Definition
Systemic Connective Tissue Disease
Chronic inflammatory disease resulting from abnormal immunoregulation
Aetiology
Unknown
Thought similar to RA
1. Genetic factors
2. Environmental factors
Epidemiology
Young females
F:M 9:1
Peak 35 years old
Geographic variations
- more common in black and asian populations
Clinical Features
Affects many organ systems
- bones / joints / tendons / skin
- heart / kidney / CNS
Systemic
- malaise / fever / anorexia / weight loss
- skin rashes / photosensitive butterfly rash
- Reynaud's Phenomenon / peripheral vasculitis
- splenomegaly
- largest cause of mortality is CRF
Joint involvement
Presenting complaint in >90%
- red swollen joints
- usually involves small joints & knees
- symmetrical involvement
Morning stiffness in 50%
Longstanding disease may produce RA like deformity
AVN
Predisposes to bone ischaemia
- aggravated by steroids
- classically in talus
DDx RA
1. No ankylosis or contractures
2. No erosive changes on xray
3. Less destructive than RA
Investigations
ANA positive / antinuclear antibodies
- screening tool
- positive in other CT diseases and normal people
dsDNA / anti double stranded DNA
- highly specific for SLE
C3/C4
- low levels complement secondary to consumption
antie-ENA / anti extractable nuclear antigen
Elevated ESR
Anaemia / Leucopaenia / Thrombocytopaenia
Management
Medical
Avoid sunlight as it exacerbates symptoms
Options
NSAIDS
Steroids
Cyclophosphamide
DMARDS
Anti-immune as per RA
IV immunoglobulin
Arthroplasty
Higher risk of deep infection