The Enthesopathies: Ankylosing Spondylitis, Psoriatic Arthritis, Reactive Arthritis, and Arthritis of IBD Terence W. Starz, MD Clinical Professor of Medicine University of Pittsburgh School of Medicine 1
A 23-year-old male with a 2-year history of left buttock pain and 1 hr.AM stiffness. No trauma or injury. Worked as a house framer- off work for 6 months because of “back strain”. Has had episodes of right Achille’s tendinitis and has developed a rash on the soles of his feet. Rx- some benefit from NSAIDs. HLA B27-positive and CRP-normal. ·The pelvic radiograph is unremarkable. ·T1W MRI scan- erosion of the left sacrum and ilium (arrows). ·STIR MRI scan-BME in the left sacrum (arrow). Best Practice & Research Clinical
THE SPONDYLOARTHROPATHIES: • Ankylosing Spondylitis • Non-radiographic Axial spondyloarthropathies • Psoriatic Arthritis • Inflammatory Bowel Disease Associated (Enteropathic)- Crohn’s and ulcerative colitis • Reactive Arthritis 3
A Disease of Antiquity: Ankylosing Spondylitis u Amenhotep II (1439-1413 BC)1 u Rameses the Great (1298- 1232 BC)1 u Marie Strumpell spondylitis u Rheumatoid “variants” u Ankylosing spondylitis, HLA B27(1973) u Spondyloarthropathies-“enthesopathies” 1Rheumatol Int. 2003; 23:1-5.
SHARED CLINICAL FEATURES: • Axial joint disease (esp. SI joints) Asym. oligoarthritis (2-4 jts.) • Dactylitis (sausage digits) • Enthesitis Syndesmophytes • Associations with infections • Eye inflammation • Bowel inflammation Mucocutaneous features HLA-B27+ and FHx • Responsible Interleukins: IL-12, IL17, IL-22, and IL23. 6
SHARED CLINICAL FEATURES: •Inflammatory Back Pain: Chronic back pain better with exercise but not with rest and pain at night, AM stiffness Insidious onset with more than 3 months in duration Usual onset <45 years of age Male prominence Marked improvement w/ NSAIDs • Peripheral Arthritis: Acute in onset Lower extremities esp. knees and ankles Asymmetrical, Oligoarticular 7
Epidemiology of AS u2.4 million adults in the US have SpA (RA-1.3 million) uThe incidence of AS may be underestimated due to unreported cases uHLA-B27 gene is associated with AS uAge of onset typically between 15 and 35 years u2-3 times more frequent clinically in men than in women 1The Spondylitis Association of Khan MA. Ann Intern Med. 2004
The prevalence of axial spondyloarthritis in different populations depends, in part, on the prevalence of HLA-B27. 10
Age at Onset Distribution of AS and Rheumatoid Arthritis (RA) Percentage of Patients (%) AS RA Economically active individuals with a major impact on their ability to work1 1Barkham N et al. Rheumatology 2005;44:1277-1281 2Zink A et al. Ann Rheum Dis 2001;60:199-206
Diarthrodial joint Synovial cavity s 12
Enthesitis versus synovitis Diarthrodial joint showing the joint capsule with the synovial membrane and tendons inserting into periosteal bone. Synovitis is characterized by inflammation of the synovial membrane. Enthesitis is defined as inflammation of the entheses, the insertion sites of tendons and ligaments to the bone surface. Enthesitis can occur with secondary synovitis. Schett, G. et al. (2017) Enthesitis: from pathophysiology to treatment Nat. Rev. Rheumatol.
Microanatomical changes in enthesitis Following mechanical stress at the enthesis, transcortical microvessels are activated and an inflammatory reaction, (osteitis) forms in the adjacent bone marrow. TCV widening via vasodilatation facilitates the efflux of immune cells (such as neutrophils) from the perientheseal bone marrow into the enthesis. Schett, G. et al. (2017) Enthesitis: from pathophysiology to treatment Nat. Rev. Rheumatol.
