A rare cause of oligoarthritis with septic presentation.

A 33-year-old man presented with new-onset, asymmetric, migratory oligoarthritis in the setting of several weeks of nausea and vomiting, diarrhoea, fevers and dysuria. He was initially treated in the inpatient setting with broad-spectrum antibiotics due to concern for an evolving sepsis presentation. Arthrocentesis of a large right knee effusion revealed inflammatory synovial fluid without findings suggestive of septic arthritis. Human leucocyte antigen B27 was positive and, taken together with the antecedent history of gastroenteritis, dysuria and inflammatory oligoarthritis, the clinical diagnosis was most consistent with reactive arthritis. Antibiotics were discontinued. His treatment course proved refractory to non-steroidal anti-inflammatory drugs and intra-articular and systemic glucocorticoid therapy with concurrent use of sulfasalazine and ultimately necessitated treatment with a tumour necrosis factor alpha inhibitor. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.