SM 246a - Inflammatory Myopathies Flashcards
Perifascicular atrophy is a hallmark of
A: PM
B: DM
C: IBM
D: none of the above
B: DM
Describe the presentation of necrotizing myopathy
- Little to no inflammation
- Lots of degeneration
- High creatine kinase
- Acute
- 2 major causes
- Signal reduction particle
- HMG-CoA Reductasse antibody
- Associated with statin use
What laboratory findings are consistent with polymyositis?
Elevated CK
Ulcerated Gottran’s lesions + alopecia in a patient with dermatomyositis should prompt which next step in managemet?
Pulmonary work-up
High risk of interstitial lung disease
A female patient presents with symmetric muscle weakness for the past 3 months. She reports trouble standing up from sitting and styling their hair.
A positive test for Anti-Jo-1 would make you concerned for what pathology?
This paitent most likly has polymyositis
Dermatomyositis also possible, depending on skin presentation (Heliotrope erupton, Gottron’s papules, calcinosis, photosensitivity, poikiloderma)
Anti-Jo-1 predicts Interstitial lung disease
Which inflammatory myopathy(/ies) does this apply to?
More likely to affect distal muscles
Inclusion body myositis
Also affects proximal muscles, but polymyositis and dermatomyositis are much less likely to affect distal muscles
Which inflammatory myopathy will have rimmed vacuoles on pathology?
What is inside these vacuoles?
Inclusion body myositis
Filled with beta-amyloid (the Alzheimer’s of muscle)
Which inflammatory myopathy(/ies) does this apply to?
Rimmed vacuoles seen on biopsy
Inclusion body myositis
Which inflammatory myopathy is associated with statin use?
Necrotizing myopathy
What is the treatment for HMG CoA Reductase Necrotizing Myositis?
Immunotherapy
List 4 inflammatory myopathies
- Polymyositis
- Dermatomyositis
- Incusion body myositis
- Necrotizing autoimmune myopathy
When are patients with dermatomyositis at highest risk for malignancy?
First year of presentation
Remains elevated for 3 years
Describe the laboratory findings associated with inclusion body myositis (IBM).
- Creatine kinase mildly elevated
- Anti-CN1A antibody may be present
Other than treatment failure, worsening proximal weakness some months into the treatment of PM can be seen with
A: glucocorticoids
B: methotrexate
C: tacrolimus
D: rituximab
A: glucocorticoids
Which antibodies are associated with ILD in patients with dermatomyositis?
- Anti-MDA5
- Check this antibody if a patient has ulcerated Gottran’s papules
- Anti-Jo1
Which necrotizing myopathy is more common in African-American women?
Signal Recognition Particle Myopathy
Which inflammatory myopathy(/ies) does this apply to?
Typical patient is a man >50 y/o
Inclusion body myositis
Inflammation and internalized nuclei can be seen on the biopsy of which inflammatory myopathy?
Polymyositis
What is the treatment for IBM?
IVIg may work
Steroids will not work
A patient with dermatomyositis is positive for Anti-TIF1-gamma antibodies.
What is the appropriate immediate next step?
- Check aldolase, creatine kinase
- Evaluate muscle disease
- Pan-scan for malignancy
- All adult-onset dermatomyositis is associated with malignancy, but Anti-TIF1-gamma very strongly
An adult patient presents with proximal extensor inflammatory myopathy. They are having trouble brushing their hair and going up stairs.
Which connective tissue disorder do they most likely have?
Which labs should you order?
What are the most concerning association with this disease?
Dermatomyositis
Aldolase, creatine kinase
Malignancy (especially Anti-TIF-gamma), ILD (Anti-MDA5, Anti-Jo1)
What is the recommended treatment for dermatomyositis?
- Corticosteroids
- AZA
- MTX
- IVIg
- Rituximab
- Cancer screening
- Pulmonary function tests
Which inflammatory myopathy(/ies) does this apply to?
Affects proximal muscles
Polymyositis
Dermatomyositis
Asymmetrical or distal weakness would suggest
A: PM
B: DM
C: IBM
D: any of the above
C: IBM
What is the treatment for polymyositis?
- Systemic corticosterois
- AZA
- MTX
- IVIG
- Rituximab
All of these methods take time to work; may be up to 6 months for maximal effect
Describe the clinical presentation of polymyositis
- Symmetric
- Proximal muscles affected more than distal
- May have dysphagia
- Insidious
- Myalgias
Malignancies are usually detected within ___ years of dermatomysitis onset, but ovarian cancer may be out to ___ years
Malignancies are usually detected within 2** years of dermatomysitis onset, but ovarian cancer may be out to **5 years
Describe the presentation of SRP myopathy
- Acute onset
- Dysphagia
- Raynaud’s phenomenon
- Myalgias
- Minimal to no inflammation
- More common in African Americans, women
- Responds to immunotherapy
Which inflammatory myopathy(/ies) does this apply to?
Patient presents with proximal muscle weakness
Polymyositis
Dermatomyositis
Which of the following medications is most commonly associated with a necrotizing myopathy
A: Azithromycin
B: Simvastatin
C: Gabapentin
D: Tramadol
B: Simvastatin
What antibody is most strongly associated with malignancy in adult dermatomyositis patients?
Anti-TIF1-gamma antibodies
All dermatomyositis patients are at increased risk of malignancy, but especially patients positive for Anti-TIF1-gamma antibodies
What will you see in a muscle biopsy of a patient with dermatomyositis?
Perifasicular atrophy
Looks like fat smashed along the edges of muscles
What will you see in a muscle biopsy of a patient with inclusion body myositis (IBM)?
-
Rimmed vacuoles
- Vacuoles contain beta amyloid
- May need congo red to prove
- Not a lot of inflammation
What will you see in a muscle biopsy of a patient with polymyositis?
- Inflammation around normal muscle fibers
- Scattered necrosis, degeneration, and regeneration
- Internal nuclei
- Variability of fiber size, but seldom hypertrophy
Which muscles are often affected by inclusion body myositis (IBM)?
- Quads, wrist flexors, finger flexors
- More likely to affect distal muscles than other inflammatory myopathies
- Eventual dysphagia
Describe the clinical presentation of inclusion body myositis
- M>F
- Older age of onset
- Distal weakness
- Difficulty shaving
- Cannot grip golf club
- Hard to walk
- Getting up out of a seat is hard (quads)
- Asymmetry
- Progressive
