Immune checkpoint inhibitors (ICIs) have revolutionised cancer treatment. However, immune-related adverse events (irAEs) are a common side effect which can mimic infection. Additionally, treatment of irAEs with corticosteroids and other immunosuppressant agents can lead to opportunistic infection, which we have classed as immunotherapy infections due to immunosuppression. However, emerging reports demonstrate that some infections can be precipitated by ICIs in the absence of immunosuppressive treatment, in contrast to the majority of reported cases. These infections are characterised by a dysregulated inflammatory immune response, and so we propose they are described as immunotherapy infections due to dysregulated immunity. This review summarises the rapidly emerging evidence of these phenomena and proposes a new framework for considering infection in the context of cancer immunotherapy.

We report an unusual presentation of pulmonary embolism (PE) where a 58-year-old man first developed symptoms of community-acquired pneumonia. Despite antibiotic therapy, he remained unwell with rising inflammatory markers, general malaise and persistent cough. He developed stony dull percussion and absent breath sounds to his left mid to lower zones. Serial chest x-rays showed progression from lobar consolidation to a large loculated left-sided pleural collection. CT chest showed left-sided lung abscess, empyema and bronchopleural fistulation. Incidentally, the scan revealed acute left-sided PE and its distribution corresponded with the location of the left lung abscess and empyema. The sequence of events likely started with PE leading to infarction, cavitation, abscess formation and bronchopleural fistulation. This patient was managed with a 6-month course of rivaroxaban. After completing 2 weeks of intravenous meropenem, he was converted to 4-week course of oral co-amoxiclav and metronidazole and attained full recovery.