ANCA negative pulmonary vasculitis: a challenging diagnosis

A man in his 40s with end-stage kidney disease due to IgA nephropathy and receiving peritoneal dialysis presented with a 1-week history of breathlessness, cough and nosebleeds. CT scan of the chest revealed ground glass changes while blood tests indicated elevated inflammatory markers and a negative vasculitis screen. This included negative ANCA and anti-GBM antibodies. Initial treatment for suspected atypical pneumonia with antibiotics yielded no clinical improvement.Over the course of the admission, his symptoms progressively worsened, leading to oxygen dependency with a FiO2 of 40% and episodes of haemoptysis. Suspicions of pulmonary vasculitis arose due to clinical deterioration, prompting consultation with a tertiary vasculitis centre. It was subsequently concluded that the clinical and radiological findings correlated with ANCA-negative pulmonary vasculitis or a rare case of IgA-associated pulmonary capillaritis. Treatment with methylprednisolone and rituximab led to significant improvement, allowing rapid oxygen withdrawal. The patient was discharged with a tapering prednisolone regimen.