Msi Week 3: Is Idiopathic Inflammatory Myopathies

Front 1

List 3 major forms of idiopathic inflammatory myopathies.

Back 1

1. Polymyositis
2. Dermatomyositis
3. Inclusion body myositis

Front 2

List 5 various forms of polymyositis and dermatomyositis.

Back 2

1. Polymyositis (primary, adult)
2. Dermatomyositis (primary, adult)
3. Juvenile dermatomyositis
4. Myositis with malignancy
5. Myositis in connective tissue diseases

Front 3

Of the three major forms of idiopathic inflammatory myopathies, which is most prevalent in children?

Back 3

Dermatomyositis

Prevalence: DM > PM > IBM

Front 4

Of the 3 major forms of idiopathic inflammatory myopathies, which is the most prevalent in adults under the age of 50?

What about adults over the age of 50?

Back 4

Under age 50:
Polymyositis
Prevalence: PM > DM > IBM

Over age 50:
Inclusion body myositis
Prevalence: IBM > PM > DM

Front 5

Malignancies are most prevalent in which form of myositis?

Back 5

Most prevalent in dermatomyositis

(DM > PM > IBM)

Front 6

List some of the common presentations of idiopathic inflammatory myopathies.

Back 6

1. *Proximal muscle weakness
2. Elevated muscle enzymes
3. Myalgia
4. Dermatologic findings
5. Extramuscular manifestations

Front 7

List 5 criteria for diagnosis of PM/DM.

Explain the number of requirements necessary for a "definite," "probable," or "possible" diagnosis.

Back 7

1. Muscle weakness
2. Elevated enzymes (CK, aldolase, Aspartate aminotransferase)
3. Electromyography (irritable myopathy with normal nerve conduction velocity)
4. Muscle biopsy (inflammation, atrophy)
5. Dermatologic findings of DM (Gottron's papules, heliotrope)

Any 4 = DEFINITE
Any 3 = probable
Any 2 = possible

Front 8

Gottron's papules are indicative of which type of myopathy?

Back 8

Dermatomyositis
(heliotrope--purplish tint to skin--is also seen in DM patients)

Front 9

If a patient presents with muscle weakness, Gottron's papules, and a high level of muscle enzymes, what is the likelyhood that this patient has DM?

Back 9

"Probable"
(meets 3 out of 5 requirements)

Front 10

What are two risk factors of muscle weakness in idiopathic inflammatory myopathies?

Back 10

1. Dysphagia
2. Respiratory muscle weakness

Front 11

Which muscles are generally involved in idiopathic inflammatory myopathies?

Back 11

*Generally involves skeletal muscle, more proximal than distal, and also symmetrical.

1. Upper/lower limbs
2. Pelvic, shoulder girdles
3. Neck flexors
4. Esophagus (upper 1/3 skeletal muscle)

*Usually do NOT involve facial muscles or extra-ocular muscles

Front 12

Describe a few activities you can ask a patient to perform to assess muscle strength.

Back 12

1. Stand from a chair w/o using hands
2. Squatting or standing from floor
3.Standing on heels and toes
4. Getting onto an exam table
5. Lifting head off exam table
6. Sitting up from supine position
7. Timed 50-ft walk.

Front 13

List 7 muscle factors that can be measured to assess IIM disease activity.

Back 13

1. Creatine kinase
2. Urinary creatine
3. Aldolase
4. LDH (lactate dehydrogenase)
5. AST/ALT (aspartate/alanine transaminase)
6. Troponin
7. Myoglobin

Front 14

Which is the most sensitive muscle enzyme that can be measured to assess for IIM?

Back 14

Creatine kinase

Front 15

T or F.

Levels of enzymes and markers can be used for assessing disease activity as well as for diagnosis.

Back 15

TRUE

Front 16

When assessing electromyography results, what characteristics of the recording indicate myopathic potentials?

Back 16

1. Low amplitude
2. Short duration
3. Polyphasic

Front 17

When comparing muscle biopsy options, which procedure allows you to take a better sample and is easier to interpret? (open or needle bioposy?)

Back 17

Open biopsy--however, a larger muscle sample is required than with a needle biopsy.

*Advantages of needle biopsy: less scar, less risk, smaller procedure, easier to interpret.

Front 18

A muscle biopsy is necessary for the diagnosis of which myopathy?

Back 18

Inclusion body myopathy

(can also be used to distinguish difference between DM and PM based on histologic appearance)

Front 19

An electron microscopy is performed if which myopathies are suspected?

Back 19

1. Inclusion body myopathy
2. Mitochondrial myopathy

Front 20

Mononuclear cells can be found within (endomysial) or outside (perimysial) muscle tissue. Which myopathies can have endomysial infiltrates?

Which myopathy has perimysial infiltrates?

Back 20

PM, IMB --> endomysial
DM --> perimysial

Front 21

When looking at a muscle biopsy, perifascicular muscular atrophy may indicate which myopathy?

