Spondyloarthritis (SpA) is a descriptive term that essentially infers the presence of inflammation of the spine. A number of different terms have been used for that purpose including Spondyloarthropathy and Spondylitis. Following rigorous debate in the Rheumatology community, Spondyloarthritis has recently been agreed upon as the most appropriate.
Spondyloarthritis does not relate to one specific disease entity but instead covers a heterogeneous group of Rheumatic diseases that are characterised by common clinical features, most frequent of which is inflammatory back pain. These patients are categorised into one of two groups dependant upon which symptoms predominate.
That is, they can be classified as having Axial SpA when the spine is the primary target of the disease or Peripheral SpA when the joints away from the spine are affected.
Axial is the term used to describe the central aspect of the skeleton and includes the spine, pelvis, sternum, and skull.
- Axial SpA is subclassified into a number of conditions, including:
- Ankylosing Spondylitis (AS);
- Psoriatic Arthritis: usually the patient also has psoriasis, an autoimmune skin condition;
- Inflammatory Bowel Disease-related arthritis: associated with Crohn’s disease or Ulcerative Colitis;
- Reactive arthritis: when the condition is triggered by an infection, most commonly affecting the urinary of intestinal tracts.
There are a number of patients with SpA who do not demonstrate sufficient features to meet the criteria for the above classifications.
These patients have been described as having undifferentiated SpA or when there is inflammatory back pain without structural changes in the sacroiliac joints or spine, the term non-radiographic Axial SpA has been used.
Although a proportion of these patients may evolve into one of the other categories, it should be noted that not all patients with SpA progress to develop AS.
A major impetus for identifying patients with inflammatory back pain and subsequently SpA is that there is often a significant delay in the diagnosis of AS and the other Spondyloarthritides described above.
The delay in diagnosis has been shown to be a predictor of functional outcome, radiographic progression and hence, damage associated with the disease, as well as the increased mortality associated with Ankylosing Spondylitis (especially when the diagnosis has been delayed for more than 12 years).
Furthermore, recent developments in the treatment of SpA have demonstrated a positive impact upon numerous facets of the disease, highlighting the value of an early diagnosis.