Lower respiratory tract infections (LRTIs), including pneumonia and bronchiolitis, continue to be a major global health concern and remain the leading cause of mortality among children under five years of age. Despite advancements in medical care and vaccination programs, LRTIs account for a substantial proportion of childhood deaths, particularly in low- and middle-income countries. The high burden is largely attributed to a combination of environmental, nutritional, and socioeconomic factors that increase vulnerability among young children. In India, LRTIs represent one of the most common causes of pediatric hospital admissions and contribute significantly to morbidity and mortality. The disease burden is disproportionately higher in rural and underprivileged populations where access to healthcare services is often limited. Several risk factors have been consistently associated with increased incidence and severity of LRTIs. Younger age, especially infancy, is a critical determinant due to immature immune responses and smaller airway anatomy. Malnutrition further compromises immunity, making children more susceptible to severe infections and complications. Additionally, poor socioeconomic conditions, including overcrowding, inadequate housing, and exposure to indoor air pollution, play a significant role in disease transmission and progression. Delayed healthcare-seeking behavior is another important factor influencing outcomes. Caregivers may not recognize early warning signs or may face barriers such as financial constraints, lack of awareness, or limited accessibility to healthcare facilities. This delay often results in children presenting with advanced disease, increasing the risk of severe complications and mortality. Given the high burden and preventable nature of many contributing factors, identifying clinical and epidemiological predictors of severity in LRTIs is crucial. Early recognition of high-risk cases allows for prompt triage, timely intervention, and appropriate allocation of healthcare resources, particularly in tertiary care settings. Understanding these predictors can also aid in developing targeted preventive strategies, improving clinical outcomes, and reducing the overall burden of pediatric respiratory illnesses. Objectives 1. To study the clinical profile of pediatric LRTIs 2. To identify predictors of disease severity 3. To assess associated risk factors

Study Design Prospective observational study Study Setting Department of Respiratory Medicine, Balaji Hospital, Raipur, Chhattisgarh Study Duration 12 months Study Population Children aged 1 month–12 years admitted with LRTI Sample Size 320 children Inclusion Criteria • Clinical diagnosis of LRTI (cough, tachypnea, chest indrawing) • Radiological confirmation where applicable Exclusion Criteria • Congenital lung disease • Immunodeficiency disorders Data Collection • Demographic details • Clinical signs (fever, cough, respiratory distress) • Oxygen saturation • Nutritional status • Laboratory parameters Severity Classification Based on WHO criteria: • Non-severe • Severe (hypoxemia, danger signs) Statistical Analysis • Chi-square test • Logistic regression • p < 0.05 considered significant

Demographic Profile • Mean age: 3.9 ± 2.8 years • <1 year: 38% • Male: 60%, Female: 40% Clinical Presentation The clinical presentation of pediatric lower respiratory tract infections (LRTIs) in this study showed a predominance of classical respiratory symptoms and signs, reflecting the acute inflammatory involvement of the lower airways. Fever was observed in 85% of the cases, making it one of the most common presenting symptoms, indicative of an underlying infectious etiology. Cough was the most frequent symptom, reported in 92% of children, highlighting its importance as a primary clinical feature in LRTIs. Tachypnea, a key diagnostic criterion for respiratory infections in children, was present in 78% of patients. It serves as an early and sensitive indicator of respiratory compromise and is widely used in clinical settings for prompt identification of pneumonia and related conditions. Chest indrawing, noted in 52% of cases, reflects increased work of breathing and is often associated with moderate to severe disease, requiring closer monitoring and possible hospitalization. Hypoxemia, defined as oxygen saturation (SpO₂) below 90%, was observed in 30% of the children and emerged as a critical marker of disease severity. It indicates impaired gas exchange and is strongly associated with increased risk of complications and mortality. The presence of hypoxemia necessitates immediate medical intervention, including oxygen therapy and supportive care. Overall, the high prevalence of these clinical features underscores the importance of early recognition and assessment of severity in pediatric LRTIs to ensure timely and appropriate management. Diagnosis Distribution Diagnosis Percentage Pneumonia 42% Bronchiolitis 28% WALRI 20% Others 10% Risk Factors Identified • Malnutrition: 46% • Passive smoking: 34% • Overcrowding: 40% • Incomplete immunization: 28% Predictors of Severity Predictor Odds Ratio p-value Age <1 year 2.9 <0.01 Malnutrition 3.2 <0.01 Hypoxemia 4.5 <0.001 Delayed hospital visit 2.1 <0.05 Key Findings • Hypoxemia was the strongest predictor of severity • Malnourished children had higher complication rates • Younger age group showed increased hospitalization These findings are consistent with previous studies showing age, nutrition, and hypoxia as major determinants of severity.

This study highlights that LRTIs remain a significant burden in pediatric populations. Pneumonia was the most common presentation, similar to other Indian studies. Young age and malnutrition were important predictors, consistent with multicentric Indian research showing undernutrition as a major risk factor. Hypoxemia emerged as the strongest predictor, aligning with studies demonstrating its role in severe disease and need for hospitalization. Environmental and socioeconomic factors such as overcrowding and poor ventilation also contributed significantly to severity.

LRTIs continue to be a major health concern. Key predictors of severity include: • Younger age • Malnutrition • Hypoxemia • Delayed healthcare access Early identification and timely intervention can significantly improve outcomes. Recommendations • Routine screening for hypoxemia using pulse oximetry • Nutritional assessment in all pediatric patients • Early referral and treatment • Strengthening immunization coverage Limitations • Single-center study • Limited microbiological evaluation • Possible recall bias in history

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