Case series: Monoarticular rheumatoid arthritis

Area of Science:

• Rheumatology
• Immunology
• Clinical Medicine

Background:

• Monoarticular rheumatoid arthritis (RA) presentation is uncommon, typically involving large joints.
• Early and accurate diagnosis of RA is crucial for effective management and preventing joint damage.

Purpose of the Study:

• To report a case series of four patients with monoarticular RA.
• To evaluate the diagnostic utility of current classification criteria for monoarticular RA.
• To propose improvements for earlier RA diagnosis.

Main Methods:

• Retrospective review of four patients diagnosed with monoarticular RA at the University of Michigan.
• Assessment using the 2010 ACR/EULAR classification criteria for RA.
• Analysis of clinical presentation, serological markers (anti-CCP, RF, CRP, ESR), and imaging findings.

Main Results:

• All four patients presented with monoarthritis (three large joint, one small joint).
• Positive serologies (anti-CCP, RF, elevated CRP/ESR) and symptom duration >6 weeks were observed.
• Imaging findings were consistent with active RA, despite not being part of the classification criteria.

Conclusions:

• The 2010 ACR/EULAR criteria, while sensitive, may lack specificity for monoarticular RA cases.
• Inclusion of imaging measures in diagnostic criteria could enhance early identification of RA in such patients.
• Further refinement of diagnostic guidelines is needed for optimal early RA diagnosis.