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Development of polymyositis after long-standing rheumatoid arthritis

Sherry Rohekar1, Laurence Rubin

  • 1Department of Rheumatology, St. Michael's Hospital, University of Toronto, Ontario, Canada.

The Journal of Rheumatology
|February 9, 2006
PubMed

Insights

Concurrent diagnoses of rheumatoid arthritis (RA) and polymyositis (PM) are rare. This case highlights the importance of considering polymyositis in patients with rheumatoid arthritis experiencing muscle weakness.

Area of Science:

  • Rheumatology
  • Neurology
  • Immunology

Background:

  • Rheumatoid arthritis (RA) and polymyositis (PM) are distinct autoimmune conditions.
  • Concurrent diagnoses in a single patient are exceptionally uncommon.

Observation:

  • A patient with a 16-year history of established rheumatoid arthritis developed overt polymyositis.
  • This clinical course suggests a potential evolution or co-occurrence of distinct inflammatory myopathies.

Findings:

  • The case underscores the diagnostic challenge of differentiating primary muscle weakness in RA from secondary inflammatory myopathies.
  • Literature review confirms the rarity of simultaneous RA and PM diagnoses.

Implications:

  • Clinicians managing rheumatoid arthritis patients should maintain a high index of suspicion for polymyositis when muscle weakness arises.
  • Broadening differential diagnoses is crucial for accurate diagnosis and timely treatment of complex autoimmune presentations.

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