Case Presentation: A 71-year-old female with metastatic thyroid cancer status-post (s/p) radioiodine ablation and total thyroidectomy on oral chemotherapy, chronic kidney disease stage IV s/p deceased donor kidney transplant in 2019 on oral immunosuppression, presented with weakness, gastrointestinal symptoms, and acute-on-chronic dysphagia. While dysphagia work-up was ongoing, patient was noted to have right wrist swelling, tenderness, and decreased range of motion, prompting an arthrocentesis of the wrist and prophylactic initiation of colchicine for suspected gout flare. Subsequent wrist imaging was notable for soft tissue swelling on x-ray, tenosynovitis of multiple extensor compartments on ultrasound, and synovitis and carpal erosion on MRI. Over the next few days, patient responded well with improved range of motion and decreased wrist swelling with presumptive diagnosis of gout. Following the arthrocentesis, synovial fluid cultures returned positive for Cryptococcus neoformans, prompting initiation of fluconazole treatment, with subsequent surgical intervention revealing a septic right wrist and evidence of osteomyelitis. Patient’s mental status progressively worsened and due to her risk of disseminated disease, a lumbar puncture was performed which revealed an elevated opening pressure, cryptococcal antigen in the cerebrospinal fluid (CSF), and CSF fungal cultures positive for C. neoformans. The patient’s antifungal therapy was escalated to Liposomal Amphotericin B and Flucytosine for broader coverage and better CNS penetration. Ultimately, the patient was transitioned to daily fluconazole with plans for lifelong suppression. At discharge, she had minimal wrist pain and her mentation returned to baseline.
Discussion: Septic arthritis, the infection of a joint space, is an uncommon disease process. There are significant clinical implications, as septic arthritis can cause irreversible joint damage and significant mortality [2]. While bacteria are the most common causative agents of septic arthritis, fungal organisms are rarely isolated. After Aspergillus and Candida, C. neoformans is the most common fungal pathogen implicated, making it an important pathogen to consider [1]. Fungal infections are often difficult to diagnose due to the chronic, indolent course of infection, as well as the nonspecific nature of presenting symptoms [3] like fatigue, weight loss, or low-grade fever, ultimately leading to delays in diagnoses and misdiagnoses. Identifying septic arthritis from joint aspirate will not only guide treatment but also the necessary work-up, leading to better outcomes.
Conclusions: Septic arthritis is a rare manifestation of C. neoformans [1]. Given its rarity and nonspecific symptoms, it can be mistaken for a less serious condition, such as gout, making it easy to miss. Thus, the provider must hold a low threshold for further work-up, especially in immunocompromised patients. Obtaining early synovial and microbiological analysis is key to accurate diagnosis [2].