Johnston: Laboratory Testing in Rheumatic Diseases Flashcards
Is there a single test that is diagnostic?
No!
-use your H and P
Markers of Inflammation
- nonspecific
- ESR: higher in women, rises with age, monitor disease activity, especially PMR (polymylagia rheumatica) and GCA (giant cell arteritis)
- CRP: assessment of disease activity, made in liver, proinflammatory cytokines increase CRP, Can activate complement, promote phagocytosis, greater than 8 is inflammatory, rises and falls quicker than ESR
When immune complexes mediate consumption, what dereases?
-complement!
Rheumatoid factor
- autoantibody that targets the Fc portion of IgG
- can be any Ig subclass, IgM most common
- RF is produced by B cells in synovial joints of RA pts
- Sensitivity for RA is 66% specificity is 82%
- present is 70-80% patients with RA; 100% in “nodular” RA
What other conditions do we find RF in?
- Sjogrens
- cryoglobulinemia
- primary biliary cirrhosis
- SLE
- etc…
what does high levels of RF mean?
-associated aggressive disease, joint erosions, worse prognosis
do all people with RA have RF?
-no!
What is the other antibody in RA that is more reliable marker than RF?
- Antibodies to citruliinated proteins (anti CCP)
- more specific
- if both Anti CCP and RF are there, probably have RA
- associated wtiha ggresive, erosive disease
If someone has ANA, is it always lupus?
- no
- happens in normal people
pattern of IF with ANA associated with drug induced lupus?
-homogenous pattern
If there is a rim pattern of IF for ANA, what antibody is there?
-andi DS DNA
Which antibody is ONLY seen in lupus (SLE)?
-anti smith antibodies
Anticentromere antibody
-scleroderma (CREST syndrome)
Criteria for SLE
- Malar rash
- discoid rash
- photosensitivity: rash due to sunlight
- oral ulcers: nasopharyngeal ulcers… usually painless
- arthritis
- serositis
What are some hematologic signs of lupus
- hemolytic anemia with reticulocytosis
- leukopenis
- lymphopenia
- thrombocytopenia
What does positive ASO titer and anti DNAase B titers mean?
- preceding group A streptococcal infection
- often affects large joints and is asymmetric
if we had lupus, what lab test would we expect?
-CBC indicating hemolytic anemia, leukopenia, and false positive RPR
What lab tests would we expect for RA?
- positive anti CCP
- Elevated ESR
- elevated RF level
What is the wierd thing with a nodule that happens with RA
-it’s on their extensor surface of forearm
with joint fluid analysis, what are the values for cells we need to know?
- <200: normal
- 200-2000 mononeuclear: non inflammatory
- 2000-5000: inflammatory
Which joint becomes symptomatic in gout?
- 1st MTP
- that’s called podagra
What are tophi
-MSU crystals… nodular deposits of it in skin
what will gout present with?
-hot red swollen joint
What imaging modality is sensitive for soft tissue?
- Ultrasound
- no radiation
Will radiography always catch RA?
-no, especially early in the disease course
What patients do we have to watch out for if we are wanting to do an MRI?
- kindey patients
- gadolinium contrast taken up in inflammed synovium, IV gadolinium can cause nephrogenic systemic fibrosis (NSF) in pt with kidney disease
- good for spine, SI, synovitis, tenosynovitis
What is CT best for?
-bony abnormalities, erosions, fractures, degenerative or inflammatory arthritis
what is the difference between oligo, pauci, and poly arthritis?
- oligo: 3 or more
- Pauci: 5 or more
- Poly: >6
What hand joint is spared in RA?
- DIP!!!!!
- those Heberen’s nodes will be in osteoarthritis
difference between swan neck and boutonniere deformity?
- swan: the DIP is flexed
- boutonneire… it isnt
what diseases have arthritis with involvement of the bowel?
- UC, Crohns disease, and Behcet’s
- reactive arthritis…. with a bowel infection
What does nail clubbing mean?
- HPO
- Hypertrophic pulmonary osteoarthritis
What is Charcot joint?
-diabetes, they have arthritis but they can’t feel it due to nerve damage
What does Cytoidbodies and vasulitis mean with arthritis having to do with ophthalmologic causes?
-retinopathy
What will there be in diabetes?
- charcots
- cheiroarthropathy
What will there be in thyroid disorders arthritis?
-carpal/tarsal tunnel syndrome
