Refractory pembrolizumab immunotherapy-related colitis requiring biological therapy in an inactive HBcAb carrier.

Immune checkpoint inhibitors are a class of cancer immunotherapy, with a constellation of side effects that require early recognition and management. We present a patient with metastatic adenocarcinoma started on pembrolizumab a month prior, who was admitted to the hospital for bloody diarrhoea. He underwent flexible sigmoidoscopy with biopsy proven grade 3 immune-mediated diarrhoea and colitis. He developed progressively worsening diarrhoea despite appropriate intravenous corticosteroids therapy, and initiation of corticosteroid-sparing therapy was complicated by discovery of hepatitis B core antibodies indicating a chronic hepatitis B carrier state. We discuss our work-up of new onset haemorrhagic diarrhoea in a patient on immunotherapy for metastatic non-small cell lung cancer, as well as a review of current guidelines for antiviral prophylaxis in these patients.

Polyangiitis overlap syndrome: a novel presentation of microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis.

Polyangiitis overlap syndrome (POS) is a diagnostic term coined by Leavitt and Fauci that characterises patients with overlapping features of more than one vasculitis. Prior case studies of antineutrophil cytoplasmic antibodies (ANCA)-associated POS have only been published in patients with eosinophilic granulomatosis with polyangiitis (EGPA) and granulomatosis with polyangiitis alongside proteinase-3/cytoplasmic (C)-ANCA positivity. We present a case of a 60-year-old woman with dyspnoea, hemoptysis, positive perinuclear-ANCA and renal biopsy demonstrating evidence of microscopic polyangiitis. In addition, our patient also had asthma, mononeuritis multiplex, eosinophilia and migratory pulmonary infiltrates, thus fulfilling the criteria for EGPA. This novel case report suggests that POS is not limited to C-ANCA positivity and has variable presentations.