Inflammatory Myopathies

Question 1

Common clinical findings in inflam myopathies

Answer 1

• Symmetric muscle weakness (PM and DM is proximal IBM is distal)
• Elevated levels CK (PM and DM > IBM
• Abnormal EMGs

Question 2

12% occur with malignancy what types?

Answer 2

breast CA, adenocarcinoma

Question 3

heart involvement with….

Answer 3

conduction abnormalities and arrhythmias, myocarditis, and CAD

Question 4

GI involvement with …

Answer 4

Decreased the motility

-weakness of tongue, pharyngeal muscles, esophagus, constipation, diarrhea and stomach pain

Question 5

What are the genetic predisposition to inflamm myopathies

Answer 5

HLA-DRB1 and -DQA1

Question 6

General pathogenesis assc with inflamm myopathies

Answer 6

(1) Cytokines + autoAbs + complement → endothelium damage → hypoxia → capillary loss
(2) Cytokines + CD8 T cells → ER stress → myofiber damage

→ loss of skeletal muscle fibers

Question 7

AutoAbs assc with iflamm myopathies

Answer 7

Anti-synthetase/Jo1
Anti-Signal recognition particle
Anti-Chromodomain helicase DN binding protein 3 and 4

Question 8

Epidemiology difference between
polymyositis
dermatomyositis
inclusion body myositis

Answer 8

polymyositis = late teen and 50-60
dermatomyositis = 5-10 and 45-56
inclusion body myositis = 50+ (rare in young people)

Question 9

proximal muscle weakness + polyarthritis + Raynaud’s + RASH

Answer 9

Dermatomyositis

Question 10

What part of body does rash in DM typically effect

Answer 10

eye lids + periorbital edema
grotton’s patches on knuckles > knees and elbow
scalp

Question 11

Predominantly infiltrate of CD8 T cells and macrophages in muscle fibers + inclusion of vacuolated fiibers (tubulofilamentous inclusions)

CD8 T cells recognize muscle fiber Ag on MHC class I → damage

Answer 11

Inclusion Body myositis

Question 12

predominantly peri-vascualr infiltrate of CD4 T cells, macrophages, and DC assc with B cells

Answer 12

Dermatomyositis

Question 13

thigh and finger flexors

Answer 13

IBM

Question 14

Predominantly infiltrate of CD8 T cells and macrophages into non-necrotic muscle fibers

CD8 T cells recognize muscle fiber Ag on MHC class I → damage

Answer 14

Polymyositis

Question 15

contractures of joints can occur are called and seen with?

Answer 15

= Mechanics hands in DM

Question 16

DM Rash without myositis

these pts are at risk for…

Answer 16

Amyopathic Dermatomyositis

severe ILD

Question 17

purple vasculitic patches over knuckles

Whats dz is this seen with

Answer 17

Gottron’s patches in Dermatomyositis (DM)

*SLE rash spares knuckles

Question 18

have calcinosis, cutaneous ulceration and lipodystrophy + proximal muscle weakness + polyarthritis + Raynaud’s + RASH

Answer 18

Juvenile Dermatomyositis

in 6-11 yo

Question 19

basophilic rimmed vacuoles

Answer 19

inclusion body myositis

Question 20

perivascular infiltration

Answer 20

DM

Question 21

muscles affected by IBM

Answer 21

distal (thigh and finger flexors)

Question 22

pulm interstitial fibrosis + hardening and fissuring of skin over fingers (Mechanics Hands) + myositis

Answer 22

Anti-sythetase syndrome seen in PM and DM

Question 23

genetic predisposition to IBM

Answer 23

HLA-B8, DR52, DRQ2

Question 24

Insidious, slowly progressive weakness of mainly distal muscles

Answer 24

IBM