|Year : 2017 | Volume
| Issue : 4 | Page : 190-191
Ultrasonography in the evaluation of peripheral enthesitis in spondyloarthropathy
Sumeet Agrawal1, Ashok Kumar2
1 Department of Rheumatology and Clinical Immunology, Artemis Health Institute, Gurugram, Haryana, India
2 Department of Rheumatology, Fortis Flt. Lt. Rajan Dhall Hospital, New Delhi, India
|Date of Web Publication||16-Nov-2017|
Department of Rheumatology, Fortis Flt Lt Rajan Dhall Hospital, Vasant Kunj, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Agrawal S, Kumar A. Ultrasonography in the evaluation of peripheral enthesitis in spondyloarthropathy. Indian J Rheumatol 2017;12:190-1
Spondyloarthritides (SpA) are characterized by considerable heterogeneity in their musculoskeletal manifestations. Entheseal inflammation is considered the pathological hallmark of this group of diseases. In fact, McGonagle et al. proposed that the synovitis of SpA is secondary to the liberation of pro-inflammatory mediators from the entheses, whereas the synovitis of rheumatoid arthritis is primary.
Enthesitis accounts for the numerous sites of pain in SpA patients, such as the spine, chest wall, and heel. Enthesitis pain is often difficult to localize (unlike that of synovitis) but accounts for significant functional limitations and stiffness. It has even been implicated in the onychopathy of psoriatic arthritis. Enthesitis significantly impairs the quality of life of SpA patients and is frequently associated with a more extensive joint involvement and functional incapacity. A Brazilian study found that patients with enthesitis had higher mean scores of Bath Ankylosing Spondylitis Functional Index, Bath Ankylosing Spondylitis Disease Activity Index, and Ankylosing Spondylitis Quality of Life. Impairment of these indices was associated with work incapacity.
Enthesitis, despite being a significant problem, did not receive due attention because of difficulties in its detection as well as scoring. Furthermore, until now, there were no effective therapies for resistant enthesitis. Thus, it remained a less studied component in the evaluation of SpA until recently. Now that the enthesitis is known to respond well to blockade of tumor necrosis factor, there is increasing use of imaging techniques such as ultrasonography and MRI in objectively documenting the presence of enthesitis.
Indices based on clinical assessment of enthesitis are available. However, these are subject to considerable interobserver variability. Imaging techniques are more reliable in this regard. Because of its unique technical capabilities, ultrasonography is providing newer perspectives in the assessment of entheseal diseases in SpA., It is radiation free, cost effective, reproducible, well accepted by patients, and offers real-time imaging facility and its ability to evaluate multiple sites during the same examination. The latter is a major advantage in the evaluation of enthesitis since it is common to see the involvement of multiple anatomically distinct sites.,
In this issue of the journal, Wakhlu et al. report on the comparison of ultrasonography and clinical examination in the evaluation of peripheral enthesitis in SpA. The subjects included 52 patients with spondyloarthritis, 26 with rheumatoid arthritis, and 26 healthy controls. They used B-mode as well as power Doppler images using linear array transducer to obtain ultrasonographic images of five peripheral entheseal sites most commonly assessed in other similar studies. They followed the criteria laid down by OMERACT for defining enthesitis by ultrasonography. However, the investigators refrained themselves from using any of the composite indices to assess ultrasonography of enthesitis. This is appropriate since they used that the OMERACT laid ultrasonographic criteria for enthesitis and all the composite indices predate this criterion. This has an important implication – a weighted scoring system to generate a composite index is needed, and once that is done, studies to look at the clinical utilities of such an index would be required. This means that we still have a long way to put ultrasonography to day-to-day use in enthesitis assessment in SpA. Till that time, perhaps, the clinical utility of ultrasonography would be confined to, at best, detection of the presence or absence of enthesitis. Wakhlu's study showed that ultrasonography (sensitivity - 94.2%) was better in detecting enthesitis than clinical examination (sensitivity - 69.2%). However, clinical examination was 100% specific in detecting enthesitis. The high specificity of clinical examination is not surprising since as it is the current “gold standard” for enthesitis. But what is important is that ultrasonography has an unexpectedly low specificity. Although ultrasonography may be more sensitive than clinical examination, the real-life importance of this modality in detecting a “subclinical” enthesitis is not yet known. Future studies should address this important issue, especially in the context of highly effective biologic therapies, which are now available. The study has its limitations which have been clearly acknowledged by the authors. One area which requires more work is the “axial entheses” such as those of the spine and chest wall which are a source of significant morbidity to patients. Imaging and especially ultrasonography may play a key role here due to its versatility.
To conclude, the study by Wakhlu et al. is a good initiative in Indian context. Apart from the information, it has provided, and it has also highlighted the shortcomings of ultrasonography in the evaluation of enthesitis which we hope will provide further impetus for more studies on the use of this modality.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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