Inflammatory Myopathies - Postlethwaite Flashcards
Definition of inflammatory myopathies?
Group of immune mediated disorders with symmetrical proximal muscle weakness and frequent involvement of other organs
Inflammatory myopathies affect what type of muscle (smooth, striated, cardiac)?
Striated muscle. That is why upper 1/3 of esophagus can be involved. it’s striated
2 main disorders associated with inflammatory myopathies?
Dermatomyositis, Polymyositis
What lab value is elevated in myositis? (hint: think muscle damage)
CK
Besides dermatomyositis and polymyositis, name 4 other inflammatory myopathies?
Antisynthetase syndrome, amyopathic dermatomyositis, Juvenile dermatomyositis, Inclusion body myositis
Dermatomyositis body involvement?
Skeletal Muscle, skin
Polymyositis body involvement?
Muscle only, not skin
Dermatoymyositis and Polymyositis location of muscle involvement? Distinguishes from what other disorder?
DM and PM only have proximal muscle involvement.
Inclusion body myositis will have distal muscle involvement too.
3 skin findings seen in dermatomyositis?
- Heliotrope rash (rash of the upper eyelids)
- Malar rash
- Gottron papules (red papules on the elbows, knuckles, and knees)
Dermatomyositis can be confused with what other disorder? What lab and clinical findings are similar?
Can be confused with SLE.
Patient can have +ANA, malar rash
What lab finding can help differentiate dermatomyositis from SLE?
+ anti-Jo-1 antibody can be seen in dermatomyositis
What 2 disorders are shown here? Which one is which?
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
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?
“Mechanic Hands”
seen in Anti-synthetase Syndrome
- anti-Jo-1 antibody
Fever, Arthritis, +/- Raynauds, ILD
“Jo is the F-A-M-IL-y Mechanic”
Inflammatory myopathies is associated with what pathologic disorders? (just look at the answer. couldnt figure out a way to ask)
12% of myositis cases associated with malignancy (breast cancer, adenocarcinoma)
- DM = 81%, PM = 19% of malignancies
CD4+ T cells are associated with what myositis?
Dermatomyositis
CD8+ T cells are associated with what myositis?
Polymyositis
Biopsy of dermatomyositis will show what?
Perimysial inflammation (CD4+ T cells) with perifascicular atrophy
As opposed to polymyositis that shows Endomysial inflammation (CD8+ T cells) with necrotic muscle fibers
Necrosis of muscle fibers is associated with what myositis? Means what type of inflammation is going on?
Polymyositis
Endomysial inflammation (CD8+ T cells) with necrotic muscle fibers
If there is upper extremity distal muscle weakness (in the fingers), what myositis are you thinking of?
Inclusion body myositis
- mostly proximal muscle weakness in lower extremities, distal in upper extremities
Inclusion body myositis seen primarily in what age/sex?
Older men
Which type of inflammatory myopathy doesnt respond to corticosteroids?
Inclusion body myositis
Does inclusion body myositis commonly involve organs? If so, which ones?
No, it doesnt
PMR stands for what?
Polymyalgia Rheumatica
Polymyalgia rheumatica symptoms?
Pain and stiffness in shoulders and hips, often with fever, malise, and weight loss
What is NOT seen in PMR?
Does not cause muscle destruction
What lab values are elevated in PMR?
What lab values are normal?
ESR, CRP elevated
CK normal (due to no muscle damage)
Polymyalgia Rheumatica is associated with what other disorder?
Temporal (giant cell) arteritis
Which is more common:
Patient with temporal arteritis develops PMR or Patient with PMR develops temporal arteritis?
- 50% of patients with temporal arteritis will develop polymyalgia rheumatic
- only 15% of patients with PMR as primary diagnosis will develop temporal arteritis
What are some symptoms of Temporal arteritis?
Systemic symptoms (fever, weight loss, fatigue)
temporal headaches
visual disturbances (can progress to sudden blindness)
jaw or tongue claudication
arthralgies
tender temporal artery
Dreaded complication of temporal arteritis?
Blindness
Describe microscopic apperance of giant cell arteritis?
giant cells (not always there), Inflammation of vessel wall, disruption of internal elastic lamina, intimal fibrosis
What treatment method is most effect for polymyalgia rheumatica? Distinguishing feature regarding this treatment method.
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
What are you looking at here? What is the key feature that gives it away?
Inclusion body myositis
KEY FEATURE = variation in muscle fiber sizes.
Muscular dystrophy defined as?
Degenerative disorder characterized by muscle wasting and replacement of skeletal muscle by adipose tissue
Deletion of dystrophin is associated with what disorder?
X-linked (Duchenne’s) Muscular Dystrophy
Mutation of dystrophin associated with?
Severity of this disease?
Becker muscular dystrophy.
Associated with milder form of disease
