICU were younger in age, median (IQR) 6.93 (3.96, 11.89) weeks compared to children who remained on the wards 11.00 (5.86, 24.14) weeks. Being underweight at the point of admission (adjusted odds ratio 3.15, 95% 1.46, 6.70, p=0.003) was associated with a PICU admission. Conclusion Number of RSV bronchiolitis hospitalisations are increasing each year. Age, weight and the use of HFNC were independent predictors for PICU admission.

Risk factors for severe bronchiolitis caused by respiratory virus infections among Mexican children in an emergency department

Severe bronchiolitis is the most common reason for hospitalization among children younger than 2 years. This study analyzed the prevalence of community-acquired respiratory virus infection and the risk factors for hospitalization of Mexican children with severe bronchiolitis treated in an Emergency department.This retrospective study included 134 children 2 years or younger with severe viral bronchiolitis, and 134 healthy age-matched controls. The study period was September 2012 to January 2015. We determined the viral etiology and coinfections with multiple viruses and compared the risk factors detected in children with severe viral bronchiolitis with those in the control group.A total of 153 respiratory viruses in these 134 patients, single or mixed infections, were identified: respiratory syncytial virus (RSV) type A or B was the most frequently detected (23.6% and 17.6%, respectively), followed by rhinovirus (RV; 16.3%) and parainfluenza virus (PIV) type 3 (12.4%). Coinfections of 2 respiratory viruses were found in 14.2% of cases; all cases had either RSV type A or B with another virus, the most common being parainfluenza virus or rhinovirus. Exposure to cigarette smoking was independently associated with hospitalization for severe bronchiolitis (OR, 3.5; 95% CI, 1.99-6.18; P = .0001), and having completed the vaccination schedule for their age was a protective factor against adverse outcome (OR, 0.55; 95% CI, 0.35-0.87; P = .010).RSV is a common infection among young children with severe bronchiolitis; thus, developing a vaccine against RSV is essential. Campaigns to reinforce the importance of avoiding childhood exposure to cigarette smoke are also needed.

Association of folic acid supplementation during pregnancy and infant bronchiolitis

Viral bronchiolitis affects 20%-30% of infants; because there is no known effective treatment, it is important to identify risk factors that contribute to its pathogenesis. Although adequate folate intake during the periconceptional period prevents neural tube defects, animal data suggest that higher supplementation may be a risk factor for child respiratory diseases. Using a population-based retrospective cohort of 167,333 women and infants, born in 1995-2007 and enrolled in the Tennessee Medicaid program, we investigated the association between the filling of folic acid-containing prescriptions and infant bronchiolitis. We categorized women into the following 4 groups in relation to the first trimester: "none" (no prescription filled), "first trimester only," "after first trimester," and "both" (prescriptions filled both during and after the first trimester). Overall, 21% of infants had a bronchiolitis diagnosis, and 5% were hospitalized. Most women filled their first prescriptions after the fifth to sixth weeks of pregnancy, and most prescriptions contained 1,000 µg of folic acid. Compared with infants born to women in the "none" group, infants born to women in the "first trimester only" group had higher relative odds of bronchiolitis diagnosis (adjusted odds ratio = 1.17, 95% confidence interval: 1.11, 1.22) and greater severity (adjusted odds ratio = 1.16, 95% confidence interval: 1.11, 1.22). This study's findings contribute to an understanding of the implications of prenatal nutritional supplement recommendations for infant bronchiolitis.

Increased risk of wheeze and decreased lung function after respiratory syncytial virus infection

Background

A relationship between hospitalization for respiratory syncytial virus (RSV) bronchiolitis and asthma development has been suggested in case-control studies.

Objective

The aim of this study was to assess the risk of current wheeze, asthma, and lung function at school age in infants previously hospitalized for RSV bronchiolitis compared to non-hospitalized children.

Methods

For this study, data from a prospective birth cohort of unselected, term-born infants (n = 553), of whom 4 (0.7%) were hospitalized for RSV bronchiolitis, and a prospective patient cohort of 155 term infants hospitalized for RSV bronchiolitis were used. Respiratory outcomes at age 6 in children hospitalized for RSV bronchiolitis were compared to non-hospitalized children.

Results

The risk of current wheeze was higher in hospitalized patients (n = 159) compared to non-hospitalized children (n = 549) (adjusted odds ratio (OR) 3.2 (95% CI 1.2–8.1). Similarly, the risk of current asthma, defined as a doctor’s diagnosis of asthma plus current symptoms or medication use, was higher in hospitalized patients (adjusted OR 3.1 (95% CI 1.3–7.5). Compared to non-hospitalized children, RSV bronchiolitis hospitalization was associated with lower lung function (mean difference FEV1% predicted −6.8 l (95% CI (−10.2 to −3.4).

Conclusions and Clinical Relevance

This is the first study showing that hospitalization for RSV bronchiolitis during infancy is associated with increased risk of wheezing, current asthma, and impaired lung function as compared to an unselected birth cohort at age 6.

[Epidemiology, clinical features and medical interventions in children hospitalized for bronchiolitis]

OBJECTIVES

To describe the epidemiology, clinical characteristics and treatments prescribed in children with bronchiolitis admitted to our hospital.

