Brucellosis sacroiliitis masquerading as inflammatory spondyloarthropathy

Brucellosis is the most common zoonosis globally, and it is endemic to the Indian subcontinent. It can mimic a number of febrile illnesses and inflammatory disease conditions. An 18-year-old boy presented with low back pain and a fever of three-month duration. Magnetic resonance imaging revealed a unilateral sacroiliitis, which was being treated as an inflammatory spondyloarthropathy. Because of non-resolving symptoms, a biopsy was performed, which showed a granulomatous inflammation that was consistent with tuberculosis or brucellosis infection. A history of exposure to livestock and consumption of unpasteurized milk led to a clinical suspicion of brucellosis, which was confirmed on a positive serology. He was treated with antibiotics with improvement in symptoms and complete resolution of the sacroiliitis. A high index of suspicion must be maintained for brucellosis, especially in patients with a rural residence, exposure to livestock, and febrile illness with a clinically suspected unilateral sacroiliitis.