Spondyloathropathies: General Features

General Features of All Spondyloarthropathies
The features shared by all spondyloarthropathies (Table 2, Table 3) are inflammatory back pain, peripheral arthritis, enthesitis, dactylitis, and uveitis. But even though all types of spondyloarthropathy can exhibit these features, the pattern of these features helps define the distinct form of spondyloarthropathy. For example, symmetric sacroiliitis, gradually ascending spondylitis, and delicate, marginal syndesmophytes (intervertebral bony bridges) are seen more commonly in ankylosing spondylitis, whereas asymmetric sacroiliitis, discontinuous spondylitis, and bulky, nonmarginal syndesmophytes are more common in reactive arthritis and psoriatic arthritis. Sacroiliac and lumbar spine disease are not typically found in rheumatoid arthritis.

Table 2
Common features of the spondyloarthropathies

Inflammatory back pain
Morning stiffness that is reduced with activity

Peripheral arthritis
Typically asymmetric, occurring predominantly in the lower limbs

Enthesitis
Achilles tendon insertion
Plantar fascia insertion on calcaneus
Patella, superior and inferior aspects
Tibial tuberosity
Metatarsal heads
Base of fifth metatarsal joint
Iliac spine, iliac crest
Ischial tuberosity
Tarsal region
Greater trochanter
Lateral epicondyle
Distal scapula
Distal ulna

Dactylitis

Radiographic evidence of reactive proliferation of new bone at the site of enthesitis

Radiographic sacroiliitis

Characteristic extra-articular features (eg, anterior uveitis)

Significant family history

Presence of human leukocyte antigen B27 TA

Table 3: Characteristics of spine and eye disease in the spondyloarthropathies

	Sacroilitis	Spondylitis	Syndesmophytes	Uveitis
Ankylosing spondylitis	Symmetric	Continuous, ascending	Delicate, marginal	Acute, unilateral, recurrent
Reactive arthritis	Asymmetric	Discontinuous*	Bulky, nonmarginal	Acute, unilateral, recurrent
Psoriatic arthritis	Asymmetric	Discontinuous	Bulky, nonmarginal	Chronic, bilateral
Enteropathic spondyloarthropathy	Symmetric	Continuous, ascending	Delicate, marginal	Chronic, bilateral
Undifferentiated spondyloarthropathy	None	Minimal	Occasional	Uncommon, usually acute, unilateral

*Areas of spinal involvement are not continuous or contiguous with areas of normal-appearing spine between areas of spondylitis.

Peripheral arthritis
Inflammatory arthritis of the peripheral joints can occur in patients with spondyloarthropathy. However, the arthritis is usually asymmetric, distinguishing it from the typical symmetric polyarthritis of rheumatoid arthritis and other connective tissue diseases.

Enthesitis and dactylitis
Enthesitis is inflammation at the site of attachment of ligaments, tendons, and other structures onto bone. It is a common clinical feature of spondyloarthropathy and is found most often in the heel or knee (Table 2). It may occasionally be seen in rheumatoid arthritis, systemic lupus erythematosus, or sarcoidosis but is rare in other diseases.

Dactylitis, or "sausage digit," is less common than enthesitis and is found more often in reactive arthritis and psoriatic arthritis than in the other spondyloarthropathies. It is occasionally seen in sarcoidosis but is rare in other rheumatic diseases.

Uveitis
Uveitis in ankylosing spondylitis and reactive arthritis is usually acute, unilateral, and recurrent and rarely involves posterior elements. In contrast, uveitis in patients with psoriatic arthritis and spondylopathy associated with inflammatory bowel disease is often chronic and bilateral and more often involves posterior elements.

Laboratory features
Patients with a spondyloarthropathy are often found to have the B27 antigen, but B27 antigen status lacks specificity and therefore is not itself diagnostic. Serologic tests for rheumatoid factor and antinuclear antibody are usually negative in patients with a spondyloarthropathy. The erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) concentration are often elevated, but elevations may not correlate with disease activity.

Cleveland Clinic Journal of Medicine
Volume 71, Number 3, March 2004

This paper discusses therapies that are experimental or are not approved by the U.S. Food and Drug Administration for use under discussion.