Overview of Systemic Lupus Erythematosus (SLE) & MCQs
Definition and Etymology
- SLE, commonly called lupus, is a systemic autoimmune disease affecting multiple
organs.
- The term "systemic" indicates widespread organ involvement.
- "Erythematosus" refers to skin reddening, historically linked to skin lesions.
- "Lupus" is Latin for "wolf," possibly referencing the wolf-like facial rash or the
disease's destructive nature.
- Modern usage encompasses a variety of diseases with skin manifestations
resembling a wolf bite, but primarily refers to a systemic autoimmune condition.
Pathophysiology of Lupus
Lus involves a malfunction of the immune system, which normally protects against
pathogens. In lupus:
Autoimmune response occurs, where immune cells attack the body's own
tissues.
Any tissue or organ can be targeted, leading to widespread damage.
The exact cause remains unclear, but it involves a combination of genetic
predisposition and environmental triggers.
Environmental and Genetic Triggers
Key triggers include:
Ultraviolet (UV) radiation from sunlight, causing DNA damage and apoptosis.
Cigarette smoking, infections (viruses, bacteria), certain medications
(procainamide, hydralazine, isoniazid).
Hormonal factors, especially estrogen, which may explain higher prevalence
in women during reproductive years.
Genetic susceptibility influences how the immune system responds to these triggers.
Mechanism of Disease Development
1. Environmental triggers cause cell damage and apoptosis, releasing nuclear
components (DNA, histones, proteins) into circulation.
1
,2. Genetic factors impair clearance of apoptotic bodies, leading to accumulation of
nuclear antigens.
3. Immune cells recognize these nuclear antigens as foreign, producing antinuclear
antibodies (ANA).
4. These antibodies form immune complexes with nuclear antigens.
5. Complex deposition in tissues activates the complement system, causing
inflammation and tissue damage.
This process is classified as a type III hypersensitivity reaction.
Additional Autoantibodies and Reactions
- Some patients develop antibodies against other cell components:
Red blood cells (causing hemolytic anemia)
Platelets (thrombocytopenia)
White blood cells (leukopenia)
Phospholipids (antiphospholipid syndrome)
- These reactions are often classified as type II hypersensitivity reactions.
- The development of these autoantibodies is not fully understood.
Clinical Presentation and Diagnostic Criteria
Common Symptoms
- Fever, fatigue, loss.
- Classic skin manifestations:
Malar rash: Butterfly-shaped rash over cheeks, sparing nasolabial folds, often
triggered by sun exposure.
Discoid rash: Chronic, plaque-like, scarring rash in sun-exposed areas.
Photosensitivity: Skin rashes or eruptions after sun exposure, usually
transient.
- Mucosal ulcers in the mouth or nose.
- Serositis: inflammation of serous membranes, leading to:
o Pleuritis: lung lining inflammation.
2
, o Pericarditis: heart lining inflammation.
- Joint involvement: arthritis affecting two or more joints.
- Renal issues: proteinuria, glomerulonephritis.
- Neurological symptoms: seizures, psychosis, possibly due to autoantibodies
targeting brain receptors.
- Hematologic disorders: anemia, thrombocytopenia, leukopenia.
Laboratory and Diagnostic Tests
Diagnosis relies on meeting at least 4 of 11 criteria, which include: p>
3. Skin and mucous membrane criteria:
Malar rash
Discoid rash
Photosensitivity
Oral or nasal ulcers
4. Serosal involvement:
Pleuritis
Pericarditis
5. Joint symptoms: arthritis in ≥2 joints.
6. Renal disorder: proteinuria or glomerulonephritis.
7. Neurological disorder: seizures, psychosis.
8. Hematologic abnormalities: hemolytic anemia, leukopenia,
thrombocytopenia.
9. Serological markers:
Antinuclear antibody (ANA): highly sensitive but not specific.
Anti-Smith antibody: specific for lupus.
Anti-dsDNA: correlates with disease activity.
Antiphospholipid antibodies (anticardiolipin, lupus anticoagulant,
anti-beta2 glycoprotein I): associated with clotting disorders.
