Seropositive Rheumatoid Arthritis Emerging During Acute Phase of Lung Abscess: A Case Report.

Area of Science:

• Immunology
• Rheumatology
• Infectious Diseases

Background:

• Rheumatoid arthritis (RA) is an autoimmune disease with preclinical immunological activation.
• Respiratory infections are known risk factors for RA, but the link to acute onset is unclear.

Purpose of the Study:

• To report a rare case of seropositive RA presenting during acute lung infection.
• To explore the potential role of acute infection in accelerating RA onset.

Main Methods:

• Case report of an 87-year-old male with lung abscess.
• Diagnosis of seropositive RA based on polyarthritis, rheumatoid factor (RF), and anti-citrullinated protein antibodies (ACPA).
• Retrospective review of PET scans to identify preclinical inflammatory changes.

Main Results:

• The patient developed RA symptoms during the acute phase of a Staphylococcus aureus lung abscess.
• Positive RF and ACPA confirmed seropositive RA, which responded to corticosteroid therapy.
• Pre-admission PET scans indicated subclinical joint inflammation, suggesting a preclinical RA phase.

Conclusions:

• Acute respiratory infection may hasten the progression from latent autoimmunity to overt RA.
• RF and ACPA testing is crucial for diagnosing new-onset arthritis following an infection.
• This case underscores the complex interplay between infection and autoimmune disease development.