Happy Monday, y’all!
Today we talked about a young female with recent nephrolithiasis, severe depression and recent hospitalization, and family history of sarcoidosis presenting with progressive inflammatory lower back pain, ultimately found to have spondyloarthropathy. We discussed the features of inflammatory back pain, reviewed some exam maneuvers, and talked about ideal imaging modality for sacroilitis!
First off, check out this great diagram made by last year’s Ambulatory Chief extraordinaire Christy Soran:
Remember the features of inflammatory back pain:
- Age of onset <40 years
- Gradual onset
- Improvement with exercise/activity
- No/minimal improvement with rest
- Pain at night
- Morning stiffness
Tips to distinguish SI joint pain from other areas of back pain?
- Buttock pain (classically alternating between two sides but can be unilateral as well)
- FABER maneuver: Flexion, ABduction, External Rotation (remember the “Figure 4”)
- If pain: indicates SI joint disease
- If limited ROM: indicates hip or iliopsoas disease
- How good is this test? sensitivity=0.60-0.77, specificity=0.16-0.75
- Can also be positive in labral tears!
Key locations of pain on exam:
Extra-skeletal manifestations of spondyloarthropathy (AKA your ROS for every patient with inflammatory LBP!)
- Anterior Uveitis (always ask about eye pain, photophobia, change in vision)
- IBD (50% of patients with AS can have asymptomatic mucosal ulcerations; ask about diarrhea, weight changes, abdominal pain/cramping)
- Psoriasis (ask about rash, nail changes, other joint involvement)
- Recent infections (GI/GU infections)
- Dactylitis/enthesitis (ask about other joint or tissue swelling)
Which imaging modality is best for spondyloarthropathy?
AP pelvis plain film is first line imaging – cost effective, sufficient for sacroilitis, and easy to order for comparison for disease progression!
What about SI joint xrays? NOT preferred as AP pelvis gives more information related to hip disease, pelvis enthesopathy and the pubic symphasis. In addition, AP pelvis is LESS radiation exposure than SI joint 3 view xrays.
Who needs MRI or HLAB27?
- Consider MRI sacrum and HLAB27 if plain films negative but history/exam highly suspicious
- Diagnosis of Ankylosing Spondylitis can be made from the following:
- Sacroilitis on imaging + > 1 sign of spondyloarthropathy
- HLAB27 antigen present + > 2 signs of spondyloarthropathy
Complications of AS?
- Osteopenia, osteoporosis
- Cervical spine fracture/injury or spontaneous subluxation of the atlantoaxial joint (C1-C2) (similar to RA)
- Cardiovascular disease
- Pulmonary disease (restrictive lung disease)
- Increased risk of nephrolithiasis (due to disordered calcium/vitamin D metabolism, also higher risk if history of IBD)
Other final pearls:
- 30% of patients can have normal inflammatory markers (usually a better prognosis!)
- Patients with nephrolithiasis and spondyloarthropathy should be evaluated for IBD
- NSAIDs are mainstay of treatment (help with pain relief, maintain mobility, and can halt radiographic progression) – first line, can be used during flares or continuously. TNFa inhibitors currently only used if symptomatic despite NSAID compliance or if NSAIDs contraindicated!
Evernote: Evernote for LBP & AS