Spondyloarthritis -Recognition and referral
Spondyloarthritis ( SpA ) represents a group of interrelated diseases with common clinical features and a close association with HLA-B27 ( Stolwkj et al Rheum Dis Clin North Am 2015 )
Axial spondyloarthritis –Radiographic axial spondyloarthritis ( ankylosing spondylitis ) Non-radial spondyloarthritis – absence of radiographic sacroiliitis but inflammation on MRI of the SI joints is frequently visible Axial SpA mostly affects the spine particularly the sacroiliac joint. Often misdiagnosed as mechanical low back pain
Peripheral SpA -Psoriatic arthritis Reactive arthritis ○ following GI or urinary infections ○ for e.g Campylobacter , Chlamydia , Salmonella , Shigella , Yersinia Enteropathic arthritis ie associated with comorbid inflammatory bowel disease. Often thought as unrelated joint or tendon problem and misdiagnosed as problems can move around between joints
NICE guideline – Spondyloarthritis in over 16s : diagnosis and management 2017 is an important document which draws attention about SpA’s and provides clear advice on when to suspect and what should be done. This guideline should help with early recognition and treatment.
How common -It is difficult to determine the prevalence of SpAs due to factors as ○ methodological differences between studies ○ case definition used to classify disease and prevalence of HLA-B27 in the population ○ heterogeneity due to differences in demographics ,geographic area ○ transient nature of some SpA symptoms The ESSG ( European SpA study group ) criteria – forms the basis of studies and incidence rates range between 0.48 and 63/100.00 while prevalence rates vary between 0.01 and 2.5 % Figures quoted for individual SpAs are ( overall SpA as high as 1 % ) ○ For AS current estimated prevalence in US range between 0.2 % and 0.5 % ○ PsArthritis 0.1 % ○ 0.065 % for enteropathic peripheral arthritis A systematic literature review quotes prevalence of AS in Europe at 0.24 % and 1.7 % in Asia Rarely starts after age of 45 yrs and is highly heritable.
What happens -Pathophysiology is not fully understood The inflammatory process occurs primarily in the entheses Entheses – are attachment points for tendons into the bones Enthesitis – inflammation is thought to start here In contrast patients with rheumatoid arthritis have synovitis and tenosynovitis Examples of entheses include ○ Achilles at the heel ○ elbow – inflammation can cause tennis anf golfers elbow ○ sacro-ilac joints – leads to characteristic X-Ray findings ○ plantar fascia Dactylitis – is a less common manifestation It is inflammation of a whole digit ( toe or finger ) involving the tendons , entheses and joints ( produces sausage digit ) Recent advances in immunological technologies have shown that different cell populations part of both the innate and the adaptive immune response play a key role in AxSpA In ankylosing spondylitis – new bone formation leading to ankylosis of the SI joints and syndesmophytes ( bony growth in ligaments in intervertebral joints ) causing irreversible impairment of spinal motility SpAs pathogenesis -can be briefly summarised as a complex interplay among susceptibility genes , microbial triggers , inflammation of bone marrow and the entheseal structures and new bone formation Extraarticular changes may involve the eye , aortic valve , lung and skin
Assessment –Symptoms can be diverse and easy to miss Presentation can be with ○ inflammatory back pain ( enthesitis and dactylitis ) ○ extra-articular ( uveitis is the commonest ) , IBD , diarrhoea , psoriatic nail symptoms Ask about a recent h/o genitourinary infection ( risk factor ) Enquire + ve family h/o SpA , psoriasis A delay in diagnosis is common – it has been noted that only 15 % receive a diagnosis within 3 months of presentation and the diagnosis takes 8 yrs on average It should be recognised that no single test can reliable diagnose or r/o SpA hence the decision is not based on an individual sign , symptom or test result ie no specific diagnostic test exists for diagnosing SpA’s Axial SpAs affect similar number of women and men.
Clinical assessment based on- clinical presentation, Radiological findings,HLA-B27 associations ,positive family history.
