Soft Tissue, Bone & Joint Pathology Flashcards
How many bones are within the skeletal system?
What kind of conditions affect it?
skeletal system is composed of 206 bones interconnected by a variety of joints
affected by circulatory, inflammatory, neoplastic, congenital and metabolic disorders
What is meant by arthritides?
pain and stiffness of a joint and inflammation of the joint
this is not a single disease, but hundreds of diseases that cause pain and stiffness of the musculoskeletal system
What are the 2 different types of arthritis?
acute arthritis:
- pain, heat, redness and swelling in a joint
chronic arthritis:
- e.g. osteoarthritis & rheumatoid arthritis
What is osteoarthritis?
a degenerative joint disease that involves progressive erosion of articular cartilage
this results in the formation of bony spurs and cysts at the margins of joints
What is the cause of osteoarthritis?
Where does it tend to be seen in men and women?
- it is an aging phenomenon with no apparent initiating cause
- associated with underlying systemic diseases such as diabetes and marked obesity
- affects the knees and hands in women and the hip in men
What is meant by secondary osteoarthritis and who tends to be affected?
secondary OA is caused by another disease or condition
it is seen in the knee of basketball players and elbow of baseball players
What is the difference between primary and secondary osteoarthritis?
primary OA:
- also known as idiopathic
- affects joints of one site with no known cause
secondary OA:
- affects a joint at one site and is due to some external or internal injury or disease
What are some common causes of secondary osteoarthritis?
- obesity
- repeated trauma or surgery to joint structures
- abnormal joints at birth (congenital abnormalities)
- gout
- rheumatoid arthritis
- diabetes
- other hormone disorders
What is involved in the pathogenesis of osteoarthritis?
deterioration or loss of cartilage that acts as a protective cushion in between the bones
as the cartilage is worn away, the bone forms spurs
fluid-filled cysts form in the marrow (subchondral cysts)
this results in pain and limitation of movements
What cells are involved in the pathogenesis of osteoarthritis?
- chondrocytes produce interleukin-1 which initiates matrix breakdown
- prostaglandin derivatives induce the release of lytic enzymes, which prevents matrix synthesis
Which joints tend to be affected by primary osteoarthritis?
How can it be recognised on the fingers?
- caused by abnormal stresses in weight-bearing joints
- affects fingers, knees and cervical and lumbar spines
- involvement of the fingers sees Herberden’s or Bouchard’s nodes
What is rheumatoid arthritis and what structures are implicated in this condition?
a chronic systemic disorder which principally affects the joints
it produces a non-suppurative proliferative synovitis leading to destruction of articular cartilage and ankylosis of joints
it also affects the skin, muscles, heart, lungs and blood vessels
Are women or men more likely to be affected by rheumatoid arthritis?
women are 3-5 times more likely to be affected than men
What is ankylosis of the joints?
stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint
this may be the result of injury or disease
What is shown here?
a normal joint with thin synovium
What is the first stage in development of rheumatoid arthritis?
polypoid fibrovascular thickening of the synovium with synoviocyte hyperplasia
this produces a pannus that is eroding into the articular cartilage
What is the second stage in the development of osteoarthritis?
continued growth of the pannus and erosion of the cartilage with penetration into the subchondral bone and cyst formation
What is the third stage in the development of rheumatoid arthritis?
filling of the joint space with pannus, producing ankylosis of the joint space
this is rheumatoid arthritis
What are the clinical features of rheumatoid arthritis?
How fast is disease course?
Which joints are frequently affected?
- starts with malaise, fatigue and generalised musculoskeletal pain
- involved joints are swollen, warm, painful and stiff in the morning or after activity
- slow or rapid disease course which fluctuates over 4-5 years
- small joints of the hands and feet are frequently affected, producing a deformed joint
What is involved in the pathogenesis of rheumatoid arthritis?
- genetic susceptibility 65-80% - HLA DR4 & DR1 or both
- primary exogenous arthritogen is EBV (or other viruses), Borrelia
- autoimmune reaction within the synovial membranes involves CD4+ T-cells
- mediators of joint damage are cytokines IL 1-6 and TNF-a and TNF-b
What are the criteria for the diagnosis of rheumatoid arthritis?
- morning stiffness
- arthritis in 3 or more joint areas
- arthritis of hand joints
- symmetric arthritis
- rheumatoid nodules
- serum rheumatoid factor
need 4 of the above criteria for diagnosis
also look for typical radiographic changes of narrowing of the joint space and loss of articular cartilage
What tests are performed in the diagnosis of rheumatoid arthritis?
- rheumatoid factor is present in most but not all patients and is less specific
- analysis of synovial fluid to confirm the presence of neutrophils (inflammatory picture)
What other organs are involved in rheumatoid arthritis?
- skin - rheumatoid nodules are the commonest cutaenous manifestation in areas of pressure
- lungs, spleen, heart, other viscera
What feature of rheumatoid arthritis is visible here?
palisaded granulomata
What is meant by sero-negative arthritides?
What are the 4 main conditions?
rheumatoid factor is usually negative in these conditions
- ankylosing spondylitis
- Reiter’s syndrome
- psoriatic arthritis
- enteropathic arthritis
What is gout?
What causes it?
it is the end-point of a group of disorders producing hyperuricemia
uric acid is the end product of purine metabolism
in gout, there is a deficiency of the enzymes involved in this process
What are the clinical features of gout?
- acute arthritis
- chronic arthritis
- tophi in various sites
- gouty nephropathy
How does someone with gout usually present?
What kind of attacks would they describe?
transient attacks of acute arthritis
crystallisation of urates within and about the joints leads to chronic gouty arthritis
and deposition of masses of urates in joints and other sites, producing tophi
What is shown here?
gout
What is pyogenic osteomyelitis?
What symptoms does it produce?
an inflammation of bone caused by an infecting organism
(most commonly Staphylococcus aureus)
it produces systemic illness with fever, malaise, chills and marked pain over the affected region
What tests are performed for pyogenic osteomyelitis and what would the findings be?
- X-ray - lytic focus of bone destruction surrounded by zone of sclerosis
- blood cultures are positive
- biopsy shows sheets of neutrophils
What is pyogenic osteomyelitis caused by?
How does this happen?
it is caused by bacteria and can occur via:
- haematogenous spread
- extension from a continguous site
- direct implantation