Recent advances in the management of acute bronchiolitis

Risk Factors Associated with Severe RSV Infection in Infants: What Is the Role of Viral Co-Infections?

The respiratory syncytial virus (RSV) represents the leading cause of viral lower respiratory tract infections (LRTI) in children worldwide and is associated with significant morbidity and mortality rates. The clinical picture of an RSV infection differs substantially between patients, and the role of viral co-infections is poorly investigated. During two consecutive winter seasons from October 2018 until February 2020, we prospectively included children up to 2 years old presenting with an acute LRTI, both ambulatory and hospitalized. We collected clinical data and tested nasopharyngeal secretions for a panel of 16 different respiratory viruses with multiplex RT-qPCR. Disease severity was assessed with traditional clinical parameters and scoring systems. A total of 120 patients were included, of which 91.7% were RSV positive; 42.5% of RSV-positive patients had a co-infection with at least one other respiratory virus. We found that patients suffering from a single RSV infection had higher pediatric intensive care unit (PICU) admission rates (OR = 5.9, 95% CI = 1.53 to 22.74), longer duration of hospitalization (IRR = 1.25, 95% CI = 1.03 to 1.52), and a higher Bronchiolitis Risk of Admission Score (BRAS) (IRR = 1.31, 95% CI = 1.02 to 1.70) compared to patients with RSV co-infections. No significant difference was found in saturation on admission, O2 need, or ReSViNET-score. In our cohort, patients with a single RSV infection had increased disease severity compared to patients with RSV co-infections. This suggests that the presence of viral co-infections might influence the course of RSV bronchiolitis, but heterogeneity and small sample size in our study prevents us from drawing strong conclusions. IMPORTANCE RSV is worldwide the leading cause of serious airway infections. Up to 90% of children will be infected by the age of 2. RSV symptoms are mostly mild and typically mimic a common cold in older children and adolescents, but younger children can develop severe lower respiratory tract disease, and currently it is unclear why certain children develop severe disease while others do not. In this study, we found that children with a single RSV infection had a higher disease severity compared to patients with viral co-infections, suggesting that the presence of a viral co-infection could influence the course of an RSV bronchiolitis. As preventive and therapeutic options for RSV-associated disease are currently limited, this finding could potentially guide physicians to decide which patients might benefit from current or future treatment options early in the course of disease, and therefore, warrants further investigation.

Association between surfactant protein B gene locus and acute bronchiolitis in infants

Purpose: The aim of this study was to investigate whether there is a relationship between surfactant protein B (SFTPB) C1580T polymorphism and acute bronchiolitis. Materials and Methods: The study analyzed the allele frequency and genotype distribution for the SFTPB C1580T polymorphism using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique in 103 acute bronchiolitis infants and 102 healthy infants. Results: The results showed no association between SFTPB C1580T polymorphism and clinical characteristics of acute bronchiolitis. The distribution of the CT genotype was higher in acute bronchiolitis infants (43%) than in healthy subjects (39%) and distribution of the TT genotype was found lower in acute bronchiolitis infants (38%) than in healthy subjects (41%). No significant differences in genotype distribution and allele frequency for the SFTPB C1580T polymorphism were found between case group and control group Conclusion: SFTPB C1580T gene polymorphism plays no important role in susceptibility to acute bronchiolitis. Further work on the relevance of SFTPB C1580T polymorphism in larger cohorts will require validating our results.

Nebulized Magnesium Sulphate in Bronchiolitis: A Randomized Controlled Trial

OBJECTIVE

To evaluate the efficacy and safety of nebulized magnesium sulphate as a bronchodilator in young children aged 1-24 mo with moderate to severe bronchiolitis in comparison to standard therapy.

METHODS

This was an open labeled randomized controlled trial comprising 60 children with moderate to severe bronchiolitis which was randomly assigned to 2 groups. Intervention group received nebulization with 3 mL of 3.2% magnesium sulphate (MgSO₄) (iso-osmolar) every 4 hourly for 24 h in addition to standard care and the control group received standard care alone. The primary outcome measure was to compare the improvement of bronchiolitis severity score (BSS) and length of hospitalization. The secondary outcome was to measure the need for noninvasive ventilation, need for admission to intensive care unit (ICU) in the initial visit, to evaluate the safety of magnesium sulphate and need for clinic revisit, hospital readmission and ICU readmission within 2 wk after discharge in both the groups.

