Abstract
INTRODUCTION: Septic arthritis of the shoulder joint is a serious condition which requires early diagnosis and treatment. This condition usually presents with shoulder pain, limited range of motion and/or fever, and is diagnosed by shoulder arthrocentesis with significant synovial fluid leukocytosis or positive synovial fluid gram stain or culture. There are some risk factors for septic arthritis, notably bacteremia, pre-existing joint pathology and an immunocompromised host such as poorly controlled type II diabetes mellitus. CASE PRESENTATION: A 45-year-old Thai female developed left shoulder septic arthritis after an Astra-Zeneca COVID-19 vaccine administration. The clinical symptoms were left shoulder pain, limited range of motion and fever. The probable risk factors were underlying diabetes mellitus type II and vaccine administration technique. The joint fluid culture showed Staphylococcus aureus. This patient was treated with combined arthroscopic debridement and an intravenous antibiotic for 1 week which was then switched to an oral antibiotic for 5 weeks. Her clinical symptoms gradually improved over the 2 weeks following the initiation of treatment. CONCLUSION: Septic arthritis is a rare complication after a vaccination. Doctors should be especially careful with immunocompromised patients, and always use a correct injection technique.