Bronchiolitis is one of the common reason for hospitalization of children and frequently caused by viral infection. The guidelines given by American Academy of Pediatrics(AAP) strongly recommends that clinician should diagnose bronchiolitis and assess the severity on the basis of history and physical examination.[1] Bronchiolitis is an acute lower respiratory tract infection in early childhood caused by different viruses, with coughing, wheeze and poor nutrition as the major symptoms with a significant proportion experiencing at least one episode.[2]The American Academy of Pediatrics Clinical Practice Guideline defines bronchiolitis as “a constellation of clinical symptoms and signs including a viral upper respiratory prodrome followed by increased respiratory effort and wheezing in children less than two years of age.” Further, the guidelines of the American Academy of Pediatrics (AAP) emphasized that clinicians should diagnose bronchiolitis and assess its severity based on history and physical examination. Routine radiographic or laboratory studies are not recommended for diagnosis.[3]It is common in children under two years old and is typically caused by viral infections. Its incidence peaks during the rainy season (June) and winter months (October to February).[4,5] Bronchiolitis is characterized by inflammation and damage to small airways (<2 mm diameter), representing a spectrum of clinical and histological abnormalities across multiple respiratory conditions.[6] Currently, bronchiolitis lacks any established pharmacological treatment. Instead, supportive treatment options are available to manage symptoms, including nebulization with bronchodilators, hypertonic saline, epinephrine, and/or steroids. Notably, the routine use of these treatments in bronchiolitis management is not supported by evidence. Studies have found no conclusive benefits to warrant the routine recommendation of nebulization with bronchodilators, hypertonic saline, epinephrine, and steroids for specific treatment of bronchiolitis.⁵ Hence, in view of the aforementioned details, understanding the epidemiological data, clinical presentation, and associated risk factors for acute bronchiolitis patients especially severe cases requiring admission is crucial to identify these patients early and manage them appropriately. Thus, the present study was planned and carried to analyse the clinico-epidemiological characteristics and associated risk factors for acute bronchiolitis patients especially severe cases requiring hospitalization.

MATERIALS AND METHODS:

This observational study was conducted at the Department of Pediatrics, People's College of Medical Sciences, Bhopal for the duration of 1.5 years, from June 1, 2023, to December 31, 2024. The study area comprised the Pediatric Ward and Pediatric Intensive Care Unit (PICU) of PCMS & RC, Bhopal. The sample size included all patients admitted with acute bronchiolitis during the study period. Data were collected from all admitted patients with acute bronchiolitis in the Department of Pediatrics, People's Hospital, Bhopal, serving as the primary source of information.The study was approved by the Institutional Ethics Committee of People's College of Medical Sciences, Bhopal, and informed consent was obtained from the parents/guardians of all participating children prior to enrollment.The study included admitted children aged 1 month to 24 months who were diagnosed with acute bronchiolitis. The attendant (parent or guardian) of each child had to provide informed consent to participate in the study, ensuring that all enrolled patients met these specific criteria.The study excluded children who had prior hospital admissions with acute wheezing episodes, as well as those whose parents were unwilling to provide consent to participate in the study. Furthermore, children outside the specified age range, specifically those below one month or above 2 years of age, were also excluded from the study.All patients of acute bronchiolitis admitted during study period were enrolled in the study after taking informed consent from the parents. All the demographic variables such as age, gender, socio-economic condition, parental literacy, housing condition were filled in predefined proforma. Clinical sign and symptoms like fever, cough, running nose, fast breathing, difficulty in feeding, respiratory rate, respiratory system examination and mental status were included. Risk factors like birth history and neonatal history (gestational age, NICU admission, smoking in antenatal mother etc.), history of smoking in the family members, indoor- outdoor pollution was recorded.Severity of the disease was judged as per BROSJOD scoring system. Sant Joan de Déu Hospital bronchiolitis score (BROSJOD) was designed in 1999. It aimed to objectify patient severity into degrees, in order to determine what kind of support was needed depending on the value obtained. The severity of bronchiolitis was assessed using the BROSJOD scoring system, which categorizes patients into three crisis levels based on their scores. Scores ranging from 0 to 5 indicate a minor crisis, scores between 6 and 10 signify a moderate crisis, and scores from 11 to 16 denote a severe crisis.Data was filled in excel sheet and coded. Data was analyzed using SPSS windows 21.0 software. Descriptive statistics like percentage and mean were used for analysis. Odd’s ratio was calculated to find out the strength of association between risk factors causing sever bronchiolitis as against mid-moderate disease. A p-value of<0.05 was considered as significant.