RESULTS

The mean age of children allocated in the control group was 7.4 ± 5.1 mo and 7.7 ± 4.5 mo in the intervention group. There was no significant difference with respect to improvement of BSS or reduced length of hospitalization in both the groups (p > 0.05). BSS monitored sequentially after enrollment at 1, 2, 4, 8, 12, 16, and 24 h did not show statistically significant differences between the groups. Mean length of hospital stay was 2.89 ± 2.25 d in treatment group and 2.96 ± 1.86 d in control group (p = 0.902). No adverse events were observed in both the groups.

CONCLUSION

Nebulized magnesium sulphate is not superior to standard therapy in children with moderate to severe bronchiolitis.

CLINICAL TRIAL REGISTRATION NUMBER

CTRI/2018/06/014400.

The Relationship between Bronchiolitis Severity and Vitamin D Status

BACKGROUND/AIM

Acute bronchiolitis is mostly caused by viral agents in children under 2 years of age. The disease mostly has a mild clinical course however severe cases are not uncommon. Vitamin D is known to exert immune-regulatory functions. We aimed to examine the association between the clinical severity of acute bronchiolitis and serum vitamin D levels in infants.

MATERIALS AND METHODS

A total of 182 children with acute bronchiolitis were prospectively enrolled. The disease severity was assessed using the Modified Tal Scoring System and their vitamin D levels were evaluated.

RESULTS

Vitamin D deficiency or insufficiency was as high as 47.8% in infants with bronchiolitis. Infants with low vitamin D levels comprised a significantly larger proportion of patients with severe bronchiolitis (p = 0.002). Infants admitted to intensive care unit had significantly higher degrees of vitamin D deficiency or insufficiency (p < 0.001).

CONCLUSION

Vitamin D deficiency is closely linked with severe bronchiolitis and the need for intensive care unit admission in infants. We believe that assessment of vitamin D levels in infants prior to bronchiolitis season and appropriate supplementation may have a protective effect against severe bronchiolitis.

Cryobiopsy in the diagnosis of bronchiolitis: a retrospective analysis of twenty-three consecutive patients

Bronchiolitis manifests as a variety of histological features that explain the complex clinical profiles and imaging aspects. In the period between January 2011 and June 2015, patients with a cryobiopsy diagnosis of bronchiolitis were retrospectively retrieved from the database of our institution. Clinical profiles, imaging features and histologic diagnoses were analysed to identify the role of cryobiopsy in the diagnostic process. Twenty-three patients with a multidisciplinary diagnosis of small airway disease were retrieved (14 females, 9 males; age range 31-74 years old; mean age 54.2 years old). The final MDT diagnoses were post-infectious bronchiolitis (n = 5), constrictive bronchiolitis (n = 3), DIPNECH (n = 1), idiopathic follicular bronchiolitis (n = 3), Sjogren's disease (n = 1), GLILD (n = 1), smoking-related interstitial lung disease (n = 6), sarcoid with granulomatous bronchiolar disorder (n = 1), and subacute hypersensitivity pneumonitis (n = 2). Complications reported after the cryobiopsy procedure consisted of two cases of pneumothorax soon after the biopsy (8.7%), which were successfully managed with the insertion of a chest tube. Transbronchial cryobiopsy represents a robust and mini-invasive method in the characterization of small airway diseases, allowing a low percentage of complications and good diagnostic confidence.

Recent advances in the understanding of bronchiolitis in adults

Bronchiolitis is injury to the bronchioles (small airways with a diameter of 2 mm or less) resulting in inflammation and/or fibrosis. Bronchioles can be involved in pathologic processes that involve predominantly the lung parenchyma or large airways, but, in some diseases, bronchioles are the main site of injury ("primary bronchiolitis"). Acute bronchiolitis caused by viruses is responsible for most cases of bronchiolitis in infants and children. In adults, however, there is a wide spectrum of bronchiolar disorders and most are chronic. Many forms of bronchiolitis have been described in the literature, and the terminology in this regard remains confusing. In clinical practice, a classification scheme based on the underlying histopathologic pattern (correlates with presenting radiologic abnormalities) facilitates the recognition of bronchiolitis and the search for the inciting cause of the lung injury. Respiratory bronchiolitis is the most common form of bronchiolitis in adults and is usually related to cigarette smoking. Currently, the diagnosis of respiratory bronchiolitis is generally achieved based on the clinical context (smoking history) and chest CT findings. Constrictive (obliterative) bronchiolitis is associated with airflow obstruction and is seen in various clinical contexts including environmental/occupational inhalation exposures, transplant recipients (bronchiolitis obliterans syndrome), and many others. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is increasingly recognized and can be associated with progressive airflow obstruction related to constrictive bronchiolitis ("DIPNECH syndrome"). Diffuse aspiration bronchiolitis is a form of aspiration-related lung disease that is often unsuspected and confused for interstitial lung disease. Novel forms of bronchiolitis have been described, including lymphocytic bronchiolitis and alveolar ductitis with emphysema recently described in employees at a manufacturing facility for industrial machines. Bronchiolitis is also a component of vaping-related lung injury encountered in the recent outbreak.

