Case Presentation: A 66-year-old Nigerian female with a past medical history of type II diabetes with a hemoglobin A1c of 9% presented with right knee pain and swelling. Her symptoms began two months prior without any preceding trauma to the knee. Since that time, she had progressive pain and swelling of her knee. One month prior to her presentation she went to an outside hospital and underwent arthrocentesis with aspirated fluid notable for negative cultures and no crystals. She was discharged with analgesics; no antibiotics were administered. Despite arthrocentesis and analgesics, her swelling recurred and her pain progressed to the point where she was unable to bear weight or ambulate, prompting her to come to the emergency department. She had otherwise not experienced fever/chills, weight loss, or night sweats. On presentation, she was afebrile with an elevated C-reactive protein and erythrocyte sedimentation rate but without leukocytosis. Her exam showed warmth and tenderness to palpation of the right knee and an obvious knee effusion with limited range of motion. Aspiration of the knee revealed 2,900 white blood cells with gram negative rods on gram stain. She was started on ceftriaxone. Two days into her hospital course she underwent arthrotomy, irrigation, and debridement with placement of a drain. Despite surgical and medical intervention her symptoms minimally improved over the next week. During hospitalization surgical pathology from synovium grew aspergillus, as well as a culture of the synovial fluid. She was started on voriconazole which was continued at discharge. Her symptoms finally resolved after one month.
Discussion: Aspergillus is a reported but rare cause of infective arthritis. It is most often associated with immunocompromised hosts, patients with solid organ transplants on immunosuppression, and patients with a history of joint instrumentation, such as steroid injections or prior knee replacement. While our patient did not have any knee instrumentation, we believe it reinforces the notion that patients with poorly controlled diabetes have altered immunity and can be more susceptible to infections more commonly seen in immunocompromised patients. Diabetes leads to a pro-inflammatory state as evidenced by up-regulation of pro-inflammatory markers. As a result, these patients do not have a normal functioning immune system. This underscores the point that patients with poorly controlled diabetes should be evaluated and treated as if they are immunosuppressed in the right clinical context. Clinicians should have a suspicion for atypical infections in these patients and may require additional work-up and close follow-up to arrive at the correct diagnosis.
Conclusions: Diabetic patients should be considered as having an immunocompromised state, particularly in the setting of evaluating for a potential infection. When performing an infectious workup in an immunocompromised patient, cultures should be followed until finalized, as fungal and atypical organisms can be slow to grow and often require long incubation times.