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Spondylarthropathies definition
- Group of related and often overlappinginflammatory joint disorders
- Enthesitis, synovitis
- Seronegative for RF
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Spondylarthropathies Aetiology (HLA), prevalence
- True aetiology unknown - ?infection - bacterial trigger in genetically predisposed people
- HLA-B27, an MHC class 1 antigen
- HLA-B27 is most prevalence in AS (85-95%_
- Prevalence: present in 10% of healthy Caucasians
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Spondylarthropathies - Pathology
- Inflammation at the entheses
- Initially inflammation and erosions, leads to fibrosis and ossification and finally ankylosis of the joints
- Systemic disease can occur, affecting the heart and lungs
- In AS, the outer fibres of the vertebral discs become inflammed where they attach to the corners of the vertebral bodies, leading to erosion and squaring of the vertebrae
- This progress to ossification and syndesmophytes form
- Get fusion of the SI joints
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Types of Spondylarthropathies (5)
- Ankylosing spondylitis
- Psoriatic arthropathy
- Reactive arthritis
- Reiter's syndrome
- Enteropathic arthritis
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AS: prevalence, M:F ratio, onset
- Prevalence: 0.5-1% of Caucasians
- M:F = 3:1
- Onset: early adulthood, with peak in mid-20s
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AS: Musculoskeletal features
- Axial more than peripheral symptoms, as most are due to spinal and SI disease
- Presentation: gradual onset of lower back pain and stiffness, symptoms worse in the AM/long rest and improve with exercise
- Chest pain, reduced expansion - if involvement of thoracic spine and enthesis at costochondral junctions
- Vertebrae: squaring and syndesmophytes + fibrosis/ossification of ligaments - this leads to a Bamboo spine
- Bamboo spine: decreased mobility and increased risk of fracture
- Question mark Posture
- Peripheral joints: less common, but affect medium/large joints e.g. shoulder, hip or knees, Achilles tendonitis, plantar faschiitis
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AS: question mark posture:
- Cervical hypertension
- Exaggerated thoracic kyphosis
- Loss of lumbar lordosis
- Compensatory flexion at the knee
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AS: Extraskeletal features (4 As)
- Systemic: anorexia, fever, weight loss, fatigue
- The 4 As:
- Anterior uveitis: red painful ege, blurred vision (~30% of patients)
- Aortic regurg/ascending aortitis: (uncommon, late signe)
- Apical lung fibrosis: (late sign)
- Amyloidosis: rare
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AS: Investigations and possible findings
- Blood tests:
- FBC: anaemia of chronic disease
- ESR/CRP
- Serology: RF negative
- HLA-B27 genotyping: expensive and unnecessary for Dx
- X-rays:
- AP pelvis: normal to erosions and sclerosis to fusion
- AP lumbar spine: squaring, syndesmophytes
- Sites of enthesitis: erosions
MRI: can see inflammation before changes on XR
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AS Management
- Physiotherapy: most important, long term to maintain normal posture and physical activity
- NSAIDs
- DMARDs: sulfasalazine
- Anti-TNF
- Surgery: joint replacement, spinal osteotomy, atlantoaxial subluxation
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Reactive Arthritis: Definition
- Aseptic arthritis that develops after an anatomically distant infection, mainly affecting yound adults
- Triggering infection is usually GI or GU
- Symptom onset few days to a few weeks post infection
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ReA: Musculoskeletal Features
- Asymmetrical, oligoarticular
- Large weight bearing joints, fingers and toes
- Dactylitis: invovlement of entire finger/toe leading to a "sausage finger"
- Enthesitis is common, can get pain in SI regio
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ReA: extraskeletal features
- Eyes: conjunctivitis (sterile, unilateral or bilateral)
- Urethritis: frequency, dysuria, sometimes urethral discharge, cervicitis or prostatitis
- Skin & muscosa lesions: circinate balantitis, keratoderma blenorrhagica
- Keratoderma blenorrhagica: a sterile pustular rash on palms and soles; looks like pustular psoriasis
- Reiter's syndrome
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Reiter's Syndrome
- Triad of:
- arthritis
- urethritis
- conjunctivitis
- in a patient with dysentery
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ReA Clinical Course
- can vary in severity
- Lasts weeks to months
- Relapses common - 60% will have 2 or more attacks
- Permanent joint damage is rare
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ReA: Investigations
- Blood etsts: FBC, ESR, CRP
- Serology for Abs against: Salmonella, Campylobacter, Chlamydia and Neisseria
- Joint aspiration: gram stain and culture (to exclude septic arthritis)
- Cervical swab, MSU, stool sample = bacterial culture
- X-rays: initially normal, later fluffy periostitis seen in the calcaneous, digits, or pelvis; erosions are rare
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ReA Management
- NSAIDs
- Local corticosteroid infections
- DMARDs - may be useful in severe, persistent disease
- Antibiotics: little influence on disease course
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Enteropathic Arthritis: Definition
- Arthritis occuring in association with IBD
- in 10-20% of patients with Crohn's disease or UC
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EntA: Clinical features
- Peripheral arthritis: asymmetrical, mono- or oligoarticular; worsens when IBD becomes worse and improves if affected bowel is removed
- Spondylitis and sacroiliitis: not related to activity of IBD and predates onset of IBD
- Enthesopathy: can accompany axial or peripheral joint disease
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EntA Investigations
- Axial AP radiograph: typical spinal changes of AS
- Peripheral: rew radiological changes
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EntA: Management
- Treatment of IBD helps the arthritis
- Corticosteroids and sulfasalazine
- NB: NSAIDs aggravate GI symptoms in IBD
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Psoriatic Arthopathy Definition
Inflammatory arthritis associated with psoriasis
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PsA: psoriasis prevalence, M:F ratio
- Psoriasis: 1-3% of the population
- 10% of those will affected develop PsA
- M=F
- Especially common in those with nail involvement
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PsA Clinical Features
- PsA may precede diagnosis of psoriasis and does not correlate with severity of skin lesions
- Joint pain, stiffness, sometimes swelling
- dactylitis and enthesitis
- Uncommon: uveitis, cardiac lesions
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PsA 5 Patterns of Joint Disease
- 1. Distal arthritis involving DIP joints
- 2. Asymmetrical oligoarthritis
- 3. Symmetrical polyarthritis indistinguishable from RA
- 4. Spondylitis
- 5. Arthritis mutilans - telescoping of the digits
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PsA Investigations
- Bloods: FBC, ESR, CRP, RhF (usually negative)
- Radiology: changes asymmetrical and affect the small joints of the hands and feet (esp DIP joints)
- Erosions with proliferation of adjacent bone
- Reabsorption of terminal phalanges
- Pencil-in-cup deformities
- Periostitis
- Ankylosis
- New bone formation at entheses
- Sacroiliitis (up to 30% of pts, usually asymptomatic)
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PsA Management
- Physio
- NSAIDs
- DMARDs
- Anti-TNF
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PsA Prognosis
- Good - joint funtion usually well preserved
- Some develop a chronic, progressive, deforming arthritis
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