Inflammatory Myopathies

Question 1

What antibody should be considered in a case of LGMD with negative genetic testing?

Answer 1

HMGCR ab

Question 2

What inflammatory myopathies are associated with rapid myositis progression over days to weeks?

Answer 2

Viral myositis and immune-mediated necrotizing myopathy (especially anti-SRP antibodies).

Question 3

What is the heliotrope sign in dermatomyositis?

Answer 3

Periorbital and upper eyelid violaceous discoloration.

Question 4

What is the Gottron sign?

Answer 4

Erythematous, scaly plaques over the MCP and IP joints.

Question 5

What is the “V sign” rash?

Answer 5

Sun-exposed rash in the anterior chest seen in DM patients

Question 6

What is the shawl sign?

Answer 6

Erythematous rash on the posterior neck and shoulders seen in DM.

Question 7

What is the rash on the lateral thigh called in DM?

Answer 7

Holster sign

Question 8

What is the relevance of subcutaneous calcifications in dermatomyositis?

Answer 8

“Calcinosis cutis” is associated with anti-NXP-2 antibodies in dermatomyositis (often juvenile).

Question 9

Nail bed telangiectasias are associated with which antibodies in DM?

Answer 9

Anti – Mi-2 antibodies.

Question 10

What condition is characterized by a hyperkeratotic eruption over the thumb and radial aspect of fingers?

Answer 10

Mechanic’s hands

Question 11

What is a prominent feature of dermatomyositis with anti-MDA-5 antibodies?

Answer 11

Interstitial lung disease.

Question 12

Which myositis conditions are associated with interstitial lung disease?

Answer 12

-Dermatomyositis with anti-MDA-5 antibodies
-Antisynthetase syndrome (Jo 1, PL 7/12)
-Overlap myositis with systemic sclerosis.

Question 13

What inflammatory myopathies are more likely to cause myocarditis?

Answer 13

IMNM and ICI-related myositis

Question 14

What inflammatory myositis is associated with pericarditis?

Answer 14

Anti-U1 RNP overlap myositis

Question 15

Gastrointestinal vasculopathy in juvenile dermatomyositis can lead to what complications?

Answer 15

Intestinal infarcts or hemorrhage.

Question 16

What inflammatory myopathy is associated with glomerulonephritis?

Answer 16

Anti-U1 RNP antibody overlap myositis.

Question 17

When can CK be normal in dermatomyositis and anti-synthetase syndrome?

Answer 17

When inflammation is limited to perimysium and fascia with minimal muscle pathology.

Question 18

What enzyme elevation is diagnostically helpful when CK is normal?

Answer 18

Selective aldolase elevation can be diagnostically helpful.

Question 19

What myositis shows extreme CK elevations (>20 times normal) if untreated?

Answer 19

Immune-mediated necrotizing myopathy

Question 20

What is the yield of antibody testing in idiopathic inflammatory myopathies?

Answer 20

About 65% to 70%.

Question 21

What are the five antibodies related to dermatomyositis?

Answer 21

Anti-NXP-2
Anti-TIF1-γ
Anti-Mi-2
Anti-MDA-5
Anti-SAE.

Question 22

Which antibodies have the strongest association with malignancy in dermatomyositis?

Answer 22

TIF1-γ antibodies
(Typically mild muscle but significant skin involvement)
Consider cancer screening up to 3 years after dx of myositis (per Kuschlaf 2024 AANEM lecture).

Question 23

What phenotype is assoicated with NXP-2 abs?

Answer 23

Calcinosis cutis
Peripheral edema
Distal weakness
Higher malignancy risk in adults.

Non length dependent weakness
Xtreme swelling
Paraneoplastic
2 much calcium

Question 24

What are the characteristics of Anti-Mi-2 antibody in dermatomyositis?

Answer 24

Severe muscle weakness, acute onset, heliotrope rash, Gottron papules, nail fold pathology, good prognosis.

Question 25

What complications are associated with anti-MDA-5 antibody syndrome?

Answer 25

Thrombotic complications, skin ulceration, palmar papules, and severe interstitial lung disease. May have amyopathic dermatomyositis (like Tif1 gamma).

Question 26

What are characteristic symptoms of SAE abs in dermatomyositis?

Answer 26

Erythematous rashes and severe dysphagia. Possibly inc cancer risk. Least common DM abs.

Question 27

What non-neurologic risk has been associated with dermatomyositis?

Answer 27

An elevated cancer risk.

Question 28

What is the most common antibody found in antisynthetase syndrome?

Answer 28

Anti-Jo-1 antibody.

Question 29

What other antibodies are associated with antisynthetase syndrome besides anti-Jo-1.

Answer 29

PL-7, PL-12, OJ, EJ, KS, Zo, Ha.

Question 30

What is the dominant feature of anti-PL-7 and anti-PL-12 antibody antisynthetase syndrome?

Answer 30

Interstitial lung disease is the dominant feature.

Question 31

What percentage of immune-mediated necrotizing myopathy cases have specific antibodies detected?

Answer 31

About 65% of cases.

Question 32

What percentage of DM cases are seronegative?

