Psoriatic Arthritis, Infectious Arthritis and Crystal Arthropathy Flashcards
what % of patients with psoriasis develop psoriatic arthritis
> 10%
what joints does psoriatic arthritis predominantly affect
joints of hands and feet
DIP joints characteristically affected
what other type of arthritis is the histology of psoriatic arthritis similar to
rheumatoid
what joint does infectious arthritis most commonly affect
single joint(usually the knee)
what organism is usually the cause of infectious arthritis in adults and in young children
adults = S. aureus
young children = H. influenza
describe the effect of infectious arthritis on the joint
acutely painful and swollen joint, aspirate purulent fluid
what are the different types of crystal arthropathy
gout(urate metabolism), pseudo-gout(calcium pyrophosphate) and hydroxyapatite(calcium phosphate)
what is necessary for gout to occur but not always sufficient to cause it
hyperuricaemia
give some causes of hyperuricaemia, and therefore gout
high dietary purine intake, HGPRT deficiency, increased cell turnover(psoriasis, cancer etc.)
give some causes of reduced uric acid excretion, and therefore gout
chronic renal disease, thiazide diuretics, hypothyroidism
what joints is gout usually seen in
lower temp. joints, such as toes, fingers
give some precipitating factors for gout
alcohol, obesity, drugs, genetics
describe the effect gout has
causes secondary degenerative changes, deposition in soft tissues(gout tophus) and renal disease
describe the histology of gout at the joints(tophus)
amorphus eosiniophilic inflammation and debris
describe some causes of pseudogout(calcium pyrophosphate)
usually idiopathic, may be hypercalcaemia, haemachromatosis, hypomagnesaemia, ochronsis
what joints is pseudogout usually seen in
knees, wrists, ankles, joints that are already damaged
describe the typical symptoms of pseudogout
usually asymptomatic, but can have chronic or acute joint pain
what is seen on X-ray of pseudo gout
dense deposits
describe what is seen histologically in pseudogout
rhomboid shaped crystals, thicker and bigger than needle shaped urate signals
where do the crystals in pseudogout form
in fibrocartilage, menisci and discs
what are the crystal arthropathies characterised by
deposition of various minerals in the joints and surrounding soft tissues
describe what gout is
potentially disabling and erosive inflammatory arthritis caused by deposition of monosodium urate crystals into joints and soft tissue
what group of people is gout most common in
females, between 20 and 80
what group of people is pseudogout usually seen in
older people
describe the clinical features of acute gout
usually monoarthropathy, abrupt onset often overnight, may have normal uric acid, red, swollen joint, very painful
what clinical features are seen in chronic gout
chronic inflammation of joint, high serum uric acid, tophi, may get acute attacks
what group of people is hydroxyapetite usually seen in
females, 50-60
what joint is most commonly affected by hydroxyappetite
shoulder
(sometimes called “Milwaukee shoulder”
describe the features of hydroxyappetite
hydroxyappetite crystal deposition around joint, acute + rapid deterioration, release of collagenases, serine proteinases + IL-1
