Pathology Flashcards
(116 cards)
Describe connective tissue diseases
Autoimmune conditions - autoantibodies present
Starts an inflammatory process leading to symptoms
May be associated with hypersensitivity
Affects 1-2% of the population
How do connective tissue diseases present
Often with MSK symptoms
Many also come with systemic symptoms
What is rheumatoid arthritis
Inflammation of the joint caused by rheumatoid factor and an autoantibody against Fc IgG
What happens in the acute phase of RA
Pannus formation - granular tissue forms on articular surfaces
Hyperplastic and reactive synovium
How is cartilage affected by RA
It is destroyed by the inflammatory process
This leads to a loss of joint space
What happens in chronic phase of RA
Fibrosis occurs
This can lead to joint deformity
What is SLE
Systemic Lupus Erythema
A systemic autoimmune condition
What is the cause of SLE
Autoantibodies are formed that attack the structural parts of DNA
Most specific is anti-double stranded DNA but may be other types (anti-RO etc)
What are the acute features of SLE
Oedema
Fibrin
Reactive features in the synovial cells
How is uric acid formed in the body
The end product of purine synthesis
So formed in the production of adenine and guanine - during DNA synthesis
What can lead to increased production of uric acid
Idiopathic - unknown enzyme defect Know defect - LN syndrome Increased cell turnover - e.g. psoriasis or cancer Alcohol High dietary purine - red meat etc
What can cause reduced excretion of uric acid
Drug side effects
Common with thiazide diuretics
Hypothyroidism
Chronic renal impairment
What causes gout
Precipitation of urate crystals, usually in joints
This elicits an acute inflammatory response leading to symptoms
What is gouty tophus
Deposition of urate crystals in the soft tissues
The presentation of gout is dependant on the level of urate in the body - true or false
False
Not necessarily related to level, more dependant on the solubility of the crystals
What are some complications of gout
Can cause secondary degenerative changes in the joint
Deposition in soft tissues (gouty tophus)
Can lead to renal disease
How would you diagnose gout
Take an aspirate of joint fluid and examine under a cross polarized light to look for the negatively bifrigent needle shaped crystals
Can also look for raised inflammatory markers and serum uric acid - not specific enough
Link to renal impairment - kidney tests
What causes pseudogout
Deposition of calcium pyrophosphate crystals in the joint
May be associated with hypercalcemia, haemochromatosis, hyperthyroidism etc
Age also contributes
Where does pseudogout usually affect
older individuals
in the large joints
Affects fibrocartilage
What are the symptoms of pseudogout
May present with joint pain
Usually asymptomatic and is an incidental finding on x-ray
Will have raise in inflammatory markers
what do calcium pyrophosphate crystals look like
Rhomboid shaped
Thicker and bigger than urate
What is Paget’s disease of bone
Caused by abnormality of bone turnover
Increase in osteoclastic activity
Get more bone but not normally structured - often weaker but thicker
Can affect all bones
What can cause Paget’s
Unknown
May have genetic component
Can be caused by viral infection
How does Paget’s present
Pain - due to fracture or nerve compression
Enlargement of bones leading to abnormal shape
Increased metabolism – heat in area