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Corynebacterium pyogenes septic arthritis with plasma cell synovial infiltrate and monoclonal gammopathy

D D Norenberg, D V Bigley, R L Virata

    Archives of Internal Medicine
    |May 1, 1978
    PubMed

    Insights

    A chronic knee infection in an elderly man was caused by Corynebacterium pyogenes. This infection triggered a localized plasma cell reaction and a benign M protein, which resolved with antibiotics.

    Area of Science:

    • Infectious disease
    • Rheumatology
    • Hematology

    Background:

    • Advanced degenerative arthritis can predispose individuals to chronic joint infections.
    • Elderly patients with comorbidities present unique diagnostic and therapeutic challenges.

    Observation:

    • A chronic septic process occurred in the right knee of an elderly male patient with pre-existing degenerative arthritis.
    • Joint exploration revealed Corynebacterium pyogenes as the causative pathogen.
    • Synovial biopsy showed significant perivascular plasma cell infiltration.

    Findings:

    • Serum protein electrophoresis identified a prominent M component, indicative of monoclonal gammopathy.
    • Antimicrobial therapy led to a decline in the M protein level.
    • No evidence of multiple myeloma progression was observed during follow-up.

    Implications:

    • The case suggests a localized plasmacytic reaction in the knee associated with Corynebacterium pyogenes infection.
    • Findings are consistent with benign monoclonal gammopathy rather than overt multiple myeloma.
    • This highlights the importance of identifying unusual pathogens in chronic joint infections and monitoring for hematologic changes.

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