[Features distinguishing ornithosis from avian acute hypersensitivity pneumonitis - a retrospective analysis]

The aim of our study was to compare the features at diagnosis in patients with ornithosis to patients with avian acute hypersensitivity pneumonitis (HP). Clinical, biological and radiological differences could potentially help clinicians to distinguish these diseases.

We conducted a retrospective study on patients admitted from 2000 to 2016 in three hospitals. Ornithosis was diagnosed based on a positive polymerase chain reaction for Chlamydophila psittaci on respiratory samples and/or a seroconversion while HP was diagnosed on the basis of at least one positive serum precipitin.

Twelve patients with HP and 13 patients with ornithosis were identified. Compared to HP, ornithosis occurred more frequently in males (P=0.047), with less previous respiratory diseases (P=0.01), shorter symptom duration (P=0.03), less frequently bilateral crackles (P=0.004), more severe disease requiring more frequently intensive care admission (P=0.005), higher CRP values (P=0.005) and more profound lymphopenia (P=0.02). Ground glass shadowing on CT scan (P=0.001) or bronchiectasis (P=0.03) were more frequently noted in patients with HP.

Our results suggest that patients with ornithosis and HP have important differences in their clinical, biological, and radiological presentation.