MATERIAL AND METHODS

Observational, descriptive and prospective study of children younger than 18 months, admitted to Hospital Virgen de la Arrixaca of Murcia (Spain), with the diagnosis of bronchiolitis, during the season of maximum incidence (December 2008-April 2009).

RESULTS

A total of 235 infants were admitted, of whom 78.7% of them were aged 5 months or less. We found a positive correlation between the number of cigarettes smoked by their mothers during pregnancy and the number of hospitalization and oxygen therapy days. Children whose mothers were smokers at the time of their admission needed a greater number of oxygen therapy days. Also infants who were not breastfed needed oxygen therapy during more days. Just under one quarter (23.8%) of them had underlying diseases, with prematurity being the most frequent and a risk factor for the ongoing of oxygen therapy and hospital stay. The use of diagnostic tests, bronchodilators, corticosteroids and antibiotics was high. The onset of high temperature was associated with an increased use of antibiotics in outside and inside the hospital setting. An abnormal chest X-ray or a raised C-reactive protein was associated with a higher use of antibiotics. Respiratory Syncytial virus (RSV) was the main aetiological agent, followed by Rhinovirus, Bocavirus, Adenovirus and Metapneumovirus

CONCLUSIONS

The majority of hospital admissions due to bronchiolitis took place during the first months of life. Infants whose mothers smoked during pregnancy had a worse clinical outcome. Despite the availability of clinical practice guidelines in our area, the use of diagnostic tests and pharmacological treatment was high.

In the trenches: a pediatrician's perspective on prevention and treatment strategies for RSV disease

Pharmacologic options in the treatment of RSV infection have no or minimal effectiveness. Therefore, for infants at high risk of RSV infection, proper hand hygiene, limiting exposure to infection, and immunoprophylaxis with palivizumab is paramount. The first injection of palivizumab must be given prior to the start of the local RSV season and subsequent injections should be administered every 30 days to provide protective levels until the end of the RSV season. Pediatricians should anticipate the start of the RSV season and attend to reimbursement issues and obtain all necessary approvals well in advance of the time when the first injections will be given. Compliance is the key to providing protection for high-risk infants. Compliance has a positive association with decreasing RSV hospitalization rates; however, it is difficult for pediatricians to achieve optimal compliance on their own. A collaborative effort involving the hospital and NICU, pediatrician, parent, home care provider, and insurer is necessary to achieve optimal compliance.

The role of breastfeeding and passive smoking on the development of severe bronchiolitis in infants

AIM

Bronchiolitis is an acute infectious disease of the lower respiratory tract which causes the obstruction of bronchioles in children younger than 2 years. The aim of this study was to investigate the effect of passive smoking alone and in conjunction with breastfeeding on the severity of acute bronchiolitis in infancy and the duration of hospitalisation.

METHODS

We studied 240 consecutive infants aged from 6 to 24 months (137 boys and 103 girls) median age 14 months, who required hospital admission for acute bronchiolitis at the Paediatric Department of Democritus University Hospital, Alexandroupolis, Greece. The outcomes of interest were the severity of bronchiolitis and the duration of hospitalisation.

RESULTS

Among the entire cohort, 122 (50.8%) children presented a severe attack of bronchiolitis. In multivariate regression analysis adjusting for confounding factors, breastfeeding for less than four months (aOR=6.1, 95% CI=3.4-10.7), exposure to environmental tobacco smoke (aOR=2.2, 95% CI=1.1-3.6) and their combination (aOR=16.2, 95% CI=6.0-34.3) showed significant association with severe bronchiolitis and prolonged hospitalisation. Passive smoking did not increase the risk of severe bronchiolitis, when infants breastfed for more than four months (aOR=1.9, 95% CI=0.8-5.1).

CONCLUSION

In conclusion, exposure to environmental tobacco smoke worsens the symptoms and the prognosis of bronchiolitis, while breastfeeding seems to have a protective effect even in children exposed to environmental tobacco smoke.

Human metapneumovirus in children with bronchiolitis or pneumonia in New Zealand

OBJECTIVES

To confirm the presence of human metapneumovirus (hMPV) in New Zealand and establish its prevalence in selected paediatric patient groups.

METHODS

Nasopharyngeal swabs were collected in two separate paediatric studies enrolling children clinically diagnosed with either bronchiolitis or pneumonia and tested for hMPV by polymerase chain reaction.

RESULTS

Nucleic acid detection tests demonstrated 5.3% of paediatric bronchiolitis cases were positive for hMPV RNA and 2.7% of children admitted with pneumonia tested positive for hMPV RNA.

CONCLUSIONS

The presence of hMPV in New Zealand has been confirmed in two selected paediatric patient groups, namely children diagnosed with bronchiolitis and pneumonia. These results indicate that hMPV is associated with a minority of cases of bronchiolitis or pneumonia in this patient group.

Infections nosocomiales virales dans un service de pédiatrie : l'exemple des gastroentérites à rotavirus et des bronchiolites à VRS

Nosocomial infections are a preoccupation in a pediatric hospital mainly during the winter with bronchiolitis and gastroenteritis epidemics. We have examined the risk factors of nosocomial infections.