Myocardial strain on admission predicts disease severity in infants hospitalized for bronchiolitis

OBJECTIVE

To assess cardiac function in infants with bronchiolitis and the association with disease severity and outcomes.

WORKING HYPOTHESIS

Cardiac function may be impaired in bronchiolitis and represent an early predictor of disease severity.

STUDY DESIGN

A prospective cohort study.

PATIENT SELECTION

Infants with suspected bronchiolitis were included.

METHODOLOGY

All cases received antigen detection and viral genome detection from nasal lavage or swabs and echocardiography within 24 hours from admission. Systolic and diastolic function in left ventricle (LV) and right ventricle (RV) were assessed using longitudinal strain (LS), a measure of myocardial deformation. Pulmonary artery pressures were estimated using tricuspid regurgitation jet (TR), when present, and end-systolic eccentricity index (EI ES). Main outcomes (duration of respiratory support, length of stay [LOS], and type of respiratory support) were collected. Data were compared to normative existing data, and a group of healthy infants, matched in age.

RESULTS

Twenty-eight infants with bronchiolitis and 10 healthy comparators were included. Cases with bronchiolitis showed significantly lower values of RV LS and LV LS compared to healthy comparators (LV: p0.04 and RV: P < .001). Ten infants (36%) had a normal biventricular function, nine (32%) had LV impairment, and nine (32%) had a biventricular impairment. No significant differences were found in TR and EI ES. Infants with biventricular impairment demonstrated a significant increase in LOS (p0.04) and higher levels of respiratory support compared to the healthy comparators (P = .03).

CONCLUSIONS

Bronchiolitis is associated with myocardial impairment. Cardiac function is related to disease severity and outcome.

Bronchiolitis: From Practice Guideline to Clinical Practice

The American Academy of Pediatrics' clinical practice guideline in bronchiolitis was last updated in 2014 with recommendations to improve care for pediatric patients with bronchiolitis. As most treatments of bronchiolitis are supportive, the guideline minimizes the breadth of treatments previously used and cautions the use of tests and therapies that have a limited evidence base. Emergency physicians must be familiar with the guidelines in order to apply best practices appropriately.

Maturation of Airway Defensive Reflexes Is Related to Development of Feeding Behavior during Growth in Rabbits

Introduction: Cough and expiration reflex are major lower airway defense mechanisms that have not been studied throughout development in relation with the feeding behavior.

Aim: To describe airway defense reflexes evoked by mechanical stimulation of the trachea in developing rabbit pups.

Material and Methods: Sixty one pups were allocated to 3 groups according to their feeding behavior: suckling (n = 22), weanling (n = 21) and weaning (n = 18) group. The incidence and sensitivity of defense reflexes triggered by mechanical tracheal stimulation were studied in anesthetized and tracheotomized animals. Data are expressed as median (25th to 75th percentile).

Results: The overall incidence of defensive responses (cough and/or expiration reflex) was found to be significantly higher in suckling [100% (50–100%); p = 0.01] and weanling [75% (40–100%); p = 0.05] animals when compared to weaning ones [37.5% (0–75%)]. However, cough motor pattern accounted for only 29% (0–62%) of all defensive responses in suckling rabbits and its frequency was significantly lower in this group when compared with weanling [100%(50–100%); p = 0.006] or weaning group [62%(50–100%), p = 0.05]. In other word the expiration reflex was the dominant response in suckling animals.

Conclusion: Incidence and motor pattern of defensive responses were found to be linked to the pup feeding behavior and the expiration reflex was the major response triggered in suckling pups. The results suggest that this reflex is especially fitted to occur during the coordinated swallowing - breathing fast activities of sucking.