Zaman Muslce path
Terms in this set (61)
the histochemical type of a given myofiber is determined by its
Type 1 fibers
slow twitch dark red get energey via oxid phos
fast twitch white get ATP anarobie glyco
fast twitch intermediate bw 1 and 2b
In what pathology can treatment alter histopathologic findings
How do you distinguish bw myopathy and neuropathy
For these you do what:
genetic or ther testing
biopsy NOT indicated
What is the single most importatn blood value to obtain when myopathy is being considered
serum creatine kinase
Denerevation in a muslce will cause what mainly
Necrosis and regeneration proceed together in which
-see infiltration by macrophages
Myonecrosis occurring over a long time results in lost muscle which is replaced by what
adipose tissue and collagen
What is myopathy to a pathologist
its a muscle ds w MYONECROSIS and STRUCTRUAL abnormalities
This atropy mainly affects Type 2 fibers
Prolonged bed rest/immobilization
Proximal affected more than distal
Atropy w muslce fasiculations
BOTH fibers affected
Fibers cluster in groups
The most common motor neuron ds in adults?
What virus is involved?
amyotrophic lateral sclerosis (ALS)
autosomal recessive spinal muscular atrophy
Enteroviruses (Polio + West Nile Virus)
Characterized by severe wasting or absence of muscles and contractures present at birth
Depletion of anterior horn cells
Arthrogryposis multiplex congenita
When you stain muslce with ATPase stain and observe clustering instead of random checkerboard distribuation the dx
Q you see type 2 on left side and type 1 on right
In this condition skeletal muscle is turned into fibrofatty tissue
Variation in muscle fiber size
whats the mutation
spontanous dystrophin mut: anchors muslce cystoskel to extracell matrix
-this is bc gene is so large so large mut rate
Pt presents w proximal muscle wakness at 1 year which progresses distally
Deletion in dystrophin X chromosome (Xp21)
Serum Cr kinase elevated
Death is from respiratory failure
-pseudohyper of calf is bc of all the fat
In this MD there is a mutation of dystrophin -> dimished amounts
It is mild ds
Death from Cardiac failure
live longer so get higher chance to have heart problems
The key pathology of DMD and BMD is?
What chromosome is dystrophin located on
X chromosome (Xp21)
Affects Proximal muscl
Mutation in Sarcoglycan complex
Limb gridle dystrophy (LGMD)
This LGMD is as sever as Duchenne
severe childhood autosomal recessive muscular dystrophy" (SCARMD)
There is a mutation in
laminin a2 (merosin)
or enzyme that glycosylates alpha-dystrogylcan
Hypotonia (flacid baby)
low ABGAR scores
CONGENITAL MUSCULAR DYSTROPHIES
enzyme that glycosylates alpha-dystrogylcan leads to what finding in CMD
neuronal migration defects, especially PACHYGYRIA (also seen in Zellweger Syndrome)
-this is bc there is abn that impairs migration of neurons
sever contractures in elebows and ankles
gene Xq28 mut
older dx, assoc w swallowing
facial and distal muscles weakness
Cant let go of HANDSHAKE
Respiratory insuff in newborns
Histo: atrophy of type 1 fibers +
This type of Myotonic dys is cased by
CTG trinucleotide expansion
Gene is expanded over 37 CTG repeats
caused by a CCTG expansion of the ZNF9 (Zink Finger Protein 9) gene on 3q21.
onset of the disease is earlier with each successive generation
These myopathies are PRIMARY muscle disorders
Unlike dystrophies these have mut of contractile and structural proteins and accum of abn proteins in sarcoplasm
These have Dysmorphic Facial features
FUNNY LOOKING KIDS
myotonia induced by vigorous exercise, cold
Can be hyperkalemic, hypokalemic, and normokalemic
Glycogenosis type 5 mut
Glycogenosis type 7 mut
histo on both shows "white holes" in the muscle
phosphorylase deficiency, McArdle disease
both impair use of glycogen for energy
muscle may look normal.
