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My name is Jemima Albayda.
I'm an Assistant Professor
at the Johns Hopkins University,
seeing patients
at the Division of Rheumatology,
Myositis Center.
Today, I will give you "An overview
of the Idiopathic
Inflammatory Myopathies".
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Our objectives with this talk
are to describe
the clinical presentation
of the idiopathic
inflammatory myopathies.
To define
the subgroups of myositis.
And present the framework
for current understanding
of classification.
To enumerate
the known antibody associations.
And discuss how they help guide
prognosis and management.
To detail the clinical evaluation
of myositis
and the role of ancillary testing.
And to briefly discuss
treatment strategies.
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The idiopathic
inflammatory myopathies
are a rare group of acquired
autoimmune muscle disorders.
Clinically, they are characterized
by muscle weakness
and by inflammatory cell
infiltrates in the muscle.
Although, it is thought
of as a muscle disorder,
it is quite heterogenous
in presentation
and treatment response.
Extramuscular manifestations
are often seen
and can include skin
and lung inflammation,
joint, heart,
and rarely GI tract involvement.
There's also a known increased risk
of malignancy,
particularly,
in cases of dermatomyositis.
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When we think about
how these diseases present,
certain features
are often considered.
There's usually
symmetrical weakness,
usually progressive
of the limb-girdle muscles,
such as the deltoids
and hip flexors.
There's elevation of serum levels
of muscle-associated enzymes,
such as creatine phosphokinase,
aldolase, LDH, and AST, and ALT.
There can be muscle biopsy
evidence of myositis.
And this can include
necrosis of type I
and type II muscle fibers,
phagocytosis, degeneration
and regeneration of myofibers,
and infiltrates,
which are inflammatory
involving the endomysial,
perimysial,
perivascular, interstitial spaces.
There is also often
electrophysiologic
evidence of myopathy.
And these can include short,
small, low-amplitude polyphasic
motor units potentials,
positive fibrillation potentials,
even at rest,
and bizarre high frequency
repetitive discharges.
In the case of dermatomyositis,
characteristic rashes
are often seen.
These features I mentioned
make up the core set
of the most commonly used
and widely accepted
criteria for myositis,
