Diffuse Alveolar Haemorrhage Masquerading as Worsening ARDS in a Young Polytrauma Patient: Diagnostic Reasoning and a Conservative Management Bundle — A Case Report

Zhaolve Huang,1 Minghao Yang,1 Jishen Luo,1 Chao Liu21Department of Emergency Intensive Care Unit, 920th Hospital of the Chinese People’s Liberation Army Joint Logistic Support Force, Kunming, Yunnan, People’s Republic of China; 2Yunnan Cancer Hospital, The Third Affiliated Hospital of Kunming Medical University, Peking University Cancer Hospital Yunnan, Kunming, Yunnan, People’s Republic of ChinaCorrespondence: Chao Liu, Yunnan Cancer Hospital, The Third Affiliated Hospital of Kunming Medical University, Peking University Cancer Hospital Yunnan, Kunming, Yunnan, People’s Republic of China, Email liuchao@kmmu.edu.cnBackground: Diffuse alveolar haemorrhage (DAH) is a rare, under-recognised complication of blunt polytrauma. In patients with severe acute respiratory distress syndrome (ARDS), new airway bleeding may be mistaken for pulmonary contusion, ventilator-associated pneumonia or transfusion-related acute lung injury (TRALI), delaying appropriate treatment. The timing of definitive fracture fixation also remains uncertain.Case Presentation: A previously healthy man in his mid-20s sustained blunt polytrauma (Injury Severity Score 29; Glasgow Coma Scale 8), including multiple open comminuted fractures, a T11 compression fracture and bilateral pulmonary contusions. After emergency external fixation, he was transferred in haemorrhagic shock and respiratory failure, with severe ARDS (PaO2/FiO2 78 mmHg), lactate 7.0 mmol/L and creatine kinase 4443 U/L. On day 4, he developed bloody endotracheal secretions, recurrent hypoxaemia, and abrupt decreases in haemoglobin (114 to 76 g/L) and platelets (139 to 65 × 109/L). Bronchoscopy showed diffuse, non-focal mucosal oozing. Vasculitis and cytokine panels were negative. Targeted next-generation sequencing of bronchoalveolar lavage fluid detected high burdens of Acinetobacter baumannii and Klebsiella pneumoniae, low-abundance Pseudomonas aeruginosa, and multiple carbapenemase and extended-spectrum β-lactamase genes. Presumed non-immune post-traumatic DAH with possible TRALI contribution was diagnosed. Treatment included withholding further transfusion, methylprednisolone 1 mg/kg/day, lung-protective ventilation, four prolonged prone-positioning sessions, antimicrobial therapy and damage-control orthopaedics, with definitive fixation on day 17. Tracheostomy was decannulated on day 28, and he was discharged to rehabilitation. At follow-up, he walked independently without recurrent DAH or ARDS.Conclusions: In polytrauma patients, new diffuse airway bleeding, disproportionate anaemia and worsening hypoxaemia should prompt consideration of non-immune DAH, particularly after transfusion. In this single case, recovery followed a combined strategy of bronchoscopic assessment, restrictive transfusion, corticosteroids, prone ventilation and physiology-guided orthopaedic management. However, concurrent interventions and the absence of histological confirmation preclude causal attribution; the findings are hypothesis-generating.Keywords: diffuse alveolar haemorrhage, acute respiratory distress syndrome, pulmonary contusion, prone positioning, transfusion-related acute lung injury