MATERIAL AND METHODS

A prospective study was conducted between November, 1999 and March, 2000 in the infants units of the Le Havre hospital. We systematically listed the admissions and contacted the family after their discharge by phone. A geographic information system was implemented to display the epidemiological data; this software is able to illustrate the sectors at risk.

RESULTS

During the study, 687 infants were hospitalized of whom 458 for bronchiolitis and community-acquired gastroenteritis. Mean age was 5.4 months old. No nosocomial bronchiolitis occurred. Prevalence of nosocomial gastroenteritis was 10% (68 cases including nine after discharge). Infants with nosocomial infection were younger than those with community-acquired infection (6.6 months vs. 11.2 months, P < 0.01). The mean length of stay was longer in nosocomial infection (7.7 vs. 4.1 days, P < 0.05). Among the infants with bronchiolitis, 16% have developed nosocomial intestinal infections (RR = 2.65, IC: 1.59-4.4; P < 0.01). The geographic analysis pointed the area with nosocomial risk (bedroom without water, nearness of nurse office and games room).

CONCLUSION

Geographic information system is a part of the quality control system and may have some interaction effect on final decision making. Incidence of nosocomial infections showed the need for a prevention strategy in a pediatric hospital.

Soluble CD14 as a predictor of subsequent development of recurrent wheezing in hospitalized young children with respiratory syncytial virus-induced bronchiolitis

BACKGROUND

Respiratory syncytial virus (RSV) infection in infancy that causes severe bronchiolitis had been implicated as potentially responsible for the subsequent development of asthma. The CD14 receptor responds to the microbial burden in the environment and modulates the development of the allergic phenotype.

OBJECTIVE

To investigate the relationship between the serum level of soluble CD14 (sCD14) in children hospitalized because of RSV-induced bronchiolitis and the subsequent development of recurrent wheezing.

METHODS

Serum levels of sCD14 were measured in 21 children younger than 14 months who were hospitalized because of RSV-induced bronchiolitis. The diagnosis of significant wheezing was evaluated by recurrent episodes of coughing, wheezing, and respiratory distress, which were relieved by inhalation of beta-agonists and corticosteroids.

RESULTS

Of the 21 children, 19 were followed up for 12 months. The mean sCD14 serum level of 14,521 +/- 1,773 pg/mL in the group of 6 children who did not exhibit recurrent wheezing was significantly higher than the level of 11,243 +/- 3,264 pg/mL in the group of 13 children who exhibited significant recurrent wheezing (P < .05). The subsequent development of recurrent wheezing was not influenced by positive family history of asthma, number of siblings, sex, or breast-feeding.

CONCLUSION

A follow-up period of 12 months in this small pilot group showed that high serum levels of sCD14 modulate the influence of RSV on subsequent recurrent episodes of wheezing.

Haplotype mapping of the bronchiolitis susceptibility locus near IL8

Susceptibility to viral bronchiolitis, the commonest cause of infant admissions to hospital in the industrialised world, is associated with polymorphism at the IL8 locus. Here we map the genomic boundaries of the disease association by case-control analysis and TDT in 580 affected UK infants. Markers for association mapping were chosen after determining patterns of linkage disequilibrium across the surrounding region of chromosome 4q, a 550-kb segment containing nine genes, extending from AFP to PPBP. The region has three major clusters of high linkage disequilibrium and is notable for its low haplotypic diversity. We exclude adjacent chemokine genes as the cause of the association, and identify a disease-associated haplotype that spans a 250-kb region from AFM to IL8. In between these two genes there is only one structural feature of interest, a novel gene RASSF6, which is predicted to encode a Ras effector protein.

Incidence of hyponatraemia and hyponatraemic seizures in severe respiratory syncytial virus bronchiolitis

AIM

To document the incidence and early evolution of hyponatraemia (serum sodium < 136 mmol l(-1)) associated with respiratory syncytial virus (RSV) bronchiolitis in infants requiring intensive care.

METHODS

In a retrospective review over two winter seasons, 130 infants were admitted with confirmed RSV infection, of whom 39 were excluded because of either pre-existing risk factors for hyponatraemia: diuretic therapy (n = 14), cardiac disease (n = 10), renal disease (n = 2) or lack of admission sodium data (n = 13).

RESULTS

The incidence of admission hyponatraemia in the remaining infants (median age 6 wk) was 33% (30/91), with 11% (10/91) exhibiting a serum sodium less than 130 mmol l(-1) . Hyponatraemic and normonatraemic infants were of a similar age (median 6 vs 7 wk, p = 0.82). With fluid restriction and diuretic therapy, the incidence of hyponatraemia at 48 h had decreased to 3.3%, odds ratio 0.07 (95% confidence interval 0.02-0.24, p < 0.001). Four infants (4%) suffered hyponatraemic seizures at admission (sodium 114-123 mmol l(-1)); three had received hypotonic intravenous fluids at 100-150 ml kg(-1) d(-1) before referral to intensive care. All four were managed successfully with hypertonic (3%) saline, followed by fluid restriction, resulting in immediate termination of seizure activity and normalization of serum sodium values over 48 h.

CONCLUSION

Hyponatraemia is common among infants with RSV bronchiolitis presenting to intensive care. Neurological complications may occur and fluid therapy in vulnerable infants should be tailored to reduce this risk.

