Rheumatoid Arthritis Pathophysiology (signs and symptoms)

Summary

This educational video delves into rheumatoid arthritis, a systemic disorder affecting multiple joints with symmetrical arthritis as a hallmark. It differentiates hand involvement in rheumatoid arthritis from osteoarthritis, highlighting characteristic deformities like boutonniere and swan neck. The script explores the cellular and molecular underpinnings, including synovitis, angiogenesis, and the role of cytokines and immune cells. It also discusses rheumatoid factor and anti-citrullinated protein antibodies, crucial for diagnosis, and the extra-articular impacts on organs, emphasizing the disease's systemic nature.

Takeaways

• 🤕 Rheumatoid arthritis is a systemic rheumatological disorder affecting multiple joints, characterized by symmetrical arthritis with pain, swelling, and nodules.
• 👐 Early hand involvement in rheumatoid arthritis typically affects the metacarpal phalangeal and proximal interphalangeal joints, differing from osteoarthritis which affects the distal interphalangeal joints.
• 🔍 As rheumatoid arthritis progresses, it can lead to deformities such as swan neck, boutonniere, and Z-thumb, and may also cause ulnar deviation of the hands.
• 🧬 The pathophysiology of rheumatoid arthritis involves inflammation of the synovial membrane (synovitis), leading to bone and cartilage erosion, and is associated with angiogenesis.
• 🔬 At the cellular level, rheumatoid arthritis involves various immune cells, including macrophages, fibroblast-like synoviocytes, T cells, plasma cells, and neutrophils, which contribute to inflammation and tissue damage.
• 💉 The activation of fibroblast-like synoviocytes and the secretion of proteases lead to cartilage degradation, and these cells can migrate to cause symmetrical arthritis.
• 🏠 T cells play a significant role by promoting inflammation, secreting interleukin-17, and contributing to the expression of RANKL, which stimulates osteoclast activity for bone erosion.
• 🌐 The exact trigger of rheumatoid arthritis is unknown, but theories include genetic factors, epigenetic modifications, smoking, and bacterial infections that may lead to modification of autoantigens.
• 🏥 Antibodies such as rheumatoid factor and anti-citrullinated protein antibodies are important for diagnosing rheumatoid arthritis and contribute to the disease's pathophysiology.
• 🌐 Extra-articular involvement in rheumatoid arthritis can affect various organs due to increased inflammatory cytokines, leading to issues like skin nodules, liver inflammation, cardiovascular problems, neurological issues, and bone marrow involvement.
• 👋 The video concludes by highlighting the complexity of rheumatoid arthritis, covering clinical manifestations, hand involvement, pathophysiology, potential causes, and extra-articular manifestations.

Q & A

What is rheumatoid arthritis?

Rheumatoid arthritis is a systemic rheumatological disorder that affects multiple joints, characterized by symmetrical arthritis with pain, swelling, and nodules around the affected areas.

How does rheumatoid arthritis affect the hands?

Rheumatoid arthritis affects the hands by causing involvement of the metacarpal phalangeal and proximal interphalangeal joints early in the disease, leading to deformities such as swan neck, boutonniere, and Z deformity of the thumb.

What is the difference between the joint involvement in rheumatoid arthritis and osteoarthritis?

In rheumatoid arthritis, the proximal interphalangeal and metacarpal phalangeal joints are primarily affected, while in osteoarthritis, the distal interphalangeal joints are commonly affected along with the proximal interphalangeal joints.

What is synovitis and why is it significant in rheumatoid arthritis?

Synovitis is the inflammation of the synovial membrane, which is significant in rheumatoid arthritis as it leads to pain, swelling, and eventually bone and cartilage erosion.

What role do fibroblast-like synoviocytes play in the pathogenesis of rheumatoid arthritis?

Fibroblast-like synoviocytes, when stimulated, become activated, proliferate, and secrete proteases that cause cartilage breakdown. They also contribute to bone erosion by stimulating osteoclast activity through RANKL expression.

How do T cells contribute to the inflammation in rheumatoid arthritis?

T cells promote inflammation by secreting cytokines such as interleukin-17, which stimulates macrophage activity and fibroblast-like synoviocyte proliferation, as well as contributing to RANKL expression for bone erosion.

What is the significance of angiogenesis in rheumatoid arthritis?

Angiogenesis, the formation of new blood vessels, occurs in the joints of rheumatoid arthritis patients and contributes to inflammation by increasing vascular permeability and allowing immune cells to migrate into the joints.

What are the two main antibodies found in rheumatoid arthritis and their roles?

The two main antibodies are rheumatoid factor, an IgM antibody that targets the Fc portion of IgG antibodies forming immune complexes, and anti-citrullinated protein antibody, which targets citrullinated proteins, both contributing to the inflammation and pathophysiology of rheumatoid arthritis.

What is citrullination and how does it relate to rheumatoid arthritis?

Citrullination is the conversion of arginine residues to citrulline in proteins, making them seem foreign to the immune system. This modification of autoantigens can trigger an immune response, contributing to the development of rheumatoid arthritis.

What are some of the extra-articular manifestations of rheumatoid arthritis?

Extra-articular manifestations of rheumatoid arthritis include skin nodules, increased CRP and hepatin production leading to anemia, cardiovascular issues such as atherosclerosis, neurological issues like fatigue and depression, and musculoskeletal problems including osteopenia and muscle weakness.

How do the cytokines produced in rheumatoid arthritis joints affect other organs in the body?

Cytokines like TNF alpha, interleukin-1, and interleukin-6 produced in the joints can enter the bloodstream, contributing to inflammation and various issues in organs such as the skin, liver, cardiovascular system, and nervous system.