A 42-year-old woman presents with progressive proximal muscle weakness, mechanic's hands (hyperkeratotic fissured skin on the lateral aspects of fingers), interstitial lung disease on HRCT, and Raynaud phenomenon. Anti-Jo-1 antibody is positive. What is the diagnosis?
- A Dermatomyositis
- B Polymyositis
- C Anti-synthetase syndrome ✓
- D Inclusion body myositis
Correct answer: C. Anti-synthetase syndrome
Explanation
Anti-synthetase syndrome is characterized by the triad of interstitial lung disease, myositis, and characteristic features including mechanic's hands, Raynaud phenomenon, and arthritis. Anti-Jo-1 is the most common antisynthetase antibody. Dermatomyositis features heliotrope rash and Gottron papules, not mechanic's hands. Inclusion body myositis causes asymmetric weakness and does not involve the lungs.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.