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Epidemiology and Outcome of Acute Bronchiolitis in Children in the Tobruk Area, Libya

Bronchiolitis is inflammation of the bronchioles, usually caused by an acute viral illness. It is the most common lower respiratory tract infection in children younger than 2 years.The aim of this study is to analyze the hospital incidence of acute bronchiolitis in children aged 2 months up to 2 years, to assess the relation, the severity of the disease to age, gender, season, family history of atopy, and to assess the treatment and outcome. The retrospective study collected the data from the admission records of patients. 198 admissions for acute bronchiolitis represented 14.6% of hospital admission rates. Most in ages between 2-6 months 128 (64.6%). Female: Male ratio 1.1:1, female patients 102 (51.5%). The history of Atopy in the family was positive in 136 (68.7%) of patients. The disease was not severe as only 27 (13.6%) were admitted to PICU, and only 3 (1.6%) of them needed mechanical ventilation, in addition to there being no mortalities. Most cases were in winter 81 (40.9%) (P-value 0.02). All patients received Salbutamol nebulizer, 47 (23.7%) received hydrocortisone injection (IV), and 45 (22.7%) received Ipratropium bromide nebulizer. Acute Bronchiolitis is an important cause of admissions in infants, especially under the age of 6 months.


INTRODUCTION
Bronchiolitis is defined as a disorder most commonly caused by a viral infection and is the most common lower respiratory infection in infants (Kliegman et al 2011). Bronchiolitis symptoms and signs include viral upper respiratory Prodrome, followed by breathlessness and wheezing (Ralston et al 2014). Bronchiolitis is often cited as the leading cause of hospitalization for infants and is commonly caused by Respiratory syncytial virus (RSV) (Shay et al 1999;Hasegawa et al 2013, Stockman et al 2012, occurring in epidemics during winter months. Preterm infants receiving assisted ventilation and those on home oxygen therapy are particularly at risk of RSV related hospitalization (Deshpande & Northern, 2003, Willson et al 2003. Young maternal age, low social class, low birth weight, and maternal smoking were among factors associated with an increased risk of hospital admission with bronchiolitis (Green et al 2016).
Pre-existing disease/comorbidity, and cardiac anomaly are associated with a significantly higher risk of death from severe RSV infection. Bronchopulmonary dysplasia, immunodeficiency, cerebral palsy, and Down's syndrome are recognized risk factors for severe bronchiolitis (Sommer et al 2011, Boyce et al 2000, Murray et al 2014. Recent studies in the US show the incidence of bronchiolitis hospitalization decreased from 17.9 to 14.9 per 1000 children aged <2 years between 2000 and 2009 (Hasegawa et al 2013). In England 2011, the estimated annual hospital admission rate for bronchiolitis was 46.1 per 1000 infants aged <1 year (Green et al 2016). In Libya, we did not find any published study on national hospitalizations for bronchiolitis.

Aims And Objectives:
We aimed to analyze hospital incidence of acute bronchiolitis in children under 2 years of age from Jan 2018 to 31 st of Dec 2018. To assess the relationship between acute Bronchiolitis and age, gender, region, and seasonal variation, and the relation to family atopy, and to assess its management and outcomes.

MATERIALS AND METHODS
A retrospective study was done through the collection of data from the Statistic office. Unfortunately, the International Classification of Disease (ICD) codes is not used in Tobruk medical center. The data was collected from the patient admission files. We have collected the data about the patients who suffered from acute bronchiolitis, aged 2 months up to 2 years old, from January to December 2018. This included the date of admission, date of discharge, gender, age, nationality, residence area, type of admission: PICU or general pediatric ward, family history of Atopy, association with bronchopneumonia, treatment, and mortality.
The primary outcome was the incidence of acute bronchiolitis in children aged 2 months up to 2 years. Secondary outcome measures were: percentage of patients in a different age group between 2 months up to 2 years, percentage of male and female patients, percentage of patients who were admitted to PICU, percentage of use of mechanical ventilation, Strategy of management, Seasonal variation, and relation to Atopy in the family.
Statistics Analysis: Data were expressed in percentages. A frequency table is used to describe the interaction between two categorical variables.

RESULTS
The total admission of patients in the Pediatric Ward and PICU in the year 2018 was 2999 after excluding the admissions in NICU. From them, 1359 patients were below the age of 2 years, 198 admissions were for acute bronchiolitis in children aged less than 2 years, representing 14.6% of the hospital admission rate for bronchiolitis per 1000 children aged < 2 years. In Table 1 we noted, the most age group affected was between 2-6 months 128 (64.6%) (P-value 0.1). F/M ratio 1.1:1 and female patients 102 (51.5%). The admissions in the general pediatric ward were more than in the Pediatric Intensive Care Unit (PICU) 171 (86.4%). Only one case admitted to PICU was with Down syndrome and with congenital heart disease 3.7%, and only 3 of 27 (11.1%) needed mechanical ventilation. The predominance of admissions to PICU was for infants aged 2-6 months 18 (66.7%) (P-value 0.13) and with male predominance 15 (55.6%).
We found a significant predominance of the presence of Atopy in the family of patients with acute bronchiolitis 136 (68.7%). The occurrence of Bronchopneumonia for about a quarter of the patients of AB 47 (23.7%), that's why they had received antibiotics. The attacks of acute bronchiolitis are at their highest in winter 81 (40.9%) (P-value 0.02) as seen in Figure 1. Regarding the management strategy, we found that all patients 198 (100%) have received Salbutamol and IV fluid, 47 (23.7%) received IV hydrocortisone, and 45 (22.7%) have received Ipratropium bromide nebulizer. 22 (11.1%) patients have left against medical advice. The predominance of patients of acute bronchiolitis was from Tobruk 162 (81.8%), as seen in Figure 2. Average Length of Stay (LOS) was 3.1-3.3 days, and if primary admission to PICU is needed, then LOS is 4.5 days. The Mortality rate due to acute bronchiolitis in the year 2018 was 0%. In our study, the predominance was in the age under one year, with a peak age between 2 and 6 months. This is the same result in a study done in Saudi Arabia (Abha city) 1997-2001. In our study, the female patients 102 (51.5%) are slightly more than male patients with ratio 1.1:1, in contrast to a study done in Pakistan and Portugal where there was male predominance (Ahmad et al 2013) (Mendes-da-Silva et al 2018). In our study, most patients had positive Atopy in the family 68.7%, this is the same result reported by Trefny et al (2000). Infants with a family history of Atopy, are at increased risk for severe RSV infection as indicated by higher rates of hospitalization, longer hospital stay, and more frequent occurrences of bronchiolitis (Trefny et al 2000). The patients admitted to PICU were 27 (13.6%) and were mainly infants aged 2-6 months 18 (66.7%). These results are the same as those of a study conducted in Saudi Arabia. The other studies show death from respiratory failure in bronchiolitis is rare and ranges for RSV bronchiolitis from 2.9 (UK) to 5.3 (USA) (Fleming et al 2005(Fleming et al , Øymar et al 2014.

CONCLUSION
The incidence of Acute Bronchiolitis in the Tobruk Area/Libya is nearly the same as the incidence reported in the other Studies.
Based on epidemiology and outcomes made in our study, we conclude that acute bronchiolitis is more prevalent in children younger than one year and patients with a positive family history of Atopy and predominant more in winter. The severe course of the disease was in infants aged less than one year, and in patients with underlying diseases such as Down syndrome and congenital heart disease.

ACKNOWLEDGEMENT
We would like to thank the workers at the Statistic Office and the Staff of the Pediatric Ward of Tobruk Medical Center.