Diagnostic Testing in Rheumatology Lecture Powerpoint

Question 1

Rheumatoid factor

Answer 1

An antibody directed against the Fc portion of IgG found in 80% of RA patients, correlates with being a more severe disease and having extra-articular disease with seronegative RA having better prognosis, titers do not change or correlate with disease activity

Question 2

What other conditions can rheumatoid factor be found in? (5)

Answer 2

• bacterial infection
• viral infeection
• sarcoidosis
• SLE
• pulmonary fibrosis

Question 3

Anti-citrullinated peptide antibody CCP antibody test

Answer 3

Antibody that may be present prior to appearance of RA symptoms, may be as sensitive as rheumatoid factor for diagnosing RA but much more specific**, rarely present in arthropathies associated with hep C

Question 4

Antinuclear antibody test

Answer 4

Positive in 99% of patients with SLE, negative ANA rules out diagnosis of SLE, but can also be found in other connective tissue diseases or drug induced so not diagnostic*** not useful to monitor disease activity

Question 5

Anti DNA antibody test

Answer 5

Very specific for lupus with very few false positive results, but not very sensitive depending on disease progression

Question 6

Anti SSA/SSB antibodies test

Answer 6

Associated 70% with sjogren’s syndrome and ANA negative lupus (rare), if seen in pregnancy can indicate neonatal lupus syndrome and congenital heart block

Question 7

Anticardiolipin antibody test

Answer 7

Seen in recurrent venous or arterial thrombosis (in young unexpected cases with antiphospholipid antibody syndrome) or recurrent fetal loss

Question 8

Antineutrophil cytoplasmic antibody (ANCA) test (c-ANCA, p-ANCA)

Answer 8

Found in patients with vasculitis associated with wegener’s granulomatosus and some rapidly progressing glomerulonephritis

Question 9

Sed rate

Answer 9

Nonspecific test for inflammation, useful in diagnosis and monitoring of polymyalgia rheumatica and giant cell arteritis, sometimes useful in diagnosis and monitoring RA, vasculitis, SLE, etc

Question 10

Lyme testing

Answer 10

Should only be done in suspected clinical setting, not useful for screening

Question 11

Synovial fluid analysis

Answer 11

Can be analyzed for gross exam, leukocyte count, wet prep, gram stain, and cultures

Question 12

Synovial fluid group 1

Answer 12

Present in noninflammatory conditions such as osteoarthrtiis, trauma, is pale yellow, transluscent, high viscosity

Question 13

Synovial fluid group II

Answer 13

Present in inflammatory conditions such as RA, spondyloarthropathies, and microcrystalline disease, deeper yellow color and opaque

Question 14

Synovial fluid group III

Answer 14

Present in septic fluid, purulent and opaque with WBC often very high, opaque, associated with positive gram stains and cultures

Question 15

Synovial fluid group IV

Answer 15

Present in hemorrhagic fluid, has bloody appearance, due to trauma, bleeding disorders, tumors, etc.

Question 16

Rheumatoid arthiritis sees __ of bone, osteoarthrtiis sees __ of bone

Answer 16

loss, increase

Question 17

C1-C2 sublaxation can indicate what rheumatological condition?

Answer 17

Rheumatoid arthritis (compression of the spinal cord might manifest as tingling in the extremities

Question 18

Pencil in cup erosions and what disease are they often seen in?

Answer 18

• Radiological finding often asymmetrical where there is dramatic joint space loss giving the proximal phalanx the appearance of a pencil sitting inside the cup of the expanded distal phalanx
• Psoriatic arthritis

Question 19

Enthesitis

Answer 19

Inflammation where tendons or ligaments attach on bone

Question 20

Radiographic findings of gout (remember we don’t diagnose gout radiographically)

Answer 20

• Tophi
• joint space preservation
• punched out erosions with sclerotic borders
• overhanging edges of cortex