Spondyloarthritis (SpA) - A Revised Overview PDF

19 SH Spondyloarthritis (SpA) MUHANNA KAZEMPOUR MD ASSISTANT PROFESSOR OF RHEUMATOLOGY AT SBMU  INTRODUCTION Spondyloarthritis (SpA) refers to a group of overlapping disorders that share clinical features. SPA include : ❑ankylosing spondylitis (AS) ❑ reactive arthritis (ReA) ❑p...

19 SH Spondyloarthritis (SpA) MUHANNA KAZEMPOUR MD ASSISTANT PROFESSOR OF RHEUMATOLOGY AT SBMU  INTRODUCTION Spondyloarthritis (SpA) refers to a group of overlapping disorders that share clinical features. SPA include : ❑ankylosing spondylitis (AS) ❑ reactive arthritis (ReA) ❑psoriatic arthritis (PsA) ❑ arthritis associated with inflammatory bowel disease (IBD) INTRODUCTION The cardinal clinical feature of spondyloarthritis is : ❑inflammation of the sacroiliac joints (i.e., sacroiliitis) and the spine (i.e., spondylitis). ❑ Inflammation of tendon insertion sites (i.e., enthesitis) ❑ inflammation of entire digits (i.e., dactylitis) ❑inflammation of one to four lower extremity joints (i.e., oligoarthritis) These disorders are classified as: ❑ predominantly axial SpA, affecting the spine, pelvis, and thoracic cage, or ❑ predominantly peripheral SpA, affecting the extremities.  ANKYLOSING SPONDYLITIS Axial spondyloarthritis (axSpA) is the current term used to describe the most common inflammatory disorder affecting the axial skeleton, with variable involvement of peripheral joints and extraarticular structures. EPIDEMIOLOGY The estimated adult prevalence of AS is ~0.17% (range 0.02–0.5%). AS shows a striking correlation with the histocompatibility antigen HLA- B27. In North American whites, the prevalence of B27 is 6%, whereas it is 80–90% in patients with AS. PATHOLOGY Sacroiliitis is typically an early manifestation of axSpA. If the process progresses, eventually the eroded joint margins are replaced by fibrocartilage regeneration and then by ossification. B, At a slightly later stage, note the larger erosions (arrows), progressive sclerosis, and focal narrowing of the articular space. D, Eventually, complete ankylosis of the synovial and ligamentous portions of the sacroiliac space on both sides is evident. The sclerosis has diminished. In the spine, the outer annular fibers are eroded and eventually replaced by bone, forming an early syndesmophyte. Progression of this process can lead to “bamboo spine.”  PATHOGENESIS HLA-B27 plays a direct role in AS pathogenesis ERAP1 and ERAP2 also plays a role in AS pathogenesis Genes related to TNF pathways Genes in the IL-23/IL-17 innate immune cells TGF-β is found in more advanced lesions. Gut microbiota dysbiosis CLINICAL MANIFESTATIONS The initial AS symptoms are usually first noticed in late adolescence or early adulthood, at a median age in the mid-twenties. In 5% of patients, symptoms begin after age 40 The initial symptom is pain that can be either sharp or dull, insidious in onset, felt deep in the lower lumbar or gluteal region, and accompanied by low-back morning stiffness of up to a few hours’ duration that improves with activity and returns following inactivity. Within a few months, the pain usually becomes persistent and bilateral. Nocturnal exacerbation of pain often forces the patient to rise and move around. In some patients, bony tenderness (presumably reflecting enthesitis or osteitis) accompanies back pain or stiffness, whereas in others it may be the predominant complaint. Common sites include: ✓costosternal junctions ✓ spinous processes ✓iliac crests ✓greater trochanters ✓ischial tuberosities ✓ tibial tubercles ✓heels. The most specific findings involve loss of spinal mobility, with limitation of anterior and lateral flexion and extension of the lumbar spine and of chest expansion. Pain in the sacroiliac joints may be elicited either with direct pressure or with stress on the joints. Faber or patric The modified Schober test is a useful measure of lumbar spine flexion. The patient stands erect, with heels together, and marks are made on the spine at the lumbosacral junction 12and 10 cm above. The patient then bends forward maximally with knees fully extended, and the distance between the two marks is measured. This distance increases by ≥5 cm with normal mobility. Lateral bending measures the distance the patient’s middle finger travels down the leg with maximal lateral bending. Normal is >10 cm. Chest expansion is measured as the difference between maximal inspiration and maximal forced expiration at the levels of either the fourth intercostal space or the xiphisternum, with the patient’s hands resting on or just behind the head. Normal chest expansion is ≥2.5 cm. Limitation or pain with motion of the hips or shoulders is usually present if these joints are involved. The course of ax-SpA is extremely variable, ranging from the individual with mild stiffness and normal radiographs to the patient with a totally fused spine. In a typical severe untreated case with progression to syndesmophyte formation, the posture undergoes characteristic changes, with obliterated lumbar lordosis, buttock atrophy, and accentuated thoracic kyphosis. Extraarticular manifestation EYE: Acute anterior uveitis INTESTINE: Inflammation in the colon or ileum Or IBD SKIN: Psoriasis HEART: ischemic heart disease, Aortic insufficiency, Third-degree heart block LUNG: upper pulmonary lobe fibrosis KIDNEY: amyloid nephropathy  acute anterior uveitis The most common extraarticular manifestation is acute anterior uveitis. Attacks are typically unilateral, causing pain, photophobia. Up to 60% of patients with AS have inflammation in the colon or ileum. This is usually asymptomatic, but overt IBD occurs in 5–10% of patients with AS.  psoriasis About 10% of patients meeting criteria for AS have psoriasis. LABORATORY FINDINGS No laboratory test is diagnostic of AS. In most ethnic groups, HLA-B27 is present in 75–90% of patients. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) : not always, elevated. Mild anemia may be present. Rheumatoid factor(RF), anti-cyclic citrullinated peptide (CCP), and antinuclear antibodies (ANAs) are largely absent unless caused by a coexistent disease, although ANAs may appear with anti-TNF therapy. RADIOGRAPHIC FINDINGS IN SACROILIAC JOINTS radiography demonstrate sacroiliitis, usually symmetric. The earliest changes by standard radiography are blurring of the cortical margins of the subchondral bone, followed by erosions and sclerosis. Progression of the erosions leads to “pseudowidening” of the joint space; as fibrous and then bony ankylosis supervene, the joints may become obliterated. RADIOGRAPHIC FINDINGS IN SPINE In the lumbar spine, progression of the disease can lead to loss of lordosis, and osteitis of the anterior corners of the vertebral bodies with subsequent erosion, and new bone formation causing “squaring” or even “barreling” of one or more vertebral bodies. Progressive ossification leads to eventual formation of marginal syndesmophytes, visible on plain films as bony bridges connecting vertebral bodies anteriorly and laterally. In chronic (≥3 months) back pain, IBP has the following characteristic features: (1) age of onset 30 min (7) awakening from back pain during only the second half of the night (8) alternating buttock pain. The presence of two or more of these features should arouse suspicion for IBP, and four or more can be considered presumptively diagnostic. DIAGNOSIS of AS The classification criteria for ax-SpA proposed by ASAS. They are applicable to individuals with ≥3 months of back pain and age of onset