Back 21

Dermatomyositis

Front 22

When looking at a muscle biopsy, rimmed vacuoles and inclusions may indicate which myopathy?

Back 22

Inclusion body myopathy

Front 23

What 3 things might you find in a muscle biopsy that could help you diagnose an idiopathic inflammatory myopathy?

Back 23

1. Mononuclear cell infiltration
2. Muscle fiber necrosis/ regeneration
3. Atrophy and fibrosis

Front 24

Deposition of complement membrane attack complex and antibody in muscle and skin microvascular is a histologic feature of which myopathy?

Back 24

Dermatomyositis

(Other features include: perimysial infiltration, perifascicular atrophy, endothelial cell injury, capillary depletion, and lack of T-cell attack on non-necrotic fibers)

Front 25

Endothelial cell injury and capillary depletion is a histologic feature of which myopathy?

Back 25

Dermatomyositis

(Other features include: perimysial infiltration, perifascicular atrophy, deposition of membrane attack complex and antibody in muscle/skin vasculature, and lack of T-cell attack on non-necrotic fibers)

Front 26

If a patient presents with nailfold capillary changes, cutaneous ulcerations, and ischemic damage to muscle, which type of myopathy would you suspect?

Back 26

Dermatomyositis

*Patients w/ DM have a vasculopathy which can lead to these manifestations:

1. Reduced muscle capillary density
2. Ischemic damage to muscle
3. Nailfold capillary changes
4. Cutaneous ulcerations
5. Intestinal perforation

Front 27

What type of immunity is involved in polymyositis?

Back 27

Cell-mediated immunity
(endomysial CD8+ T cells surround and invade muscle fibers)

*

Front 28

Evidence suggests antigen-directed T-cell mediated attack on muscle fiber in which type of myopathy?

Back 28

Polymyositis

Front 29

A heliotrope sign is indicative of which myopathy?

Back 29

Dermatomyositis.

Heliotrope sign: *Violaceous eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and swelling

Front 30

Pink patches on the knuckles and other extensor surfaces are known as....?

These cutaneous features are often seen in which myopathy?

Back 30

Gottron's papules over fingers (knuckes)
Gottron's sign over extensor surfaces

*Dermatomyositis

Front 31

What is the name for rough, cracked skin at the tips and lateral aspects of the fingers forming irregular dirty-appearing lines that resemble those seen in a laborer?

This cutaneous feature is often a sign of which myopathy?

Back 31

Mechanic's hands

*Dermatomyositis

Front 32

What type of rash is seen in Dermatomyositis?

Back 32

Erythematous rash

Front 33

What is the name of the skin condition that consists of areas of increased and decreased pigmentation, prominent blood vessels, and thinning of the skin?

Back 33

Poikiloderma

*Seen in dermatomyositis

Front 34

What cutaneous feature might you find on a Dermatomyositis patient that also may be detected in an x-ray?

Back 34

Calcinosis

Front 35

What type of imaging might be helpful in establishing a diagnosis and excluding myositis?

Back 35

MRI

*Inflammation appears as bright areas. Fatty replacement and atrophy can also be seen.
(Thighs are most often studied. Anterior > Posterior)

Front 36

Can autoantibodies be detected in PM and DM?

Back 36

Yes, more than 90% of the time.

Front 37

Is a positive ANA test result suggestive of PM or DM?

Back 37

A positive ANA is seen in 60-80% of DM and PM cases.

(Also positive in 23% Inclusion body myositis)

Front 38

What is the most common myositis-specific antibody?

Back 38

Anti-Jo-1 (20 % of DM, PM cases)

Front 39

Do myositis-specific antibodies appear before or after the disease onset of PM, DM?

Back 39

Appear PRIOR to disease

(These antibodies have high disease specificity, but absence does not exclude diagnosis)

Front 40

List 2 anti-synthetases that can be associated with PM and DM.

What are anti-synthetases directed against?

Back 40

1. Anti-Jo-1 (20%)
2. Non-Jo-1 (4 - 8%)

*Directed at aminoacyl-tRNA synthetase enzymes. These cytoplasmic enzymes catalyze attachment of the amino acid to the cognate tRNA.

Front 41

What conditions can result form anti-synthetase syndrome?

Back 41

1. Myositis
2. Interstitial lung disease
3. Arthritis
4. Raynaud's phenomenon
5. Fevers
6. Mechanic's hands

Front 42

List 4 established myositis-specific antibodies.

Back 42

1. Anti-synthetases (Anti-Jo1, Non-Jo1)
2. Anti-Mi-2
3. Anti-SRP
4. Anti-PM-Scl

Front 43

Which established myositis-specific antibody has a high specificity for myositis and a relative specificity for dermatomyositis?

Back 43

Anti-Mi-2

*Rash often prominent

Front 44

Which established myositis-specific antibody is associated with polymyositis (no skin involvement)?

