Spondyloarthropathies (Seronegative RA)

By admin Last updated Oct 26, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Brent H. Messick

Kevin E. Burroughs

Basics

Description

Spondyloarthropathy (SpA) is a term applied to the clinical, radiologic, and immunogenetic features shared by a group of diseases that include:
- Ankylosing spondylitis (AS)
- Reactive arthritis (ReA)
- Psoriatic arthritis (PsA)
- Arthritis associated with inflammatory bowel disease (IBD)
- Juvenile onset spondyloarthritis
- Undifferentiated spondyloarthropathy (USpA):
  - These conditions are variably associated with the HLA B27 antigen. Individuals with these conditions frequently exhibit overlapping clinical and radiologic features.
Synonym(s): Seronegative spondyloarthropathies; HLA B27-related spondyloarthropathy

Epidemiology

AS and USpA are the most common types of SpA.
AS and ReA are more common in males.
SpA is seen in all age groups, but most cases present at 20–50 yrs of age.

Incidence

ReA incidence: 0.6–3.1/100,000⁷ (Level of Evidence 1c)

Prevalence

SpA: 0.5–2% of the Caucasian population
AS: 1–2/1,000
ReA: 1/1,000
PsA develops in 5% of patients with psoriasis.

Risk Factors

Male
Caucasian
Unprotected sex
Positive family history
ReA is significantly increased in persons with HIV.

Genetics

HLA B27 positivity:
- AS 90–95%
- ReA 80%
- USpA: 70%, PsA 40%
- IBD-associated 30%
8% of Caucasians and 4% of African Americans are HLA B27-positive.
<20% of HLA B27-positive individuals will develop SpA.

Etiology

Most cases of SpA are associated with HLA B27.
ReA is triggered by an infectious agent (Chlamydia, Ureaplasma, Shigella, Salmonella, Campylobacter, and others).

Diagnosis

There are 2 criteria for research purposes: European Spondyloarthropathy Study Group (ESSG) and Amor. However, diagnosis of SpA remains clinical.

History

Inflammatory back pain:
- Insidious onset of low back pain before the age of 40
- Morning stiffness (>30 min)
- Often associated with night pain
- Persists for more than 3 mos
- Improved with exercise and NSAIDs (inflammatory vs mechanical back pain)
Other joint or enthesis involvement, eye, bowel, skin, mucous membrane, gut, genitourinary symptoms

Physical Exam

Low back pain at night with prominent early morning stiffness (sacroiliitis, spondylitis)
Peripheral joint pain and swelling (often lower limb and asymmetric)
Pain and inflammation at the insertion of tendons or ligaments (enthesitis), sausage digits (dactylitis)
Ocular: Conjunctivitis, iritis
GI: Oral ulcerations, gut inflammation
Skin and nails: Psoriasis, keratoderma blennorrhagica, psoriatic nail dystrophy
Genitourinary: Urethritis, cervicitis, circinate balanitis
Constitutional: Fever and weight loss (ReA)
Lumbar spine: Restricted range of motion:
- Schober's test: Mark the spinous process of L5 and make a mark 10 cm above that point. Ask the patient to bend forward. The distance between the 2 points should increase by more than 5 cm in a normal subject.
Peripheral joints: Tender and/or warm
Enthesitis: Tenderness around the heel (Achilles or plantar fascia)
Skin and nails: Psoriatic nail changes and plaques (scalp, extensor surface of knees)

Diagnostic Tests & Interpretation

Lab

Elevated ESR or C-reactive protein
Elevated WBCs in peripheral and synovial fluid:
- Note: These studies have poor sensitivity and specificity.

