AB160. SOH24AB_040. Coccidiomycosis: a rare case of ankle septic arthritis with extended incubation period

Background: Coccidioidomycosis is a fungal infection found endemically in the southwest of the United States (US). Musculoskeletal involvement is unusual and often results in a delayed diagnosis. The typical incubation period for coccidioidomycosis is 7–21 days. We present an unusual case of septic arthritis of the ankle joint, resulting from coccidioidomycosis infection with an exceptionally extended incubation period of greater than 10 years.

Case Description: We present a case of an immunocompetent man in his 70s who presented with a three-year history of progressive ankle pain and swelling following an innocuous ankle sprain. The patient had an extensive travel history, including construction work in Arizona and hiking in Colorado. Initial examination revealed no signs of active infection at the ankle joint. Investigations: computed tomography (CT) and magnetic resonance imaging (MRI) showed significant talar bone avascular necrosis, collapse and oedema, possibly suggestive of osteomyelitis. In the meantime, the patient’s skin integrity deteriorated and developed exudative discharge as well as progressive swelling of the ankle joint. Image guided aspiration samples yielded coccidiomycosis. Treatment: fungal experts in US recommended lifelong itraconazole 200 mg twice daily. A two-stage salvage arthrodesis was performed, to avoid a below knee amputation. Additionally, he underwent a two-stage reconstruction by plastics. Samples from the first stage flap grew Acinetobacter baumannii and e. Cloacae which were trimethoprim and sulfamethoxazole sensitive. Thus, both antibiotics were given for six weeks post op as well as continuing itraconazole.

Conclusions: Coccidioidomycosis infection although unusual, should be considered in patients with a travel history to endemic areas, even when outside the usual incubation period. These infections require both an aggressive surgical approach and antibiotic therapy.

Keywords: Septic arthritis; fungal; incubation period; arthrodesis; ankle joint