Arthritides Flashcards
What is rheumatoid arthritis?
Chronic INFLAMMATORY systemic disease characterised by symmetrical deforming polyarthritis and extra-articular manifestations.
What is the aetiology of rheumatoid arthritis? Associations? (x2)
Unknown. Associated with other autoimmune phenomena including Raynoud’s syndrome and Sjogrens syndrome, and HLA DR-1 and DR-4 halotypes.
What is the pathophysiology of rheumatoid arthritis?
Inflammation of synovium and shows increased angiogenesis, cellular hyperplasia and migration of mononuclear inflammatory cells (T, B, macrophages and plasma cells). This leads to EROSION. Prominent cytokines include TNF, IL-1 and IL-6 which promote proliferation and metalloproteinase expression (thought to lead to joint destruction). NB: angiogenesis occurs to support the hypertrophic synovium.
What is the role of metalloproteinases?
Matrix enzymes that catalyse both collagen and proteoglycan degradation
What is the epidemiology of rheumatoid arthritis: Prevalence? Gender? Age?
1% prevalence. Three times more common in females. Peak incidence 50s years.
!!! What are the signs and symptoms of rheumatoid arthritis? Early signs? Late signs? (x8) Onset? Where?
- Gradual onset. Associated with multiple peripheral joints, usually hands at MCP and PIP (although occasionally monoarticular), and symmetrically.
- ARTICULAR: Joint pain and swelling, warm, morning stiffness, impaired function
- Rheumatoid nodules: firm subcutaneous nodules on elbows, palms and over extensor tendons
- EARLY SIGNS: spindling (swelling) of fingers at MCP and PIP.
- LATE SIGNS: ulnar deviation of fingers as a result of subluxation at MCP, radial deviation of wrist, swan neck deformity, Boutonniere deformity, Z deformity of the thumb, trigger finger, wasting of the small muscles of the hand, palmar erythema
- SYSTEMIC: fever, weight loss, fatigue
What is swan neck deformity?
MCP and DIP fixed flexion, PIP extension.
What is Boutonniere deformity?
MCP and DIP joint extension, PIP flexion (opposite of swan neck)
What is Z deformity of the thumb?
AKA hitchhiker thumb deformity; MCP flexion, IP exftension.
What is trigger finger?
Unable to straighten the finger and tendon sheath nodule palpable.
What are the investigations for rheumatoid arthritis? (x3)
- Diagnosis clinical and laboratory/radiographic testing usually more important in providing prognostic information
- BLOODS: anti-CCP antibodies (more specific), rheumatoid factor (monoclonal IgM against Fc portion of IgG; strong association with rheumatoid nodules and extra-articular manifestations), ANA (in 30%)
- ACUTE PRESENTATION (rare): consider joint aspiration to exclude septic arthritis
- X-RAYS: soft tissue swelling, angular deformity, periarticular EROSIONS and osteoporosis
What disease activity scores are there for rheumatoid arthritis? (x5)
- Disease activity score (DAS)
- 28-joint count version of disease activity score (DAS28)
- Simplified disease activity index (SDAI)
- Clinical disease activity index (CDAI)
- Routine assessment patient index data (RAPID3)
What are the complications of rheumatoid arthritis? (x4 (x4, x4, x3, x3))
- Vasculitis of skin leading to nail-fold infarcts (see photo), digital gangrene, ulcers, purpuric rash
- Anaemia of chronic disease, megaloblastic anaemia (from increased folic acid demand), aplastic anaemia (from drugs), Haemolytic anaemia (in Felty’s syndrome; syndrome of RA, splenomegaly and neutropenia)
- Pleural effusions, fibrosis, rheumatoid nodules in parenchyma
- Pericarditis, myocarditis, conduction abnormalities
What is osteoarthritis?
Note this is different form osteoporosis. Age-related degenerative synovial joint disease when cartilage destruction exceeds repair causing pain and impaired function.
What is the aetiology of osteoarthritis? (x1 and x4)
- PRIMARY: unknown aetiology. Likely to be multifactorial, linked to age, genetics, female sex, menopause and obesity
- SECONDARY: other disease can cause altered joint architecture and stability. Commonly associated diseases include developmental abnormalities (hip dysplasia, Perthes’ disease, slipped femoral epiphysis), previous trauma, inflammatory conditions (RA, gout, septic arthritis), metabolic (alkaptonuria, haemochromatosis, acromegaly)
What is slipped femoral epiphysis?
Occurs in teens and pre-teens who are still growing. For reasons that are not well understood, the ball at the head of the femur (thighbone) slips off the neck of the bone in a backwards direction.
What is alkaptonuria?
