E018 COVID-19 vaccine-induced myositis

Abstract Background/Aims Through the COVID pandemic there have emerged reports of autoimmunity or new rheumatic diseases presenting in patients after they had COVID-19. This is thought to be caused by cross-reactivity COVID-19 spike protein human antigens. Given use mRNA vaccinations which express we might expect see presentation following their use. We discuss a case where this appears occurred. Methods Our patient 24-year-old male with mixed phenotype acute leukaemia who been treated allogenic stem cell transplant and was currently remission. He presented fevers, palpitations, myalgia bilateral arm leg swelling. Symptoms began day receiving first dose an vaccination (Pfizer/BioNTech.) There were no other symptoms recent change medications. Physical examination revealed tender oedema his forearms, biceps thighs bilaterally sparring hands. reduced power shoulder (MRC 3/5), elbow (4), wrist (4+) hip (4) movements. Observations tachycardia fevers up 40C. Results Laboratory studies showed markedly elevated C-reactive (202), creatinine kinase (6697) troponin (593) whilst investigations for infection negative. An autoimmune panel positive anti-PM-SCL-75-Ab. electrocardiogram sinus tachycardia. Echocardiogram normal. Bilateral upper limb dopplers deep vein thrombus. MRI diffuse symmetrical within muscles, keeping inflammatory myositis. A quadricep muscle biopsy evidence MHC class 1 up-regulation, suggesting process. In addition, numerous macrophages evident endomysium. While can seen graft-versus-host disease (GVHD), would usually found perimysium. After discussion between haematology, rheumatology neurology, felt vaccine induced myositis myocarditis. Autoimmune less likely due relative sparing hands absence Raynaud’s phenomenon. gram intravenous methylprednisolone then given 3 days. The marked response defervescence, improving laboratory markers, improved decreased stepped down reducing regime prednisolone discharged. Due relapse weaning he has started on mycophenalate mofetil rituximab now continues improve. Conclusion are but our patient’s complicated differential diagnosis GVHD concurrent Ongoing work needed clarify exact link myositis, it important recognise start treatment early order preserve bulk ensure recovery. Disclosure L. Thompson: None. T. Nadin: J. Meiring: S. Thomas: R. Kumari: Carter: M. Akil: A. Alfred: N. Morley: