[Polymyositis and dermatomyositis in adults. Tunisian multicentre study]

To study the clinical features and the outcome of polymyositis (PM) and dermatomyositis (DM) in Tunisia.

Retrospective multicentre study conducted by the Tunisian Society of Internal Medicine. Adult patients with confirmed and probable PM and DM, according to the Bohan and Peter's criteria, were included in the study and followed-up between 1987 and 2005.

Twenty cases of PM and 50 cases of DM were included. Female/male sex-ratio was 2.5. The mean age at diagnosis was 40.7 years. Muscle weakness concerned girdle muscles in 94.3% and pharyngeal muscles in 42.8% of the patients. Interstitial lung disease and heart involvement occurred respectively in 35.7 and 20%. Eyelid erythema, peri-ungual erythema and Gottron's sign occurred in respectively 86, 50 and 36% of the cases of DM. Malignant disease was found in 12.8% of the patients (mainly gynecological and nasopharyngeal cancers). All patients received high dose corticosteroids with additional immunosuppressive drugs in 40% of the cases. The outcome was stabilization or partial improvement in 71.5% of the cases. Death occurred in 20% and was caused by respiratory failure, sepsis and cardiac failure.

The particularities of PM and DM in Tunisia are the preponderance of DM, early onset of the disease and high frequency of the nasopharyngeal cancer.