Antisynthetase syndrome sine myositis presenting as severe acute respiratory failure.

A female in her late 40s presented to the emergency department during the COVID-19 pandemic with shortness of breath, fever and productive cough following a recent diagnosis of bilateral non-massive pulmonary emboli. She had elevated inflammatory markers and her chest X-ray revealed bilateral infiltrates. Her SARS-CoV-2 PCR was negative, and she was treated for community-acquired pneumonia. However, despite treatment she rapidly deteriorated and developed severe respiratory failure, requiring mechanical ventilation.On further investigation, she tested positive for anti-Jo-1 antibodies and a diagnosis of antisynthetase syndrome sine myositis was made. This led to successful treatment with high dose corticosteroids and intravenous immunoglobulin.This case highlights an uncommon presentation of a rare condition, as well as the benefits of working in a multidisciplinary team on the intensive care unit.