Myopathies Flashcards
inflammatory myopathies
heterogenous group of muscle diseases
symmetric upper and lower PROXIMAL muscle weakening
also neck, abs, upper 1/3 esophagus, diaphragm, thoracic muscles, sphincter ani
Sx: GI (REFLUX, incontinence, intestinal bleeding), ILD, arthritis, HEART (myocarditis, CAD, arrhythmia)
can occur with other autoimmune CT disease
associated with: BREAST CA, ADENOCARCINOMA (DM more than PM)
lab: elevated CK, abnormal electromyograms
Tx: corticosteroids, cytotoxic drugs
dermatomyositis
more in females
5-15 yrs, 45-60 yrs
SKIN
bigger association with: BREAST CA and ADENOCARCINOMA
perivascular infiltrates: PERIMYSIAL, CD4 T cells (macrophages, dendritic cells, B cells)
anti-Jo-1
myopathy
associated with arthritis
antisynthetase syndrome
anti-Jo-1
Sx: MYOSITIS, non-erosive symmetric polyarthritis of SMALL joints, MECHANIC’s HANDS
amyopathic dermatomyositis
Sx: DM type rash, NO myositis (can develop late), SEVERE ILD
juvenile dermatomyositis
peak onset: 6-11 years
Sx: CALCINOSIS, cutaneous ULCERATION, LIPODYSTROPHY
inclusion body myositis
MEN over 50
histo: sarcoplasmic and nuclear INCLUSIONS with RIMMED VACUOLES
Sx: insidious muscle weakness in over MONTHS to YEARS localized to THIGH and FINGER FLEXORS
PROXIMAL LOWER extremities, DISTAL UPPER extremities
RESISTANT to GLUCOCORTICOIDS
ENDOMYSIAL, CD8 T cells (and macrophages), mononuclear inflammatory cells surround and invade non-necrotic muscle fibers
MHC CLASS I
polymyositis
more common in females
late teens, older 50-60 yrs
ENDOMYSIAL, CD8 T cells (and macrophages), mononuclear inflammatory cells surround and invade non-necrotic muscle fibers
MHC CLASS I
complement, Ab, cytokines cause endothelial damage, hypoxia, capillary loss leads to loss of skeletal muscle fibers
anti-Mi2
Ab: nuclear helicase
dermatomyositis
Ab against tRNA synthetases
associated with ILD
anti-PM-Scl
associated with overlap syndrome
includes features of scleroderma, mild muscle disease, arthritis, limited skin sclerosis
polymyalgia rheumatica (PMR)
over 50
AM STIFFNESS/PAIN SHOULDER/HIP: disuse leads to atrophy and weakness
bursitis (subdeltoid, subacromial), tendon inflammation, pitting edema in distal extremities
lab: elevated ESR
association: temporal giant cell arteritis (15%), carpal tunnel (10-15%) due to tenosynovitis
Tx: glucocorticoid (doesn’t respond then NOT PMR)
temporal (giant cell) arteritis
older, females
necrotizing inflammation of large sized arteries originating from aorta
GRANULOMA
Sx: headache, jaw claudication, visual, systemic, arthralgia, tender swollen temporal artery, upper respiratory
complication: AORTIC ANEURYSM (wide mediastinum)
association: polymyalgia rheumatica (50%)
IFN-y, macrophages, giant cells, MMPs
lab: elevated ESR, hepatic enzymes: AST, ALKALINE PHOSPHATASE
Dx: biopsy
Tx: glucocorticoids ASAP (so don’t go BLIND)
ESR (sed rate)
measures rate RBC gall through plasma in 1 hr
distance between the top of plasma level and the top of the sedimented RBC is ESR
indirect measure of fibrinogen levels, influenced by RBC properties
C-reactive protein (CRP)
direct measure of serum CRP
more SENSITIVE than ESR
wider range
X-linked muscular dystrophy
male, BIG CALVES, GOWER sign
DYSTROPHIN gene
Duchenne: deletion
Becker: mutated