Interleukin-6, interleukin-8, interleukin-11, and interferon-gamma levels in nasopharyngeal aspirates from wheezing children with respiratory syncytial virus or influenza A virus infection

The differences between respiratory syncytial virus (RSV) and influenza A virus (IFAV) in the pathogenesis of wheezing in young children have not been clearly defined. The aim of this study was to assess the contributions of RSV vs IFAV in the pathogenesis of upper airway inflammation in wheezy young children. We compared interleukin (IL)-6, IL-8, IL-11, and interferon-gamma (IFN-gamma) levels in nasopharyngeal aspirates (NPA) from non-asthmatic children with respiratory virus infections (RSV in 17 children and IFAV in 13 children), asthmatic children with viral infections (RSV in nine children, IFAV in 10 children), and 22 unaffected healthy children (controls). Levels of IL-11 in NPA from asthmatic children were significantly higher than those from non-asthmatic children with RSV infection, and RSV infection enhanced the IL-11 production in NPA significantly compared to IFAV infection. Nasopharyngeal epithelium from children with RSV infection secreted more IL-6 than that of children with IFAV infection. There was little difference in the IL-8 and IFN-gamma levels between asthmatic and non-asthmatic children with RSV or IFAV infection. In conclusion, asthma enhanced IL-11 production in RSV infection rather than IFAV infection in early childhood. There was a trend towards greater IL-6 production in RSV infection compared with IFAV infection.

Prevention and treatment of respiratory syncytial virus bronchiolitis and postbronchiolitic wheezing

Respiratory syncytial virus (RSV) is the primary cause of hospitalization for acute respiratory tract illness in general and specifically for bronchiolitis in young children. The link between RSV bronchiolitis and reactive airway disease is not completely understood, even though RSV bronchiolitis is frequently followed by recurrent episodes of wheezing. Therapy with ribavirin does not appear to significantly reduce long-term respiratory outcome of RSV lower respiratory tract infection, and corticosteroid or bronchodilator therapy may possibly improve outcomes only on a short-term basis. No vaccine against RSV is yet available. It is not known whether prophylaxis with RSV intravenous immune globulin or palivizumab can reduce postbronchiolitic wheezing.

Clinical perspectives on the association between respiratory syncytial virus and reactive airway disease

Asthma is a leading cause of morbidity and mortality among children worldwide, as is respiratory syncytial virus (RSV). This report reviews controlled retrospective and prospective studies conducted to investigate whether there is an association between RSV bronchiolitis in infancy and subsequent development of reactive airway disease or allergic sensitization. Findings indicate that such a link to bronchial obstructive symptoms does exist and is strongest for children who experienced severe RSV illness that requires hospitalization. However, it is not yet clear what roles genetic predisposition and environmental or other risk factors may play in the interaction between RSV bronchiolitis and reactive airway disease or allergic sensitization. Randomized, prospective studies utilizing an intervention against RSV, such as a passive immunoprophylactic agent, may determine whether preventing RSV bronchiolitis reduces the incidence of asthma.

Leucocyte populations in respiratory syncytial virus-induced bronchiolitis

OBJECTIVES

To enumerate the cellular composition of the airways in infants with acute bronchiolitis.

METHODOLOGY

Cells were obtained by airway lavage from the upper and lower airway and the peripheral blood of infants with respiratory syncytial virus (RSV)+ bronchiolitis, RSV- bronchiolitis and age-matched controls.

RESULTS

Neutrophils are the predominant cells present in the upper and lower airway. Neutrophils are present at a higher number/unit volume in the airway than in the peripheral blood.

CONCLUSIONS

Neutrophils, being the dominant cellular infiltrate into the airway, are likely to contribute to the pathophysiology of bronchiolitis. Therapies targeted at limiting neutrophil influx or neutrophil-mediated damage in the airway may have a therapeutic role.

Bronchiolitis

Bronchiolitis is a commonly encountered disease of infants and young children. Mortality is low, but morbidity is significant. Treatment requires considerable commitment of time from medical and nonmedical personnel. Decisions about treatment modalities remain controversial. Patients may remain susceptible to pulmonary problems for years and may be predisposed to the development of asthma. Much is known about this disease, but much remains to be learned.

[Clinical, therapeutic and developmental aspects of acute bronchiolitis in Tunisia]

Fourteen infants with severe acute bronchiolitis were admitted to the Intensive Care Unit (ICU) of Tunis. This pathology represents 36% of severe bronchopulmonary infections admitted to this ICU. Their age ranged between 2 and 48 weeks (mean: 15 weeks). Eight infants had hypotrophy. Two infants had congenital heart disease and one infant had tracheo-bronchomalacia. Viruses were found in 6/11 patients. Respiratory syncytial virus (RSV) was identified in five patients and an adenovirus in one patient. Five patients had respiratory arrest at ICU admission. Ten infants had evidence of atelectasis on chest X-ray films. Thirteen patients required mechanical ventilation. One infant had inappropriate antidiuretic hormone secretion resulting in convulsions. One infant had supraventricular tachycardia. Both had RSV infection. One patient who had congenital heart disease and RSV infection died. In the other 12 patients receiving mechanical ventilation, the mean duration of ventilation was 9 days (range: 2-30 days). The second patient who had congenital heart disease and RSV infection had severe respiratory sequelae at discharge.

