[Polymyositis and dermatomyositis in adults. Tunisian multicentre study]

Area of Science:

• Rheumatology
• Internal Medicine
• Clinical Immunology

Background:

• Polymyositis (PM) and dermatomyositis (DM) are inflammatory myopathies with varying clinical presentations.
• Understanding regional variations in disease characteristics is crucial for effective management.

Purpose of the Study:

• To investigate the clinical features and outcomes of PM and DM patients in Tunisia.
• To identify specific epidemiological and clinical characteristics of these conditions in the Tunisian population.

Main Methods:

• A retrospective multicenter study was conducted.
• Adult patients diagnosed with PM or DM between 1987 and 2005, based on Bohan and Peter's criteria, were included.

Main Results:

• The study included 20 PM and 50 DM cases, with a female-to-male ratio of 2.5 and a mean age at diagnosis of 40.7 years.
• Common symptoms included muscle weakness (94.3% girdle, 42.8% pharyngeal). Significant comorbidities were interstitial lung disease (35.7%) and heart involvement (20%).
• Dermatomyositis-specific skin manifestations were frequent. Malignancy, particularly gynecological and nasopharyngeal cancers, was observed in 12.8% of patients. Treatment involved high-dose corticosteroids and immunosuppressants in 40% of cases, with stabilization or partial improvement in 71.5% and a 20% mortality rate.

Conclusions:

• Dermatomyositis is more prevalent than polymyositis in Tunisia.
• Early disease onset and a high incidence of nasopharyngeal cancer are notable features in Tunisian PM/DM patients.
• While treatment leads to improvement in most, significant mortality due to complications necessitates ongoing research and management strategies.