Asymmetrical weakness in polymyositis associated with neuropathic involvement

Good response to plasmapheresis and mycophenolate mofetil in a patient with anti-synthetase syndrome associated with peripheral neuritis and severe prosthetic aortic valve stenosis

Background

Idiopathic inflammatory myopathies (IIM) are a disease complex that encompasses several distinctly acquired muscle illnesses. Anti-synthetase syndrome is a subset of IIM that is characterized by the presence of antibodies against aminoacyl-tRNA synthetases (ARS). This syndrome has a characteristic phenotype of IIM. Anti-synthetase syndrome was rarely associated with peripheral nerve involvement and endocarditis.

Case presentation

We report a 46-year-old female patient with a history of mitral and aortic valve replacement for seven years and on warfarin, presented with symmetrical muscular weakness, generalized edema, progressive dyspnea, dysphagia, fever, fatigue, myalgia, and polyarthralgia. The motor power grading was 2 in proximal muscles of upper limbs and 3 in the distal muscles involving hands and wrists, and it was 0 in proximal muscles in lower limbs and 2 in distal muscles involving ankle and toes movements. Also, her oxygen saturation decreased remarkably. Echocardiography revealed that the patient had severe stenosis (70%) of the prosthetic aortic valve. Electrophysiological studies showed axonal polyneuropathy with average F wave latencies. She was diagnosed with anti-synthetase syndrome for elevated muscle enzymes, interstitial lung disease (ILD), mechanic’s hands, fever, polyarthralgia, and positive anti-Jo-1 antibody. There was a significant improvement with plasmapheresis, mycophenolate mofetil (MMF), and high-dose prednisolone.

Conclusions

To the best of our knowledge, this is a case of anti-synthetase syndrome accompanied by neuropathic involvement and cardiac valve prosthetic stenosis. These were reported as an unusual presentation of the anti-synthetase syndrome. The significant improvement with plasmapheresis gives us a treatment choice for similar critical cases.