[Organising Pneumonia - a review and results from Icelandic studies]

Organising pneumonia (OP) is a relatively rare interstitial lung disease. It s definition is based on a characteristic histological pattern in the presence of certain clinical and radiological features. Organising pneumonia represents also what has been called Bronchiolitis Obliterans Organising Pneumonia (BOOP). Recently it has been recommended to call OP cryptogenic organising pneumonia (COP) when no definite cause or characteristic clinical context is found and secondary organising pneumonia (SOP) when causes can be identified such as infection or it occurs in a characteristic clinical context such as connective tissue disorder. The most common clinical symptoms are dyspnea, cough, fever and general malaise. It is common that symptoms have been present for some weeks before the diagnosis is made. Patients commonly have lowered PO2 and a mildly restrictive spirometry. Radiographic features are most often patchy bilateral airspace opacities but an interstitial pattern or focal opacities can also be seen. Most of patients respond well to steroids but relapses are quite common. The aim of this paper is to present an overview of the disease and the main results from studies on OP in Iceland. The mean annual incidence for OP in Iceland was 1.97/100,000 inhabitants. Annual incidence for COP was 1.10/100,000 and 0.87/100,000 for SOP. This is higher than in most other studies. In Iceland patients with OP had a higher standardized mortality ratio than the general population despite good clinical responses. No clinical symptoms could separate between SOP and COP.