1 Rheum Labs Flashcards
How might a patient with SLE present?
Woman with Fatigue x 6 months
Intermittent pain and swelling BL hand/fingers and knees x 3-4 months
Occasional sharp chest discomfort with a deep breath
Redness on cheeks
Fingers change colors and become painful when she goes to frozen section of store
ACR criteria for SLE Dx
(4 or more of the following)
Malar rash
Photosensitivity
Polyarthritis
Renal disorders (proteinuria, cellular casts)
Hematologic disorders (anemia, leukopenia, thrombocytopenia)
(+) Anti-DNA (+) anti-SM, (+) antiphospholipid Ab
Discoid rash
Mucosal ulcers
Serosa this (pleuritic or pericarditis)
Neurological disorders (HA, seizures, etc)
(+) ANA
General lab work results for SLE
CBC: Anemia, Leukopenia, and/or Thrombocytopenia
Serum creatinine: elevated with renal dysfunction
U/A: hematuria, proteinuria, cellular casts
LFTs
ESR/CRP: elevated with inflammation
C3 and C4: Low complement levels indicate active lupus
What is the relationship between ANA and SLE?
(+) in >95%
Cardinal feature BUT NOT SPECIFIC
ANA is reported in what 2 parts?
Titer of antibodies with serial dilution (ie 1:40)
Staining pattern of antibodies (homogenous, speckled, nucleoli, centromere)
• Loosely associated with underlying autoimmune disease - not specific
Following a positive ANA in suspected SLE cases, what should you order?
Anti-dsDNA antibodies
Anti-Sm (anti-Smith) antibodies
Antibody that is useful for distinguishing patients with SLE because it is rarely found in other disorders
Anti-dsDNA
Useful in clinical management too b/c often fluctuates with SLE disease activity
Antibody that is detected in 10-50% of SLE patients and generally remains positive, even in remission
Anti-Sm antibody
What are antiphospholipid antibodies?
Anticardiolipin Ab, Beta 2 glycoprotein Ab, Lupus anticoagulant
Present in patients with antiphospholipid syndrome
What is antiphospholipid syndrome?
Primary condition OR in the setting of an underlying disease, usually SLE
Arterial, venous thromboembolic events and RECURRENT FETAL LOSS
How might a patient with Rheumatoid Arthritis present?
40 yo woman with fatigue x 6 months
Intermittent aching and occasional redness and swelling in hands, fingers, and knees x 3-4 months
MORNING STIFFNESS that lasts about 2 hours. Tylenol no help. Ibuprofen minimal help.
No myalgia/weakness
Mild erythema and soft tissue swelling of the PIP and MCP BUT DIPs SPARED
ULNAR DEVIATION at MCPs
Lab results you might see in a patient with RA
ESR: 62 mm/hr (normal <20)
CRP: 4.0 mg/dL (normal 1.0)
CBC w diff: normal except MILD thrombocytosis
ANA: positive at 1:80 with immunofluorescent-stained speckled pattern
Serum uric acid: 3.4 mg/dL (normal)
RF: can be positive OR negative
Test with moderate specificity for RA
Rheumatoid Factor
Associated with several autoimmune/rheumatologist and non-rheumatic diseases, so need to order with antiCCP
Rheumatic diseases associated with Rheumatoid Factor
RA Sjogren syndrome Mixed connective tissue disease SLE Polymyositis or Dermatomyositis
Non rheumatic diseases associated with RF
Bacterial endocarditis Hep B or C TB Sarcoidosis Malignancy Primary biliary cholangitis
What lab is helpful to support dx of RA and is recommended to be ordered together with RF?
Anti-CCP
Testing for antibodies to citrullinated peptides (ACPA) - antibodies against cyclic citrullinated peptides is the most commonly used assay
Specificity for RA is HIGH
How might Sjogren Syndrome present?
49 YO female with fatigue x 6 months
Dry mouth and dry eyes
Recent cavities
Joints and muscles ache diffusely
What labs should you order for Sjogren?
Anti-Ro/SSA
Anti-La/SSB
ANA
ANA is positive for 95% of Sjogren patients. What can you order with it to be more specific for Sjogren?
Anti-Ro/SSA and Anti-La/SSB
Generally 60-80% of patients with primary Sjogren syndrome exhibit one or both of these antibodies
How does polymyalgia rheumatica typically present?
82 yo female with fatigue
Recent onset of aching pain in upper arms, low back, hips, thighs (makes it hard to brush hair)
Morning stiffness for over an hour and with long car rides
Active shoulder ROM decreased bilaterally
What non-specific inflammatory markers should you order if suspecting polymyalgia rheumatica?
ESR/CRP
Characteristic finding in PMR is elevated ESR and/or CRP
Associated with giant cell temporal arteritis
How would fibromyalgia present?
31 yo female with fatigue x 6 months
“Hurt all over” - myalgia and arthralgia
Sleeps 10 hours but wakes up still exhausted
Mind feels “foggy”
PE normal except for multiple tender points
What would you expect lab report to show in fibromyalgia patients?
NORMAL (CBC, ANA, RF, CRP, ESR)
How would you expect ankylosing spondylitis to present?
32 yo male with fatigue x 6 months
Ongoing low back pain and progressive stiffness
Symptoms worse in morning
LBP improves with exercise but worse with inactivity
Hx of plantar fasciitis
