Rheumatology - Important Ix Flashcards
1
Q
Rheumatoid factor: what is it? Do these patients have better or more severe disease?
A
- RF is antibody against the Fc fragment of human IgG
- Seropositive pts (RF+) have more severe rheumatoid arthritis
- Doesn’t rise during disease flare
2
Q
Anti-CCP
-What is it and when is it useful?
A
- Anti-cyclic citrullinated peptide antibody
- More specific in RA than RF
- Doesn’t rise during disease flares
3
Q
What is an ANA?
A
- Antibodies to nuclear antigens
- Most commonly suggestive of SLE
4
Q
What ANA subtypes are associated with diseases?
A
- Anti-dsDNA: SLE
- Anti-Ro and Anti-La: SLE, Sjogren’s
- Anti centromere and anti Scl70: Systemic sclerosis
- Anti-Jo-1: polymyiositis
- Anti DsDNA is the only rise with disease activity
5
Q
What happens to complements C3 and C4 during SLE flares?
A
-They fall :(
6
Q
What are ANCAs?
A
- Anti-neutrophil cytoplasmic antibodies
- Abs direct against enzymes present in neutrophils
- Found in vasculitis
7
Q
What is C ANCA and when is it found?
A
Antibody to proteinase -3
-Found in GPA (Wegener’s granulomatosis), infection and neoplasia
8
Q
What is P ANCA and when is it found?
A
- Antibody to myeloperoxidase
- Found in microscopic polyangiitis and neoplasia
9
Q
What is HLA B27 and why is it important?
A
- Class 1 surface antigen found in 10% of white people
- Strong association with Ankylosing Spondylitis - 90% of pts with AS are HLA27 +ve
10
Q
What blood tests should you perform?
A
- FBC: Hb, platelets, neutrophils, lymphocytes, -U&Es
- Uric acid: gout
- LFTs: DMARD toxicity
- CK, ALT, LDH: rise in myosotis
11
Q
What other Ix can you perform (apart from bloods)
A
- Urinalysis: SLE/vasculitis cause protein/blood in urine
- Synovial fluid analysis
- Biopsy: CGA
- X-ray
- US
- DEXAMETHASONE scan: evaluation for osteoporosis
