RA Flashcards
RF for RA
- Genetics
- infectious agent
- Sex hormones
- Smoking
- Parental Hx of substance abuse
infectious agents that cause RA
EBC
mycoplasma
Rubella
innate susceptibility but infxn causes it to switch on
sex hormones and RA
more common in women
subsides during pregnancy
less common in women taking OC
RA patho (general)
trigger sets off an autoimmune reaction in a genetically susceptible person
RA patho (8) (long)
- inflammation in synovial membrane and synovial space
- destructive enzyme activation
- reactive oxygen species form
- synoviocyte cells proliferate extensively, cross synovial membrane and get into cartilage
- synovium relates MMP that destroys cartilage and stimulate osteoclastic bone reabsorption
- pro inflammatory cytokines released cause systemic symptoms
- osteoclast activation = osteoporosis
- articular surface damage causing destruction of the bones
- fibrous adhesions = permanent joint deformities
cells that cause RA inflammation
CD4/T cells
monocytes
neutrophils
fibroblasts
enzyme destruction to which joint
cartilage
tendons
ligaments
bone
PDGF
angiogenesis into the joint
pro inflammatory cytokines RA
TNF alpha
IL-6
produce systemic symptoms
systemic symptoms caused by cytokines
weight loss
organ inflammation
fever
pathogenies of RA
- activation of pro inflammatory cytokines causing joint swelling, stiffness, destruction
- pannus acts like locally invasive bone tumor
- cytokines cause systemic inflammation symptoms and worsened comorbidities
Epidemiology of RA
F > M
MC in Native American, least common in Caribbean Black
35-50 years
Family hx
hallmark feature of RA
persistent symmetric poly arthritis that affects small joints of hands, wrists, ankles and feet
insidious onset
RA joints on PE
swelling, tenderness, warmth and decreased ROM
atrophy of interosseous muscles
worse in AM
lab eval of RA (6)
- ESR/CRP
- CBC (ACD, thrombocytosis)
- RF (non diagnostic)
- Anti-CCP
- Anti MCV
- ANA
RF
IgM against IgG
60-80% of pts with RA over course of dz but NOT specific for RA
NEITHER necessary nor specific
seropositive RA
presence of RF in serum
increased likelihood of severe erosive arthritis, rheumatoid nodules, extra-articular dz
ACPA abs include
anti-CCP abs
AntiMCV
anti-CCP Abs
MOST specific biomarker for RA but found in other dz
indicates higher likelihood of erosive arthritis and worse prognosis
ANA in RA
if NEGATIVE can help distinguish RA from SLE
joint aspiration
inflammatory fluid (>10k WBC)
- crystals, - culture
imaging study of choice
Plain fim XR
bone erosion and uniform joint space narrowing
RA on plain film
osteopenia
symmetric narrowing of joint spaces
erosions
bony crowding due to loss of cartilage
first 4 criteria for RA diagnosis (1987)
- Morning stiffness lasting at least 1 hr
- soft tissue swelling or fluid in 3 joint spaces
- at lease one area swollen in wrist, MCP, PIP
- symmetric arthritis