Lab Testing In Rheumatic Dx Flashcards
What are the non-specific acute phase reactants?
ESR (erythrocyte sedimentation rate): rise w/ age, monitor dx activity (PMR, GCA)
CRP (c-reactive protein): synthesized in liver, monitor dx activity, pro-inflammatory cytokines inc CRP, CRP activates complement > phagocytosis
What CRP value represents an inflammatory process? Does this value fluctuate faster or less than ESR?
> 8 mg/L
More
Are serologies an appropriate single definitive diagnostic tool?
No
What is Rheumatoid Factor? What produces it?
Auto-antibody (IgM) that targets Fc portion of IgG
B-cells in synovial joints of RA pts
Is RF found in healthy people? Is it always found in sick people?
Yes
No
What’s the significance of the RF level?
High levels associated w/ more aggressive dx and worse prognosis
What lab result gives a 99.5% specificity for RA?
Pos anti-CCP + Pos RF
Whats does anti-CCP target? What does it signal?
Citrullinated proteins
Aggressive and erosive dx
Which test alone is most specific for RA?
Anti-CCP (more-so than RF)
What marker is 99% indicative of SLE?
Anti-SM antibodies in an ANA
What is a rim pattern ANA associated w/?
Anti-DS DNA in Lupus
What hematologic results would you expect in a pt being worked up for SLE?
Hemolytic anemia w/ reticulocytosis (lots of young/immature RBCs)
Leukopenia
Lymphopenia
Throbocytopenia
Is ANA (anti-nuclear antibody) found in normal healthy pts?
Yes, 30% of the time
What test comes up as a false positive in SLE?
RPR (test for syphilis)
What lab is used to support a streptococcal infection?
ASO titer (antistreptolysin O antibody) - group A strep infection
What is rheumatic fever?
Rheumatic fever is a reaction to the group A strep infection
What are the Jones criteria?
Sxs of rheumatic fever
Carditis Joint inflammation (arthritis) Chorea (involuntary purposeless movements) Sub-Q nodules Erythema marginatum (rash)
Does a strep infection cause arthritis? If so, where?
It can, part of rheumatic fever response
Asymmetrically in large joints (knees, hips, elbows, ankles)
Difference between RA vs strep infection?
RA = symmetrical joint involvement
Strep infection = asymmetrical joint involvement
What uric acid level is a factor in gout attacks?
Uric acid (urate) > 6.8 mg/dl
Gout is due to in part..?
Under excretion (kidney dx) or over-production (alcohol, food) of uric acid
Where and when do gout attacks often occur?
1st MTP joint of the foot at night
What’s the state of a gouty joint?
Hot, swollen, tender, dusky/red
What are tophi?
Associated w/ gout, nodular deposits of monosodium urate crystals in the skin
Number of joints involved terminology includes:
Mono arthritis (one joint) Oligo arthritis (2-3) Pauci arthritis (4-5) Poly arthritis (6 or more)
In regards to inflammation, what are the cardinal signs?
Pain, swelling, redness, heat, tenderness, stiffness
What’s the involvement of distal interphalangial joints in RA vs OA?
RA = not involved OA = involved
What is the swan neck deformity and what’s it associated w/? Boutonniere?
Both involved w/ RA
Swan: flexion of DIPJ (swans head), extension of PIPJ
Boutonniere is the opposite
What Bowel dxs are associated w/ arthritis?
IBD:
- ulcerative colitis
- chrohn’s dx
- Behcet’s
Bowel infection > reactive arthritis
What’s a Charcot’s joint associated w/? What is it?
DM
Painless joint d/t excessive n dmg by DM
What’s Cheiroarthropathy and what is it associated w/?
Hands are stiff and skin on hands are thick
DM
What’s Carpal/Tarsal tunnel syndrome associated w/ regarding arthritic pairings?
Thyroid dx
Xerophthalmia is associated w/ what dxs regarding arthritis?
Sjogren’s
Sarcoid
What are cytoid bodies and when are they seen?
White lesions of the retina
SLE
Rim patterned DNA =
ANA result of Anti-DS DNA
What are the possible results of a joint analysis?
Normal fluid (clear, <200 cells)
Non-inflammatory (200-2000 cells)
Inflammatory (2000-50000, cloudy)
Septic (>50000, cloudy)