OBSERVATION AND RESULTS:

Table 1: Risk factors for severe acute bronchiolitis: Demography, season & host factors (n=80)

Odds ratio is more than 1 when child’s age is less than 1 year, he/she is malnourished (weight for length <median), disease occurring in autumn and winter season, associated comorbidity and partial vaccination; it means the chances of developing serious crisis is more in these groups compared to second group. Though the statistically significant association is seen only in the presence of comorbidity (table 1).

Table 2: Risk factors for severe acute bronchiolitis: Antenatal/Natal/Post natal factors

In this study, patients having history of NICU admission showed statistically strong significant association with severe bronchiolitis. Chances of developing severe bronchiolitis is also more in patients having history of preterm birth and in babies born with low birth weight (OR>2) (table 2).

Table 3: Duration of symptoms at the time of presentation as risk factors for severe acute bronchiolitis

Table 5 shows that delay in seeking health care leads to increased severity of the disease. Higher mean duration of fast breathing, chest indrawing, audible wheeze, feeding difficulty, and vomiting all are significantly associated with severe acute bronchiolitis.

Table 4: Disease severity as per BROSJOD scoring system (n=80)

Table 5: Risk factors for severe acute bronchiolitis: Family history (n=80)

Present study is showing OR>1 (more chances of developing severe bronchiolitis) in lower socioeconomic strata, patients exposed to allergens, cigarette/bidi smoking, and presence of siblings in the family (table 3). Although none was found to be statistically significant.

Table 6: Data on Outdoor/Indoor pollution in two groups (n=80)

Present study found statistically strong association between severe bronchiolitis and indoor pollution (history of renovation in the house in last 2 months and poor living conditions), outdoor pollution (intense traffic) and presence of cockroaches also had OR of >2, signifying as risk factor for severe disease (table 4). Surprisingly, use of air fresheners and sprays in the house, presence of pet in the house using wood chulha and carpet in the house found to be negatively associated with severity of the disease.

DISCUSSION:

