Soft Tissue Disorders Flashcards
SLE - Cause
- Unknown
- Strong genetic component
- Strong association with Anti-nuclear antibodies (ANAs)
SLE - Pathophysiology
Involves 3 processes
- Susceptibility
- Genetic predisposition
- Environmental factors - Autoimmune proliferation
- Hyperactive B/T cell activation
- Defective clearance (apoptotic cells + immune complexes) - Autoantibody production
- Development of autoantibodies + autoreactive T cells
- Apoptosis + self exposure
- Self-recognition + cross reactivity
SLE - Demographics
- Far more common in women (10:1)
- More common in people of African origin
SLE - Clinical Features
Characteristic: Butterfly malar rash after sun exposure
Non-specific: fever + malaise
Organ specific:
- Brain: seizures, psychosis, migraine
- Hands: arthropathy
- Legs: myositis
- Kidneys: Renal failure
- Antiphospholipid syndrome
SLE - Investigations
Lupus band test: specific for SLE
- Band of IgM/IgG at dermoepidermal junction
ANA: active SLE always associated with ANA
FBC, U+Es, Clotting: looking for organ-specific pathology
SLE - Management (overview)
- Patient Education
- Disease Monitoring
- Pharmacological Management
SLE - What do you need to educate patients about
- Reduce sunlight exposure
- Smoking cessation
- Pregnancy (should be planned in advance)
- COCP can exacerbate SLE
SLE - How do you monitor the disease
- Anti-dsDNA antibody titres
- Complement system activation
- ESR
SLE - What pharmacological treatment options are there
- Manage CVD risk
- Analgesia (arthritis)
- Hydroxychloroquine (skin + joints)
- High dose steroids (organ involvement)
- DMARDs (steroid-sparing)
Polymyositis - Definition
Inflammatory myopathy of unknown origin
Dermatomyositis - Definition
Polymyositis + skin inflammation
PM + DM - Demographics
- Dermatomyositis usually occurs in childhood
- Polymyositis usually occurs 40-60yrs
PM + DM - Pathophysiology
- Inflammation in muscles + the vessels that supply them
- Can be associated with an underlying malignancy
- DM also has skin inflammation
PM + DM - Clinical features
- Subacute onset
- Proximal arm + leg weakness
- DM: rash commonly affecting face, trunk + dorsum of hands, lilac coloured rash
PM + DM - Investigations
Biochemical, electrical + histological markers of muscle damage
- Creatinine Kinase: raised in 70%
- EMG: abnormal in nearly all cases
- Muscle biopsy: inflammatory infiltrate + necrosis
Autoantibodies
Screening for malignancies
PM + DM - Management
- Early diagnosis important for muscle conservation
- High dose pred: tapered to symptoms + CK level
- DMARDs (2nd line): for resistant disease
- IV Ig (esp useful for rash)
