Arthritis, spondyloarthropathies Flashcards
what gene mediates RA
HLA-DR4
pathophysiology of RA?
synovial inflammation and hypertrophy due to unknown cause
APC presents antigen to T cells, activating macrophages and pro inflammatory mediators. also activates B cells which secrete RF to activate osteoclasts to cause bone erosion, chondrocytes to cause cartilage destruction and synoviocytes for hypertrophy
what is the hypertrophied synovium called?
pannus
true/false - smoking has increased risk of RA
true
RF/anti-CCPis more specific for RA
anti-CCP
why would a patient with RA have a raised alk phos
because osteoclast activity causes raised alk phos
what would you see on a typical x ray for RA
soft tissue swelling
periarticular osteopaenia
erosion
RA complications in the hands?
swan necking of fingers
ulnar deviation of MCPs
DAS 28 score of <2.6 is indicative of
remission
DAS 28 score of 2.6-3.2 is indicative of
low activity
DAS 28 score of 3.2-5.1 is indicative of
moderate activity
DAS 28 score of >5.1 is indicative of
active disease
most commonly affected joints of osteoarthritis
hands, knees, hips
pathophysiology of osteoarthritis
localised loss of hyaline cartilage and remodelling of adjacent bone with osteophyte formation at joint margin
thickening of synovium
may lead to synovial thickening, sclerosis and subchondral cyst
risk factors for osteoarthritis
genetics ageing females obesity joint injury occupation joint malalignment reduced muscle strength
what joints are affected in localised OA
hips, interphalangeal joints, facet joints of lower cervical and lower lumbar spines
what joints are affected in generalised OA
spinal/hand joints and at least 2 other regions
DIP, thumb bases, first MTP, lower lumbar and cervical facet, knees and hips
how does OA appear on X ray
marginal osteophytes
loss of joint space
subschondral sclerosis
subchondral cysts
complications of cervical OA
pain
occipital headaches
impinged nerve roots due to osteophytes
complications of lumbar OA
osteophytes can cause spinal stenosis
what mineral causes gout
monosodium urate
what mineral causes pseudogout
calcium pyrophosphate
what mineral causes hydroxyapatite
calcium phosphate
what factors may cause increased urate production in gout
inherited enzyme defects psoriasis haemolytic disorders alcohol high purine diet - high sugar, red meat, seafood
what factors may cause decreased urate excretion in gout
chronic renal impairment volume depletion hypothroidism diuretics cyclosporin
pathophysiology of gout
purines from diet and DNA/RNA converted to xantine, converted to plasma urate and excreted. gout is deposition and precipitation of crystals in joints. causes phagocytosis by monocytes and neurophils. neutrophils rupture to release lysosymes and monocytes secrete pro inflammatory mediators and proteases to cause inflammation/tissue damage
gout is usually a mono/polyarthropathy
monoarthropathy
what is classically seen in chronic gout
tophi
true/false - in acute gout serum urate is always increased
false - not always as it is so sudden onset
if you looked at monosodium urate under a microscope, how would it appear
negatively birefringent needle shape
indications for prophylactic therapy for gout?
2 or more gout attacks in a year gouty trophi uric acid calculi chronic renal impairment heart failure chemotherapy
what type of drugs are allopurol, febuxostat
xanthine oxidase inhibitors
prevent conversion of purine to xanthine
name a few uricosuric drugs and what ypu must always check before prescribing
sulfinpyrazone, proenecid, benzbromazone
check kidney function
true/false - you must start gout prophylaxis during acute attack
no! do it after 2 weeks as if its done too soo it can cause another acute attack
you want to reach the serum urate target in a susceptible patient who has had gout before. she is on allopurol. she hasnt yet reached target serum levels. what other drug must she be on
an NSAID, until serum target reached
what is the serum target for gout
300-360umol/L
what joints does calcium pyrophosphate deposition disease affect
knee, ankle, wrist
calcium pyrophosphate- how does it appear under a microscpe
positively birefringent with rhomboid shape
causes of pseudogout
osteoarthritis age amyloidosis trauma hypothyroidism hyperparathyroidism haemochromatosis
hydroxyapatite - what joint does it affect and what happens
crystal deposition in and around joint, most commonly shoulder
release of collagenases and proteases
acute, rapid deterioration
what is soft tissue rheumatism
localised pain and inflammation/damage to ligaments, tendons, muscles or nerves near joint
what is the most common area for soft tissue rheumatism
shoulder
who is joint hypermobility more common in
women marfans ehlers danlos children under 14
what is modified beighton score
extension of 9 joints to look for hyperextension
+ve if 4 or more joints
what are spondyloarthropathies
inflammatory arthritides with involvement of spine and joints in HLA B27 individuals
mechanical vs inflammatory back pain
mechanical - relief by rest, worse at end of day, worse with activity
inflammatory - worse on rest, better on activity, morning stiffness
shared features of spondyloarthropathies
sacroiliac and spinal involvement inflammatory arthritis enthesitis dactylitis uveitis mucocutaneous lesions no rheumatoid nodules rare aortic incompetence or heart block
features of AS
axial arthritis anterior uveitis aortic regurg apical fibrosis amyloidosis/IgA nephropathy achilles tendinitis plAntar fasciitis
what is tragus to wall
patient to stand with back, buttock and heel to wall. Try to push head against wall. Patients with AS will struggle to do so due to spinal fusion
what is modified schobers test
test for lumbar spinal fusion. Get patient to bend forward without bending knees. Measure 10cm up from dimples of venus and then whilst bending. Should be 15 cm ish
what would an x ray of AS reveal
sacroiliitis
syndesmophytes
bamboo spine
reduced bone density in later disease
what would an x ray of PsA look like
marginal erosion/whiskering
pencil in cup deformity
osteolysis
enthesitis
most common infections causing reactive arthritis
chlamydia
salmonella, shigella, yersina
triad in reactive arthritis
urethritis
conjunctivitis/uveitis
arthritis
what is enteropathic arthritis associated with and where does it occur
IBD
knee, ankle, elbow, wrist, spine, hip, shoulder
