Postinfectious Bronchiolitis Obliterans (PIBO) Among Children In Malaysia: A Retrospective Study LUI Sze Chiang1, CHE DAUD Che Zubaidah1, MOHAMMAD N.Fafwati Faridatul Akmar1, KAMAL Maria1, MUSA Azizah1, SHARIBUDIN Nor Khailawati1, ZAINUDDIN Hafizah2, MOHD HAIRI Farizah3, GAN Eu Ann4, KAILASAM Pavithira Devi5, NG Eunice Chin Nien6, GAN Cheng Guang7, GANAPATHI Rasheila8, ABU OSMAN Mohd Shahrulfahmi9, A RAZAK Hasliza10, ABD RAHIM Siti Aishah11, NG Wen Ying12, KASSIM Asiah1 1. Hospital Tunku Azizah, Kuala Lumpur 7. Hospital Segamat 2. UiTM Selayang Campus, Kuala Lumpur 8. Hospital Enche’ Besar Hajjah Kalthom, Kluang 3. Faculty of Medicine, University of Malaya 9. Hospital Duchess of Kent, Sandakan 4. Hospital Melaka 10.Hospital Sultanah Aminah, Johor Bahru 5. Hospital Pakar Sultanah Fatimah, Muar 11.Hospital Wanita dan Kanak-kanak, Likas, Kota Kinabalu 6. Hospital Sultanah Nora Ismail, Batu Pahat 12. Hospital Sultan Ismail, Johor Bahru. Table 1: Demographic Characteristics of the Study Population ID : P-115 NMRR-19- 3699-49459 INTRODUCTION: Postinfectious bronchiolitis obliterans (PIBO) is an irreversible obstructive lung disease following lower respiratory tract infection (LRTI) in children, especially during the first three years of life1. PIBO diagnosis is based on clinical and radiological changes. It is estimated that 1% of LRTI in children will develop PIBO. However, the local data are scarce. OBJECTIVE: To describe the characteristics of the children less than five years old diagnosed with PIBO from the year 2015-2019 (5 years period). METHODOLOGY: A retrospective study involved ten hospitals under MOH visited by a Respiratory Paediatrician. Children less than five years old diagnosed with PIBO between 1st January 2015 and 31st December 2019 were recruited. The diagnosis was made by the Visiting Respiratory paediatrician from clinical and radio-imaging. For the study, all radiological images were reported by a designated paediatric radiologist. Data were entered into SPSS version 26 and analyzed. Table 2: Clinical history among patients with PIBO in Malaysia Figure 3: Pathogens causing LRTI and PIBO in children ACKNOWLEDGMENT: We would like to thank the Director-General of Health Malaysia for his permission to present this poster. REFERENCES: 1. Yu J. Postinfectious bronchiolitis obliterans in children: lessons from bronchiolitis obliterans after lung transplantation and hematopoietic stem cell transplantation. Korean J Pediatr. 2015;58(12):459-465. doi:10.3345/kjp.2015.58.12.459. 2. Li YN, Liu L, Qiao HM, Cheng H, Cheng HJ. Post-infectious bronchiolitis obliterans in children: a review of 42 cases. BMC Pediatr. 2014;14:238. Published 2014 Sep 25. doi:10.1186/1471-2431-14-238. 3. Chan KC, Yu MW, Cheung TWY, et al. Childhood bronchiolitis obliterans in Hong Kong-case series over a 20-year period. Pediatr Pulmonol. 2021;56(1):153-161. doi:10.1002/ppul.25166. 4. Eber CD, Stark P, Bertozzi P. Bronchiolitis obliterans on high-resolution CT: a pattern of mosaic oligemia. J Comput Assist Tomogr. 1993;17(6):853-856. doi:10.1097/00004728-199311000-00003. DISCUSSION: In this study, children with PIBO were young (median age=15 months), male, and Adenovirus was the commonest pathogen, similar to the previous study2,3. Diagnosis of PIBO can be made as early as one-month post lung infection(Median age=2 months). Prematurity and history of ventilation during the neonatal period were found in at least 28% and 16% of children, respectively, which may be due to abnormal growth of a premature lung postnatally. Environmental factors like tobacco smoke exposure in 50% of children may increase the risk for the development of PIBO. At least 30% of them had a family history of atopy that may be related to an immunological response following lung infection in this group of children. More than 70% of the children required respiratory support during their first respiratory infection leading to PIBO. This may indicate the severity of infection, which