Discovertebral erosions and destruction in psoriatic arthritis

To evaluate the prevalence and clinical features of destructive abnormalities of the discovertebral junction in psoriatic arthritis (PsA).

One hundred consecutive patients with PsA (38 with spondylitis, 48 with polyarthritis, 14 with oligoarthritis; 52 men and 48 women; mean age 45.74 years, range 18-76, mean duration of disease 79.84 mo, range 8-336) were evaluated. The study protocol included a questionnaire on the patient's usual work, occurrence of previous trauma or infection to the spine, characteristics of articular involvement, and presence and characteristics of back pain. Radiographic study of involved joints and of the spine was performed and lesions occurring at the discovertebral junction were classified according to Cawley's suggestions.

Twelve patients showed destructive abnormalities of the discovertebral junction (12.0%). These patients had age and disease duration significantly greater than the patients without abnormalities (p = 0.0001 and 0.0001, respectively). Nine of them had spondylitis and 3 polyarthritis (p = 0.02). Cervical tract was affected in 4 cases (33.3%) and thoracic in 12 (100%). Lumbar spine changes occurred in 6 patients (50%). Lesions were localized to only one level in 4 cases and at multiple levels in the remaining 8. According to Cawley's classification type 1 lesions involved 6 thoracic discovertebral junctions, type 2 involved 15 junctions (4 cervical, 5 thoracic, 6 lumbar), type 3 only one thoracic junction. Back pain occurred in only 5 cases (41.6%), all belonging to the spondylitic subset. Pain was localized to those tracts of the spine with radiographically documented disease and was exacerbated with physical activity.

Discovertebral erosions seem to be another characteristic aspect of spondyloarthropathies. In PsA, the lesions occur markedly in older spondylitic patients with a greater duration of disease and may often be totally asymptomatic.