Psoriatic Spondylitis: A Disease Manifestation in Debate

Abstract

With the advent of classification criteria for psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA), patients with axial manifestations associated with psoriasis, initially described in the l950s as a specific entity termed psoriatic spondylitis (PS), are now categorized within PsA, ankylosing spondylitis (AS), and axSpA. Thus, different terms are used to describe axial disease in patients with PsA including PS, axial psoriatic arthritis (axPsA), and psoriatic spondyloarthritis. Patients with PS may present with inflammatory and/or mechanical back pain, but also may display axial disease on imaging despite not complaining of back pain. Cervical spondylitis has been reported in 35% to 75% of patients with PsA. Axial disease is silent in 20% and 25% of patients with axial PsA and PsA, respectively. The majority of axPsA patients have peripheral arthritis alongside the axial involvement, whereas only 2% to 5% of PsA patients have solely axial arthritis with no peripheral arthritis.A debate is currently underway as to whether inflammatory axial disease and psoriasis represent axSpA with psoriasis or a subset of PsA named axPsA. Studies have recognized that axial disease in PsA patients seems to be different demographically, genetically, clinically, and radiographically when compared with AS with or without psoriasis. This narrative review summarizes current knowledge regarding axial involvement of PsA in terms of history, terminology, classification, epidemiology, clinical presentation, imaging, diagnosis, and treatment, with the aim of providing advice for management of PS in clinical evidence-based practice. Data-driven studies are needed to develop clear, nonoverlapping classification criteria for spinal involvement in PsA.

MRI Findings in Axial Psoriatic Spondylarthritis

“…Up to 75% of axial PsA patients with longstanding disease have cervical spine damage involving C1-C2, where odontoid erosions and atlantoaxial instability can be found, leading to further complications, such as spinal cord compression and neurological deficit [ 1 , 15 ]. The lower cervical spine might undergo bone production, inflammation of the inter-apophyseal joints, and ossification of the anterior longitudinal ligament [ 15 ].…”

“…Diaz et al’s study [ 21 ] showed that inflammatory changes in the spine and SIJ are less frequent compared to the high prevalence of back pain. At the same time, the axSpA and IBP criteria had poor sensitivity for MRI findings [ 1 ].…”

“…Conventional, segmental MRI investigations limit the ability to assess psoriatic arthritis or spondyloarthropathy evolution, as only up to 5% of patients have pure axial disease [ 1 , 5 ]. Therefore, a whole-body MRI has been introduced, especially for patients who have both spine and sacroiliac joint damage.…”

“…Even though axial PsA has some clinical and imaging particularities compared to AS, some studies still debate whether axial PsA is an independent disease or an axSpA with associated psoriasis [ 1 ].…”

“…They all have some standard features, including pain, stiffness, axial involvement, arthritis, dactylitis, enthesitis, and a high prevalence of the HLA-B27 allele. There are multiple terms to indicate patients with axial PsA, such as psoriatic spondylitis (PS), axial psoriatic arthritis (axPsA), or psoriatic spondyloarthritis [ 1 ].…”