Incidence and severity profile of viral respiratory tract infections in children admitted to the tertiary level pediatric intensive care unit

Abstract

Background : Viruses cause a significant percentage of community acquired pneumonia (CAP) especially in children less than 2 years of age. Respiratory syncytial virus (RSV), influenza A, and para-influenza types 1 are the most common causes of viral pneumonia in children. Other viral pathogens include adenovirus, rhinovirus, influenza B, and enteroviruses Methods : This is a retrospective chart review of all patients aged 1 month to 16 years admitted to PICU at Sir Ganga Ram Hospital with the diagnosis of viral pneumonia during 6 months. Patients were excluded if their nasopharyngeal and oropharyngeal secretions had not been sent for viral studies within 24 hours of admission. DNA and RNA real time PCR test was performed using Respi-Finder kit and Quisymphony extraction machine (Qaigen, Germany). Results : During the study period, 306 patients were admitted to our PICU out of which 67 (11.6%) were admitted with diagnosis of pneumonia. 25 children were excluded from the study as 12 had bacterial pneumonia, viral DNA/RNA PCR was not sent in nine patients and in four patients, the etiological agent could not be determined. The final study group comprised of 42 patients with a median age of 9.5 months (Range 6 weeks -10 years) with a male to female ratio of 2.5:1. Average duration of symptoms prior to admission was 4.3 days. Most common symptom was cough seen in around 90% of patients followed by fever (80 %); fast breathing (73%), decreased feeding (30 %).Blood culture sent at admission was sterile in all patients. RSV was the most common virus isolated in 57 of the patients followed by Rhinovirus/ enterovirus in 26%, H1N1 (9.5%), influenza B (9.5%), Boca virus (7.1%), parainfluenza virus (7.1%), coronavirus and adenovirus in 2.3 % each. Infection with a single virus was seen in 28 children and co-infection with two or more of the viruses were seen in 14 children. Supplemental oxygen therapy was used in 15 children (35.7%) and 17 children (35.7%) needed some form of ventilator assistance. Non — invasive ventilation was used in 11 children (26.2%) and invasive mechanical ventilation in 14.2 % of the study subjects. ET aspirates sent for cultures immediately after intubation were sterile in all patients. Four (9.5%) children had hypotension at the time of admission requiring inotropic support, from whom influenza B was isolated from two patients and RSV A and Adenovirus were isolated from one patient each. Two children had evidence of multiple organ dysfunction requiring continuous renal replacement therapy. Adenovirus and influenza B was isolated from these patients. OUTCOME — In our cohort of children with viral pneumonia, three patients had in-hospital mortality. Among them, two had superadded bacterial infection (Acinetobacter baumanii) and one had Severe combined immunodeficiency. Conclusion : RSV was the most common etiological agent of viral pneumonia in our study. Around 1/3 of our patients’ with viral pneumonia required ventilator assistance.