Systemic Lupus Erythematosus

Question 1

What is SLE?

Answer 1

Systemic lupus erythematosus (SLE) is an inflammatory, multisystem disorder with arthralgia and rashes as the most common clinical features and cerebral and renal disease as the most serious problems.

Question 2

What are the factors that predispose one to SLE?

Answer 2

i. Hereditary

ii. Genetics. There is an increased frequency of HLA-BS and DR3 in Caucasians. There is a stronger association with HLA-DR2 in Japanese lupus patients.

iii. Complement. There is an inherited deficiency of C2 and C4 (which has a linkage disequilibrium with HLA-DR3 and DR2).

iv. Sex hormone status. Premenopausal women are affected.

v. Immunological factors- Loss of ‘self’ tolerance has several consequences:
- B cell activation
- Development of and failure to remove immune complexes from the circulation.
- Impaired T cell regulation of the immune system
- Abnormal cytokine production.

vi. Environmental Triggers- Drugs such as hydralazine, methyldopa, isoniazid and D-penicillamine can induce lupus not associated with anti-dsDNA. Flare-ups can be induced ….the contraceptive pill and hormone replacement therapy (HRT). Ultraviolet light is another well recognized trigger. A viral agent causing SLE is a possible etiological factor.

Question 3

Briefly discuss the pathogenicity of SE.

Answer 3

• SLE is characterized by a widespread vasculitis affecting capillaries, arterioles and venules. Fibrinoid is found along blood vessels and tissue fibres.
  -The synovium of the joints may be edematous and also contain fibrinoid deposits which contains immune complexes.
• Hematoxylin bodies are seen in inflammatory filtrates and are thought to result from the interaction of antinuclear antibodies and cell nuclei.

Question 4

What are the general clinical features of SLE?

Answer 4

1. Joint involvement: the most common clinical feature. Patients present with symptoms similar to rheumatoid arthritis
2. The skin: Erythema in butterfly distribution on face, purpura, urticaria, pigmentation, alopecia, rashes on palm and sole, Raynaud phenomenon
3. Lung involvement: recurrent pleurisy and effusions, pneumonitis
4. Heart: pericarditis, myocarditis
5. Kidneys: glomerulonephritis
6. Nervous system: epilepsy, aseptic meningitis, polyneuropathy
7. Eyes: optic neuritis, episcleritis
8. GI system

Question 5

What are the investigative tests for SLE?

Answer 5

1. Blood
   - Full blood count (FBC) usually shows anaemia, leucopenia and thrombocytopenia.
   - The Erythrocyte sedimentation rate (ESR) is raised in proportion to the disease activity.
   - Serum antinuclear antibodies (ANA) are positive in almost all cases
   - Rheumatoid factor is positive in 30-50% of the patients.
   - Serum complement levels are reduced during active disease
   - Serological test for syphilis- a third of patients have a false positive test for syphilis
   - Immunoglobulins are raised (usually IgG and IgM)
2. Histology. Characteristic histological and immunofluorescent abnormalities are seen in biopsies from, for example, the kidney and skin.
3. Diagnostic imaging
   - CT scans of the brain sometimes show infarcts or haemorrhage with evidence of cerebral atrophy.
   - MRI can detect lesions in white matter which are not seen with CT.

Question 6

How is SLE managed?

Answer 6

• Arthralgia, arthritis, fever and serositis all respond well to standard doses of NSAIDs.
• Antimalarial drugs (chloroquine or hydroxychloroquine) help mild skin disease, fatigue and arthralgias that cannot be controlled with NSAIDs.
• Corticosteroids orally or as high-dose intravenous boluses and /or immunosuppressive drugs such as azathioprine or cyclophosphamide are essential for more severe disease and when the symptoms are poorly controlled.

Question 7

The HLEs?