A 45-year-old woman presents with progressive dyspnoea, non-productive cough, and skin rash over her metacarpal joints (Gottron's papules). Pulmonary function tests show FVC 58%, FVC/FVC ratio preserved. HRCT chest shows bilateral ground-glass opacities and lower lobe reticulation. Anti-MDA5 antibodies are positive. The MOST likely diagnosis and concerning complication are:
- A Dermatomyositis with rapidly progressive ILD ✓
- B Systemic sclerosis with usual interstitial pneumonia
- C Antisynthetase syndrome with NSIP pattern
- D Rheumatoid arthritis-ILD with UIP pattern
Explanation
Anti-MDA5 (melanoma differentiation-associated gene 5) antibodies are pathognomonic for amyopathic dermatomyositis (ADM) and are associated with rapidly progressive ILD (RP-ILD) with very high mortality (up to 50% at 6 months). The HRCT pattern in anti-MDA5 ILD is typically NSIP-like or OP-like with ground-glass opacities. Gottron's papules confirm dermatomyositis. Early aggressive treatment with combination immunosuppression (high-dose corticosteroids + calcineurin inhibitor + cyclophosphamide or rituximab) is required. Anti-MDA5 RP-ILD is a rheumatological emergency.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.