Flashcards in Systemic Lupus Erythematosus Deck (21)
What diseases come under the category of ‘connective tissue disease’?
Mixed connective tissue disease
Which gender does SLE more commonly affect?
Describe the presentation of SLE including some specific features.
Malaise, fatigue, weight loss, fever, lymphadenopathy
Long history of Raynaud’s phenomenon
Describe the characteristics of the rash seen in SLE.
It tends to go across the nose
It may look a bit like acne
It is not painful or itchy
Some rashes become depigmented when the inflammation spreads to the dermis (depigmentation and scarring is irreversible)
Describe the pathogenesis of SLE.
SLE patients have a defect in apoptosis
Apoptotic cells are not cleared properly so they persist and expose their nuclear antigens and autoantibodies are generated against these nuclear antigens
The defect in apoptosis is combined with B cell hyperactivity
The overactive B cells are exposed to the nuclear antigens and the plasma cells begin to produce autoantibodies that circulate and form immune complexes
The immune complexes deposit in tissues and activate complement leading to inflammation
What is the first investigation performed in the diagnosis of SLE?
Check for anti-nuclear antibodies (this is not specific for SLE though)
The pattern with which the antinuclear antibodies bind to the nuclear antigens is important in reaching a diagnosis. List some different patterns and the antigens they are associated with.
Homogenous – DNA
Speckled – antibodies to Ro, La, Sm and RNP
Nucleolar – topoisomerase – scleroderma
Centromere – limited cutaneous scleroderma
What conditions are associated with the presence of anti-Ro and anti-La antibodies?
Neonatal lupus syndrome
Subacute cutaneous lupus erythematosus
What are some other tests that can be done for SLE?
Measuring complement levels
Beta 1 glycoprotein
Describe the haematological features of SLE.
SLE is generally associated with low blood counts
Autoimmune haemolytic anaemia
What renal changes might occur in SLE?
Active urinary sediment
List some clinical features that could help pre-empt severe attacks in SLE.
Malaise, weight loss, alopecia, rash
List some laboratory markers that could help pre-empt severe attacks in SLE.
Raised anti-dsDNA antibodies
Reduced complement levels
Describe the differences between mild, moderate and severe disease in SLE.
Mild – skin and joint involvement
Moderate – inflammation of other organs (e.g. pleuritis, pericarditis)
Severe – severe inflammation of vital organs
Describe the treatment of mild disease.
Paracetamol and NSAIDs
Hydroxychloroquine (good for arthropathy and cutaneous manifestations)
Describe the treatment of moderate disease.
Start with a HIGH dose and titre downwards
Describe the treatment of severe disease.
Azathioprine – useful steroid-sparing drug
Has a risk of neutropenia/bone marrow suppression so needs regular blood monitoring
Cyclophosphamide – one used if there is severe organ involvement
Problem – infertility
Name and explain the mechanism of action of two new treatments for severe disease.
Reversible inhibitor of inosine monophosphate dehydrogenase
This is the rate limiting step in de novo purine synthesis
Lymphocytes rely heavily on de novopurine synthesisRituximab
Causes depletion of B cells
Useful in lupus nephritis
SLE has and early peak and a late peak in mortality. What are the usual causes of the two peaks?
Early – renal failure, CNS disease, infection
Late – MI and stroke
What can usually be seen on the blood film of a patient with SLE?
Schistocytes (evidence of microangiopathic haemolytic anaemia)