What are the extra-articular manifestations of scleromyositis?

Extra-Articular Manifestations of Scleromyositis

Scleromyositis presents with a characteristic multisystemic pattern including interstitial lung disease, cardiac involvement (particularly myocarditis), Raynaud's phenomenon, calcinosis, arthritis, and ocular manifestations, with pulmonary and cardiac complications being the most prognostically significant. 1

Key Organ System Involvement

Pulmonary Manifestations

• Interstitial lung disease (ILD) is a common and prognostically important extra-muscular complication in scleromyositis 2, 1
• ILD patterns typically include nonspecific interstitial pneumonitis 3
• Pulmonary involvement is associated with worse functional outcomes and increased mortality 1

Cardiac Manifestations

• Myocarditis represents a serious and potentially life-threatening complication 2
• Asymptomatic arrhythmias (such as sinus tachycardia) may be detected on electrocardiography 3
• Diastolic dysfunction can be identified on echocardiography even in asymptomatic patients 3
• Cardiac involvement is associated with poor prognosis and requires aggressive monitoring 1

Vascular Manifestations

• Raynaud's phenomenon is a characteristic feature of scleromyositis 2, 1
• Striking vasculopathic lesions at muscle biopsy are hallmarks of scleromyositis and provide anatomopathological evidence for the distinct nature of this condition 1
• These vascular changes help differentiate scleromyositis from other myositis subtypes 1

Musculoskeletal Extra-Articular Features

• Arthritis occurs as a distinct extra-articular manifestation separate from the primary myositis 2
• Calcinosis can be present and may be refractory to treatment 2
• Calcinosis cutis is more commonly seen in juvenile forms but can occur in adults 3

Cutaneous Manifestations Beyond Primary Scleroderma

• Mechanic's hands (roughened, cracked skin on the lateral and palmar aspects of fingers) serve as cutaneous markers of myositis activity 4
• Cutaneous vasculitis and ulcerations may occur 3

Ocular Manifestations

• Scleral thinning (potentially 360 degrees) can occur 5
• Anterior and posterior chamber inflammation with cellular infiltration 5
• Ocular manifestations require systemic immunosuppressive treatment and multidisciplinary management 5

Gastrointestinal Involvement

• Vasculopathy can affect the gastrointestinal tract 3
• Dysphagia related to cricopharyngeal weakness or spasm may be evident on videofluoroscopy 3

Clinical Pitfalls and Important Considerations

Diagnostic Challenges

• Some patients present with "seronegative" scleromyositis with subtle systemic sclerosis features and no detectable autoantibodies, making diagnosis challenging 1
• The anti-PM/Scl antibody is specifically associated with scleromyositis but is not currently integrated into diagnostic criteria 1, 4
• Muscle biopsy showing vasculopathic lesions provides strong diagnostic support when serological markers are absent 1

Prognostic Implications

• Extra-muscular complications, particularly pulmonary and cardiac involvement, are associated with poor prognosis 1
• The pattern and severity of extra-articular manifestations should guide treatment intensity 1
• Early recognition of these manifestations is critical as they significantly impact mortality and quality of life 1

Management Approach

• Multidisciplinary coordination is essential, involving rheumatology, pulmonology, cardiology, and ophthalmology as needed 5
• Aggressive immunosuppressive treatment is often required for significant extra-articular manifestations 2, 5
• Novel therapies such as tofacitinib have shown efficacy in refractory cases with multiple extra-articular features 2