E110 Abdominal pain in dermatomyositis

Abstract Background/Aims Dermatomyositis (DM) is a group of inflammatory myositis characterised by proximal muscle weakness, cutaneous manifestations, and multisystem involvement. Anti-nuclear matrix protein-2 (anti-NXP2) defines a distinctive clinical subset accounting for approximately 20-25% of adult DM cases. Anti-NXP2 positivity confers a severe disease phenotype with marked muscle weakness, frequent neck flexor and distal limb involvement, dysphagia, subcutaneous oedema, and a higher propensity for calcinosis compared to other DM subtypes. Visceral vasculitis—particularly gastrointestinal (GI) involvement—represents one of the most catastrophic complications in this subset, with reported mortality exceeding 40% Methods A 32-year-old woman presented with photosensitive facial rash and progressive proximal weakness. Laboratory tests showed raised creatine kinase, lactate dehydrogenase and aspartate aminotransferase with positive anti-NXP2 antibody. She received intravenous methylprednisolone pulses and intravenous immunoglobulin followed by mycophenolate mofetil. However, her weakness flared on tapering prednisolone below 20 mg/day. Four months later, she developed dysphagia, dysphonia and dyspnoea (mMRC 3). She was again given methylprednisolone pulses followed by intravenous cyclophosphamide, with which she had partial improvement in her weakness. However, her skin rashes persisted and tofacitinib was added. Six months into the illness, she developed persistent post-prandial abdominal pain and vomiting, followed by the development of new rash, neck and cubital ulcers. There was also 8kg weight loss. On current admission, she had severe proximal muscle weakness, anaemia, neutrophilic leucocytosis, thrombocytopenia, mild transaminitis, ESR 86 mm/hour and CRP 92 mg/L. CT enterography revealed long-segment small-bowel thickening. She was advised to undergo bowel rest, and methylprednisolone pulses were started along with rituximab and tacrolimus. Results In hospital, she developed massive per-rectal bleeding and abdominal rigidity. Exploratory laparotomy revealed a 1cm D2 perforation. Histopathology of the excised tissue demonstrated transmural inflammation with fibrinoid necrosis and break in the internal elastic lamina, confirming vasculitis. Despite surgery and intensive care, she succumbed to refractory shock. Conclusion Anti-NXP2 dermatomyositis represents a high-stakes myositis phenotype in which gastrointestinal vasculitis may transform an otherwise controllable disease into a fulminant, life-threatening emergency. Vigilant surveillance and timely, targeted immunomodulation remain the key to improving survival in this formidable subgroup. Disclosure B. Banerjee: None. R. Tyagi: None. R. Nada: None. V. Dhir: None.