Overview of prevention and management of acute bronchiolitis due to respiratory syncytial virus

Respiratory Syncytial Virus is the Most Common Causative Agent of Viral Bronchiolitis in Young Children: An Updated Review

BACKGROUND

Viral bronchiolitis is a common condition and a leading cause of hospitalization in young children.

OBJECTIVE

This article provides readers with an update on the evaluation, diagnosis, and treatment of viral bronchiolitis, primarily due to RSV.

METHODS

A PubMed search was conducted in December 2021 in Clinical Queries using the key terms "acute bronchiolitis" OR "respiratory syncytial virus infection". The search included clinical trials, randomized controlled trials, case control studies, cohort studies, meta-analyses, observational studies, clinical guidelines, case reports, case series, and reviews. The search was restricted to children and English literature. The information retrieved from the above search was used in the compilation of this article.

RESULTS

Respiratory syncytial virus (RSV) is the most common viral bronchiolitis in young children. Other viruses such as human rhinovirus and coronavirus could be etiological agents. Diagnosis is based on clinical manifestation. Viral testing is useful only for cohort and quarantine purposes. Cochrane evidence-based reviews have been performed on most treatment modalities for RSV and viral bronchiolitis. Treatment for viral bronchiolitis is mainly symptomatic support. Beta-agonists are frequently used despite the lack of evidence that they reduce hospital admissions or length of stay. Nebulized racemic epinephrine, hypertonic saline and corticosteroids are generally not effective. Passive immunoprophylaxis with a monoclonal antibody against RSV, when given intramuscularly and monthly during winter, is effective in preventing severe RSV bronchiolitis in high-risk children who are born prematurely and in children under 2 years with chronic lung disease or hemodynamically significant congenital heart disease. Vaccines for RSV bronchiolitis are being developed. Children with viral bronchiolitis in early life are at increased risk of developing asthma later in childhood.

CONCLUSION

Viral bronchiolitis is common. No current pharmacologic treatment or novel therapy has been proven to improve outcomes compared to supportive treatment. Viral bronchiolitis in early life predisposes asthma development later in childhood.

3% nebulized hypertonic saline versus normal saline for infants with acute bronchiolitis: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

This study evaluated the efficacy and safety of 3% nebulized hypertonic saline (NHS) in infants with acute bronchiolitis (AB).

METHODS

We systematically searched the PUBMED, EMBASE, Cochrane Library, China National Knowledge Infrastructure Database, WANFANG, and VIP databases from inception to June 1, 2022. We included randomized controlled trials comparing NHS with 0.9% saline. Outcomes included the length of hospital stay (LOS), rate of hospitalization (ROH), clinical severity score (CSS), rate of readmission, respiratory distress assessment instrument, and adverse events. RevMan V5.4 software was used for statistical analysis.

RESULTS

A total of 27 trials involving 3495 infants were included in this study. Compared to normal saline, infants received 3% NHS showed better outcomes in LOS reduction (MD = -0.60, 95% CI [-1.04, -0.17], I2 = 92%, P = .007), ROH decrease (OR = 0.74, 95% CI [0.59, 0.91], I2 = 0%, P = .005), CSS improvement at day 1 (MD = -0.79, 95% CI [-1.23, -0.34], I2 = 74%, P < .001), day 2 (MD = -1.26, 95% CI [-2.02, -0.49], I2 = 91%, P = .001), and day 3 and over (MD = -1.27, 95% CI [-1.92, -0.61], I2 = 79%, P < .001), and respiratory distress assessment instrument enhancement (MD = -0.60, 95% CI [-0.95, -0.26], I2 = 0%, P < .001). No significant adverse events related to 3% NHS were observed.

CONCLUSION

This study showed that 3% NHS was better than 0.9% normal saline in reducing LOS, decreasing ROH, improving CSS, and in enhancing the severity of respiratory distress. Further studies are needed to validate these findings.

Changes in T-Cell Subsets and Serum IFN-γ, IL-17, and IgE Levels in Children with Respiratory Syncytial Virus Capillary Bronchitis and Their Clinical Significance

Objective

To investigate the changes in T-cell subsets and serum IFN-γ, IL-17, and IgE levels in children with respiratory syncytial virus capillary bronchitis and their clinical significance.

Methods

The clinical data of 50 children with respiratory syncytial virus capillary bronchitis admitted to our hospital between July 2020 and June 2021 were retrospectively reviewed, and they were included in the observation group, while 50 children with a healthy physical examination during the same period were chosen as the control group. The T-cell subsets (CD4, CD8, and CD4/CD8) and serum IL-4, IL-8, IFN-, IL-17, and IgE levels of children in the two groups were compared, and the clinical significance of the changes in the levels of the indices mentioned above was analyzed.

Results

There was no statistically significant difference in T-cell subset levels (CD4 and CD8) between the two groups (P > 0.05); the level of CD4/CD8, IL-4, IL-8, IL-17, and IgE in the observation group were substantially higher than those in the control group (P < 0.05), while the serum IFN-γ levels in the observation group were significantly lower than those in the control group (P < 0.05).

Conclusion

Increased CD4/CD8 levels in children with respiratory syncytial virus capillary bronchitis cause an imbalance in the Th1/Th2 immune response, similar to changes in bronchial asthma, suggesting a link between the two diseases. Increased serum levels of IL-4, IL-8, IL-17, and IgE and decreased serum levels of IFN-γ have been seen in children with respiratory syncytial virus capillary bronchitis, suggesting the severity of the children's disease may in part be reflected in the levels of the aforementioned serum indicators.

Identification of bronchiolitis profiles in Italian children through the application of latent class analysis

BACKGROUND

Bronchiolitis is the primary infection of the lower respiratory tract in children under 2 years of age. Although it is generally considered a single nosological entity, recent studies suggested remarkable clinical heterogeneity. To date, no studies have identified classes of children with bronchiolitis within the Italian population. This study aimed to identify discrete profiles of Italian children hospitalized with bronchiolitis using a clustering approach and to compare findings with those obtained in international cohorts.

METHODS

This was a retrospective single-centre study conducted on children aged ≤2 years hospitalised with bronchiolitis (n = 401) at the Department of Infectious Diseases and the University Department of General Pediatrics in "Giovanni Di Cristina" Pediatric Hospital of Palermo, Italy, between November 2012 and May 2019. Bronchiolitis profiles were determined by latent class analysis, classifying children based on clinical characteristics at admission and viral aetiology.

RESULTS

Three profiles were identified. Class 1 (49%) was composed of 45% male children; all children were aged ≤6 months at hospitalization; 77% were infected with RSV; 100% had respiratory distress, 11% had apnea and none had cough. Class 2 (77%) was mainly composed of male subjects (51%); 19% were aged > 6 months at admission; 37% were infected with RSV; 12% had respiratory distress, 5% had apnea and 90% had cough. Class 3 (19%) included the largest proportion of male subjects (94%) and was mostly composed of children aged > 6 months at the time of admission (68%); 70% had cough, 12% showed respiratory distress and none presented with apnoea. Children in Class 1 were more frequently born near the epidemic season (p = 0.028); breastfeeding duration was significantly longer for children in Class 3 (p = 0.004).

CONCLUSIONS

The study identified distinct clinical profiles of bronchiolitis by a clustering approach in a single-centre study of children hospitalised for bronchiolitis in Italy. The three bronchiolitis profiles share some similarities with those identified in international studies using the same statistical approach. These findings may help to increase the understanding of the phenotypic variability that typically characterizes bronchiolitis, with relevant implications for future research.