3.2.2 Muscle Pathology I Flashcards
What are the characteristics of Dermatomyositis?
Proximal weakness
Rash - over 90% of the time
Complement deposition in capillaries
PERIVASCULAR INFLAMMATION - PERIMYSIUM
Associated with cancer - must screen individuals for cancers
What are some of the clinical features of the muscular dystrophy diseases?
Pelvic girdle weakness
Pseudohypertrophy of calf muscles
Initial CK increase and later decrease.
What determines whether a muscle cell will be a type 1 or type 2 muscle fiber?
The motor neuron
What is this an image of?
Neurogenic atrophy
Many nuclear clumps (end-stage fibers) seen as well as some endomysial fibrous tissue increase.
These are diseases like - ALS, vasculitis, trauma, nerve compression.
What is this an image of?
Muscular dystrophy
Endomysial fibrosis, regeneration, sometimes lymphocytes, rounded fibers, hypertrophic and smaller fibers can be seen.
Compare the Type 1 and 2 muscle fiber :
Action
Strength
Lipids
Glycogen
Physiology
Color
What is this an image of?
Inclusion body myositis with abnormal fiber with vacuoles
What are these images indicative of?
Dermatomyositis
Facial rash and perivascular inflammation
What are the characteristics of Inclusion Body Myositis?
What is this an image of?
Skeletal muscle - note the abundance of fat
What are the characteristics of Polymyositis?
Proximal weakness w/o skin involvement
ENDOMYSIAL PROCESS
Describe the pathological findings of Inclusion Body Myositis.
Inflammation and fibrosis
Intracytoplasmic vacuoles surrounded by basophilic granules: RED ON TRICHROME = RIMMED VACUOLES
What is this an image of?
Oil Red O stain for fat
What is this an image of?
Dermatomyositis
Perifascicular pattern of injury
Describe the inclusions in IBM.
What are some general features that might lead one to believe there is a myopathy?
Fiber size variability
Fiber splitting
Degeneration/regeneration (basophilia)
Increased centralized nuclei
What is found in these capillaries in regards to dermatomyositis?
Membrane attack complex. Dermatomyositis has abnormal activation of MAC
What is the difference between these two images?
Left - Normal staining with dystrophin
Right - Duchenne MD with dystrophin staining
What is this an image of?
Dermatomyositis
Perifascicular pattern of injury - cells on the outside are smaller than the cells on the inside
What is being stained dark and what is being stained light?
Dark - Type 2 fibers
Light - Type 1 fibers
What type of stain is this?
PAS stain for glycogen
What is this an image of?
Inclusion body myositis
Gomori trichrome showing rimmed vacuoles.
What are some of the characterisitcs of neurogenic atrophy?
Disease of the anterior horn cell or its axon
Initial - individuals atrophic angular fibers
Later - groups of atrophic angular fibers
