Paradoxical Reaction Presenting as Sacroiliitis in Brucellosis: A Case Report and Literature Review

Although brucellosis is one of the most common zoonotic infections worldwide, the development of a paradoxical reaction during treatment hasrarely been reported in the literature. We present a 17-year-old patient who developed acute sacroiliitis in the second week of treatment for olecranon bursitis brucellosis, despite her initial clinical findings showing signs of improvement. After excluding other potential etiologies for sacroiliitis, clinical and radiological recovery was achieved by adding anti-inflammatory therapy without modifying the existing antimicrobial regimen. Consequently, the clinical picture was evaluated as a paradoxical reaction. This case emphasizes that new symptoms or clinical worsening during brucellosis treatment should not always be interpreted as treatment failure or relapse; the possibility of a paradoxical reaction should be considered.