Acute Unilateral Sacroiliitis Mimicking Infection on Magnetic Resonance Imaging with Response to Nonsteroidal Antiinflammatory Drugs: A Distinct Presentation of Spondyloarthritis?

Sacroiliitis is associated with the spondyloarthropathies (SpA) including ankylosing spondylitis, psoriatic arthritis, and reactive arthritis (ReA), and may be visualized using magnetic resonance imaging (MRI). Here, we describe 4 cases of acute unilateral sacroiliitis with florid MRI appearances that mimicked infection but demonstrated a prompt and complete response to nonsteroidal antiinflammatory drugs (NSAID). All patients in this report...