Rheumatology 10 - Poly/Dermatomyositis

Question 1

define polymyositis vs dermatomyositis

Answer 1

polymyositis - muscle inflammation only

dermatomyositis - skin + muscle inflammation

Question 2

key investigation for dermatomyositis

Answer 2

creatinine kinase CK

should be less than 300

Question 3

reasons for raised CK level

Answer 3

rhabdomyolysis 
AKI
heart attack
statin use 
strenous exercise 
AI myositis

Question 4

what can poly/D’myositis be caused by?

Answer 4

underlying cancers

esp lung/breast/ovarian/gastric

Question 5

presentation of polymyositis

Answer 5

muscle pain, fatigue, weakness
bilateral proximal muscle weakness
shoulder + pelvic girdle
develops over weeks

Question 6

presentation of dermatomyositis x6

Answer 6

muscle weakness / pain signs +

Gottron papules (scaly erythematous patches on knuckles, elbows, knees)
photosensitive erythematous rash
purple rash on face and eyelids
swelling around eyes
subcut calcinosis

Question 7

diagnosing poly/dermatomyositis

Answer 7

clinical picture
elevated CK
autoAbs (anti Jo 1)
EMG

definitive-muscle biopsy

Question 8

managing poly/dermatomyositis

Answer 8

assess for underlying malignancy

steroids mainly