Interstitial lung disease in polymyositis and dermatomyositis.

Purpose. - Interstitial lung disease is one of the most common respiratory manifestations in polymyositis and dermatomyositis. It still remains a seve re complication of the disease, leading to death related to ventilatory ins ufficiency in 30-66% of patients. Current knowledge and key points. - Time onset of interstitial lung disease is variable, although interstitial lung disease onset precedes initial man ifestations of polymyositis/dermatomyositis in roughly half of the patients . Moreover, clinical presentation of interstitial lung disease can be dicho tomized, according to patients' pulmonary manifestations, into: 1) both acu te and aggressive lung disease similar to Hamman-Rich syndrome; 2) slowly p rogressive lung disease, and 3) an asymptomatic pattern. The methods of cho ice adopted for early diagnosis of interstitial lung disease are high-resol ution computed tomography scan and pulmonary function tests, which should b e performed during both initial evaluation of polymyositis/dermatomyositis and follow-up. Because anti-JO1 antibody is considered to be a marker of in terstitial lung disease in polymyositis/dermatomyositis, close pulmonary fo llow-up of anti-JO1-positive patients with polymyositis is therefore requir ed for early detection of subclinical impairment. Furthermore, histological lung findings provide prognostic data; patients with bronchiolitis obliter ans organizing pneumonia (BOOP) indeed appear to have a more favorable outc ome than those with usual interstitial pneumonia or diffuse alveolar damage . Finally, as a guide to both the severity and progress of interstitial lun g disease, the significance of other investigations, notably bronchoalveola r lavage, remains controversial. Future prospects and projects. - Specific therapy of interstitial lung dise ase has not yet been clearly established in polymyositis/dermatomyositis pa tients. Corticosteroid therapy is considered the first line of therapy for polymyositis/dermatomyositis patients with interstitial lung disease. The a ssociation of cyclophosphamide and corticosteroids may be the most effectiv e in patients with steroid-resistant interstitial lung disease. Early diagn osis and management of this disease is therefore of the utmost importance. (C) 2001 Editions scientifiques et medicales Elsevier SAS.