CRP18 SILENT THROMBOSIS: A RARE CASE OF UNILATERAL PULMONARY FIBROSIS FOLLOWING BLUNT CHEST TRAUMA IN A PEDIATRIC PATIENT

Jeya Pradeena Nair1, Nor Diyana Ismail1, Stephanie Ang Gek Xing2, Chai Jia Ning3, Faizah Mohd Zaki3, Ooi Yin Khurn4, David Ng Chun-Ern2, Dayang Zuraini Sahadan1
1Respiratory Unit, Paediatric, Hospital Sultan Idris Shah, Serdang, Selangor 2Paediatric, Hospital Tuanku Ja’afar, Seremban 3Paediatric Radiology, Hospital Pakar Kanak-Kanak, UKM 4Paediatric Cardiology, Hospital Sultan Idris Shah

Background
Pulmonary fibrosis in children is rare, and unilateral fibrosis following blunt trauma is exceedingly uncommon. We report a unique case of unilateral pulmonary fibrosis associated with silent pulmonary artery thrombosis post blunt chest trauma.

Case Presentation
An 11-year-old boy presented with an infected left chest wall hematoma one week after blunt trauma from a fall onto a dressing table. He experienced chest pain, swelling, and reduced air entry over the left lower zone. Imaging showed persistent left lower lobe consolidation and volume loss, unresponsive to antibiotics. Four months later, he reported reduced effort tolerance and declining lung function. CECT Thorax with HRCT revealed left lower lobe fibrosis, pleural thickening, and features of chronic pulmonary embolism. CT pulmonary angiography showed no active emboli, while echocardiography indicated reduced flow in the left pulmonary artery without cardiac shunting. A ventilation/perfusion scan demonstrated chronic parenchymal changes with no mismatch. Thrombophilia and infection screens, including Protein C & S, D-dimer, autoimmune markers, and TB tests, were all negative.

Discussion
This case underscores a rare yet significant post-traumatic complication in children. The absence of severe acute respiratory symptoms illustrates the silent nature of pulmonary artery thrombosis. The unilateral fibrosis likely results from chronic hypoperfusion and ischemic remodelling.

Conclusion
Blunt chest trauma in children can lead to silent pulmonary artery thrombosis and subsequent unilateral pulmonary fibrosis. Early recognition and vascular imaging are essential to prevent irreversible lung damage.