An unwanted souvenir: Case report of delayed diagnosis of a coccidioidomycosis prosthetic joint infection

Background

Coccidioides spp, are dimorphic fungi endemic to arid and semi-arid regions of the Western USA, Central America, and South America, which can cause coccidioidomycosis. Although the majority of infections are mild or sub-clinical, disseminated coccidioidomycosis can occur, typically affecting immunocompromised individuals. This report presents a case of disseminated coccidioidomycosis that remained undiagnosed for decades.

Case report

A 68 year old Caucasian female presented to the Accident and Emergency (A&E) Department of a UK hospital in late 2024 with fever, chills, vomiting, and joint pain. On examination she was febrile and hypotensive, with a clear chest and unremarkable cardiovascular and abdominal examinations. She had an extensive past medical history, involving rheumatoid arthritis and sarcoidosis (treated with a range of immunosuppressive agents), and knee swelling and pain, for which she underwent a unilateral total knee replacement with no resolution of symptoms.

During the most recent presentation, a range of microbiology samples were collected, including a knee aspirate (inoculated into a blood culture bottle). A fungus was isolated which was later identified by the National reference laboratory as Coccidioides immitis. The patient was treated with dual-antifungal therapy and remains on lifelong suppressive fluconazole (alongside steroids), under regular follow up.

Conclusion

Although there was an extensive travel history to endemic countries, and compatible clinical features, no diagnosis was made for many years. The recent laboratory investigations which clinched the diagnosis were also challenging as no travel history was provided, and our diagnostic equipment was not set up to detect this pathogen.

This case underscores the diagnostic challenges of coccidioidomycosis in non-endemic regions, emphasizing the critical role of a detailed travel history. It also highlights the occupational risks associated with handling Coccidioides in the laboratory, and the need for increased awareness of rare pathogens, particularly in immunocompromised patients with relevant travel histories.