Seronegative Spondyloarthropathy
Seronegative spondylarthritis/spondyloarthropathy is a category of inflammatory diseases such as ankylosing spondylitis, psoriatic arthritis, inflammatory bowel disease-associated inflammatory arthritis, and reactive arthritis. It affects areas where ligaments and tendons attach to bones called “entheses”.
Rheumatoid factor (RF) is usually negative in these spondyloarthropathies hence, it is called seronegative spondyloarthropathy.
Patients complain of inflammatory joint pain along with morning stiffness & pain at rest lasting for more than an hour which usually subsides with activity.
They are characterized by inflammation of the spine, sacroiliac (SI) joints, peripheral joints, enthesitis, dactylitis, as well as extra-articular manifestations such as uveitis and skin rashes. Serologically, they are rheumatoid factor (RF) and antinuclear antibody (ANA) negative.
PATHOPHYSIOLOGY:
- Enthesitis, or inflammation of the sites where the tendons or ligaments insert into the bone, is a key pathological finding in spondyloarthropathy. It is thought that microtrauma from stress also triggers inflammation at the enthesis. This finding differentiates it from rheumatoid arthritis and other inflammatory polyarthritis.
- Presence of HLA-B27 gene
- Environmental exposure of the immune system to microorganisms
These inflammatory processes lead to change in bone and pathologic new bone formation, which is seen in Ankylosing Spondylitis but not in rheumatoid arthritis
SYMPTOMS :
- Inflammatory back pain
- Low back pain radiates to buttocks. Nocturnal pain occurs during second half of the night
- Pain, swelling around periarticular or tendon insertional sites
- Morning pain & stiffness lasting for more than an hour
SIGNS :
- Dactylitis may be seen
- Uveitis, iritis
- Skin involvement in the form of psoriasis
- Low bone mineral density
INVESTIGATION :
- Physical Exam:Restricted spinal mobility & range of motion, tenderness of sacroiliac joints & peripheral joints on palpation
- Edema, warmth, tenderness, redness at tendon insertional sites
- Positive Schober’s test
- XRAY of LS (bamboo spine appearance, vertebral body squaring) & SI joint
- MRI Spine
- Inflammatory markers, HLA-B27
TREATMENT :
Treatment goal for seronegative spondyloarthropathy will be reducing pain and other symptoms, improving mobility and avoiding complications of the disease.
Medications: NSAIDS, TNF inhibitors, non-biological DMARDS, systemic glucocorticoids to relive pain.
Physical Therapy: Mobility exercises & stretches to improve & maintain spinal flexibility & mobility.Aerobic exercises & breathing exercises.
Biologics: TNF inhibitors like infliximab, etanercept, adalimumab, golimumab, and certolizumab can be used for remission of symptoms.
