Chapter 3- Rheumatoid Arthritis Flashcards
Define Rheumatoid arthritis
a chronic inflammatory polyarthritis of unknown etiology that targets the synovial tissue of moveable joints.
define the epidemiology of R.A.
more common in Women.
Costs are associated to disability.
peek age 55
What are the suspected causes of R.A.?
What increases the risk of developing R.A?
multifactorial: genetics, environmental, immunologic, hormonal and infectious diseases.
Other: Smoking, decrease risk d/t BC pills
What are the genetic factors resulting in an increased risk for R.A?
- presence of HLDA-DR4 antigen believed to be associated to R.A.
- Link to metalloproteinase-3 gene
- R.F rheumatoid factor - genetic link.
Describe the Synovial joint
bones are held together by fibrous capsule lined with synovium.
provides nutrients to the avascular cartilage and produces hyaluronic acid (joint lube).
produces collages and fibrocetin used for the synovial matrix
Why does R.A. affect the synovial joint?
unknown cause
Describe the Synovial matrix
2 layers. 1st layer (synovial intimal layer) 1-3 cells thick: macrophage cell (type A) and fibroblast type cells (Type B).Both increase with Rheumatoid synovitis.
2nd layer subintimal area has the blood vessels. Becomes infiltrated with cells that differentiate into osteoclasts > which promotes angiogenesis > which leads to inflammation.
What happens to the synovial cavity with R.A?
its normally a potential space that allows free movement, but then it becomes filled with a large amount of neutrophil fluid due to inflammation. This decreases the free space available for movement
How are the immunologic elements T-cells, macrophages/fibroblasts and B-cells are involved in the development of R.A.?
[T-cells slide]
T-cells are a keyPerson in the inflammatory process. HLA-DRA, acts on APCs then They release cytokines (TNF-a, and IL-$j) which drive inflammatory process.
How are the immunologic elements T-cells, macrophages/fibroblasts and B-cells are involved in the development of R.A.?
[B-cells slide]
B-cells are activated with the T-cells and cytokines. These cells then differentiate and produce additional plasma cells which results in antibodies (ie: RF and ACPAs).
In the synovial cavity, the B-cells produce more T-cells and more cytokines.
This results in ++ inflammation/fluid. Think of a continuous chain process.
How are the immunologic elements T-cells, macrophages/fibroblasts and B-cells involved in the development of R.A.?
[Effector cell activation]
after T and B cells kick started the inflammation process > the macrophages and fibroblasts go on to act independently in the synovial lining to perpetuate the inflammatory process.»_space; they produce many cells.
What do macrophages in the synovial produce?
cytokines: TNF- alpha, IL-1, IL-7, IL-8, and GM-CSF. prostaglandins leukotrienes nitricocide pro-inflammatory mediators > others
What do Synovial fibroblast secrete?
cytokines including IL-6, IL-8, and GM-CSF
proteases
collagenases
What manifests the progressive process of chronic synovitis?
- hypertrophy of lining cells
- neo-angiogenesis
- new blood vessels supporting hyperthrophied synovium, and influx of fluid, lymphocytes, and PMNs into synovial cavity d/t ++ plasma. > this activates other inflammatory cytokines and fluid in cavity
- panus formation- inflammation fo synovial issue > microvascular injury > profound proliferation + hypertrophy of synovial tissue called panus.
What are cytokines?
T-lymphocytes are present and when activated they stimulate the production of pro-inflammatory cytokines.
- mediators of cell-to-cell communication
What happens to cytokins with R.A. ?
Theres an imbalance of pro-inflammatory and anti-inflammatory cytokines, with pro-inflammatory cytokines dominating.
How do TNF-a and IL-1 play a role in developing RA?
they stimulate synoviocytes to produce substances that degrade tissues and activate other inflammatory mediators.
Trigger: IL-6, IL-8, and GM-CSF, prostaglandins, osteoclasts, and metalloproteinases, cartilage/pannus junction.
What do prostaglandins do?
increase sensitive pain and contribute to the destruction of cartilage.
What do Osteoclasts do?
cause bone resorption and destruction
What do MMPs do?
destroy bone, cartilage and dissolve ligaments and tendons.
What do GM-CSF do?
promotes the matruations of monocytes to macrophages that, in turn, produce more cytokines.
what does IL-6 and IL-8 do?
IL-8 produced by the synovium in the joint cavity where it recruits neutrophils into the synovial fluid.
IL-6 also suppresses the production of albumin by the liver, alters lipids metabolism and is a factor in the elevation of markers of inlammation, (CRP, and ESR).
What Cytokines produce the sxs of RA including fever, muscle wasting and loss of appetite.
