Pathology - Skeletal Muscle Pathology Flashcards
what are the characteristics of muscular dystrophies
muscle fiber necrosis and regeneration
what is Duchenne muscular dystrophy?
X-linked, loss of function mutation of a structural protein call dystrophin
what is the most common muscular dystrophy
Duchenne Muscular Dystrophy
Dystrophin is a key component of the
dystrophin glycoprotein complex
the dystrophin glycoprotein complex provides
mechanical stability to the muscle fiber and it’s cell membrane during muscle contraction
defects in the dystrophin glycoprotein complex can lead to what?
sarcolemma tears: calcium influx from ECF -> ultimately triggering muscle fiber necrosis
for Duchenne muscular dystrophy, weakness begins in ? and extends to ?
pelvic girdle muscles
shoulder girdle
what is a test for Duchenne muscular dystrophy?
Gower’s sign
For Duchenne muscular dystrophy patients, what is remarkedly elevated in first decade of life then decreases as diseases progresses
creatine kinase
what is generally similar but less severe than Duchenne Muscular dystrophy and has slower progression
Becker Muscular Dystrophy
what is becker muscular dystrophy?
X-linked mutation in dystrophin which results in truncated dystrophin protein that retains partial function
what is myotonia?
sustained involuntary muscle contractions
what is myotonic dystrophy?
autosomal dominant disorder caused by expanision of triplet repeats
what are the two types of myotonic dystrophy
type I and II
what is type I myotonic dystrophy?
expansion of CGT trinucleotide repeat within the myotonic dystrophy protein kinase (DMPK) gene
what is type II myotonic dystrophy?
CCTG repeat expansion within the gene nucleic acid-binding protein (CNBP) gene
what is the most common drug-related myopathy?
statin myopathy
myopathy is thought to result from?
- Decreased cholesterol concentrations may impact sarcolemma
- Depletion of Coq10 (Ubiquinone)
what is myasthenia Gravis?
Autoimmune condition associated with autoantibodies directed against acetylcholine receptors
what is a tumour of thymic epithelial cells
thymoma
what are common initial findings of myasthenia gravis?
ptosis and diplopia
what is a red flag for myasthenia gravis?
Myasthenic crisis
what is the first line of treatment for myasthenic crisis?
acetylcholinesterase inhibitors
what are two common types of skeletal muscle tumours
rhabdomyosarcoma and synovial cell sarcoma
what is the most common soft tissue sarcoma of childhood?
alveolar and embryonal rhabdoomyosarcoma
what are the 4 subtypes of rhabdomyosarcoma
Alveolar, Embryonal, Pleomorphic, Spindle cell/sclerosis
what is rhabdomyosarcoma?
malignant mesenchymal tumour with skeletal muscle differentiation
what is the malignant cell of rhabdomyosarcoma?
rhabodomyoblast
what are rhabodomyoblast rich in
myosin and actin filaments
what is the most common soft tissue tumour in adolescents and young adults?
synovial cell sarcoma
what is fibromyalgia?
Syndrome of persistent widespread pain, stiffness, fatigue, disrupted sleep, and cognitive difficulties. It is often accompanied by anxiety/depression and impairment of activities of daily living.
what is used to diagnose fibromyalgia?
widespread pain index - score of 0-19
AND
Self-adminstered patient questionnaire - score of 0-12
what is chronic fatigue syndrome
Characterized by unexplained and profound fatigue that is worsened by exertion
- Accompanied by cognitive dysfunction and impairment of daily functioning that persists for at least 6 months
what is another name of chronic fatigue syndrom
Myalgic encephalomyelitis
