Inflammatory Myopathies - Postlethwaite

Question 1

Definition of inflammatory myopathies?

Answer 1

Group of immune mediated disorders with symmetrical proximal muscle weakness and frequent involvement of other organs

Question 2

Inflammatory myopathies affect what type of muscle (smooth, striated, cardiac)?

Answer 2

Striated muscle. That is why upper 1/3 of esophagus can be involved. it’s striated

Question 3

2 main disorders associated with inflammatory myopathies?

Answer 3

Dermatomyositis, Polymyositis

Question 4

What lab value is elevated in myositis? (hint: think muscle damage)

Answer 4

CK

Question 5

Besides dermatomyositis and polymyositis, name 4 other inflammatory myopathies?

Answer 5

Antisynthetase syndrome, amyopathic dermatomyositis, Juvenile dermatomyositis, Inclusion body myositis

Question 6

Dermatomyositis body involvement?

Answer 6

Skeletal Muscle, skin

Question 7

Polymyositis body involvement?

Answer 7

Muscle only, not skin

Question 8

Dermatoymyositis and Polymyositis location of muscle involvement? Distinguishes from what other disorder?

Answer 8

DM and PM only have proximal muscle involvement.

Inclusion body myositis will have distal muscle involvement too.

Question 9

3 skin findings seen in dermatomyositis?

Answer 9

• Heliotrope rash (rash of the upper eyelids)
• Malar rash
• Gottron papules (red papules on the elbows, knuckles, and knees)

Question 10

Dermatomyositis can be confused with what other disorder? What lab and clinical findings are similar?

Answer 10

Can be confused with SLE.

Patient can have +ANA, malar rash

Question 11

What lab finding can help differentiate dermatomyositis from SLE?

Answer 11

+ anti-Jo-1 antibody can be seen in dermatomyositis

Question 12

What 2 disorders are shown here? Which one is which?

Answer 12

A = Dermatomyositis; Note the changes on the knuckles and dorsum of the hand (Gottron’s sign)

B = SLE; Rash is absent on the knuckles but present on the phalanges

Question 13

What is this called?

What syndrome is this associated with?

What antibody is associated with this condition?

What other symptoms are involved in this syndrome?

Answer 13

“Mechanic Hands”

seen in Anti-synthetase Syndrome

• anti-Jo-1 antibody

Fever, Arthritis, +/- Raynauds, ILD

“Jo is the F-A-M-IL-y Mechanic”

Question 14

Inflammatory myopathies is associated with what pathologic disorders? (just look at the answer. couldnt figure out a way to ask)

Answer 14

12% of myositis cases associated with malignancy (breast cancer, adenocarcinoma)

• DM = 81%, PM = 19% of malignancies

Question 15

CD4+ T cells are associated with what myositis?

Answer 15

Dermatomyositis

Question 16

CD8+ T cells are associated with what myositis?

Answer 16

Polymyositis

Question 17

Biopsy of dermatomyositis will show what?

Answer 17

Perimysial inflammation (CD4+ T cells) with perifascicular atrophy

As opposed to polymyositis that shows Endomysial inflammation (CD8+ T cells) with necrotic muscle fibers

Question 18

Necrosis of muscle fibers is associated with what myositis? Means what type of inflammation is going on?

Answer 18

Polymyositis

Endomysial inflammation (CD8+ T cells) with necrotic muscle fibers

Question 19

If there is upper extremity distal muscle weakness (in the fingers), what myositis are you thinking of?

Answer 19

Inclusion body myositis

• mostly proximal muscle weakness in lower extremities, distal in upper extremities

Question 20

Inclusion body myositis seen primarily in what age/sex?

Answer 20

Older men

Question 21

Which type of inflammatory myopathy doesnt respond to corticosteroids?

Answer 21

Inclusion body myositis

Question 22

Does inclusion body myositis commonly involve organs? If so, which ones?

Answer 22

No, it doesnt

Question 23

PMR stands for what?

Answer 23

Polymyalgia Rheumatica

Question 24

Polymyalgia rheumatica symptoms?

Answer 24

Pain and stiffness in shoulders and hips, often with fever, malise, and weight loss

Question 25

What is NOT seen in PMR?

Answer 25

Does not cause muscle destruction

Question 26

What lab values are elevated in PMR?

What lab values are normal?

Answer 26

ESR, CRP elevated

CK normal (due to no muscle damage)

Question 27

Polymyalgia Rheumatica is associated with what other disorder?

Answer 27

Temporal (giant cell) arteritis

Question 28

Which is more common:

Patient with temporal arteritis develops PMR or Patient with PMR develops temporal arteritis?

Answer 28

• 50% of patients with temporal arteritis will develop polymyalgia rheumatic
• only 15% of patients with PMR as primary diagnosis will develop temporal arteritis

Question 29

What are some symptoms of Temporal arteritis?

Answer 29

Systemic symptoms (fever, weight loss, fatigue)

temporal headaches

visual disturbances (can progress to sudden blindness)

jaw or tongue claudication

arthralgies

tender temporal artery

Question 30

Dreaded complication of temporal arteritis?

Answer 30

Blindness

Question 31

Describe microscopic apperance of giant cell arteritis?

Answer 31

giant cells (not always there), Inflammation of vessel wall, disruption of internal elastic lamina, intimal fibrosis

Question 32

What treatment method is most effect for polymyalgia rheumatica? Distinguishing feature regarding this treatment method.

Answer 32

low dose of corticosteroids. If after 7 days, patient still hasnt responded, bump up dose. If still doesnt respond after another 7 days, rethink diagnosis of PMR

Question 33

What are you looking at here? What is the key feature that gives it away?

Answer 33

Inclusion body myositis

KEY FEATURE = variation in muscle fiber sizes.

Question 34

Muscular dystrophy defined as?

Answer 34

Degenerative disorder characterized by muscle wasting and replacement of skeletal muscle by adipose tissue

Question 35

Deletion of dystrophin is associated with what disorder?

Answer 35

X-linked (Duchenne’s) Muscular Dystrophy

Question 36

Mutation of dystrophin associated with?

Severity of this disease?

Answer 36

Becker muscular dystrophy.

Associated with milder form of disease