The present study analyzed the association of risk factors with severity of acute bronchiolitis in admitted patients. These patients of bronchiolitis were admitted in PICU and paediatric ward of People’s Hospital of People’s College of Medical Sciences and Research Centre, Bhopal. This study observed maximum patients were in the age group less than 6 months (42.5%) followed by 32.5 % in 6-12 months age group. Similar to our results, Nguyen SN et al[3]found the majority (57%) being under 6 months of age. Robledo-Aceves M et al[6]reported the mean age of children with severe bronchiolitis was 6.6 ± 5.7 months (range, 1–24 months), Atay Ö et al[7]reported the mean age was 9±2.4 months with maximum number in 7 to 12 months [28 (27.7%)]. Bakalovic G et al[8] also revealed that the majority of patients were aged less than 6 months (87.7%).Jeswani NL et al[9]found the mean corrected age of hospitalized patients was 5.08 ± 4.70 months (range: 1-24 months);418 (71%) were under 6 months, 287 (49%) were under 3 months. We found a distinct seasonal pattern of cases and the majority of cases occurring during specific times of the year. Autumn (September, October, and November) accounts for the highest frequency of cases 37/80 cases (46.25%), followed closely by winter (December, January, and February) with 25 cases (31.25%).This seasonal distribution suggests that environmental factors such as temperature and humidity may play a role in the development and spread of bronchiolitis. In consistent to our study, an Indian study by Hindupur A et al[10]confirmed the seasonality of RSV infection with increased positivity in September to February. Another study by Nguyen SN et al[3]found that patients with bronchiolitis were admitted in the hospital throughout the year, but there was a notable peak in admissions during in the month of March (11.1%), followed closely by January and February. Similarly, Jeswani NL et al[9] found that there was a peak in hospital admission rates during the fall season (46%), followed by winter (28%), spring (17%), and summer (9%). Another study by Bakalovic G et al[8]observed the highest number of cases during winter, peaking in the month of January 29/155 (18.7%) followed by February 24/155 (15.5%) and least in April 6/155 (3.9%). Similarly, other study by Stockman Lauren J et al[11]alleges the highest number of diseased in the winter months. Hervás Det al[12] in their study also revealed that seasonal distribution of RSV and non-RSV bronchiolitis follows different rates in different months, depending on climate and epidemiological conditions in the world. In our study, all 100 % children of bronchiolitis had nasal symptoms & cough, and their duration varied from 2 days to 10 days. 61 children developed feeding difficulty and feeding was found to be reduced upto 60% in some children. One child presented with febrile seizure too. Similarly, Nguyen SN et al[3]found that all patients of acute bronchiolitis presented with cough, tachypnea, and runny nose. Ravaglia C et al[13] observed the most common clinical signs of bronchiolitis in children were tachypnea, tachycardia, and worsening respiratory symptoms, were preceded by a 2–3 days history of rhinorrhea.We found 7 patients with comorbidity; 6 had congenital heart diseases and one had Down syndrome. In the study by Jeswani NL et al,[9] other comorbidities present were consolidation / atelectasis, acute otitis media, and urinary tract infection. Eriksson M et al[14]reported 2.8-6.4% infants having congenital heart disease. Present study also found statistically strong association between severe bronchiolitis and indoor pollution; history of renovation in the house in last 2 months (OR=3.37; 95%CI=0.98-11.54; p value=0.04) and poor living conditions (OR=4; 95% CI=0.95- 16.73; p value=0.04). Outdoor pollution (intense traffic) and presence of cockroaches in the house also had OR of >2, signifying as risk factor for severe disease. Surprisingly, the use of air fresheners, sprays in the house, presence of pet in the house, wood chulha and carpet in the house were found to be negatively associated with severity of the disease. This could be because these factors do not contribute directly to the pathogenesis of acute bronchiolitis, which is more of a viral infection rather than allergic condition. Similar to our study, Robledo-Aceves M et al[6] identified environmental factors like overcrowded living conditions, pest and cockroach infestation are associated with severe viral bronchiolitis. Similar to our study, Ruiz- Charles MG et al[15] did not found the presence of pets, pest infestation, or farm animals association with severe viral bronchiolitis. Our study found that delay in seeking health care leads to increased severity of the disease. Higher mean duration of fast breathing, chest indrawing, audible wheeze, feeding difficulty, and vomiting all are found to be significantly associated with severe acute bronchiolitis. Kneyber MCJ et al[16] reported that wheezing is a common occurrence after RSV bronchiolitis in infancy, and can persist for 5 years or more. however, no significant difference was found in the incidence of recurrent wheezing between children who had RSV bronchiolitis and those in a control group after 5 years of follow-up. Eriksson M et al[14]reported repeat hospitalization for wheezing happened in 8.4 and 4.9% of children without risk factors over and under the age of 2 months, respectively (p < 0.001). A study by Parker MJ et al[17]on 312 infants with wheezing and respiratory distress identified four risk factors for major medical interventions (MMI): high accessory muscle score, low oxygen saturation, high respiratory rate, and poor fluid intake. Infants with these risk factors were more likely to require MMI, while those without them were at low risk and suitable for outpatient management. Most infants without risk factors (87.8%) were discharged within 12 hours and these findings can guide hospitalization decisions for infants with bronchiolitis.

CONCLUSION:

To conclude, findings highlight the significant impact of environmental factors, such as indoor and outdoor pollution, on the severity of the disease. Specifically, the study reveals that history of renovation in the house, poor living conditions, and exposure to intense traffic are significant risk factors for severe bronchiolitis. Additionally, the study confirms that delay in seeking healthcare leads to increased severity of the disease, with higher mean duration of symptoms such as fast breathing, chest indrawing, and feeding difficulty significantly associated with severe acute bronchiolitis.The study also underscores the importance of understanding the seasonal pattern of bronchiolitis, with the majority of cases occurring during autumn and winter months.

Conflict of interest: None declared

Funding: Nil

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