Inflammatory Arthritis Flashcards
Define Rheumatoid Arthritis (RA)
A systemic, chronic inflammatory autoimmune disorder involving symmetrical inflammatory arthritis of synovial joints and various extra-articular manifestations.
What is the aetiology of RA?
It is thought that the causation of RA involves…
- The interaction of:
Genetic predisposition (HLA DRB1 gene) and environmental risk factors (Smoking, periodontitis, female gender, obesity, aging)
- Combined with exposure to an unknown pathogen/ disturbance of the immune system that initiates the autoimmune reaction within synovial membranes (key cytokines involved are TNF-a and interleukin-1)
Describe the pathological process of RA within synovial joints
Swelling of synovial membrane, effusion of synovial fluid into joint space and hypertrophy of inflamed synovial membrane
Joint effusion, soft-tissue swelling, ligamentous instability occurs.
Invasion of inflamed synovial membrane – inflammatory granulation tissue (pannus) spreads over articular cartilage and activated synovial cells produce proteases, which contribute to the erosion of underlying tissues (articular cartilage and bone)
Erosion of articular cartilage, loss of joint space, subchondral bone invasion, deformity and ankylosis
What is the common joint pattern of involvement in RA?
RA is a symmetrical polyarthritis - affects 5 or more joints at the same time, and appears symmetrically on both sides of the body
Tends to start in the hands and feet
Who does RA usually affect?
Can occur at any age but typically diagnosed between 30-50
Male: Female = 1:2-3
What are some common symptoms of early RA?
Joint Stiffness - early morning stiffness lasting >30mins
Persistent Joint Swelling - in one or more joints
Positive Squeeze Test - pain when squeezing the MCP or MTP joints
Basically signs of active synovitis in multiple joints
What are some common pathological musculoskeletal features present in long standing RA?
Upper Limb…
Poor grip strength in hands
Subluxation of MCP joints and ulnar drift
“Swan neck” and “Boutonnière” deformities at IPJs of fingers
Carpal tunnel syndrome
Fixed flexion deformities of the elbows
Lower Limb…
Knee involvement is common - fixed flexion deformity of knee
Valgus knee deformity - due to collateral and cruciate laxity and erosion on tibial plateau
Popliteal cysts - fluid filled swelling posterior to knee
Pesplanovalgus deformity of ankle
HAV
Lesser toe deformities
What extra-articular features are common in RA?
Vascular Complications…
Raynauds
Vasculitis - can cause accelerated atherosclerosis and increased risk of CVD and PVD
Muscular Disorders…
Cachexia - muscle weakness and atrophy secondary to joint deformity
Rheumatoid nodules - vascular granulation tissue with central area of necrosis, occurring at sites of pressure or bony prominences
Neurological Complications…
Higher incidence of entrapment/compression neuropathies
Peripheral neuropathy - due to chronic vasculitis
Cardiorespiratory Complications…
Inflammation of the lining of the lungs leading to pleural effusions and pulmonary fibrosis
Inflammation of the tissue surrounding the heart leading to pericarditis
Describe the common podiatric implications of RA
Deformities - Pesplanovalgus, HAV, claw/hammer/retracted toes
Tendon sheath inflammation - Tibialis Posterior Tendon Dysfunction (TPTD) and peroneal tenosynovitis
Tendon and fascia inflammation - Plantar Fasciitis and Achilles tendinitis
Bursitis - Retro-calcaneal or inter-metatarsal bursitis
Synovitis of small joints - MTPJs, IPJs, midfoot and tarsal joints, talocrual joint e.t.c
Widening of the forefoot due to inflammation of internal structures and joint capsules - Daylight’s sign
Irritation/ compression of interdigital nerves due to inflammation of forefoot structures - PDN
Soft tissue pressure lesions - Plantar metatarsal callosities, dorsal HD due to lesser toe deformities
Raynaud’s disease
Peripheral neuropathy
Increased risk of ulceration due to:
Joint deformities
Soft tissue pressure lesions
Increased risk of macro and microvascular diesease, PVD etc
Increased risk of peripheral sensory neuropathy and loss of protective sensation
What tests are used to measure the disease activity of RA?
DAS 28 and DAS 44 (Disease Activity Score)
Measures of global disease activity used by rheumatologists to measure global disease activity and inform treatment decisions
DAS 28 is a composite score…
Number of swollen joints
Number of tender joints
Levels of inflammation in the blood (ESR or CRP)
Global health VAS (100mm)
Score of >5.1 = active disease
Score of <3.2 = low disease activity
Score of <2.6 = remission
Does not include foot or ankle joints
How is RA pharmacologically managed?
Analgesics e.g Codeine - for pain relief
Topical medicaments e.g Capsicum cream - for pain relief
NSAIDs e.g Naproxen, Ibuprofen, Celecoxib - to reduce inflammation and manage pain
Oral or IA/ IM Corticosteroids e.g Prednisolone - to suppress inflammation
Conventional Synthetic DMARDs e.g Methotrexate, Sulfasalazine - to suppress immune system and inflammatory response
Biologic DMARDs e.g
Anti TNF - Adalimumab, Infliximab, Etanercept
B-cell depletion - Rituximab
T-cell depletion - Abatacept
IL-6 signalling - Tocilizumab
To powerfully suppress the immune system by targeting and inhibiting specific inflammatory cytokines
Targeted Synthetic DMARDs e.g Janus Kinase (JAK) inhibitors such as Tofacitinib, Baricitinib, Filgotinib - to suppress the immune system by
Inhibiting the production of Janus Kinase enzymes (which are required for phosphorylation of activated cytokines receptors)
Define the term “spondaloarthropathy”
Spondaloarthropathies (SpAs) are a group of inflammatory arthritic conditions that share certain clinical and histological features…
A common genetic background (HLA-B27 positive)
The absence of RH factor (Seronegative)
‘Spondylo’ = spine or vertebrae, meaning these conditions often affect the back, pelvis and neck
Similar to RA, these conditions involve pain, swelling, stiffness and deformity
What conditions fall under the definition of an SpA?
Psoriatic Arthritis
Enteropathic Arthritis
Ankylosing Spondylitis
Reactive Arthritis
Remember the mnemonic P.E.A.R
What clinical features differentiate SpAs from other inflammatory arthropathies like RA?
Spinal/Axial involvement
Joint involvement pattern is usually asymmetrical oligo-articular (4 joints affected), poly-articular (5 joints or more) or mono-articular
Peripheral involvement usually begins in the distal IPJs
Enthesitis, sarcoiliitis, dactylitis, uveitis and urethritis are common in patients with SpAs
Presence of HLA-B27 gene is common in about 30-90% of patients with SpAs
Certain shared co-morbidities such as aortic regurgitation, pulmonary fibrosis and amyloidosis are common
The onset age is usually under 45 years
Males are often more symptomatic than females
What is psoriatic arthritis (PsA)?
A chronic, progressive, autoimmune, inflammatory arthritis linked with the skin condition psoriasis.
Age of onset = 30-50 years
HLA-B27 positive
Anodular peripheral (typically asymmetrical) arthritis - can present as oligoarthritis, polyarthritis (symmetrical), arthritis multicans, distal IPJ predominant, spondylitis with or without sarcoiliitis
Has extra-articular manifestations such as…
Dactylitis
Enthesitis
Tenosynovitis
Psoriatic skin lesions and nails
Forefoot deformities
Associated with synovitis and juxta-articular erosions with new bone formation (proliferation AND destruction of bone) - can involve increased bone density in shaft of bone
