Master the board step 3

Rheumatology
Answer: B. MRI of the SI joint is more sensitive than an x-ray, detecting edematous,
inflammatory changes years before an x-ray in ankylosing spondylitis (AS). HLA-B27 can
be present in 8 percent of the general population and is not necessary to confirm a diagnosis
of AS. The ESR is not always elevated and is a nonspecific test. The rheumatoid
factor will be negative in AS. In a CCS case, all of these tests should be performed, with
the x-ray done first and then going on to the MRI if the x-ray is negative.
The most common wrong
answer for ankylosing
spondylitis treatment is
steroids. They do not work.
Treatment
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NSAIDs
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Biological agents, such as infliximab or adalimumab
··
Sulfasalazine
Methotrexate does not
work well on the spine and
sacroiliac joints.
Do not use steroids.
Reactive Arthritis
Reactive arthritis (formerly known as Reiter’s syndrome) presents with an asymmetric
arthritis with a history of urethritis or gastrointestinal infection.
There may be constitutional symptoms, such as fever, fatigue, or weight loss.
··
Arthritis: May be monoarticular, oligoarticular, or more diffuse
··
Genital lesions: Circinate balanitis (around head of penis); urethritis or
cervicitis in women
··
Conjunctivitis
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Keratoderma blenorrhagicum: A skin lesion characteristic of reactive arthritis
Diagnostic Testing
There is no specific diagnostic test. Look for the triad of knee (joint), pee
(urinary), and see (eye) problems with a history of Chlamydia, Shigella,
Salmonella, Yersinia, or Campylobacter.
Treatment
Treat with NSAIDs.
Psoriatic Arthritis
Psoriatic arthritis presents as joint involvement with a history of psoriasis.
Rheumatoid factor is absent. The sacroiliac spine is involved, as it is in all seronegative
spondyloarthropathies. The following are key features of psoriatic arthritis:
··
Nail pitting
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Distal interphalangeal (DIP) involvement (Remember: RA involves the
proximal joint.)
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“Sausage-shaped” digits (dactylitis)
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Enthesitis: Inflammation of tendinous insertion sites
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