Functional model of enthesitis Enthesitis is initiated during a mechanosensation and by innate immune activation involving mechanical and/or infectious stress that leads to the activation of prostaglandin E2 (PGE2) and IL- 23, followed by release of TNF and IL-17, leading to the influx of immune cells such as polymorphonuclear neutrophils. Schett, G. et al. (2017) Enthesitis: from pathophysiology to treatment Nat. Rev. Rheumatol
Local and systemic enthesopathies 17
Enthesitis can result from repeated mechanical overloading, such as that which occurs during sporting activities, in otherwise healthy individuals. 'Tennis elbow' or 'golfer's elbow' is a typical example of an isolated enthesitis resulting from mechanical overload. In such cases, enthesitis usually affects only one enthesis, also involves the body of the tendon and usually resolves spontaneously. However, enthesitis is also a pathognomonic feature of PsAand SpA, where it occurs frequently, often affects more than one enthesis and shows a remarkable degree of chronicity 18
Axial (from the word "axis”-central) skeleton consists of the bones including the vertebrae, sacrum, coccyx, ribs, and sternum. 19
Sacroiliac joint The upper portion of the joint, the sacrum and the ilium are not in contact- connected with powerful posterior, inter-osseous, and anterior ligaments. The anterior and the lower half of the joint is a typical synovial joint with hyaline cartilage on the joint surfaces. The SI joint is an axial joint with an approximate surface of 17.5 square cm. The joint surface is smooth in juveniles and becomes irregular. 20
SACROILIITIS: Causes of sacroiliitis: •Inflammatory: SpAs, infection (bacteria, fungal, mycobacterial). •Traumatic: fracture, OA •Generalized Disease: Gout, Hyperparathyroidism, Paget’s disease, paraplegia, neoplastic mets. •Involves the lower 2/3rdsynovial-lined portion. •In A.S. and IBD it is symmetric and bilateral. •In psoriatic arthritis and reactive arthritis is asymmetric and unilateral. •Earliest x-ay change: erosions of the iliac side of the SI joint where the cartilage is thinner. •Early on: “pseudo-widening” of the SI joints, then sclerosis and ankyloses/fusion. 21
Spinal ligaments 25
Ankylosing spondylitis IBD Reactive arthritis Psoriatic arthritis 28
Dactylitis “Sausage digit”
Dactylitis The anatomical relationship between the accessory pulleys A1– A5 and the flexor tendons (flexor digitorum profundus and flexor digitorum superficialis) seems to be important for flexor tenosynovitis, which is a common feature of dactylitis.
a. Dactylitis of the right second toe. b | T1-weighted fat- suppressed post-contrast coronal high-resolution MRI of the same digit showing widespread inflammatory changes in the digital soft tissues and also bone edema (asterisks). Dynamic contrast- enhanced hand MRI from a patient with dactylitis of the middle digit showing that the initial contrast enhancement corresponds to the A1 pulley at the metacarpophalangeal joint (arrow). An axial image showing accumulation of contrast agent adjacent to the flexor tendon (arrowheads). b. c. d.
The uveal tract consists of the iris, ciliary body and choroid sandwiched between the outer layer (cornea and sclera) and inner layer (retina) of the eye. Nature Reviews Rheumatology14, 704–713 (2018).
Uveitis associated with different forms of spondyloarthritis. Uveitis associated with ankylosing spondylitis (AS) or reactive arthritis (ReA) is almost always acute anterior uveitis, whereas uveitis associated with psoriatic arthritis (PsA)24 or inflammatory bowel disease (IBD) is more likely to be chronic or posterior to the lens of the eye. Nature Reviews Rheumatology 14, 704–713 (2018)
No definitive 'arthritogenic peptide' triggering an immune response in AS has been identified to date
SpAand HLA-B27 Disease Approximate Prevalence of HLA-B27 (%) AS 90 Reactive arthritis (ReA) 40-80 Juvenile spondyloarthropathy 70 Enteropathic spondyloarthropathy 35-75 Psoriatic arthritis 40-50 Undifferentiated spondyloarthropathy 70 Acute anterior uveitis 50 Aortic incompetence with heart block 80 Khan MA. Ann Intern Med 2002;136(12):896-907
Rheum Dis Clin of NA, 2017:43,401-414.