AKA black urine disease. Inherited disorder that prevents the body breaking down tyrosine and phenylalanine. It results in a build-up of homogentisic acid in the body which is excreted in the urine
How is osteoarthritis classified? (x5)
- Based on distribution of affected joints.
- Hand: commonly carpometacarpal (CMC; distal row of carpal bones to metacarpal bones) and trapeziometacarpal (thumb) joints, and wrist joint
- Shoulder
- Spine: spondylosis (different from spondylitis), commonly lumbar and cervical
- Hip
- Knee
! What is the pathophysiology of osteoarthritis? (x5 mechanisms)
- There is failure in maintaining the balance between cartilage matrix synthesis and degradation:
- Matrix metalloproteinases are found in increased concentrations in cartilage; Catabolic cytokine, IL-1, stimulates production of metalloproteinases; NO activates metalloproteinases; Anabolic cytokine levels such as IGF-1 are decreased; Mechanical loading harms chondrocytes and cartilage
- These processes occur in cartilage (leading to fissuring (tears) and fibrillation (softening)) and other joint structures. The result is bone remodelling (subchondral sclerosis, osteophyte formation) and bone marrow lesions of subchondral bone (bone cysts).
- Chronically, this can lead to alterations in the joint anatomy leading to increased and redistributed focal loading on joints e.g., varum and valgum in knee OA, which can potentiate further degeneration.
What is the epidemiology of osteoarthritis: Gender? Age? Ethnicity?
More common in females. Increasing age. More common in Caucasians and Asians.
What are the signs and symptoms of osteoarthritis? (x6)
- Joint pain that is worse on use, and associated with stiffness/gelling after inactivity
- Functional impairment
- Crepitus during joint movement
- Joint effusion (lack signs of inflammation such as warmth and redness)
- Heberden’s nodes and Bouchard’s nodes
- Malignment
- No systemic features
What are Heberden’s nodes?
DIP swellings associated with osteophytes
What are Bouchard’s nodes?
PIP swellings associated with osteophytes
What are the investigations for osteoarthritis? (x2)
- X-ray shows four classic features: joint space narrowing from cartilage loss, subchondral cysts, subchondral sclerosis and osteophytes.
- BLOOD: normal ESR and CRP (differentiates from inflammatory arthritides)
What is ankylosing spondylitis?
Seronegative INFLAMMATORY arthropathy affecting preferentially the axial skeleton and sacroiliac joints.
What is the aetiology of ankylosing spondylitis? (x2)
Strong genetic linkage with HLA-B27. HLA-B27 may share molecular characteristics with bacterial epitopes, facilitating an autoimmune cross reaction with T cells. Infective triggers have also been suggested.
What is the pathophysiology of ankylosing spondylitis? Results? (x4)
- In contrast to RA where the pathological processes are inflammation and erosion, AS has inflammation, cartilage erosion and subsequent repair (ossification)
- Inflammation starts at the entheses (sites of attached of ligaments to vertebral bodies) and mediated by mononuclear cell infiltrates. This leads to erosion of cartilage.
- Persistent inflammation leads to reactive ossification.
- Changes start in the lumbar spine and progress up.
- Result: squaring of vertebral bodies, formation of syndesmophytes (vertical ossifications bridging the margins of the adjacent vertebrae), fusions of syndesmophytes and facet joints (leading to ANKYLOSIS aka spinal immobility), and calcification of anterior and lateral spinal ligaments
- Peripheral joints and extra-articular sites such as eye and bowel may be affected
What is the epidemiology of ankylosing spondylitis: Gender? Age?
Earlier presentation in males. Males 6x more common than females at 16 years, and 2x more common at 30 years. Peak incidence in late-teens and early-20s.
What are the signs and symptoms of ankylosing spondylitis? (x7 +5)
- Lower back: SLEEP DISTURBANCE, worse in morning, improves on activity, returns with rest.
- Unilateral buttock pain from inflammation of a sacroiliac joint
- Progressive loss of spinal movement including reduced spinal flexion
- Symptoms of asymmetrical peripheral arthritis
- Thoracic kyphosis in later stages (leading to question-mark posture)
- Enthesitis: most commonly lower limbs: heel, knee, ischial tuberosities.
- Pleuritic chest pain (caused by costovertebral joint involvement) and associated with reduced chest expansion (dyspnoea)
- EXTRA-ARTICULAR: anterior uveitis (common), apical lung fibrosis, reduced chest, aortic regurgitation, IBD
What tests can be used to assess spinal mobility in ankylosing spondylitis? (x2)
- OCCIPUT-WALL DISTANCE: increased distance between back of head and wall
- SCHOBER’S TEST: mark is made on the skin of the back in the middle of a line drawn between the posterior iliac spines. A mark 10cm above this is made and patients asked to bend forwards. The distance between the two marks should increase by at least 5cm, but is reduced in AS.