A comparison of ganciclovir and acyclovir to prevent cytomegalovirus after lung transplantation

In an attempt to modify the sequelae of cytomegalovirus (CMV) infections after lung transplantation, 25 allograft recipients were randomized to either ganciclovir 5 mg/kg once a day 5 d/wk (Group G) or acyclovir 800 mg four times a day (Group A). All subjects received ganciclovir during postoperative Weeks 1 through 3, and they were then given either A or G regimens until Day 90. At termination of study enrollment, the cumulative incidence of all CMV infections (including seroconversions) was increased in Group A compared with that in Group G (75% versus 15%, p < 0.01), as was the incidence of overt CMV shedding and/or pneumonitis (50% versus 15%, p < 0.043). In comparison with those in Group G, subjects in Group A were also afflicted with an increased prevalence of obliterative bronchiolitis (OB) during the first year after transplantation (54% versus 17%, p < 0.033). Intravenous catheters for ganciclovir administration resulted in four complications among three of the subjects in Group G (23%). The short-term benefits of ganciclovir were ultimately limited, moreover, in that cumulative rates of CMV and prevalence of OB are now similar in both treatment groups after approximately 2 yr of observation. We conclude that prolonged ganciclovir prophylaxis decreases the early incidence of CMV and OB among lung transplant recipients, but these effects are of finite duration. Although CMV prevention appears to have considerable potential value in this population, definitive viral prophylaxis will require development of protracted or repeated treatment regimens, or longer-acting agents.

Pathogenesis and treatment of bronchiolitis

The pathogenesis, epidemiology, clinical features, sequelae, and treatment of bronchiolitis are reviewed. Acute bronchiolitis is the most common severe lower-respiratory-tract infection of infancy. During epidemics, more than 80% of cases may be caused by respiratory syncytial virus (RSV). Although signs and symptoms may become severe, most infections are self-limited and improvement occurs within several days. Approximately 1-2% of infants less than one year of age require hospitalization. Generally, patients who develop severe, life-threatening RSV bronchiolitis are those with underlying cardiopulmonary disease, immunosuppression, bronchopulmonary dysplasia, or a history of premature birth. In severe bronchiolitis, necrosis of the respiratory epithelium, excessive mucus production, and lymphocytic infiltration result in edema, dense plugs of debris, and subsequent bronchiolar obstruction. IgE-mediated reactions and release of inflammatory mediators may result in exacerbation of acute obstruction and may contribute to chronic obstructive pulmonary dysfunction, a common sequela of bronchiolitis. Patients hospitalized with bronchiolitis usually require supportive therapy and may require mechanical ventilation. Based on recent data, a trial of aerosolized beta 2 agonists is warranted in all patients. Systemic corticosteroids have not proved efficacious and have a limited role in the treatment of acute bronchiolitis. Inhaled corticosteroids may be useful in reducing the severity of chronic wheezing that may follow acute bronchiolitis. Ribavirin may be considered in patients with severe illness or in those at high risk for severe RSV disease. Intravenous immune globulin may have a role in the treatment of lower-respiratory-tract infections involving RSV; however, since few studies have been performed in humans, it is not possible to determine its place in the treatment of bronchiolitis. A trial of aerosolized beta 2 agonists is warranted in patients with bronchiolitis. Ribavirin may be considered in patients with severe disease or those at high risk for severe disease.

[Three cases of chronic respiratory tract lesions associated with adult T-cell leukemia (ATL)]

Three cases of chronic respiratory tract lesions as a complication of adult T-cell leukemia (ATL) are reported. Case 1 was seropositive for HTLV-1 on recent examination following treatment of bronchiolitis. Chest radiograph revealed over inflation of the lungs and bilateral diffuse small nodular shadows. Pulmonary function test resulted hypoxemia and mixed ventilation disorder. Pathological examination confirmed lymphocytic infiltration of the bronchiolar wall. Both clinically and pathologically the patient was diagnosed as having diffuse panbronchiolitis (DPB). Therefore, this case was considered to be the bronchiolar type of HTLV-1 associated bronchiolo-alveolar disorder (HABA). The other two cases with smoldering or chronic ATL presented with long-standing symptoms of productive cough due to chronic respiratory lesions. We consider that all three cases had HTLV-1 virus associated pulmonary lesions, but with different clinical and pathological presentations. Among 12 cases of bronchiolitis experienced at our hospital, three were positive for HTLV-1.

Vitamin A status of children with a history of respiratory syncytial virus infection in infancy

In order to extend our earlier observation that children who experience frequent respiratory episodes may benefit from Vitamin A supplementation, 206 children aged 2-7 years who had been hospitalized for bronchiolitis during infancy were randomized into a controlled trial of Vitamin A supplementation. Of these, 149 met the criteria of protocol compliance after 12 months of follow-up. Mean plasma retinol at baseline was 39.2 micrograms/100 ml (s.e.m. = 1.0) and did not increase after 12 months (mean = 36.0 micrograms/100 ml, s.e.m. = 0.7) despite the older age of the cohort. The range observed (11.7-73.9 micrograms/100 ml) included some children at risk of marginal Vitamin A deficiency. Mean plasma retinol levels were 20% lower than those of children experiencing frequent respiratory episodes recorded earlier. Oral supplementation did not change plasma retinol levels, nor did it affect respiratory morbidity.

