Allergic bronchopulmonary aspergillosis presenting as complete lung collapse with respiratory failure

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic fungal disease that commonly complicates the natural course of patients with asthma and cystic fibrosis. Patients with ABPA commonly present with recurrent pulmonary infiltrates or bronchiectasis. They also experience difficulty treating asthma. Characteristic radiological findings include central bronchiectasis and high-attenuation mucus. Complete unilateral lung collapse is an uncommon presentation of ABPA, with few cases reported in published literature. We present a case of a man in his mid-40s, with acute cerebrovascular disease, who subsequently developed neurological deterioration, compounded by development of respiratory failure attributed to a complete left lung collapse, requiring invasive mechanical ventilation. Initially suspected to have aspiration pneumonia, he was eventually diagnosed with ABPA and was treated accordingly. This case illustrates an uncommon aetiology for complete lung collapse in this clinical setting and serves to remind us to consider ABPA as a differential diagnosis in such patients as well.