Muskuloskeletal 4 - Systemic Lupus Erythematosis Flashcards
1
Q
What is systemic lupus erythematosus?
Describe epidemiology
A
- Rare disease (3/10000 per GP surgery)
- Difficult diagnosis
- One of a family of overlapping diseases
- Chronic autoimmune disease, M:F 1:9
- Chronic tissue inflammation in the presence of antibodies directed against self antibodies
- Presentation 15-40 years
- Increased in Afrocarribbean, Asian and Chinese populations
- Affects joints and skin mainly, but also lungs, kidneys and haemotology
2
Q
List the autoimmune connective tissue diseases
A
- Rheumatoid arthritis
- Systemic sclerosis
- Polymyositis
- Dermatomyositis
- Sjogrens syndrome
- Systemic lupus erytematosus
3
Q
List genetic associations of systemic lupus erythematosus
A
- Multiple genes implicated
- Complement deficiency (eg. C1q and C3 closely associated (you will develop the disease))
- Fc receptors, IRF5, CTLA4, MHC class II HLA genes (overrepresented in disease)
4
Q
Describe clinical features of systemic lupus erythematosus
A
Presentation
- Malaise, fatigue, fever and weight loss
- Lymphadenopathy
Specific features
- Butterfly rash (affecting the cheeks sparing the nose)
- Alopecia
- Arthralgia
- Raynauds
Other features (severe disease)
- Inflammation of kidney, CNS, heart and lungs
- Accellerated atherosclerosis
- Vasculitis (rash affecting the hands and feet)
5
Q
List the SLE-ACR criteria
A
4 or more out of
- Malar rash
- Discoid rash
- Photosensitivity
- Oral ulcers
- Arthritis
- Serositis: (a) pleuritis or (b) pericarditis
- Renal disorder e.g. proteinuria > 0.5g/24h
- Neurological disorder e.g. seizures/ pyschosis
- Haematological disorder
- Immunologic disorder e.g anti-dsDNA Abs
- Antinuclear antibody in raised titre
6
Q
Describe SLE pathogenesis
A
- Genetic predisposition
- Environmental triggers
- Innate and adaptive immune activation
- Immune complexes and autoantibodies form. Complement mediated autoimmunity causes tissue injury
- Cycle repeats a number of times
- Clinical disease onset
- Associated with abnormal clearance of apoptotic cells (deficient)
7
Q
Describe autoantibody formation in SLE
A
- Abnormal clearance of apoptotic cell material
- Dendritic cell uptake of autoantigens and activation of B cells
- B cell Ig class switching and affinity mutation
- IgG autoantibodies
- Immune complexes
- Complement activation and cytokine generation
8
Q
Describe diagnosis of SLE
A
- Antinuclear antibodies (non specific, pattern important. Looks for presence of antibodies that bind to nuclei)
- Anti-dsDNA (double stranded DNA, present in 90% patients) and anti-Sm (highly specific but less sensitive. 20% patients have smith antibody)
- Anti-Ro and/or La (common in subacute cutaneous LE, neonatal lupus syndrome)
- Increased complement consumption
- Anti-cardiolipin antibodies
- Lupud anticoagulant
- beta 1 glycoprotein
9
Q
Describe the haematology seen in SLE
A
- Lymphopaenia
- Normochromic anaemia
- Leukopaenia
- Autoimmune haemolytic anaemia (schistocytes, spherocytes, anisocytosis, poikilocytosis)
- Thrombocytopaenia
10
Q
Describe renal observations of SLE
A
- Proteinuria
- Haematuria
- Active urinary sediment
11
Q
How is disease severity of SLE assessed?
A
- Identify pattern of organ involvement
- Monitor function of affected organs (renal, lungs/CVS, skin, haemotology, eyes)
- Identify pattern of autoantibodies expressed (anti-dsDNA, anti-Sm and anti-cardiolipin antibodies)
12
Q
List the signs of disease attacks in SLE
A
Clinical features
- Weight loss
- Fatigue
- Malaise
- Hair loss
- Alopecia
- Rash
- Oral ulceration
13
Q
How is SLE divided?
A
Mild
- Joint with/without skin involvement
Moderate
- Inflammation of other organs,
- Pleuritis
- Pericarditis
- Mild nephritis
Severe
- Severe inflammation in vital organs
- Severe nephritis
- CNS disease (depression/psychosis)
- Pulmonary disease
- Cardiac involvement
- Autoimmune haemolytic anaemia, thrombocytopenia, thrombotic thrombocytopenia purpura
14
Q
How is mild SLE treated?
A
- Paracetamol with/without NSAID (monitor renal function)
- Hydroxychloroquine (arthropathy, cutaneous manifestations, mild disease activity)
- Topical corticosteroids
15
Q
How is moderate SLE treated?
A
- Indicated in failure of NSAIDs, and organ/life threatening disease
- Corticosteroids (high initial dose, iv methylprednisolone, initial oral dose for 4 weeks, reduce slowly over 2-3 months to 10mg/d)