3
Definition and Etymology
- SLE, commonly called lupus, is a systemic autoimmune disease affecting multiple
organs.
- The term "systemic" indicates widespread organ involvement.
- "Erythematosus" refers to skin reddening, historically linked to skin lesions.
- "Lupus" is Latin for "wolf," possibly referencing the wolf-like facial rash or the
disease's destructive nature.
- Modern usage encompasses a variety of diseases with skin manifestations
resembling a wolf bite, but primarily refers to a systemic autoimmune condition.
Pathophysiology of Lupus
Lus involves a malfunction of the immune system, which normally protects against
pathogens. In lupus:
Autoimmune response occurs, where immune cells attack the body's own
tissues.
Any tissue or organ can be targeted, leading to widespread damage.
The exact cause remains unclear, but it involves a combination of genetic
predisposition and environmental triggers.
Environmental and Genetic Triggers
Key triggers include:
Ultraviolet (UV) radiation from sunlight, causing DNA damage and apoptosis.
Cigarette smoking, infections (viruses, bacteria), certain medications
(procainamide, hydralazine, isoniazid).
Hormonal factors, especially estrogen, which may explain higher prevalence
in women during reproductive years.
Genetic susceptibility influences how the immune system responds to these triggers.
Mechanism of Disease Development
1. Environmental triggers cause cell damage and apoptosis, releasing nuclear
components (DNA, histones, proteins) into circulation.
1
,2. Genetic factors impair clearance of apoptotic bodies, leading to accumulation of
nuclear antigens.
3. Immune cells recognize these nuclear antigens as foreign, producing antinuclear
antibodies (ANA).
4. These antibodies form immune complexes with nuclear antigens.
5. Complex deposition in tissues activates the complement system, causing
inflammation and tissue damage.
This process is classified as a type III hypersensitivity reaction.
Additional Autoantibodies and Reactions
- Some patients develop antibodies against other cell components:
Red blood cells (causing hemolytic anemia)
Platelets (thrombocytopenia)
White blood cells (leukopenia)
Phospholipids (antiphospholipid syndrome)
- These reactions are often classified as type II hypersensitivity reactions.
- The development of these autoantibodies is not fully understood.
Clinical Presentation and Diagnostic Criteria
Common Symptoms
- Fever, fatigue, loss.
- Classic skin manifestations:
Malar rash: Butterfly-shaped rash over cheeks, sparing nasolabial folds, often
triggered by sun exposure.
Discoid rash: Chronic, plaque-like, scarring rash in sun-exposed areas.
Photosensitivity: Skin rashes or eruptions after sun exposure, usually
transient.
- Mucosal ulcers in the mouth or nose.
- Serositis: inflammation of serous membranes, leading to:
o Pleuritis: lung lining inflammation.
2
, o Pericarditis: heart lining inflammation.
- Joint involvement: arthritis affecting two or more joints.
- Renal issues: proteinuria, glomerulonephritis.
- Neurological symptoms: seizures, psychosis, possibly due to autoantibodies
targeting brain receptors.
- Hematologic disorders: anemia, thrombocytopenia, leukopenia.
Laboratory and Diagnostic Tests
Diagnosis relies on meeting at least 4 of 11 criteria, which include: p>
3. Skin and mucous membrane criteria:
Malar rash
Discoid rash
Photosensitivity
Oral or nasal ulcers
4. Serosal involvement:
Pleuritis
Pericarditis
5. Joint symptoms: arthritis in ≥2 joints.
6. Renal disorder: proteinuria or glomerulonephritis.
7. Neurological disorder: seizures, psychosis.
8. Hematologic abnormalities: hemolytic anemia, leukopenia,
thrombocytopenia.
9. Serological markers:
Antinuclear antibody (ANA): highly sensitive but not specific.
Anti-Smith antibody: specific for lupus.
Anti-dsDNA: correlates with disease activity.
Antiphospholipid antibodies (anticardiolipin, lupus anticoagulant,
anti-beta2 glycoprotein I): associated with clotting disorders.
3
