Can prognosis be predicted with clinical and laboratory findings in patients with lower respiratory infection?

Introduction: Lower respiratory tract infections; It is one of the most important causes of mortality in children under 5 years of age, especially in developing countries. According to the 2005 report of the World Health Organization, lower respiratory tract infections are the most common cause of death in children under 5 years of age and responsible for 19% of child deaths. Studies in preschool children in both developed and developing countries show that most respiratory infections generally have viral etiology. The most common viral agents are respiratoryatuarsinsial virus, followed by humannrinovirus and parainfluenza virus. With the development of molecular diagnostic tests in recent years, the frequency of use has increased and the detection of viral agents has become easier. If the effects of viral agents, symptoms and physical examination findings on the severity and clinical presentation of the patient are better understood, it is thought that the clinical course of the patients can be predicted. Objective: The aim of this study; The aim of this study is to evaluate the clinical and laboratory findings of the patient at the time of admission together with the viral agent detected especially in the severely ill group requiring hospitalization for lower respiratory tract infection and to predict how the clinical course and prognosis will improve. Method: Between January 2014 and December 2018; Patients under the age of 5 years (except neonatal period) who were hospitalized in Ege University Children's Hospital with the diagnosis of lower respiratory tract infection (acute bronchiolitis and pneumonia), were sent to the respiratory viral panel with a nasopharyngeal specimen. Demographic, clinical and laboratory data of the patients were obtained from the hospital information system and patient files. Nasopharyngeal and nasal swab samples obtained from the patients were studied in the laboratory of Ege University Medical Faculty Department of Microbiology by using real-time polymerase chain reaction (RT-PCR) method using FTD Respiratorypathogens 21 ov kit (FastTrackDiagnosis, Luxembourg). The cases included in the study; age (in months), sex, birth week and birth weight, month and year of admission, body temperature, oxygen saturation value (in%), nasal discharge, cough, wheezing, difficulty in breathing, bruising, intercostal withdrawal clinical symptoms, number of attacks of lower respiratory tract infection, concomitant chronic disease, wheezing infant, acute phase reactant values (C-reactive protein, procalcitonin total lymphocyte and neutrophil count), positive bacterial blood, sputum, transtrakealaspiration and urine culture results sent within the first 48 hours of hospitalization, duration of hospitalization, medical treatments (inhaler, intravenoussteroid) and magnesium sulphate, antibiotic), respiratory support (oxygen, HFNC, BIPAP, IMV, ECMO) and treatment result (discharged or exitus). All these clinical and laboratory data were evaluated to predict the severity of the clinical course. For this purpose, the patients were divided into three groups according to WHO classification as severe, moderate-severe and mild clinical course. Criteria for inclusion in the severe clinical group; The patients who required invasive and non-invasive mechanical ventilation support and those who died after the treatment were evaluated as severe group. Oxygen saturation at admission was below 92% for the moderate-heavy group and patients receiving oxygen or high-flow nasal oxygen (HFNC) support were included. Other patients were evaluated as mild group. Results: Between January 2014 and December 2018, a total of 1242 patients who were hospitalized under the age of 5 with the diagnosis of Lower Respiratory Tract Infection, at the Ege University Medical Faculty Children's Hospital for the purpose of detecting a causative agent were identified. 459 (37%) of our patients were female and 783 (63%) were male. The mean age was calculated as 13.9 (min: 1- max: 62) months. 459 (37%) of our patients were female and 783 (63%) were male. The mean age was calculated as 13.9 (min: 1- max: 62) months. When divided into age groups; 535 patients (43.1%) between 1-6 months, 239 patients (19.2%) between 7-12 months, 256 patients (20.6%) between 13-24 months, 83 patients (6.7%) between 25 and 36 months, 129 patients (10.4%) between 37 -60 months were seen. 1242 patients included in the study; 746 (60.1%) were mild, 378 (30.4%) were moderate-severe and 118 (9.5%) were in severe group. When the mean age of the patients was compared according to clinical weight groups; The mean age was 13 months (min: 1- max: 53) in the severe group, 8 months (min: 1- max: 60) in the moderate-severe group, and 8 months (min: 1- max: 62) in the mild group. Oxygen saturation (SpO2) at admission was as follows; 89% (min: 60- max: 100) in the severe group, 90% (min: 60- max: 100) in the moderate-severe group, 97.5% (min: 89- max: 100) in the mild group and was statistically significant for the severe clinical course. At the time of admission, 403 (32.4%) of the 1242 patients with concomitant chronic disease and 839 (67.6%) of those without comorbid disease. Among the comorbid diseases; chronic lung diseases (CAD) in 125 patients (10.1%), congenital heart disease (CHD) in 96 patients (7.7%), neurometabolic diseases in 94 patients (7.6%), immunodeficiencies in 73 patients (5.9%) and other group (gastrointestinal system diseases, genetic diseases, renal failure) in 158 patients (12.7%) were obtained. The presence of LRTI in patients with comorbid disease was evaluated as statistically significant. When the previous LRTI episodes of the patients were evaluated, it was seen that 54.5% of the patients had the first episode. When comparing the number of attacks between the groups; the number of episodes was significantly higher in the severe group between the mild and severe groups in terms of severe clinical course. As a result of the follow-up in our study, a total of 11 patients died and were observed in the severe clinical group and were observed in the PICU. When the distribution of positive viral agents was examined; RSV (n: 579, 46.6%), HRV (n: 439, 35.3%), FLU (n: 116 9.3%), PIF (n: 119 9.6%), HBoV (n: 138, 11.1%), HMpV ( n: 85 6.8%), enterovirus (n: 29 2.3%), coronavirus (n: 67 5.4%), adenovirus (n: 81 6.5%) and a total of 349 patients (28.1%) with more than one virus together (coinfection) determined. Viruses with the highest risk for severe clinical course were FLUB, HBoV and adenovirus. Laboratory values were evaluated with neutrophilia and lymphopenia; CRP and procalcitonin levels were more frequently associated with severe clinical group. When the service or pediatric intensive care unit (PICU) hospitalizations are examined; Of 118 patients evaluated as severe group, 13 (11%) were in the ward and 105 in the PICU; Of the 378 patients in the moderate-heavy group, 352 (93.1%) were in the ward and 26 (6.9%) were in the PICU; Of the 746 patients in the mild group, 740 (99.2%) were hospitalized and 6 (0.8%) were hospitalized in the PICU. Statistically significant clinical severity of ICU hospitalization was evaluated as risk factor between the groups. Conclusion: In our study, patients who were hospitalized in our clinic with the diagnosis of LRTI between January 2014 and December 2018, under the age of 5 years and who were found to be positive for viral agents by PCR method were evaluated according to the clinical course weight groups; Age, type of virus, fever, previous LRTI, neutrophilia, lymphopenia, low SpO2 at admission, dyspnea and tachypnea and accompanying chronic disease were clinically significant. Key words: lower respiratory tract infection, respiratory viruses, mortality