limbs and back week 4 Flashcards
describe the joint capsule
it is connected to the periosteum
lined with synovium
Describe synovium
a few cells think vascular smooth and non-adherent surface permeable to proteins and crystalloids no microscopic gaps able to maintain normal joint fluid under pressure
Describe synoviocytes
macrophage and fibroblast like
cell to cell interactions mediated by cadherin-II
What do synoviocytes do?
secrete hyaluronic acid into the joint same to retain fluid in the joint
Describe synovial fluid
highly viscous, similar consistency to plasma
glycoproteins ensure a low coefficient of friction between the cartilaginous surfaces
What are also lined by synovium?
tendon sheaths and bursae
Does hyaline cartilage have a blood supply?
no it is avascular
where does hyaline cartilage receive its nutrients from?
diffusion of molecules from the synovial fluid
why type of collagen is in cartilage?
type II
what is the structure of hyaline cartilage?
the type II collagen forms a meshwork enclosing giant macromolecules such as keratin and chondroitin sulphate (aggrecans).
These molecules have a negative charge and retain water om the structure
Why is “loading” essential for healthy cartilage?
it encourages the movement of water, minerals and nutrients between the cartilage and the synovial fluid.
What do chondrocytes secrete?
collagen and proteoglycans
What is rheumatoid arthritis?
a progressive inflammatory autoimmune disease with articular and systemic effects
What are common symptoms of RA?
pain and stiffness of the small joints of the hands and feet
the wrists, elbows, shoulders, knees and ankles are also affected
In most cases many joints are involved
When is the pain of RA worse?
significantly worse in the morning
sleep is often disturbed
what do joints with RA look like?
warm and tender with joint swelling
deformities and non-articular features if disease can not be controlled
Describe presentations of RA
palindromic transient remitting chronic persisting - most common rapidly progressive
what are some of the complications of RA?
ruptured tendons ruptured joints (baker's cysts) spinal cord compression joint infection amyloidosis (rare)
What are some of the non-articular manifestations of RA?
soft tissues surrounding the joints can be affected lung problems vasculitis heart and peripheral vessels the nervous system the eyes the kidneys
What are the investigations for RA?
blood count
the ESR and or CRP are raised in proportion to the activity of the inflammatory processes
serology - ACPA is present earlier in the disease (and may predate it by years)
X-rays show soft tissue swelling in early disease
MRI indicates synovitis and early erosions
aspiration - if effusion is present. Aspirate looks cloudy due to presence of leukocytes
doppler ultrasound is a very good way of demonstrating persisting synovitis when deciding on the need of DMARDs or their efficacy
What is the cause of RA?
its exact cause is unknown
genetic and environmental factors contribute
What inflammatory cells are involved in the pathophysiology of RA?
Differentiation of T cells into Th17 - production of Il17
B cells - antibody and cytokine production
mononuclear cells
What are the main cytokines involved in RA?
IL-17, TNF alpha, IL6, IL1
What is the pannus and what does it do in RA?
the osteoclast rich portion of the synovial membrane destroys the bone
What do enzymes secreted by the synoviocytes do?
Degrade the cartilage
What is rheumatoid factor?
the autoantibody that was first found in RA
the antibody against the Fc portion of IgG (an antibody against an antibody)
RF and IgG join to form an immune complex that contributes to the disease pathogenesis
What are the physical measures for the treatment of RA?
constant advice and support from physiotherapists and nurses combination of rest and exercise exercise in hydrotherapy pool advice on managing daily living shoe-wear psychosocial support
What are the surgical options for the treatment of RA?
useful role in long term management
less needed as therapeutics improve
prophylactic objectives - prevent joint destruction
reconstructive -restore function
Describe the drug therapy of RA
There is no curative agent available for RA but drugs are now available that prevent the disease deterioration.
Symptoms are controlled with analgesia and NSAIDs
Describe the use of corticosteroid therapy in RA
there is evidence to suggest that the early use of corticosteroids slows down the course of the disease
corticosteroids are the most common cause of secondary osteoporosis
when treating for extended periods calcium and vitamin D supplements as well as biphosphonates are required
Describe the use of DMARDs in RA treatment
Disease-modifying anti-rheumatic drugs
mainly act through cytokine inhibition reduce inflammation
their beneficial effect is not immediate and may be partial or transient
When are DMARDs used in RA?
As early as possible
