3.1 Autoimmunity and inflammation in MSK Flashcards
What joint is often used to tell RA from OA?
Distal IP joint - affected only in OA
What are the clinical manifestations of RA?
Morning stiffness for at least 1 hour and present for at least 6 weeks
Swelling of 3 or more joints for 6 weeks
Symmetrical joint swelling
Rheumatoid nodules
Erosions and bony declacification on x-ray
What will you see on testing for RA?
Rheumatoid factors or anti-citrullinated peptide/protein antibodies
Elevated acute phase reactants
What are the extra-articular manifestations of RA?
Rheumatoid nodules Lung disease - pleural effusion, pneumonitis, interstitial lung disease, nodules Pericarditis Vasculitis Neutropenia + splenomegaly Scleritis and episcleritis
What is rheumatoid factor?
Antibody to Fc portion of IgG - present in 75% cases but not specific for RA (IgM correlates best with RA)
What is the gene locus thought to be associated with RA?
HLADRB1 (30%) - associated with more sever disease rather than risk of diseases
What joints are most commonly affected in seronegative arthritis?
Sacroiliac joint and axial skeleton (usually present with lower back pain more to one side)
What are the types of seronegative arthritis?
Ankylosing spondylitis, reactive arthritis, psoriatic arthritis, arthritis associated with inflammatory bowel disease
What are the extra-articular features of seronegative arthritis?
Usually inflammation of tendon insertion (enthesitis) Iritis Urethritis Skin disease Keratoderma on feet
What is the gene thought to be associated with seronegative arthridities?
HLA-B27
What do you ALWAYS see in SLE?
Anti-nuclear antibodies
What are the key auto antigens in SLE?
usually chromatin, ribonucleases, phospholipids
