Working Diagnosis:
Ankylosing Spondylitis

Treatment:
Initial treatment began with an NSAID trial with Naproxen 500mg BID, which improved her pain, but not her stiffness. This was followed by a gradual return to gymnastics as her pain remained controlled. She was then seen by a rheumatologist who diagnosed her with Seronegative Ankylosing Spondylitis based on her presentation of seronegative spondyloarthritis that was HLA B-27 positive with associated sacroiliitis. The patient obtained repeat inflammatory markers, a hepatitis panel, and TB testing before additional treatment options. After a few months, She was successfully transitioned to Etanercept (TNF-alpha inhibitor) with as-needed Naproxen. This treatment sufficiently alleviated her pain and stiffness and allowed her to return to competition.

Outcome:
Following her Naproxen trial, return to play began four months after her symptoms had initially begun, with a slow return to gymnastics practice. During this time, her training was particularly focused on activities that caused no pain. She avoided activities requiring arching or flexing of the spine. As she began Etanercept, her disease activity reduced to a level of tolerable pain, and she was able to return to full competition approximately nine months after symptom onset.

Author's Comments:
Ankylosing Spondylitis (AS) is a chronic inflammatory disease primarily affecting the axial spine with a wide range of clinical signs and symptoms, hallmarked by chronic back pain with progressive spinal stiffness, also involving the SI joints[1]. AS most commonly presents before the age of forty, with most patients experiencing symptoms before the age of thirty[1]. The Assessment of SpondyloArthritis International Society (ASAS) dictates the diagnostic criteria of Ankylosing Spondylitis to be patients under the age of 45 with three or more months of lower back pain and stiffness with radiographic evidence of sacroiliitis (grade 2+ bilaterally or grade 3/4 one side on MRI) and/or or HLA-B27+ with at least one of the following: inflammatory back pain, uveitis, arthritis, Crohn’s/UC, Psoriasis, high CRP, positive response to NSAIDs, dactylitis (swelling of fingers or toes), family history[2]. Biologic agents and NSAIDS can significantly improve pain and functionality, but exercise should play the primary role in treatment[3]. Abnormalities on standard radiographs are typically not seen until up to 8 to 11 years from disease onset, which can lead to significant delays in diagnosis and initiation of therapy. Earlier radiographic changes, particularly of sacroiliitis, can be detected sooner via MRI[3]. Considerations should be made towards spinal fractures[3,4] and cardiac disease[3] when clearing athletes to return to competition. For patients with AS, spinal fractures can be up to four times more common than in the general population, with “81.2% occurring in the cervical spine”[4]. The most common locations of the fractures included the dens, lower cervical vertebrae, and cervico-thoracic junction. The frequency of fractures increases with every passing year from diagnosis[4]. Patients with AS also have an increased risk of conduction abnormalities along with ischemic heart disease, heart failure, and valvular heart disease[4]. A 2024 meta-analysis focused on exercises for the improvement of AS symptoms showed the order of effectiveness to be running, followed by Pilates, stretching, yoga, Tai Chi, Exergame, and Swiss Ball[5], though the study did note a low quality of evidence as the data were mostly based on probabilities from results (without standardization in duration or intensity) rather than direct comparison.

This case highlights the diagnostic challenges of an insidious disease that typically presents in patients who are at an athletically competitive age. Given that the disease presents with complications that can place athletes at significant health risks that can be exacerbated by competition, it is imperative that providers include it in their differential diagnoses to rule out during similar cases.

Editor's Comments:
This is an uncommon diagnosis with a common chief complaint and highlights the importance of including inflammatory causes of back pain in young athletes, even when the presentation appears consistent with a mechanical or overuse injury. For sports medicine providers, early recognition of ankylosing spondylitis is important because disease-specific therapies, such as etanercept in this case, may be needed to adequately control symptoms and allow athletes to safely return to competition.

References:
1. Wenker, Kyle J. "Ankylosing Spondylitis."; StatPearls [Inernet]., U.S. National Library of Medicine, 20 June 2023, www.ncbi.nlm.nih.gov/books/NBK470173/.

2. Rudwaleit, M et al. "The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection." Annals of the rheumatic diseases vol. 68,6 (2009): 777-83. doi:10.1136/ard.2009.108233

3 . Harper, Brock E, and John D Reveille. "Spondyloarthritis: Clinical Suspicion, Diagnosis, and Sports." Current Sports Medicine Reports, U.S. National Library of Medicine, 1 Feb. 2009, pmc.ncbi.nlm.nih.gov/articles/PMC2898732/.

4 . Thumbikant P, et al. "Spinal Cord Injury in Patients with Ankylosing Spondylitis." Spine. 2007;32(26):2989�"2995. doi: 10.1097/BRS.0b013e31815cddfc

5. Luo, Yekui, et al. "Effectiveness of Exercise Intervention in Relieving Symptoms of Ankylosing Spondylitis: A Network Meta-Analysis." PloS One, U.S. National Library of Medicine, 14 June 2024, pmc.ncbi.nlm.nih.gov/articles/PMC11178210/.

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