Answer 32

About 30% (per Kuschlaf AANEM lecture 2024)

Question 33

Which antibodies are commonly detected in immune-mediated necrotizing myopathy?

Answer 33

Anti-SRP, anti-HMG-CoA reductase IgG, and rarely antimitochondrial M2 antibodies.

Question 34

What characterizes Anti-SRP antibody syndrome?

Answer 34

Severe weakness, rapid progression, and extremely high CK levels (typically five-digit). Can have myocarditis and respiratory failure due to diaphragmatic weakness (or ILD).

Question 35

What can develop within months if SRP IMNM is not treated early?

Answer 35

Muscle fibrosis and fat replacement.

Question 36

What percentage of patients with anti-HMG-CoA reductase IgG myopathy are statin-naive?

Answer 36

At least one-third of patients are statin-naive.

Question 37

What subtypes of IMNM are associated with increased cancer risk?

Answer 37

HMGCR and seronegative

Question 38

What is the pathological manifestation of antimitochondrial antibody-related myositis in over 50% of cases?

Answer 38

Immune-mediated necrotizing myopathy (less commonly presents as a granulomatous myositis). 1/4 patients have primary biliary cirrhosis.

Question 39

Name myositis associated antibodies (associated with myositis but not specific for it)

Answer 39

U1 RNP U2 RNP SSA (most common) PM Scl Ku

Question 40

What percentage of systemic sclerosis/overlap myositis syndrome cases have anti-PM-Scl and anti-Ku antibodies?

Answer 40

60%

Question 41

What Myositis associated antibodies are associated with dropped head syndrome?

Answer 41

PM-Scl-75 and PM-Scl-100.

Question 42

What systemic conditions are associated with anti-U1 RNP antibodies?

Answer 42

Glomerulonephritis and pericarditis.

Question 43

What does MRI show in dermatomyositis?

Answer 43

Edema in subcutaneous tissue, epimysium, perimysium, and patchy muscle edema.

Question 44

What characterizes immune-mediated necrotizing myopathy on MRI?

Answer 44

Severe diffuse edema and enhancement intramuscularly, with little to no fascial involvement.

Question 45

What can be seen early on MRI in anti-SRP antibody myopathy?

Answer 45

Fatty replacement and muscle atrophy may occur early in anti-SRP antibody myopathy.

Question 46

Who should be screened for malignancy in relation to dermatomyositis?

Answer 46

All adults over 40 with dermatomyositis, especially with anti-TIF1-γ and anti-NXP-2 antibodies.

Question 47

Incidence of cancer in antisynthetase syndrome, anti-SRP myopathy, or overlap myositis?

Answer 47

Low incidence; routine cancer screening not recommended.

Question 48

What is offered as a first-line treatment in anti-HMG-CoA reductase IgG myopathy?

Answer 48

IVIg

Question 49

What are patterns of muscle involvement in immune checkpoint inhibitor-related myositis?

Answer 49

1. Proximal limb-girdle weakness, 2. Ocular myositis (diplopia, ptosis, resembling myasthenia gravis but neg AchR abs and neg RNS) 3. Involvement of neck extensors/paraspinal muscles

Question 50

How soon after starting immune checkpoint inhibitors do symptoms of myositis typically appear?

Answer 50

Symptoms typically appear within 1 to 2 months after initiation.

Question 51

Which muscles showed a predilection in immune checkpoint inhibitor-related myositis?

Answer 51

Axial muscles, especially neck extensor muscles.

Question 52

What did muscle biopsies usually show in ICI related myositis?

Answer 52

Immune-mediated necrotizing myopathy with clusters of necrotic fibers; inflammation was less common.

Question 53

What was observed about CK levels in ICI related myositis?

Answer 53

CK levels were elevated, yet lower than in other immune-mediated necrotizing myopathy subtypes.

Question 54

What can be used to treat immune-mediated necrotizing myopathy?

Answer 54

Steroids (IVIG if refractory). If mild symptoms do not need to d/c ICI (not sure I would have to guts to do this).

Question 55

What percentage of patients with COVID report myalgia?

Answer 55

50% of patients report myalgia.

Question 56

What percentage of patients show asymptomatic CK elevations in COVID?

Answer 56

16% to 33% show asymptomatic CK elevations.

Question 57

What are the three clinical phenotypes of myopathy associated with COVID-19?

Answer 57

Rhabdomyolysis Classic dermatomyositis Isolated paraspinal myositis.

Question 59

What is mixed connective tissue disease (MCTD)?

Answer 59

Type of overlap syndrome. Main features of at least two overlapping connective tissue diseases including: SLE, systemic sclerosis, rheumatoid arthritis, myositis. Defined by the presence of anti-U1 RNP antibodies and Raynaud’s phenomenon

Question 60

What antibody is associated with immune mediated Rippling Muscle Disease?

Answer 60

Anti Cavin 4 abs (caveolin associated protein) All should have percussion induced muscle rippling.

Question 61

What ab is seen with IBM?

Answer 61

NT5C1A Seen in about 40-60% of IBM (no difference in seropostive or seronegative clinically) Can see false + in other inflammatory myopathies, SLE/Sjogren's, MND, VCP, and even in normal volunteers (per Kuschlaf AANEM 2024 lecture)