Inflammatory Myopathies
The two major types of autoimmune, inflammatory myopathies
dermatomyositis and polymyositis
The antibody most specific for polymyositis/dermatomyositis
Anti-Jo1
Name a drug our patient was on that could have lead to myopathy
perimysial inflammation
purple discoloration of upper eyelid
Heliotrope rash
This disorder features CD8+ T cells and leads to endomysial inflammation
polymyositis
The antibody seen in dermatomyositis with malignancy risk, often in older adults
anti-TIF1-γ
Glycogen accumulation in muscle biopsies suggests this inherited enzyme deficiency
McArdle disease (myophosphorylase deficiency)
endomysial inflammation --> polymyositis
symmetric, red, scaly papules on hands/ fingers
Gottron papules
This disorder involves antibody mediated cellular damage
dermatomyositis
The main antibody involved in limited scleroderma
anti-centromere
These disorders show ragged red fibers
mitochondrial myopathies
Can have increased aldolase, myoglobin, and LDH
Both dermatomyositis and polymyositis
Progression of inflammatory myopathies' muscle weakness (using anatomical terms)
proximal --> distal weakness
This disorder is more often associated with paraneoplastic syndromes
dermatomyositis
The most specific antibody of SLE
Anti-Sm
Infections that can cause myopathies
HIV, influenza, Coxsackie
Level of ESR in inflammatory myopathies
elevated (OR NORMAL)
Associated conditions of inflammatory myopathies
Malignancy
Esophageal weakness
Myocarditis
Respiratory failure, ILD
This disorder is often confused as an inflammatory myopathy, but does not involve true muscle weakness
PMR
Autoimmune diseases with anti-RF antibodies (that we learned about)
RA, Sjogren's, SLE, scleroderma
Enzyme deficiency that leads to exercise intolerant myopathy
(Hint: carnitine shuttle)
carnitine palmitoyltransferase deficiency
The upregulation of this MHC molecule on muscle fibers is a hallmark of immune activation in polymyositis
MHC class I
Types of malignancies associated with inflammatory myopathies
adenocarcinomas (CLOBPS)
Cervix
Lung
Ovaries
Bladder
Pancreas
Stomach