What is the best treatment approach for a patient with sacroilitis, considering potential underlying conditions like inflammatory bowel disease or psoriatic arthritis?

Treatment of Sacroilitis

Start with NSAIDs as first-line therapy, and if inadequate response after a trial period, add a TNF inhibitor—methotrexate monotherapy should be avoided for sacroilitis treatment. 1

Initial Treatment Approach

First-Line Therapy

• NSAIDs are strongly recommended as initial treatment for active sacroilitis over no treatment, based on their established analgesic effects and benefit demonstrated in adult spondyloarthritis 1
• Consider a 1-2 week NSAID washout before MRI imaging if diagnostic confirmation is needed, as NSAIDs can mask up to 20% of active sacroiliitis lesions on imaging 2

When NSAIDs Fail

Adding a TNF inhibitor is strongly recommended over continued NSAID monotherapy when sacroiliitis remains active despite NSAIDs 1. This recommendation is based on:

• Low-quality pediatric evidence supplemented by randomized controlled trials in adult spondyloarthritis showing clear benefit 1
• TNF inhibitors approved for this indication include etanercept, adalimumab, infliximab, and golimumab 1, 3

What NOT to Use

Methotrexate monotherapy is strongly recommended against for treating sacroilitis 1. However, methotrexate may have utility as:

• Adjunct therapy in patients with concomitant peripheral polyarthritis 1
• Prevention of anti-drug antibodies against monoclonal TNF inhibitors 1

Alternative DMARD Option

Sulfasalazine is conditionally recommended only for patients who:

• Have contraindications to TNF inhibitors, OR
• Have failed more than one TNF inhibitor 1

This recommendation is conditional due to limited efficacy demonstrated in randomized controlled trials of juvenile spondyloarthritis 1

Adjunctive Therapies

Glucocorticoids

• Bridging therapy with oral glucocorticoids (<3 months) is conditionally recommended during initiation or escalation of therapy 1
• Most useful in settings of high disease activity, limited mobility, and/or significant symptoms 1
• Intraarticular glucocorticoid injections of the sacroiliac joints are conditionally recommended as adjunct therapy 1

Physical Therapy

• Physical therapy is conditionally recommended for patients with sacroiliitis who have or are at risk for functional limitations 1
• PT may help identify and reduce mechanical factors contributing to microtrauma and repetitive stress that could contribute to disease activity 1

Context-Specific Considerations

Inflammatory Bowel Disease Association

• Sacroiliitis occurs in approximately 17% of Crohn's disease patients 4
• Female gender, back pain, and later age of CD diagnosis are associated with sacroiliitis 4
• IBD disease activity (clinical, endoscopic, or radiographic) does not correlate with presence of sacroiliitis 4
• Treatment approach remains the same: NSAIDs first, then TNF inhibitors if inadequate response 1

Psoriatic Arthritis Association

• Sacroiliitis is a recognized manifestation within the psoriatic arthritis spectrum 1, 5
• These patients are typically classified within enthesitis-related arthritis, psoriatic arthritis, or undifferentiated arthritis categories 1
• Follow the same treatment algorithm: NSAIDs → TNF inhibitors 1

Common Pitfalls to Avoid

• Do not use methotrexate as monotherapy for sacroilitis—it lacks effectiveness for axial disease despite utility in peripheral arthritis 1
• Do not delay TNF inhibitor therapy if NSAIDs fail—there is strong evidence supporting early escalation 1
• Do not perform MRI while patient is on NSAIDs if trying to establish diagnosis, as this may lead to false-negative results in 20% of cases 2
• Do not assume IBD disease activity correlates with sacroiliitis activity—they are independent processes requiring separate assessment 4

Treatment Algorithm Summary

1. Confirm diagnosis: MRI findings of sacroiliitis plus clinical examination findings (SI joint tenderness) and/or inflammatory back pain 1
2. Start NSAID therapy 1
3. If inadequate response to NSAIDs: Add TNF inhibitor 1
4. Consider bridging glucocorticoids if high disease activity during therapy escalation 1
5. Add physical therapy if functional limitations present 1
6. Reserve sulfasalazine only for TNF inhibitor contraindications or failures 1