Despite sharing several clinical features such as axial disease, enthesitis, peripheral arthritis and extra-articular manifestations, psoriatic arthritis and ankylosing spondylitis show very little genetic overlap. HLA-B*27 is the only genetic risk factor common to both diseases, and axial disease in psoriatic arthritis is actually more commonly associated with other HLA genes than with HLA-B*27. Nature Reviews Rheumatology 14, 363–371 (2018)
Ankylosing Spondylitis (AS) u AS is a chronic, progressive immune-mediated inflammatory disorder that results in ankylosis of the vertebral column and sacroiliac joints1 u The spine and sacroiliac joints are the common affected sites1 u Chronic spinal inflammation (spondylitis) can lead to fusion of vertebrae (ankylosis)1 -syndesmophytes 1 Taurog JD. et al. Harrison‘s Principles of Internal Medicine, 13 th Ed. 1994: 1664-67.
AS: ADebilitating Rheumatic Disease Over time, joints in the spine can fuse together and cause a fixed, bent-forward posture AS patients have an important impact on health care and non health-care resource utilization, resulting in a mean total cost (direct and productivity) of about $6700 to $9500/year/pt.1 More than 30% of patients carry a heavy burden of disease and have a decreased QoL2 Kelley’s Textbook of Rheumatology 8thed. Saunders Elsevier;2009:p.1171 2 Braun J & Sieper. J Rheumatology 2008;47:1738-40
Ankylosing Spondylitis “Bamboo Spine” Repeated process of healing and bone formation leads to formation of syndesmophytes ‘bone bridges’ “Sacroiliitis”
AS: Extra-articular Manifestations (EAM) EAM Prevalence in AS Patients (%) Anterior uveitis 30-50 IBD 5-10 Subclinical inflammation of the gut 25-49 Cardiac abnormalities Conduction disturbances Aortic insufficiency“Bamboo Spine” Anterior uveitis 1-33 1-10 Psoriasis 10-20 Terminal ileitis Renal abnormalities 10-35 Lung abnormalities Airways disease Interstitial abnormalities Emphysema 40-88 82 47-65 9-35 Cardiac abnormalities Bone abnormalities Osteoporosis Osteopenia 11-18 39-59 “Bamboo Spine” Rheumatology 2009;48:1029-1035
Int. J. Clin. Rheumatol. (2018) 13(4) Int. J. Clin. Rheumatol. (2018) 13(4)
Spectrum of axial spondyloarthritis The spectrum of axial spondyloarthritis, normally starts with inflammation in the sacroiliac joints (non-radiographic stage; part a). Structural damage that is visible on X-ray scans (radiographic stage) develops later but not in all patients. Abnormalities in the spine also develop later and only in some patients. Some patients with non-radiographic disease show no abnormalities on MRI of the sacroiliac joints (part b). However, in most patients, inflammation of the sacroiliac joints is detectable by MRI before structural changes occur (part c). Structural changes that are visible on X-ray scans include sclerosis, erosion and new bone formation (part d). Syndesmophytes of the spine (bone growth between vertebrae) are characteristic of spinal involvement in axial spondyloarthritis. Sieper, J. et al. (2015) Axial spondyloarthritis Nat. Rev. Dis. Primers
Diagnostic approach For patients with chronic back pain (for ≥3 months) starting at ≤45 years of age, the following diagnostic approach is proposed. X-rays are used to detect radiographic changes of the sacroiliac joints. Patients without radiographic disease are further evaluated based on the presence of several features that are indicative of axial spondyloarthritis and, if needed, for the presence of HLA-B27 and MRI changes of the sacroiliac joints. Note that axial spondyloarthritis in the absence of both a positive imaging result and a positive HLA-B27 test is rather rare. Other causes of signs and symptoms (*) should always be excluded. Sieper, J. et al. (2015) Axial spondyloarthritis Nat. Rev. Dis. Primers
Pathogenesis of axial spondyloarthritis Lancet 2017;390, 1–7 2017, 73-84
The pathophysiology of axial spondyloarthritis The interaction of genetic factors, in particular HLA-B27, with various stresses including mechanical stress, endoplasmic reticulum stress and microbial stress at body surfaces lead to the production of pro-inflammatory cytokines including IL-23, sTNF, and IL-17 which are proposed to be strong inflammatory drivers leading to new bone formation and ultimately ankylosis of the axial joints. Sieper, J. et al. (2015) Axial spondyloarthritis Nat. Rev. Dis. Primers
Multiple pathways implicated in IBD and SpApathogenesis impact the host– microbiota relationship. Approximately one-half of SpApatients exhibit signs of microscopic gut inflammation. Best Practice & Research Clinical Rheumatology 28 (2014), 687.