-the previous mutations
lysosomal storage of glycogen in skeletal and cardiac muscle, due to deficiency of acid MALTASE, causes hypotonia, cardiomyopathy, and death in infancy.
glycogenosis type II (Pompe disease),
affect more severely muscle and brain
weakness and ophthalmoplegia
"RAGGED red fiber"
large numbers of abnormal mitochondria
A 14 yr old boy presents with stroke like episodes (MELAS)
Sore muscles WITHOUT Exercise
Myonecrosis and mononuclear inflammatory infiltrates
Elevated CK & ESR.
polymyositis, dermatomyositis, and inclusion body myositis.
-cant tell differ on histo bw them so dont worry about it but on all of them you will see a lot of inflammatory infilatres
Involves Proximal muscles first
Scleroderma, Raynaud phenomenon, interstitial pneumonitis, and renal involvement
Abs to tRNA synthetases.
Atrophy predominantly at the periphery
NADAH stain shows PERIFASICULAR atrophy
Membrane attack complex of complement (MAC)
the most common muscle disease in old people.
Sporadic inclusion body myositis (IBM)
Begins w invovement of distal msucles
Mild CK elevation.
Myofibers with vacuoles or cracks
Paired helical filaments similar to those of Alzheimer's disease
Histo: beta amyloid, tau protein, apolipoprotein E, presenillin 1, PRION protein
Basically Alzheumers of muscles
What is PM/DP TX?
PM and DM are treated with corticosteroids. Azathioprine , methotrexate, and cyclosporin are used in severe cases.
IBM is REFRACTORY to corticosteroids and immunosuppressive agents
Progressively increasing weakness with exertion and recovery of strength with rest or following administration of anticholinesterase
Extraocular and facial muscles, PTOSIS, DIPLOPIA, and inability to chew.
Death is due to respiratory compromise
-an IgG autoimmune ds w autoabs against the postsynaptic Ach R at NMJ
-nota bene: the reason you get weakness w use is bc the autoantibodies COMPETE with Ach so at the beginning of use Ach can kcik of Autoabs but as you use them more the Ach dec in amount and AutoAs win. Thus with rest you get inc in Ach again so symptomes improve
What tumor is MG assoc w
Thymic Hyperplasia or Thymoma
-Thymectomy improves symptomes
Pt comes in w proximal muscle weakness that improves w use
The Eyes are fine
Anticholinesterase does nothing for him
This develops classicly as a paraneoplastic process MC in setting of which cancer?
Small Cell Lung Cancer
- it is Lambert-Eaton Syndrome
Unlike in MG the Lambert-Eaton AutoAbs are against what?
presynaptic Ca shannels
All Skeletal Muscle tumors are
benign or malignant?
-the benign rhabomyoma is rare
Most common soft tissue sarcoma of childhood & adolescence
Mostly in Head and Neck
KNOW think that it affects mostly young children 2 to 13
MC subtype of Rhabdomyosarcoma
Histo: see high cytologic variabilty w several stages of skeletal muscle morphogenesis
Which stain is most specific for Rhabdomyosarcoma
extremities, the trunk
club-shaped tumor cells
subset of embryonal rhabdomyosarcoma
Body orifices like vagina
Grapelike tumor masses
fascicular, spindled, and leiomyomatous growth pattern
Spindle cell rhabdomyosarcoma
Lobate hyperchromatic nuclei and multipolar mitotic figures
This has the worst prognosis of rhabdomyosarcoma
followed by chemotherapy
ending with radiation
This is really the only tumor that is painful
Blunt-ended, elongated nuclei
painless firm masses.
Solitary -> can be HUGE
Mitotic figure per 10 high power field
'mitotic hot spots'
KIT NEG (CD117)
Only way to differ GIST from LMSC is via
GIST is Postive
LMSC is negative
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