Seronegative Spondyloarthropathies

The Spondyloarthropathies are a group of disorders is characterized by

• Arthritis [of peripheral joints or spine, usually involving also the sacroiliac joints.]
• A negative test for rheumatoid factor [that is why they are called seronegative spondyloarthropathy.]
• Associtation with medical problems like psoriasis, inflammatory bowel diseases [Ulcerative colitis or Crohns disease], uveitis, urogenital or gastrointenstinal infections.
• Enthesitis (inflammation at the site of insertion of tendons and ligaments to bone)

There is a strong correlation with HLA-B27 .

Ankylosing spondylitis, Reiter’s syndrome, enteropathic arthritis, psoriatic arthritis, Behçet’s disease and juvenile idiopathic arthritis are included in seronegative spondyloarthropathies.

Criteria for Spondylarthropathy

[The European Spondylarthropathy Study Group (ESSG)]

Presence of Inflammatory back pain, or synovitis (asymmetric, predominantly in the lower limbs)  along with one or more of the following:

• Past or present psoriasis
• Past or present ulcerative colitis or Crohn’s disease
• Past or present pain alternating between the two buttocks
• Past or present enthesitis [spontaneous pain or tenderness on examination of the site of insertion of the Achilles tendon or plantar fascia]
• An episode of diarrhoea occurring within one month before onset of arthritis
• Nongonococcal urethritis or cervicitis occurring within one month before onset of arthritis
• Family history: first-degree or second-degree relative with ankylosing spondylitis, psoriasis, acute iritis, reactive arthritis or inflammatory bowel disease
• Bilateral grade 2-4 sacroiliitis or unilateral grade 3 or 4 sacroilitis.[see below for meanings of grades]

Apart from ESSG, Amor criteria is also used for diagnosis of spondylarthropathies.

On plain radiographs, sacroilitis grading according to the New York criteria.

Grade 0 – Normal
Grade I –  Some blurring of the joint margins – suspicious
Grade II – Minimal sclerosis with some erosion
Grade III –

• Definite sclerosis on both sides of joint

• Severe erosions with widening of joint space with or without ankylosis

Grade IV – Complete ankylosis

Undifferentiated spondylarthropathy

In this subgroup of spondyloarthropathies, features are consistent with the spondyloarthropathies but the patients do not fulfil criteria for any specific spondyloarthropathy. This condition may represent ay represent either an early phase or incomplete form of specific spondyloarthropathy.However,  certain features like age of onset – 50 years, greater female preponderance  and low association with  HLA-B27 positivity does suggest that undifferentiated spondyloarthropathy is separate entity.

Management is by non steroidal anti inflammatory drugs and physical therapy mainly. Sulfasalazine has been suggested to have some role in the management of undifferentiated spondyloarthropathies.

Epidemiology of Spondyloarthropathies

Prevalence of spondyloarthropathies is reported to be around 2% with slight male preponderance. Those individuals who are positive for HLA B27 have 20 times more risk of developing spondylarthropathy.

Ankylosing spondylitis and undifferentiated spondyloarthropathy are the most frequent subtypes.

Presentation

Patients usually present between 20 to 40 years of age.

Back pain, either lumbar or dorsal, buttock pain in single or both or alternating are chief presenting complaints. Pain is worse in the night and may be associated with stiffness in the morning.

Pain in peripheral joints, especially lower limbs may also be present.

Enthesitis [pain and tenderness at tendon insertion] and dactylitis [ inflammation involving a whole finger or toe] with tendovaginitis and arthritis (sausage digit) may be present.

Associated complaints depending upon the disease profile may be nongonococcal urethritis or cervicitis, or acute diarrhoea one month or less before the onset of arthritis, psoriasis, balanitis or inflammatory bowel disease, anterior uveitis may be present. There might be a family history of spondyloarthropathy.

Differential diagnosis

• Rheumatoid arthritis
• Prolapsed intervertebral disc
• Systemic lupus erythematosus
• Gout
• Osteoarthritis

Lab Investigations

ESR and CRP are  often raised in relation to disease activity. Rheumatoid factor as noted, is negative. Serum uric acid, antinuclear antinuclear antibodies, bacterial serology should be done to rule other causes or know any association.

Imaging

Xray of the sacroiliac joints should be done for checking sacriliitis. Xray of the affected painful part should be done. MRI may be needed in certain cases to rule out disc herniation. HLA testing is not normally done due to high false positive rates.

Management

Seronegative spondyloarthropathies depend on type of spondyloarthropathy. NSAIDs, Disease modifying anti rheumatic drugs [DMARDs – sulfasalazine, methotrexate], TNF – blockers like etanercept, infliximab and adalimumab are the drugs used for  management. Physiotherapy and occupational therapy are also used along with.

Surgery may be indicated  in severely destroyed joints

Prognosis of Spondyloarthropathies

Spondyloarthropathies  are associated with spontaneous remissions or exacerbations. Disease continues for many decades. Poor prognostic factors are

• Young age at onset (less than 16 years)
• ESR>30
• Hip arthritis
• Lumbar spine movement limitation
• Poor response  NSAIDs

Image credit: Enthesis.info