[Pulmonary function in rheumatoid arthritis in a Tunisian population]

The rheumatoid polyarthritis (PR) is a frequent pathology in Tunisia. The most frequent extra articular expression of this disease is in the respiratory tract.

To determine the lung functional profile of PR of the Tunisian population by establishing possible relations between ventilatory variables and clinico-biological parameters of PR.

It is a cross sectional study which concerned 87 patients (77 women) having a confirmed PR. They benefited from a measure of the lung function by a total physical Pléthysmography and by the technique of double transfer NO-CO. Clinical and biological checkup were realized.

Three kinds of pulmonary function defects were found: obstructive ventilatory defect (13%), restrictive defect (7%) and mixed defect (1%). Ventilatory flows and the lung volumes correlated negatively with the inflammatory syndrome (p<0.05). Alveolar-capillary diffusion capacity (DLco) was altered in an isolated way or associated with the respiratory functional syndromes (obstructive and restrictive) (6%). This abnormality had a vascular origin with an isolated fall of the lung capillary volume (Vc), a membrane origin with an isolated fall of the diffusion membrane (DM) or a combined origin with the decline of Vc and DM. This latter case was found at a late stage of PR. 58% of PR patients had a normal pulmonary function.

All these functional findings were linked to PR itself (inflammatory and auto-immune origin) or to the lung toxicity due to the treatment by Methotrexate (alveolar and bronchial damage).