SLE - finished

Question 1

Define SLE

Answer 1

A progressive (often severe) autoimmune condition characterised by the presence of a large number of autoantibodies, which involves multiple systems.

Question 2

Main tissues affected in SLE?

Answer 2

Skin
Joints
Kidneys
Serosal membranes

Question 3

Epidemiology of SLE?

Answer 3

90% are female
Onset = 20-40
Caucasian

Question 4

How do ANA’s invoke an inflammatory response?

Answer 4

ANA’s attach to their target antigen (ds-DNA most specific for SLE), and thus an immune complex is formed.
These immune complexes are detected in the serum or at sites of active disease eg
- walls of small blood vessels
- skin
- glomerular basement membrane

Deposition of the immune complexes in these sites results in complement activation and inflammation

Serum complement levels are decreased during active phases of the disease

Question 5

How is B-cell hyperactivity implicated in SLE?

Answer 5

Polyclonal B cell activation results in the secretion of increased amounts of both self and non self antibodies.

Hypergammaglobulinaemia results from the excess antibodies

Question 6

What is cellular damage in SLE mediated by? (2)

Answer 6

Immune complex mediated inflammation
Direct action on autoantibodies on cells
e.g. Anti-RBC antibodies

Question 7

What are the 6 main clinical presenting ssx of SLE?

Answer 7

Slutty present Are My Fav, SRS (Seriously)

Arthritis
Malar rash
Fever
Sun sensitivity
Raynauds phenomenon
Serositis

Question 8

Pathogenesis of SLE

Answer 8

Genetically susceptible individual in exposed to an environmental trigger.

This causes CD4 T Helper Cells to become reactive to self antigens and activate B cells to synthesise antibodies which target self antigens.

IgG autoantibody productions (ANA’s)

This results in various autoantibody mediated clinical manifestations

Question 9

What are the clinical manifestations of SLE?

Answer 9

SLuttiness can give you MANsions SLASH RICHes

Small blood vessel vasculitis:

• as a result of immune complex deposition and subsequent complement activation in small blood vessels, which may result in thrombosis, ischaemia and tissue necrosis
• Arterioles commonly affected = skin, pleura, GIT, CNS, Kidney, Heart
• Typical manifestations of vasculitis include GIT bleeding, diarrhoea and digital gangrene

Lymphoid system hyperplasia (50% of pts):

• Due to lymphocyte proliferation
• Lymphadenopathy and splenomegaly are typically seen.

Skin Inflammation/Involvement:

• Immune complex deposits in the basement membrane of the skin.
  
  • skin rash (malar rash)
  • skin atrophy
  • hyperkeratosis
  • Raynauds phenomenon
  • skin ulceration
• • skin rash is seen in 70% of patients at some point
• • in DLE, immune complex is limited to the area covered by the rash where as in SLE immune complexes can we isolated from non-rash areas
• • rash may be precipitated by sun exposure

Arthritis (90% pts):

• non erosive (no pannus) = arthralgias
• may have tendon contractures (<10%)
• involves small and large joints
• joint involvement often mild
• fingers, wrist (50%) knees and toes most commonly affected (may resemble RA in early stages)

Heart involvement:
- pericarditis, myocarditis or endocarditis (rarely serious)

CNS involvement (25%):

• cause not well understood - possible antibody damage to vascular endothelium, possible antibody causing dysfunction of neurons
• can observe: dementia, psychiatric disorders, migrane, convulsions, CN palsies, SC dysfunction

Renal involvement (66%):

• most common cause of death
• immune complex deposition causes glomerulonephritis

Serositis:
Pericarditis
Pleuritis

Haematological involvement:

• Haemorrhagic diathesis
• Thrombocytopaenia
• Haemolytic anaemia
• Neutropaenia (increased risk of infections)

Question 10

List some areas affected by SLE

Answer 10

Skin
GIT
Heart
Kidneys
Serosal membranes
Jointa
CNS
Blood vessels
Blood
Lymphoid tissue

Question 11

List the top 6 most prevalent clinical features of SLE

Answer 11

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Haemotologic
Arthritis
Skin
Fever
Fatigue
Weight loss

Question 12

Outline the process of diagnosis of SLE

Answer 12

At least 4 of the following must occur simultaneously:

Renal
Ana positive
Serositis
Haemotological

Oral ulcers
Neuro changes

Malar rash
Arthropathies/arthritis
Immune disorders
Discoid rash
Sunlight sensitivity

RASH ON MAIDS = 90% FEMALE