Small-airways disease in recipients of allogeneic bone marrow transplants. An analysis of 11 cases and a review of the literature

In a retrospective review of 116 consecutive allogeneic bone marrow transplants (BMT), severe obstructive airways disease was identified in 11 patients. Lung pathology demonstrated bronchiolitis in 9 patients and physiologic studies showed small-airways disease consistent with bronchiolitis in the other 2. None of the 5 patients with associated infection survived, while 3 of the 6 patients without an identified pathogen stabilized or improved. Analysis of the 11 cases presented and all 25 cases reported in the literature (1982 to 1985) supports the conclusion that graft-versus-host disease is a major risk factor for bronchiolitis in BMT recipients. Among the proposed mechanisms for the development of bronchiolitis after allogeneic BMT, the 2 most likely are graft-versus-host disease directly causing bronchiolitis, and increased immunosuppressive therapy given for graft-versus-host disease predisposing to viral bronchiolitis. The available evidence would suggest that it is prudent to obtain serial pulmonary function tests even in asymptomatic patients post-BMT, and particularly in those with chronic graft-versus-host disease, in the hope that early detection will allow for early intervention that will arrest or reverse the progression of the obstructive airways disease.

Parental smoking, presence of older siblings, and family history of asthma increase risk of bronchiolitis

Bronchiolitis is a common lower respiratory tract illness in infants and has substantial acute morbidity and sequelae. To identify risk factors for bronchiolitis, a case-control study was conducted in which 53 subjects who had bronchiolitis were matched with two controls who had no bronchiolitis in infancy. In multivariate analysis, direct effects of passive smoking and older siblings achieved statistical significance. Family history of asthma appeared to interact with older siblings. Among subjects without a family history of asthma, statistically significant predictors proved to be older siblings (odds ratio, 2.31) and passive smoking (odds ratio, 3.87). Among subjects with a family history of asthma, older siblings proved to be an even stronger predictor (odds ratio, 46.81), while the odds ratio for passive smoking did not change much (odds ratio, 4.03). The combined presence of older siblings and passive smoking yielded an odds ratio of 8.94 among subjects without a family history of asthma and 181.67 among subjects with a family history of asthma. Analysis provided risk estimates that were particularly high for certain groups. Among infants with a family history of asthma, 49% who have an older sibling may develop bronchiolitis. If they are also exposed to cigarette smoke, almost 80% may develop bronchiolitis. Among infants without a family history of asthma, bronchiolitis may develop in 46% of infants if there is both an older sibling and exposure to smoke. Exposure of infants to cigarette smoke might diminish more rapidly if clinicians and parents were aware of such high risks. Efforts to reduce morbidity from bronchiolitis in infants might best be directed at the reduction of smoking in families with previous children, particularly if there is a family history of asthma, and at methods that protect infants from respiratory virus carried by siblings.

The spectrum of cytomegalovirus infection following human heart-lung transplantation

Data were analyzed from 19 long-term survivors of cardiopulmonary transplantation in this institution, including nine patients with normal pulmonary function and 10 recipients with posttransplant obliterative bronchiolitis. In all cases, donor cytomegalovirus titers (IgG), preoperative recipient titers (IgG), and serial postoperative recipient titers (IgM, IgG, and complement fixation) were available. In addition, surveillance cytomegalovirus cultures and pulmonary function tests were obtained prospectively after surgery in all 19 patients. A total of 12 patients developed active cytomegalovirus infection (serologic conversion confirmed by positive cultures) after transplantation, six of whom subsequently developed obliterative bronchiolitis. However, infection was clinically associated with pulmonary deterioration in only four of these patients, three of whom had cytomegalovirus pneumonitis. With the exception of obliterative bronchiolitis, no other permanent sequelae of cytomegalovirus infection were evident in this small group. Progressive obliterative bronchiolitis was also seen in four of the seven recipients who had no evidence of cytomegalovirus infection at any time. Although viral causes have been associated with obliterative bronchiolitis, the current data suggest that cytomegalovirus infection in the absence of pneumonitis does not appear to be a significant risk factor for obliterative bronchiolitis in cardiopulmonary transplant recipients. A larger group of patients will be required to ultimately establish the role of cytomegalovirus infection in this setting.

Parainfluenza virus bronchiolitis. Epidemiology and pathogenesis

An investigation of the epidemiology and pathogenesis of bronchiolitis due to parainfluenza virus (PV) was carried out. Bronchiolitis due to PV occurred most commonly in non-Caucasian males. Breast-fed infants exhibited a reduced risk of developing bronchiolitis. Once an episode of PV bronchiolitis occurred, both exposure to cigarette smoke and bottle feeding were associated with an increased frequency of recurrent wheezing, and subsequent infection with respiratory virus almost uniformly resulted in wheezing. Cell-mediated immune responses to PV antigen and titers of PV-specific IgE were greater among patients with bronchiolitis than among patients with upper respiratory tract infection. The epidemiology and pathogenesis of bronchiolitis due to PV is similar to that of respiratory syncytial virus. Lower respiratory tract infection may predispose to episodes of bronchoconstriction on subsequent exposure to cigarette smoke or other viral infections.

