Abstract
INTRODUCTION: Septic arthritis is an uncommon but severe complication of intra-articular procedures and is associated with significant morbidity and mortality when diagnosis or source control is delayed. Large cohort data have demonstrated adverse joint and systemic outcomes even when surgical washout is performed. CASE PRESENTATION: We report the case of a 64-year-old woman with Type 2 diabetes mellitus who developed septic arthritis of the knee 2 days after intra-articular hyaluronic acid injection, a procedure generally considered safe but known to carry a small risk of infection. Synovial fluid cultures identified Streptococcus anginosus and subsequently Streptococcus gordonii, organisms recognised for their propensity to cause invasive and disseminated infections. Despite prolonged hospitalisation and exposure to multiple sequential broad-spectrum antibiotic regimens, the infected joint was not surgically drained. During treatment, the patient developed persistent diarrhoea, abdominal pain and systemic inflammatory features. Repeated testing for Clostridioides difficile was negative, despite recognised associations between antibiotic exposure, acid-suppressive therapy and enteric complications. Computed tomography later demonstrated intestinal dilatation and ultimately pneumoperitoneum. Emergency bowel resection was performed, but the patient died shortly thereafter from multiple organ failure. Histopathological examination revealed extensive inflammatory ulceration of the colon. CONCLUSIONS: This case illustrates a complex and fatal clinical course occurring in the context of persistent septic arthritis managed without joint drainage and prolonged antimicrobial exposure. Although causality cannot be established from a single report, the case reinforces the importance of timely source control in native joint septic arthritis, highlights the consequences of prolonged empirical antimicrobial therapy in the absence of adequate surgical debridement and underscores the need for early multidisciplinary reassessment when gastrointestinal symptoms arise during prolonged hospitalisation.