What is lumbar spondylitis?

Lumbar Spondylitis: Diagnosis and Management

Lumbar spondylitis is an inflammatory condition affecting the lumbar spine, most commonly seen as part of axial spondyloarthritis, characterized by inflammation of the vertebral bodies, intervertebral discs, and adjacent structures that can lead to pain, stiffness, and potential fusion of spinal segments.

Types and Causes

Lumbar spondylitis can be classified into two main categories:

1. Inflammatory spondylitis:

   • Part of axial spondyloarthritis (axSpA) spectrum, including ankylosing spondylitis
   • Autoimmune-mediated inflammation
   • Genetic predisposition (HLA-B27 positive in 90-95% of cases) 1
   • Typically affects younger patients (onset before age 45) 1

2. Infectious spondylitis (spondylodiscitis):

   • Caused by bacterial, fungal, or tubercular infections
   • Most commonly involves Staphylococcus aureus 2
   • Usually affects two adjacent vertebral bodies and the intervertebral disc 2
   • Can result from hematogenous spread, direct extension, or iatrogenic causes 3

Clinical Presentation

Inflammatory Spondylitis

• Insidious onset of low back pain before age 45
• Morning stiffness lasting more than 30 minutes
• Pain improves with exercise but not with rest
• Night pain/early morning awakening due to pain
• Alternating buttock pain 1
• Symptoms lasting more than 3 months 1

Infectious Spondylitis

• Often presents with nonspecific symptoms
• Fever and back pain are common
• Diagnosis frequently delayed by several weeks 2
• May extend to paravertebral soft tissues and epidural space 3

Diagnostic Approach

Imaging

1. Conventional radiography:

   • First-line imaging modality 1
   • May show erosions, sclerosis, joint space narrowing, and eventual ankylosis
   • Should not be repeated more frequently than every 2 years for monitoring 1

2. MRI:

   • Essential for identifying early inflammatory disease 1
   • Requires T1-weighted sequences and fat-suppressed fluid-sensitive sequences
   • Bone marrow edema is the hallmark of active sacroiliitis 1
   • In spondylodiscitis, shows focal or linear increased signal in vertebral endplates 3

3. CT scan:

   • Demonstrates structural changes that may not be apparent on radiographs
   • Particularly useful for thoracic spine and facet joints 1
   • Essential for evaluating fractures in ankylosing spondylitis 1

Laboratory Tests

• HLA-B27 testing (sensitivity 90-95% in ankylosing spondylitis) 1
• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)
• Blood cultures in suspected infectious spondylitis 3

Management

Inflammatory Spondylitis

1. First-line treatment:

   • NSAIDs as initial therapy 1
   • Structured exercise programs 4

2. Biologic therapy:

   • TNF inhibitors recommended as first biologic option 1
   • Secukinumab or ixekizumab recommended for patients with primary non-response to TNF inhibitors 1

3. Monitoring:

   • Regular assessment using validated tools like ASDAS-CRP 1
   • Referral to rheumatologist for ongoing management 1

Infectious Spondylitis

• Antibiotic therapy based on microbiological diagnosis 2
• Majority of cases can be cured with antibiotics alone 2
• Surgical intervention may be necessary for spinal instability, neurological compromise, or abscess formation 3

Complications

• Spinal fusion and ankylosis in inflammatory spondylitis 1
• Unstable fractures with high risk of neurological injury in ankylosed spine 1
• Neurological deficits from compression in both types
• Chronic pain and disability affecting quality of life

Special Considerations

• Fracture risk: Patients with ankylosing spondylitis have increased risk of spinal fractures even with minor trauma 5
• Delayed diagnosis: Can occur due to over-reliance on radiographs or misinterpretation of normal inflammatory markers 1
• Surgical challenges: Operative management of the spine with ankylosing spondylitis is difficult and has high complication rates 5

When to Refer

• Refer to rheumatologist for diagnosis, treatment, and ongoing management of inflammatory spondylitis 1
• Consider orthopedic referral for patients with refractory pain or disability with structural damage 1
• Infectious disease consultation for complex infectious spondylitis cases

Proper diagnosis and timely management of lumbar spondylitis are essential to prevent progression, manage symptoms effectively, and maintain quality of life.