Systemic lupus erythematosus (SLE) - causes, symptoms, diagnosis & pathology

Summary

Systemic lupus erythematosus (SLE) is an autoimmune disease where the immune system attacks the body’s own tissues, often triggered by environmental factors like UV radiation. The disease causes inflammation and damage to various organs, including the skin, kidneys, heart, and joints. Key symptoms include rashes, joint pain, and organ-specific issues, often accompanied by the presence of antinuclear antibodies. Diagnosis can be challenging, requiring the presence of specific clinical criteria. Treatment focuses on managing flare-ups and preventing complications, using methods like corticosteroids, immunosuppressants, and lifestyle changes to avoid triggers such as sunlight.

Takeaways

• 😀 Lupus is an autoimmune disease where the immune system attacks the body’s own tissues, leading to inflammation and damage in various organs.
• 😀 The term 'lupus' comes from Latin, meaning 'wolf,' likely referring to the rash resembling a wolf bite on the skin.
• 😀 Lupus can affect multiple organs, but commonly involves the skin, joints, kidneys, heart, and nervous system.
• 😀 The immune system mistakenly targets nuclear components (like DNA and histones) released during cell death, causing immune complexes to form and damage tissues.
• 😀 Environmental triggers, such as UV radiation, infections, certain medications, smoking, and hormones (especially estrogen), can contribute to lupus flare-ups.
• 😀 A genetic predisposition plays a role in lupus, with certain genes making individuals more susceptible to the disease.
• 😀 Common symptoms include a butterfly-shaped rash on the face, joint pain, kidney problems, chest pain, and neurological issues like seizures or psychosis.
• 😀 Lupus is diagnosed when 4 out of 11 diagnostic criteria are met, including rashes, arthritis, kidney issues, blood abnormalities, and specific antibodies.
• 😀 Antinuclear antibodies (ANA) are common in lupus, but more specific antibodies like anti-Smith and anti-dsDNA are associated with active disease.
• 😀 Treatment for lupus includes managing flare-ups with corticosteroids, immunosuppressive drugs, and lifestyle changes such as avoiding sunlight to prevent triggers.
• 😀 Antiphospholipid antibodies in lupus can cause a hypercoagulable state, leading to an increased risk of blood clots and conditions like stroke or deep vein thrombosis.

Q & A

What is systemic lupus erythematosus (SLE) and how does it affect the body?

Systemic lupus erythematosus (SLE), commonly referred to as lupus, is an autoimmune disease where the body's immune system attacks its own tissues. It primarily affects multiple organs, including the skin, kidneys, joints, and heart, leading to inflammation and tissue damage.

What does the term 'erythematosus' refer to in systemic lupus erythematosus?

'Erythematosus' refers to the reddening of the skin, which is a common symptom in lupus, where lesions or rashes often appear, particularly in sun-exposed areas.

Why is lupus often referred to as 'wolf' in Latin, and does it relate to the skin lesions?

The term 'lupus' comes from the Latin word for 'wolf.' It is believed that early descriptions of lupus referred to the skin lesions resembling wolf bites, but this is more of a historical explanation and not necessarily a definitive cause.

How does the immune system contribute to the development of lupus?

In lupus, the immune system mistakenly attacks the body’s own tissues due to the presence of nuclear antigens released during cell death. These antigens trigger an immune response, producing antibodies that form immune complexes, which deposit in various organs and cause inflammation.

What role do UV radiation and genetic susceptibility play in triggering lupus?

UV radiation, such as from sunlight, can cause cellular damage that leads to cell death and the release of nuclear antigens. For individuals with certain genetic predispositions, this can trigger the immune system to attack these antigens, potentially leading to lupus development.

What is the significance of antinuclear antibodies (ANAs) in lupus diagnosis?

Antinuclear antibodies (ANAs) are a hallmark of lupus and are present in most cases. They are antibodies that target the body's own nuclear components. While ANA tests are sensitive for lupus, they are not specific, as these antibodies can also appear in other autoimmune diseases.

What is the relationship between lupus and sex hormones, particularly estrogen?

Lupus is more common in women, especially during reproductive years, which suggests that sex hormones, particularly estrogen, may play a role in increasing the risk. Estrogen may influence immune system function, contributing to the higher incidence in women.

What are the key diagnostic criteria for lupus?

Lupus diagnosis requires meeting at least four out of eleven diagnostic criteria. These include skin rashes (malar and discoid), photosensitivity, oral ulcers, arthritis, kidney problems, neurological symptoms, and specific blood test results like ANA and anti-dsDNA antibodies.

How does the complement system contribute to the tissue damage seen in lupus?

The complement system is activated by immune complexes formed by antinuclear antibodies binding to nuclear antigens. This activation causes an inflammatory response, which damages tissue by creating channels in cell membranes, leading to cell death.

What treatments are commonly used to manage lupus flare-ups?

To manage lupus, patients are often advised to avoid UV exposure and use sun protection. During flare-ups, corticosteroids may be prescribed to reduce inflammation, and in severe cases, immunosuppressive drugs may be used to control the immune response. Additionally, patients with antiphospholipid syndrome may require anticoagulation therapy to prevent blood clots.