Severe RSV bronchiolitis in an immunocompromised child

A 9-year-old with immunodeficiency developed a severe, diffuse respiratory illness that necessitated mechanical ventilation. Open lung biopsy revealed Respiratory Syncytial Virus (RSV) as the sole pathogen. RSV detection should be included in the differential diagnosis of diffuse lung disease in an immunocompromised child.

[Pulmonary infections in cystic fibrosis: pathogenesis and therapy]

Infections of airways and lung in patients with cystic fibrosis determine quality of life and prognosis. Despite overall improvement of management of infections the underlying causes leading to infection early in life remain an enigma. As a consequence of infection various morphologic alterations arise. The most prominent are development of bronchiectases afflicting more than 70% of patients at age two. The spectrum of bacterial involvement has undergone significant changes. In contrast to earlier reports Pseudomonas aeruginosa at present is the most commonly encountered pathogen. Mucoid forms are typical for cystic fibrosis and are rarely seen in other conditions. Pseudomonas cannot be eradicated once it is established. Antipseudomonas chemotherapy leads to a diminution of bacteria from 10(8)/ml sputum to 10(6) at best. However, clinical results are convincing. Thus regular antispeudomonas treatment has been advocated by one CF-centre. Apart from conventional chemotherapy alternative approaches of treatment such as vaccination or immunoregulation need to be explored in greater detail.

Management of bronchiolitis

The incidence, etiology, epidemiology, clinical presentation, treatment, prognosis, and prevention of bronchiolitis are discussed with a critical evaluation of the available studies on various therapeutic approaches. Bronchiolitis is a lower respiratory-tract viral infection that affects 6-10% of all children below two years of age. Respiratory syncytial virus (RSV) is the usual pathogen. The symptoms range from mild wheezing to severe respiratory distress. An infected child usually has a fever, a rapid pulse, an increased breathing rate, and difficulty in breathing. Because most of the infants hospitalized with bronchiolitis have hypoxemia, the administration of oxygen is the mainstay of therapy. Correct fluid therapy is essential to avoid dehydration and overhydration. Limited data are available on the use of drugs in the management of bronchiolitis. Although a variety of adrenergic drugs, theophylline, and corticosteroids are used, sound efficacy data are lacking, and most studies have documented a lack of therapeutic benefits. One study reported that the combined use of corticosteroids and albuterol may be beneficial in severely ill patients. Recent studies have shown that the continuous administration of ribavirin may decrease viral shedding. Antibiotics are not indicated unless a secondary bacterial infection is present. Oxygen and fluid therapy have a clear role in the management of patients with bronchiolitis; however, no specific guidelines are available for the use of drugs in the treatment of these patients.

The relationship of respiratory infections in early childhood to the occurrence of increased levels of bronchial responsiveness and atopy

We assessed the relationship of antecedent acute respiratory illness to the occurrence of airway responsiveness and atopy in a population-based cohort of 194 children 12 to 16 yr of age from East Boston, Massachusetts. A history of croup or bronchiolitis as reported by their parents was determined at study onset when the children were 5 to 9 yr of age. During the second and third years of the study, acute respiratory illness was assessed. Five years after the prospective respiratory illness assessment, airway responsiveness was evaluated with eucapneic hyperpnea to subfreezing air, and atopy was evaluated with skin tests to 4 environmental antigens. Both a prior history of croup of bronchiolitis (OR = 2.29, p = 0.04) and greater than 2 acute lower respiratory illnesses (OR = 3.72, p = 0.012) were associated with increased levels of airway responsiveness. Neither index of respiratory illness experience was related to the presence of atopy. However, maternal cigarette smoking was significantly associated with atopy in these children (OR = 2.24, p = 0.02). These data suggest that respiratory illness in early life is associated with airway hyperresponsiveness as measured later in childhood. The data further suggest the need for longitudinal studies to better assess the etiologic role of these potential risk factors.

Antibiotic treatment of pneumonia and bronchiolitis. A prospective randomised study

Routine administration of antibiotics in the treatment of pneumonia and bronchiolitis in infants and small children was evaluated in an open randomised prospective trial. From 1979-82 136 children between the age of 1 month and 6 years were allocated to one of two treatment groups shortly after their admission to a paediatric ward. Group A patients were to be given antibiotics but those in group B were not. None of the children had received antibiotics before hospital admission. A viral infection was diagnosed in 38 of the 72 patients from group A and in 34 of the 64 patients from group B. Respiratory syncytial virus was detected in 84% of these patients. Samples of tracheal secretions showed no differences between the groups in respect of cytology and bacterial flora. Nor were there any significant differences in the course of acute disease, the frequency of fever relapse and pulmonary complications. Fifteen patients from group B were subsequently treated with antibiotics: two of these developed secondary purulent infections of the middle ear and one showed a slight pleural effusion. These results do not support the routine use of antibiotics in infants and small children admitted to hospital with pneumonia and bronchiolitis.

