Synopsis
Recognise organising pneumonia as a clinicoradiological syndrome, exclude secondary causes and infection, and use specialist corticosteroid treatment with relapse-aware monitoring.
- Organising pneumonia is a tissue-repair pattern with intra-alveolar granulation tissue; cryptogenic organising pneumonia is diagnosed only when no cause is found.
- Secondary triggers include infection, connective-tissue disease, medicines, radiotherapy, malignancy, inflammatory bowel disease and transplantation.
- Patients often have weeks of dry cough, breathlessness, fever, malaise and weight loss that fail to resolve with routine antibiotics.
- HRCT commonly shows patchy peripheral or peribronchovascular consolidation, ground glass and migrating opacities, but no single sign is pathognomonic.
- The reverse-halo sign can support the pattern but also occurs in fungal infection, infarction, granulomatous disease and malignancy.
- A brisk corticosteroid response is typical but is not retrospective proof; lymphoma, eosinophilic disease and infection can transiently improve or fluctuate.
- Relapse during taper or after stopping treatment is common and usually prompts diagnostic and exposure review before simply increasing steroids.
- Biopsy is unnecessary in every typical case but becomes important when imaging, clinical behaviour or treatment response is atypical.
- Cryptogenic disease has no ongoing causal treatment beyond controlling the inflammatory process; secondary organising pneumonia requires the trigger addressed.
- Pulmonary function, oxygenation and imaging trajectory should guide treatment duration rather than pursuing complete radiographic clearing at any toxicity cost.
Key red flags
Rapidly spreading bilateral opacity, profound desaturation, tachypnoea or exhaustion can resemble ARDS and requires emergency respiratory and critical-care assessment.
A persistent focal mass-like consolidation, haemoptysis, unilateral nodes or weight loss out of proportion to inflammation should enter an urgent lung-cancer pathway.
Failure to improve after an adequate supervised corticosteroid trial should prompt urgent reconsideration of infection, lymphoma, adenocarcinoma, eosinophilic pneumonia, vasculitis or an incorrect pathological label.
Investigation priorities
Define extent, distribution and features requiring another pathway.
Management branches
Subacute multifocal consolidation persists despite appropriate initial antimicrobial care.
- Reassess physiological stability and obtain HRCT, looking for organising distribution while identifying pleural, nodal or mass-like features that require a cancer or infection pathway.
- Review all medicines, radiotherapy, systemic inflammatory symptoms, immune status and microbiology; do not use the word cryptogenic until secondary causes have been addressed.
- Discuss at respiratory or ILD MDT whether clinicoradiological confidence is sufficient or lavage and tissue would change the decision.
- Document the working diagnosis and planned response measures, including when non-response will trigger biopsy or a renewed malignancy and infection search.