Psoriatic Arthritis, Infectious Arthritis and Crystal Arthropathy

Question 1

what % of patients with psoriasis develop psoriatic arthritis

Answer 1

> 10%

Question 2

what joints does psoriatic arthritis predominantly affect

Answer 2

joints of hands and feet

DIP joints characteristically affected

Question 3

what other type of arthritis is the histology of psoriatic arthritis similar to

Answer 3

rheumatoid

Question 4

what joint does infectious arthritis most commonly affect

Answer 4

single joint(usually the knee)

Question 5

what organism is usually the cause of infectious arthritis in adults and in young children

Answer 5

adults = S. aureus

young children = H. influenza

Question 6

describe the effect of infectious arthritis on the joint

Answer 6

acutely painful and swollen joint, aspirate purulent fluid

Question 7

what are the different types of crystal arthropathy

Answer 7

gout(urate metabolism), pseudo-gout(calcium pyrophosphate) and hydroxyapatite(calcium phosphate)

Question 8

what is necessary for gout to occur but not always sufficient to cause it

Answer 8

hyperuricaemia

Question 9

give some causes of hyperuricaemia, and therefore gout

Answer 9

high dietary purine intake, HGPRT deficiency, increased cell turnover(psoriasis, cancer etc.)

Question 10

give some causes of reduced uric acid excretion, and therefore gout

Answer 10

chronic renal disease, thiazide diuretics, hypothyroidism

Question 11

what joints is gout usually seen in

Answer 11

lower temp. joints, such as toes, fingers

Question 12

give some precipitating factors for gout

Answer 12

alcohol, obesity, drugs, genetics

Question 13

describe the effect gout has

Answer 13

causes secondary degenerative changes, deposition in soft tissues(gout tophus) and renal disease

Question 14

describe the histology of gout at the joints(tophus)

Answer 14

amorphus eosiniophilic inflammation and debris

Question 15

describe some causes of pseudogout(calcium pyrophosphate)

Answer 15

usually idiopathic, may be hypercalcaemia, haemachromatosis, hypomagnesaemia, ochronsis

Question 16

what joints is pseudogout usually seen in

Answer 16

knees, wrists, ankles, joints that are already damaged

Question 17

describe the typical symptoms of pseudogout

Answer 17

usually asymptomatic, but can have chronic or acute joint pain

Question 18

what is seen on X-ray of pseudo gout

Answer 18

dense deposits

Question 19

describe what is seen histologically in pseudogout

Answer 19

rhomboid shaped crystals, thicker and bigger than needle shaped urate signals

Question 20

where do the crystals in pseudogout form

Answer 20

in fibrocartilage, menisci and discs

Question 21

what are the crystal arthropathies characterised by

Answer 21

deposition of various minerals in the joints and surrounding soft tissues

Question 22

describe what gout is

Answer 22

potentially disabling and erosive inflammatory arthritis caused by deposition of monosodium urate crystals into joints and soft tissue

Question 23

what group of people is gout most common in

Answer 23

females, between 20 and 80

Question 24

what group of people is pseudogout usually seen in

Answer 24

older people

Question 25

describe the clinical features of acute gout

Answer 25

usually monoarthropathy, abrupt onset often overnight, may have normal uric acid, red, swollen joint, very painful

Question 26

what clinical features are seen in chronic gout

Answer 26

chronic inflammation of joint, high serum uric acid, tophi, may get acute attacks

Question 27

what group of people is hydroxyapetite usually seen in

Answer 27

females, 50-60

Question 28

what joint is most commonly affected by hydroxyappetite

Answer 28

shoulder

(sometimes called “Milwaukee shoulder”

Question 29

describe the features of hydroxyappetite

Answer 29

hydroxyappetite crystal deposition around joint, acute + rapid deterioration, release of collagenases, serine proteinases + IL-1