Differential diagnosis and management of ankylosing spondylitis masked as adhesive capsulitis: a resident's case problem.

Study Design: Resident's case problem.

Background: Ankylosing spondylitis is a potentially debilitating seronegative spondyloarthropathy, with inflammatory low back pain as the most commonly reported symptom. In the absence of low back pain, identification of other diagnostic criteria or associated impairments and joint involvement, such as involvement of the hip or shoulder, may be beneficial.

Diagnosis: A 32-year-old man with right shoulder pain and decreased range of motion was referred with a diagnosis of adhesive capsulitis. He had been managed by multiple healthcare providers for 3 years before being referred to a physical therapist. Glenoid labral pathology was evident on prior magnetic resonance imaging, which had led to a persistent focus on the shoulder. The evaluation by the physical therapist revealed significant mobility deficits in the cervical, thoracic, and lumbar spine. Radiographs and laboratory tests were ordered and a referral was made to rheumatology after the initial physical therapy assessment. The diagnostic work-up confirmed the diagnosis of ankylosing spondylitis and led to multidisciplinary management of the disease.

Discussion: Low back pain is often the primary symptom of ankylosing spondylitis later in the disease process. Earlier indicators of ankylosing spondylitis, such as severely impaired mobility and spine stiffness, may help guide detection in the absence of spinal pain. In this case, an appropriate diagnosis led to improvement in the management strategy of what might have appeared to be unrelated shoulder pain. Early differential diagnosis is important, as emerging interventions show promise when used earlier in the disease process.