Where should I refer a patient with ankylosing spondylitis?

Referral for Ankylosing Spondylitis

Patients with ankylosing spondylitis should be referred to a rheumatologist for diagnosis, treatment, and ongoing management.

Referral Criteria

Patients with chronic low back pain should be referred to a rheumatologist when they have:

1. Inflammatory back pain characteristics:

   • Morning stiffness lasting more than 30 minutes
   • Pain at night/early morning
   • Improvement with exercise
   • Age of onset < 45 years
   • Symptoms lasting > 3 months

2. Laboratory findings:

   • HLA-B27 positive status (highest sensitivity at 90% and specificity at 90%)
   • Elevated inflammatory markers (ESR/CRP) may be supportive but have lower sensitivity (50%)

3. Imaging evidence:

   • Sacroiliitis on X-rays or MRI (if available)

Why Rheumatology Referral is Essential

Rheumatologists are the specialists of choice for ankylosing spondylitis because:

1. Disease complexity: AS requires specialized management with multiple treatment modalities including NSAIDs, biologics, and physical therapy 1

2. Medication expertise: Rheumatologists can appropriately prescribe and monitor:

   • NSAIDs as first-line treatment
   • Anti-TNF therapy for patients with persistently high disease activity
   • Other biologics when indicated

3. Early diagnosis importance: Rheumatologists can diagnose pre-radiographic axial spondyloarthritis, allowing earlier intervention 1

4. Monitoring disease progression: Regular assessment of disease activity using validated tools

When to Consider Additional Specialist Referrals

While rheumatologists are the primary specialists for AS management, additional referrals may be needed in specific circumstances:

1. Orthopedic surgeon:

   • Patients with refractory pain or disability with radiographic evidence of structural damage requiring total hip arthroplasty
   • Severe disabling spinal deformity requiring corrective osteotomy
   • Acute vertebral fracture 1

2. Ophthalmologist:

   • Patients with symptoms of uveitis or other eye complications

3. Gastroenterologist:

   • Patients with concurrent inflammatory bowel disease

Referral Efficiency

The most efficient referral pathway involves:

1. Pre-referral testing: HLA-B27 testing has the highest utility with a likelihood ratio of 9, meaning only 3 HLA-B27 positive patients with chronic back pain need to be seen by a rheumatologist to diagnose one case of axial spondyloarthritis 1

2. Appropriate imaging: Plain radiographs of the pelvis can be ordered prior to referral, but their absence should not delay referral if clinical suspicion is high

3. Medication response: Document response to NSAIDs as this information is valuable for the rheumatologist

Common Pitfalls to Avoid

1. Delayed referral: Waiting for radiographic changes can delay diagnosis by years, as radiographic sacroiliitis may take several years to develop

2. Over-reliance on inflammatory markers: Normal ESR/CRP does not rule out AS (sensitivity only 50%)

3. Referring to the wrong specialist: Sending patients to pain management or general orthopedics first can delay appropriate treatment

4. Missing extra-articular manifestations: Failing to recognize associated conditions like uveitis, psoriasis, or inflammatory bowel disease

The evidence strongly supports early referral to rheumatology for patients with suspected ankylosing spondylitis to improve outcomes related to morbidity, mortality, and quality of life 1.