# Rare Case Studies of Bilateral and Symmetric Sacroiliac Disease

## TL;DR

This paper highlights the importance of diagnosing sacroiliac joint disease and presents rare cases of symmetric inflammation not linked to common conditions.

## Contribution

The paper presents rare case studies of bilateral sacroiliac disease unrelated to typical spondyloarthritis conditions.

## Key findings

- Sacroiliitis is often misdiagnosed as fibromyalgia due to negative serology results.
- Three rare cases of symmetric sacroiliac disease were identified, not linked to ankylosing spondylitis or other common conditions.
- Proper SIJ imaging is crucial for accurate diagnosis and treatment of unexplained low back and buttock pain.

## Abstract

Inflammatory sacroiliitis is common in rheumatology practice. Spondyloarthritis is often underdiagnosed due to the lack of proper evaluation of the sacroiliac joints (SIJs), clinically and radiographically. If SIJ is inflamed or arthritic, the arthritic said patient typically has spondyloarthritis, in the absence of infections or crystal arthritis. Sacroiliitis, in particular, when diagnosed between 12 and 45 years of age, is indicative of spondyloarthritis. People are often misdiagnosed and mislabeled as fibromyalgia because their serologies are negative. Our goal is to point out the importance of proper evaluation, diagnosis, and importance of inflammatory SIJ disease and conditions that involve SIJ inflammation.

We present three rare conditions presenting with bilateral and symmetric SIJ disease, none of which is ankylosing spondylitis, Crohn's colitis, ulcerative colitis, psoriatic arthritis, and reactive arthritis (Reiter syndrome); there are reports of concurrent SIJ disease in rheumatoid arthritis and SLE.

The authors believe that SIJ disease is overlooked, is underdiagnosed, and can lead to incorrect treatment. We suggest a greater focus on SIJ imaging in the diagnosis and treatment of unexplained illnesses associated with low back pain, morning stiffness, or unexplained buttock pain. Providers should review their own SIJ films. The meaning of SIJ widening, cortical irregularity, spurs, and the significance of the anterior inferior SI joints, bone marrow edema, and fusion (namely, the natural history of sacroiliac pathophysiology).