HLA –B27 Human leucocyte antigen ( HLA -B27 ) is the hallmark genetic marker which has strong links with SpAs ( also knon as seronegative spondyloarthropathies ) HLA-B27 is found in about 3 % to 8 % of the population and is more common in N Europeans and rare in Africans It is a MHC ( major histocompatibility complex ) class I molecule It is reported that up to 90 % of patients with AS ( ankylosing spondylitis ) carry this antigen whereas it can be found in 50 % to 80 % of other SpA’s As it is also found in the healthy population its role has been questioned and it is argued that in right clinical setting a positive HLA-B27 test can raise the diagnostic likelihood from modest to high It should be noted that presence of HLA-B27 alone does not correlate well with occurence of SpA hence interpretation of HLA-B27 testing must be done with consideration of the disease prevalence in a given population NICE clearly states that SpA can happen in people who are HLA-B27 negative.
Other tests –Other laboratory abnormalities are non-specific A positive HLA-B27 result increases the likelihood of SpA’s A plain XRay of SI joint – is the recommended first line imaging for axial SpA For people who had ○ short symptoms ○ are young ○ diagnosis cannot be established based on clinical features and radiography but SpA is still suspected Offer plain Xray of symptomatic hands and feet for people with suspected peripheral SpA For people with peripheral SpA when a diagnosis cannot be made from plain X Ray consider US of the hands and feet to assess for joint involvement suspected enthesitis sites ( Axial SpAs may not always be apparent on plain X-Ray )
For back pain which started < 45 yrs and duration > 3 months –Refer rheumatology if 4 or more factors present LBP started < 35 wakes the patient up during the 2nd half of the night Buttock pain Pain improves with movement Marked response to NSAIDs ie improvement within 48 hrs 1st° relative suffers with SpA Current or past h/o arthritis Current or past h/o enthesitis Current or past h/o psoriasis NICE recommends to perform a HLA-B27 if 3 features present and refer if positive.
Advice to -Advice to seek help if new signs and symptoms and risk factors listed above are noted pay attention for people with a current or past h/o inflammatory bowel disease , psoriasis or uveitis and advice to seek attention if they note symptoms as described above
Psoriatic arthritis offer people with psoriasis annual check for psoriatic arthritis psoriatic arthritis can involve small joints , large jts ( eg knees ) or a combination of both ( it may also involve the axial jts , fingers and toe jts , inflammation of conn tissue between tendons / ligaments and bones ) use a scoring system like Psoriasis Epidemiological Screening Tool ( PEST ) keeping in mind that PEST does not detect axial arthritis or inflammatory back pain.
Urgent referral to rheumatology new onset inflammatory arthritis for SpA assessment dactylitis Enthesitis without any onvious mechanical cause if - it is present in multiple sites OR is persistent - any of the following are also present ○ back pain without apparent mechanical cause ○ present or past h/o uveitis ( same day -ophthalmological ) ○ current or past h/o psoriasis ○ GI or genitourinary infection ○ inflammatory bowel disease first degree relative with SpA or psoriasis
Acute anterior uveitis -if presentation is with eye pain , eye redness , sensitivity to light or blurred vision these people should be evaluated for possible SpA by the ophthalmologist.
Suspected SpA -refer promptly to rheumatology for correct diagnosis and early management-
Early diagnosis and treatment improves outcome . The aim is to reduce symptoms , functional limitations , slow progression, decrease complications & improve QoL. Treatment can include physiotherapy physical therapy , pharmacological agents as NSAIDs , biological DMARDs ,standard DMARDs , steroid injections , targeted synthetic DMARDs and surgery
Differentials –Congenital spinal deformity Degenerative disc disease Herniated disc Lumbar spondylosis Osteoarthritis Muscle pain Spinal stenosis Referred pain Scheuermann’s disease Vertebral infection Cauda equina syndrome Malignancy Diffuse Idiopathic Skeletal Hyperostosis ( severe degenerative thoracic and lumbar spondylosis seen more commonly in diabetics )
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Published date: Recommendations | Spondyloarthritis in over 16s: diagnosis and management | Guidance | NICE