Vaping-Associated Lung Injury With Suspected Diffuse Alveolar Haemorrhage: A Case Report

E-cigarette or vaping product use-associated lung injury (EVALI) is a recognised condition with diverse presentations, including acute lung injury and, rarely, diffuse alveolar haemorrhage (DAH). This case report describes a rare instance of suspected DAH associated with herbal-based vape product use, highlighting diagnostic challenges and effective management. A 44-year-old patient with Hashimoto's thyroiditis, asthma and six-week use of herbal or plant-based vaping solutions presented with one week of cough, fever and haemoptysis. Examination revealed respiratory distress, bilateral crackles and wheezing. Arterial blood gas showed type 1 respiratory failure (PaO₂ 10.2 kPa, FiO₂ 0.7), and chest imaging displayed bilateral interstitial opacities suggestive of DAH. Differentials, including pneumonia, pulmonary embolism, vasculitis, Goodpasture's syndrome and malignancy, were evaluated. Bronchoscopy confirmed left upper lobe haemorrhage, with bronchoalveolar lavage showing progressive red blood cells, supporting suspected DAH. Extensive autoimmune, infectious and neoplastic workup (e.g., antinuclear antibody, viral polymerase chain reaction (PCR), cultures) was negative. Empirical antibiotics and antifungals were stopped after negative cultures. On day 3, suspecting DAH, high-dose intravenous methylprednisolone (1,000 mg/day for three days) was initiated for immune-mediated inflammation, yielding rapid clinical and radiological improvement. EVALI with suspected DAH was diagnosed by exclusion post-workup, and vaping cessation was advised. At three months, the patient remained stable without recurrence. This case underscores EVALI as a key differential in vaping patients with haemoptysis and bilateral infiltrates when other aetiologies are excluded. A thorough vaping history, comprehensive workup and prompt corticosteroid therapy can yield favourable outcomes. The rare link between DAH and EVALI warrants further research into its prevalence and management.