Exam 3: Rheumatology Flashcards
What lab finding is a cardinal feature of SLE and present in 95% of patients with SLE, but is not specific to SLE?
ANA
What are the two subtypes of ANA?
Anti-dsDNA
Anti-Sm
Is Anti-dsDNA or Anti-Sm more common in patients with SLE?
Anti-dsDNA, rarely found in disorders other than SLE
What other lab should be ordered with RF so support a diagnosis of RA?
Anti-CCP
What antibodies are present with Sjögren’s syndrome?
Anti-Ro/SSA, Anti-la/SSB antibodies
Is ANA positive or negative in most Sjogrens patients?
ANA is positive 95% of the time
What elevated lab finding is a characteristic finding in PMR? What is commonly associated with this?
Elevated ESR and/or CRP
-Associated with giant cell temporal arteritis
What are the indications to perform an arthrocentesis?
- New onset acute mono arthritis
- suspected crystal induced arthritis
- suspected infection/septic arthritis
- inflammatory vs non-inflammatory arthritides
- unexplained joint, bursa, or tendon sheath swelling
What is the most feared complication of joint aspirations?
Septic joint
What are the possible complications of glucocorticoid joint injections?
- Septic joint
- tendon rupture
- nerve damage
- osteonecrosis
What are the normal characteristics of synovial fluid?
Highly viscous, clear, and essential acellular
What are the 3 things that can cause non-inflammatory joint effusions?
OA, trauma, and a vascular necrosis
What are the 5 things that can cause inflammatory joint effusions?
Septic arthritis, RA/SLE, spondyloarthritis, Lyme disease, and gout
What WBC on joint aspiration is considered inflammatory?
> 2000
What is the normal volume of synovial fluid in a joint space?
<3.5 ml
What is often the WBC count in septic arthritis?
> 20,000, often >100,000
What neutrophil (PMN) count is found in septic arthritis?
≥ 75%
What is an expected finding from arthrocentesis in a gout patient?
Monosodium urate crystals, negatively birefringent and needle shaped
What is the gold standard for evaluating joint crystals?
Polarized light microscopy
What color do MSU crystals appear when parallel to compensator?
Yellow, negatively birefringent
What color do CPPD crystals appear when parallel to compensator?
Blue, positively birefringent
What is an expected finding from arthrocentesis in a patient with pseudogout?
Calcium pyrophosphate dihydrate (CPPD)
-Positively birefringent and rhomboid shaped