Experimental pneumonia in gnotobiotic calves produced by respiratory syncytial virus

A bovine isolate of respiratory syncytial virus (RSV), when inoculated intranasally into eight gnotobiotic calves produced significant macroscopic lesions of the lung (2-25% consolidation) but failed to produce any clinical signs of disease. The microscopic lesions comprised proliferative and exudative bronchiolitis with accompanying alveolar collapse and infiltration by mononuclear cells of the peribronchiolar tissue and alveolar walls. Virus was recovered from the nasopharynx between days 2 and 11 after infection with peak titres between days 4 and 7. Demonstration of viral antigen by immunofluorescence in nasopharyngeal cells followed a similar detection pattern. Virus was recovered from lung or detected by immunofluorescence in the bronchiolar epithelium up to 11 days following inoculation. A serological response to RSV was demonstrated both by virus neutralization and single radial haemolysis (SRH) tests, in serum of calves from 11 days following inoculation. Specific anti-RSV IgM was detected from 9 days following infection. It is suggested that the close resemblance between the experimental disease in calves and the pathology of acute bronchiolitis in children make cattle a particularly relevant model for the human disease.

Pathogenicity of various adenovirus serotypes in the presence of Escherichia coli in chickens

Ten strains of adenovirus representing 10 serotypes were administered intratracheally to 3-week-old specific-pathogen-free chickens, which also received 2.9 X 10(5) colony-forming units of a pathogenic Escherichia coli intranasally. One group was given only E. coli, and one was retained as an uninoculated control. Gross pathologic alterations post-mortem were minimal and limited to multiple scattered, pale areas in the lungs of an occasional chicken in various groups. Histopathologic changes in the lungs were those of multifocal, interstitial, and occasionally diffuse pneumonia. Moderate to marked interstitial pneumonia was incited by adenovirus strains 75-1A, B-3 A-2, C-2B, and X-11; Ind-C, Stein, Tipton, J-2, and T-8 caused similar but milder lesions. Strains 75-1A, A-2, C-2B, T-8, and X-11 incited moderate to marked multifocal pneumonia; Ind-C, Stein, Tipton, J-2, and B-3 caused mild multifocal pneumonia. In all groups, the pneumonic lesions were more severe 5 days postinoculation than 12 days postinoculation. Bronchiolitis and tracheitis lesions also varied in severity with serotype. A mild hepatitis was seen with serotypes T-8 and 75-1A. Neither the uninoculated control group nor the group inoculated with only E. coli exhibited gross or histopathologic alterations.

Activation of oxidative and arachidonic acid metabolism in neutrophils by respiratory syncytial virus antibody complexes: possible role in disease

The effect of respiratory syncytial virus (RSV) antibody complexes on the metabolism of human neutrophils was determined by examining the generation of luminol-dependent chemiluminescence, superoxide, and thromboxane B2. Incubation of neutrophils with RSV antibody complexes resulted in a significant increase in the production of chemiluminescence. The increase in chemiluminescence appeared to be due to (1) active phagocytosis of RSV antibody complexes as evidenced by 70% inhibition with cytochalasin B (P less than 0.001) or (2) increased superoxide production as evidenced by 40% inhibition with superoxide dismutase (P less than 0.001). The generation of superoxide was confirmed by specific analysis in a superoxide dismutase-inhibitable ferricytochrome c reduction assay. Of particular importance was the observation that RSV antibody complexes induced the release of significant quantities of thromboxane B2 from neutrophils as determined by radioimmunoassay. Oxygen radicals and/or products of arachidonic acid metabolism may, in part, mediate the pathogenesis of RSV infection through direct tissue damage and bronchoconstriction.

Bronchiolitis: a clinical review

Bronchiolitis is an acute viral infection primarily caused by respiratory syncytial virus, affecting children under 2 years of age with a peak prior to six months. The clinical picture results from an inflammatory process of the small bronchi and bronchioles. Infants present with tachypnea and wheezing often accompanied by respiratory distress and hyperinflation. Supportive care is essential, children respond slowly to hydration and careful observation. Respiratory distress requires hospitalization with treatment including oxygen and ventilator support as indicated.

[Bronchiolitis: new pathogenetic aspects and personal cases]

The etiological, epidemiological and pathogenetical features of bronchiolitis and some clinical and biochemical data concerning seventy nine cases were discussed. It has been underlined the possible pathogenetical role of immunoallergic mechanism (immunoreactions type II, III, IV and VI), and of alterations of humoral immunocompetence (rise of IgM and deficit of IgA). Moreover it has been pointed out that hereditary, socioeconomical and environmental factors could play an important role in determining the seriousness of the clinical picture. The relationship between bronchiolitis and the respiratory diseases of the following years have been examinated.

Atopy predisposing to acute bronchiolitis during an epidemic of respiratory syncytial virus

Thirty-one infants admitted to hospital with acute bronchiolitis during an epidemic of respiratory syncytial virus were compared with a control group of 32 infants to establish whether the two groups differed in atopic background. Past history of respiratory illness, eczema, and present reactions to skin testing differed significantly between the two groups. Thus, infants with acute bronchiolitis had a significantly higher atopic predisposition than the controls.