IL-1, IL-6, and TNF-alpha
What are some differential diagnoses of Rheumatoid arthritis?
Acute vital arthritis, bacterial endocarditis Scarvoidosis Reiter's syndrome Polymyositis Sjogren's syndrome Amyloidosis Rheumatic fever Polymyalgia Rheymatica Systemic lupus erythmatosus systemic sclerosis polyarticular gout Vasculitis IBS Psoriatic arthritis Acute relapsing symmetric synovitis tuberculous arthritis Gouty arthritis Reactive arthritis Chronic fatigue syndrome
What are the typical sxs of RA
pain,
stiffness,
swelling of the diarthrodial joints (muscle atrophy common)
*morning stiffness is result of accumulated fluid in joints d/t no activity.
* small joints affected first then larger.
*joints are additive not migratory.
*Sxs can be sudden
* joint pain starts Axsx.
What are the most comonly affected joints?
- proximal interphalangeal (PIP) and metacarpophalangeal (MCP) joints > hands
- Metatarsophalangeal (MTP) joints of the feet
- wrists and elbows
- shoulders
- ankles and knees
What are the joints that are less affected, or affected later in the disease?
Hips Temporomandibular joints (TMJ) of the jaw Atlantoaxial joint of the cervical spine, symphysis pubis manubriosternal joint cricoarytenoid joint sternoclavicular joints ossicles of the ears.
How do you diagnosis RA?
using an algorithm - a +ve diagnosis is typically a score of >6 to 10.
using ACR or ACR-EULAR definitions: Letters A-D:
A- joint involvement (score 0,1,2,3,5)
B- Serology (score 0,2,3)
C- Acute-phase reactants (score 0,1)
D- duration of sxs (score 0-1)
How are people clinically diagnosed?
initial assessment: complete exam, blood chemistry, CBC with platelets, RF, ACPA, ANA, CRP, and ESR. Urinalysis, radiographs of affected joints.
Client’s GP usually notes sxs, limitations in activity, monitor effectiveness of tx.
Tx starts right away
Monitoring every 6 months the following:
1. duration of morning stiffness
2. presence of inflamed joints; changes?
3. mechanical changes (motion, strength, ROM, etc)
4. Signs of active synovitis (swelling, effusion)
5. pain and tenderness with movement
6. presence of heat or redness-
7. presence of Rheumatoid nodules
8. systemic manifestations
What formula can be used to quantify and serially measure the disease and response to treatment?
- disease activity Score
- Ritchie Index
- Thompson Index- evaluates a limited number of affected joints and uses a weighted score to estimate “burden of synovitis”
How does the Patient play roles in the management of his disease?
Providing information and check-ins. Confirm if tx is affective. Are there adverse sxs?,
Possibly complete a questionnaire.
Note: depression is frequently observed in pt with R.A. and may affect overall morbidity. Beck depression index is used to evaluate depression.
What are the 3 most commonly used laboratory tests to diagnosis and monitor the disease activity.
- RF - limited usefulness
- Anti-CCP antibody for ACPAs - specific to R.A. ^ levels = work disease, note that specificity is 98%
- CRP (and ESR): most common of acute phase reactants. ^ levels are associated with progression of joint erosions. Fluctuate during disease. This method is used to differ RA from OA.
*AMCV antibodies recognize a form of citrullinated vimentin found in R.A. This has a lower sensitivity and is used in when theres an -ve Anti-CCP test. Not currently used for prognosis but undergoing studies.
What are seropositive patients?
+ve RF associated with HLA-DR4 molecules.
Rheumatoid nodules and vasculitis,
They have an increased risk of systemic involvement and worse prognosis
+ve RF can bee seen in other pt with other rhumatic diseases. Explain.
Can be found in 4% of pt, and increased to 25% in elder population.
- Sjogern’s syndrome: 75-90% have +ve
- Mixed connective tissue disease (50-60%)
- Systemic lupus erythematosus (15-35%)
Also seen in those with Hep B and C, sarcoidosis, malignancy and primary biliary cirrhosis.
What are the typical CBC abnormalities associated with an RA diagnosis?
- WBC normal, or modestly elevated.Differential should be normal
- hemoglobin and hematocrit should be normal or mild decrease. Normocytic anemia common in chronic disease. Serum iron low, but ferritin normal. MCV normal
- mild thrombocytosis,
What are some other abnormalities in blood chemistries associated with RA? (Not related to CBC reports)
- globulins elevated (polyclonal grammopathy)
- Lipids low in late-stage
- HDL low d/t inflammation
- low albumin > poor prognosis
- serum creatinine should be normal