(Also may represent an acute onset, severe disease)

Back 44

Signal recognition particle autoantibodies
(anti-SRPs)

Front 45

Which established myositis-specific antibody may be found in patients who have features of both Systemic scleroderma (SSc) and PM/DM or isolated SSc or PM/DM?

Back 45

Anti-PM-Scl Autoantibodies

*Scleroderma usually limited in extent of cutaneous involvement

*Inflammatory arthritis is also common

Front 46

What type of specificity and sensitivity do the myositis autoantibodies have when it comes to diagnosing a patient?

Back 46

HIGH specificity
LOW sensitivity

Front 47

Compare the rate of muscle weakness seen in DM, PM, and IBM.

Back 47

Progression of weakness:
DM (fastest) > PM > IBM (slowest)

Front 48

Which muscles are characteristically involved in Inclusion body myositis?

Back 48

Forearm flexors and quadriceps

Front 49

Are the affected muscles in IBM typically distal or proximal?

Back 49

DISTAL

(Remember that proximal muscle weakness is more characteristic of PM and DM)

Front 50

Would you expect a patient with PM, DM, or IBM to be more at risk for falling?

Back 50

IBM

(This condition typically affects distal muscles-- the quadriceps being a particularly affected group).

Front 51

Rimmed vacuoles with basophilic granules and eosinophilic inclusions + inclusion bodies w/ microtubular filaments are histologic features of which myopathy?

Back 51

Inclusion body myositis

Front 52

What form of polymyositis may show features of IBM?

Back 52

"Resistant PM"
1. Older age
2. Longer duration to diagnosis
3. Lower Female: Male ratio
4. Distal weakness, neuropathy
5. Lower CK

Front 53

The risk of malignancy in myositiis is greatest during which year after onset?

Back 53

1st year

Front 54

What type of cancer is most often seen along with DM?

Back 54

Ovarian cancer

(Colon, lung, pancreatic, breast, lymphoma also prevalent)

Front 55

Which antibody represents a high risk of malignancy with myositis?

Back 55

anti-p155/140

Front 56

If a patient is taking Chloroquine or colchicine and presents with symptoms indicative of an idiopathic inflammatory myopathy, what should be your concern?

Back 56

Drug-induced myopathy

The following drugs can be of concern:
1. Chloroquine
2. Colchicine
3. D-Penicillamine
4. L-Tryptophan
5. Lipid lowering agents
6. Endocrine
7. Drugs of abuse

Front 57

If a patient is diagnosed with a metabolic myopathy and is also taking high doses statin drugs along with cyclosporine, what should be your concern?

Back 57

Statin myopathy could ensue, which can be very severe.

Symptoms may range from myalgia to rhabdomyolysis (rapid breakdown of skeletal tissue)

Statin drugs are used to improve blood cholesterol. High doses increase a patients chance of statin myopathy and interacting drugs like cyclosporine can also increase risk.

Front 58

List 5 metabolic myopathies.

Back 58

1. Myophosphorylase deficiency
2. myoadenylate deaminase deficiency
3. Phosphofructokinase deficiency
4. Abnormal carnitine metabolism
5. Acid maltase deficiency

Front 59

The following symptoms may indicate which type of myopathy?

Cramps, exercise intolerance, easy fatiguability, rhabdomyolysis.

Back 59

Metabolic myopathy

Front 60

What class of drugs are generally used for PM/DM?

Back 60

Corticosteroids

Daily oral prednisone
IV pulse methylprednisone if patient displays serious risk factors
Consider IV pulses for children to avoid giving them steroids every day

Front 61

What types of drugs can be used for myopathies to avoid bad side effects of high-dose long-term steroids?

Back 61

Immunosuppresive agents

(Also indicated for flare on prednisone taper and for disease resistance)

Front 62

How should you NOT administer methotrexate?

Back 62

Avoid IM injections

Front 63

Why might Methotrexate be a better option than Azathioprine for myopathies?

Back 63

Earler onset of action (6-10 wks)

Front 64

What is an advantage of using intravenous gammaglobulin for treating myopathies?

Back 64

Low risk of side effects

Front 65

What is a potential mechanism of Intravenous gammaglobulins (IVGG) in dermatomyositis?

Back 65

Reduces complement MAC deposition and MHC expression, increases capillaries
(Binds C3b to block MAC formation/deposition)

Front 66

List 4 treatments that can be used for idiopathic inflammatory myopathies?

Back 66

1. Corticosteroids
2. Methotrexate
3. Azathioprine
4. IVGG (intravenous immunoglobulin)

Front 67

Which 3 drugs can possibly be used to treat interstitial lung disease?

Back 67

1. Prednisone
2. Cyclophosphamide
3. Tacrolimus

Front 68

What is the mortality rate for PM and DM?

Back 68

5 yrs = 80%
8 yrs = 73%

Front 69

Mortality rates in PM and DM are increased based on what factors?

Back 69

1. Older age
2. Cardiac/pulmonary involvement
3. Dysphagia
4. Steroid resistance
5. Malignancy