Systemic lupus erythematosus (SLE)

Question 1

Give a short description of the condition

Answer 1

An inflammatory, autoimmune, multi-system disorder with arthralgia and rashes as the most common clinical features and with renal and cerebral disease as the most serious complications

Question 2

What demographics are at the greatest risk?

Answer 2

10:1 ratio of pre-menopausal women to men
2:1 ratio of girls and post-menopausal women to men
Afro Caribbean women are affected the most - ethnic prevalence

Question 3

What are the predisposing factors for developing SLE?

Answer 3

Susceptibility genes
Oestrogen
Drugs - hydralazine, isoniazid, procainamide
UV light
EBV

Question 4

Describe the pathogenesis of SLE

Answer 4

Environmental trigger leading to apoptosis
Release of material from cell
Reduced clearance - genetic factor in SLE #1
Material from nucleus as a result from apoptosis become nuclear antigens
This is recognised as foreign - genetic factor in SLE #2
Antinuclear antibodies form because of an immune response to the perceived foreign bodies
Deposition in tissues - inflammation
This inflammation leads to symptoms - type 3 hypersensitivity reaction
In addition some patients develop antibodies to RBCs, WBCs and phospholipids
These then get phagocytosed, leading to further symptoms - type 2 hypersensitivity reaction

Question 5

What are the general clinical features of SLE?

Answer 5

Fever
Joint pain - similar to RA but is non-erosive
Skin - malar (butterfly) rash, discoid rash (erythematous plaque rash leading to scarring and pigmentation), general photosensitivity rashes
Myalgia

Question 6

What organs and organ systems can be affected by SLE other than the skin?

Answer 6

Lungs, heart, kidneys, brain, gastrointestinal system, eyes

Question 7

How does SLE affect the lungs?

Answer 7

Pleurisy
Bilateral exudative pleural effusions
Pneumonitis
Atelectasis
All resulting in a restrictive lung defect (loss of lung volumes, raised hemidiaphragms)

Question 8

How does SLE affect the heart?

Answer 8

Pericarditis leading to pericardial effusions
Myocarditis leading to arrhythmias
Non-infective endocarditis involving the mitral valve

Question 9

How does SLE affect the kidneys?

Answer 9

Lupus nephritis

Question 10

How do we screen and monitor for symptoms of lupus nephritis?

Answer 10

Regular screening for proteinuria and haematuria
Patients can be asymptomatic with proteinuria - early stages of nephritis
Renal biopsy to identify type and severity of renal involvement

Question 11

How does SLE affect the brain?

Answer 11

Ranging from depression to severe psychiatric disorders
Strokes
Polyneuropathy
Seizures
Symptoms fluctuate

Question 12

How does SLE affect the GI system?

Answer 12

Mouth ulcers are common

Question 13

How does SLE affect eyes?

Answer 13

Retinal vasculitis

Question 14

What investigations are needed?

Answer 14

FBC
U&E
Autoantibodies

Question 15

What would be found in an FBC?

Answer 15

Potential leucopenia, lymphopenia or thrombocytopenia depending on what antibodies are attacking which blood cells
Anaemia of chronic disease
ESR is raised in proportion to disease activity
CRP is raised in flare ups involving infection/arthritis etc so not useful

Question 16

What would be found on U&E?

Answer 16

Urea and creatinine only raised when renal disease is severe

Reduced serum albumin or increased urine albumin to creatinine ratio are early indicators of lupus nephritis

Question 17

What can be interpreted from the various antibodies that might be looked for?

Answer 17

ANA - sensitive not specific
Anti-dsDNA - tend to remain high even in clinical remission and is more specific
Anti-Ro
Anti-Sm- more specific
Anti-La

Question 18

What general measures are used in management?

Answer 18

Avoid sunlight

Address CVS risk factors

Question 19

How are symptoms treated?

Answer 19

Arthralgia, arthritis, fever and serositis all respond to normal doses of NSAIDs

Question 20

How are flare-ups managed?

Answer 20

Corticosteroids and immunosuppressive drugs

Question 21

Give two unusual complications of SLE

Answer 21

Neonatal lupus syndrome

Antiphospholipid syndrome

Question 22

Describe neonatal lupus syndrome

Answer 22

A combination of rash, hepatitis and foetal heart block

A 2% chance when pregnant mothers have anti-Ro or anti-La antibodies