Summary

A previously healthy 21-year-old young woman presented with worsening dyspnoea and haemoptysis. Imaging was suggestive of widespread pulmonary haemorrhage. There was no other organ system involvement in particular no evidence of renal involvement. Raised antimyeloperoxidase titres allowed diagnosis of isolated diffuse alveolar haemorrhage (DAH) secondary to microscopic polyangiitis (MPA). The patient rapidly deteriorated with worsening respiratory failure despite invasive mechanical ventilation and required extracorporeal membrane oxygenation (ECMO). This maintained the patient long enough to allow aggressive therapy in the form of immunosuppression and plasma exchange. She made a remarkable recovery and is asymptomatic 2 years on. Isolated DAH in the absence of renal disease is an atypical presentation of MPA and can lead to diagnostic uncertainty. A literature review reveals increasing reports of successful use of ECMO in severe DAH due to pulmonary vasculitis. Despite this, the need for systemic anticoagulation in the presence of pre-existing haemorrhage remains a challenging dilemma.