Imaging

Joint space narrowing, signs of inflammation, multiple joint involvement, and distal involvement in the hands and feet with added features of bone proliferation suggest seronegative spondyloarthropathy:
- Differentiation of these relies on the distribution of radiographic abnormalities and clinical information.
Peripheral arthritis with soft tissue swelling, juxta-articular osteopenia, joint space narrowing, and erosions
Areas of periostitis or osteitis are not uncommon (PsA, ReA).
Psoriatic arthritis:
- Typically involves the hands, wrists, and feet. Bilateral or unilateral, symmetric or asymmetric.
- Involvement of several joints in a single digit produces the classic “sausage digit.”
- Irregular and indistinct appearance of marginal bone about the joint, characterized as “fuzzy” or “whiskering.” May also see one side of joint thinned, the other broad (“pencil-and-cup”).
- In foot sclerosis, enthesitis, periostitis, and soft tissue swelling can give an “ivory phalanx” appearance.
- At the sacroiliac (SI) joint, advanced changes are usually bilateral and show bone erosions and narrowing to the point of fusion.
Reactive arthritis:
- Similar features to psoriatic arthritis
- Lower extremity involvement more common than upper. Sausage digit and pencil-and-cup deformities can also occur.
- In the spine, large, comma-shaped, paravertebral ossification may also be seen.

P.549

Ankylosing spondylitis:
- More commonly involves the axial skeleton, although peripheral joints can be affected.
- The spine findings are characterized by osteitis, syndesmophyte formation, facet inflammation, and eventual facet joint and vertebral body fusion (bamboo spine of AS).
- SI joint disease is bilateral and symmetric, and typically precedes spine involvement.
- MRI may detect up to 75% of early sacroiliitis not seen on plain radiography.⁶ (Level of Evidence 1b)
- Spine involvement is centered at the thoracolumbar or lumbosacral junction. Focal areas of osteitis become sclerotic and are termed “the shiny corner sign.”
- US may show areas of abnormal vascularization of the entheses.

Differential Diagnosis

Rheumatoid arthritis
Osteoarthritis
Psoriatic arthritis
Seronegative arthritis
Gout
Septic (gonococcal) arthritis
Sarcoidosis

Treatment

The goal of treatment is to reduce pain and stiffness and maintain posture and function.
Eye, skin, genitourinary, and bowel involvement should be treated accordingly.
Patients with spondylitis should engage in a lifelong program of exercise to preserve posture and mobility.
Antibiotic therapy is indicated for proven acute bacterial infections, but does not reduce arthritis.

Medication

First Line

NSAIDS and topical/intra-articular steroids for acute pain

Second Line

Sulfasalazine for patients that do not respond to NSAIDs.
Disease-modifying antirheumatic drugs: Methotrexate, etanercept, and infliximab are used for chronic pain and inflammation.⁴ (Level of Evidence 3a)
Pamidronate for refractory cases

Additional Treatment

Joint splinting and rest may be indicated for acute flares.
Physical therapy and home exercise plans

Referral

Referral to an ophthalmologist for ocular symptoms because these may require additional treatments

Surgery/Other Procedures

Joint arthroplasty may be required for those with severe peripheral joint disease.

Additional Reading

Gardner GC, Kadel NJ. Ordering and interpreting rheumatologic laboratory tests. J Am Acad Orthop Surg. 2003;11:60–67.

Jacobson JA, Girish G, Jiang Y, et al. Radiographic evaluation of arthritis: degenerative joint disease and variations. Radiology. 2008;248:737–747.

Kataria RK, Brent LH. Spondyloarthropathies. Am Fam Physician. 2004;69:2853–2860.

Mease PJ. Disease-modifying antirheumatic drug therapy for spondyloarthropathies: advances in treatment. Curr Opin Rheumatol. 2003;15:205–212.

Olivieri I, Salvarani C, Cantini F, et al. Ankylosing spondylitis and undifferentiated spondyloarthropathies: a clinical review and description of a disease subset with older age at onset. Curr Opin Rheumatol. 2001;13:280–284.

Oostveen J, Prevo R, den Boer J, et al. Early detection of sacroiliitis on magnetic resonance imaging and subsequent development of sacroiliitis on plain radiography. A prospective, longitudinal study. J Rheumatol. 1999;26:1953–1958.

Townes JM, Deodhar AA, Laine ES, et al. Reactive arthritis following culture-confirmed infections with bacterial enteric pathogens in Minnesota and Oregon: a population-based study. Ann Rheum Dis. 2008.

Codes

ICD9

696.0 Psoriatic arthropathy
720.0 Ankylosing spondylitis
721.90 Spondylosis of unspecified site without mention of myelopathy