Histoplasma capsulatum periprosthetic knee infection complicated by autoimmune-mediated systemic inflammatory response syndrome.

Histoplasma capsulatum periprosthetic knee infection has rarely been reported in the literature due to its low frequency. Notwithstanding, it is important to keep it among the differential diagnoses to avoid delays in treatment. The current report presents the case of infectious knee monoarthritis in an immunocompetent patient after unicompartmental knee arthroplasty. The joint infection was accompanied by disseminated histoplasmosis, which initiated an autoimmune reaction, ensuing a systemic inflammatory response syndrome. The management protocol used in this case was successful and included staged arthroplasty reconstruction combined with chronic antifungal and steroid pharmacotherapy. Approximately 4 years after total knee arthroplasty revision, there were no clinical signs of localized or systemic infection.