Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

NYCC MSP > Non-Inflammatory Muscle Pathology > Flashcards

Non-Inflammatory Muscle Pathology Flashcards

(56 cards)

Start Studying
1
Q

Widespread muscular necrosis is called ____

A

rhabdomyolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

In terms of location, muscular necrosis can be ____ or ____

A

widespread or segmental (localized)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cells around the outside of muscle cells that maintain the muscle cell are called ____

A

satellite cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Explain the steps of segmental regeneration of muscle

A
  1. injury to m. fiber causes segmental disintegration of sarcoplasm
  2. macrophages accumulate & penetrate the basement membrane to phagocytose sarcoplasmic contents
  3. activated satellite cells proliferate forming myoblasts
  4. macrophages leave w/ debris
  5. myoblasts align in center of fiber and begin to fuse
  6. fiber continues to regenerate until normal (up to 6mo)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Name 3 non-inflammatory muscle pathologies

A
  • Rhabdomyolysis
  • Duchenne muscular dystrophy
  • Becker muscular dystrophy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the etiology of Rhabdomyolysis?

A

skeletal muscle trauma
(also side effect of statin drugs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens to muscle in Rhabdomyolysis?

A

diffuse, widespread, varying degrees of necrosis & regeneration of muscle fibers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How long can Rhabdomyolysis last?

A

can be acute, subacute, or chronic (eg. exercise induced compartment syndrome)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What will a biopsy of Rhabdomyolysis show?

A

clusters of macrophages in and around muscle fibers
(sarcoplasmic contents poured into circulation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the risk factors for Rhabdomyolysis?

A
  • Drugs: statins (eg. for hypercholesterolemia), cocaine, amphetamines
  • trauma (crushing inj), severe exertion
  • metabolic myopathies
  • alcoholism
  • heat intolerance/stroke
  • influenza (muscle soreness = cell lysis)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the clinical manifestations of Rhabdomyolysis?

A
  • swelling, tenderness, & ++ weakness in mm
  • fatigue
  • joint pain
  • diffuse muscular pain
  • ^creatinine kinase, K+, creatine in blood
  • myoglobinuria –> acute renal failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why might patients with Rhabdomyolysis present with joint pain?

A

Hilton’s law
not a joint problem, but shared innervation with involved muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How would Rhabdomyolysis affect urine?

A

Myoglobinuria (myoglobin dumped into urine) causing tea-coloured urine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What causes acute renal failure in patients with Rhabdomyolysis?

A

myoglobin dumped into urine damages kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the possible treatments for Rhabdomyolysis?

A
  • early & aggressive hydration to prevent kidney damage
  • diuretics
  • address hyperkalemia & low blood Ca2+ levels
  • prognosis varies depending on extent of kidney damage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Are muscular dystrophies cureable?

A

No, they are progressive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the general muscle characteristics of muscular dystrophies?

A
  • fiber necrosis w/ regeneration (imbalanced)
  • progressive fibrosis (eventual loss of contractility)
  • infiltration by fatty tissue (marbling)
  • no inflammation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What form(s) of muscular dystrophy is/are seen in pediatric patients?

A

X-linked: Duchenne & Becker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What form(s) of muscular dystrophy is/are seen in adults?

A

Myotonic dystrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the etiology of Duchenne muscular dystrophy?

A
  • X-linked recessive inheritance (passed by mother)
  • Xp21 gene mutation = no dystrophin produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What sex is primarily affected by Duchenne muscular dystrophy?

A

males
(only 1 X chromosome to mutate; not likely to survive to reproduce)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the function of dystrophin?

A
  • links sarcolemma (m. cell mem.)to muscle cell fibers
  • transfers force from fibers to membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Describe the pathogenesis of Duchenne muscular dystrophy

Study These Flashcards
A
  • lack of dystrophin influences ^influx of Ca2+ (hypercontraction) & release of soluble m. enzymes (eg. creatine kinase) into serum
  • breakdown of sarcolemma –> necrosis & repair
  • progressive m. fibrosis
  • necrosis > repair
  • m. fibers replaced by fibrofatty CT
  • late stage: extrafusal fibers disappear
24
Q

Duchenne muscular dystrophy primarily affects ____ fibers, but ____ fibers are still numerous

Study These Flashcards
A

extrafusal; intrafusal/spindle

25
What are the clinical manifestations of Duchenne muscular dystrophy?
- **pseudohypertrophy of calves** - ^serum creatine kinase - abnormal m. morphology in utero - developmental/intellectual delays by 2-3yrs of age - m. weakness by 3-4yrs (hips & shoulders initially) - toe walk; waddling gait - hyperlordosis & scoliosis - falling, difficulty running/jumping/stairclimbing & getting up from floor - GI issues (less motility; smooth m)
26
What is pseudohypertrophy of the calves?
muscle fibers replaced by fibrofatty CT in calves, causing appearance of hypertrophied calf muscles (Duchenne MD)
27
Where does muscle weakness begin in Duchenne muscular dystrophy?
Pelvic (hip) and shoulder regions
28
What are the typical outcomes of Duchenne muscular dystrophy?
- wheelchair bound by age 10 - bedridden by age 15 - death occurs due to respiratory insufficiency (diaphragm) or cardiac arrhythmia by age 20
29
What is the etiology of Becker muscular dystrophy?
truncated dystrophin protein
30
How does Becker MD compare to Duchenne MD?
- lower quality rather than absent dystrophin - milder & later onset (better neural function)
31
What are the clinical manifestations of Becker muscular dystrophy?
- exercise intolerance (m. cramping) - rhabdomyolysis - myoglobinuria
32
Name 3 congenital myopathies
- central core dz - rod myopathy - central nuclear myopathy
33
Congenital myopathies are also called ____
"floppy baby/child syndromes" (don't develop head control)
34
What is the primary symptom of congenital myopathies?
hypotonia - decreased DTRs - decreased m. volume
35
Name an example of a condition with severe hypotonia that results in death within the first year of life
Spinal muscular atrophy (Werdnig-Hoffman Dz)
36
What is the 2nd most common lethal autosomal recessive condition?
Spinal muscular atrophy
37
What is the most common lethal autosomal recessive condition?
cystic fibrosis
38
What is the etiology of Central core disease?
chromosome 19 mutation of gene coding for ryanodine receptors (autosomal dominant)
39
What is the function of ryanodine receptors (RyR)?
help control Ca2+ release from SR
40
Central core disease primarily affects ____ fibers
type I (slow twitch)
41
How do biopsied muscle fibers appear in Central core disease?
- involved fibers show **central area of degeneration** - may resemble fibers in denervating conditions, but no associated denervation present
42
Central core disease puts individuals at higher risk for ____
malignant hyperthermia
43
What are the clinical manifestations of Central core disease?
children will become ambulatory but have less than normal muscle strength
44
What is malignant hyperthermia?
- spike in body temperature occurs after anesthesia - Rhabdomyolysis or m. damage results from ^Ca2+ release through mutated RyR in SR
45
How is Malignant hyperthermia treated in patients with Central core disease?
dantrolene (binds to RyR)
46
What is the etiology of Rod myopathy?
- various mutations, most commonly affecting Nebulin (connects z-line to actin)
47
Describe the pathogenesis of Rod myopathy
- rod-like inclusions arise from Z-band and accumulate in sarcoplasm - inflammation & denervation not present - non-progressive
48
What are the clinical manifestations of Rod myopathy?
- hypotonia - delayed motor milestones - secondary skeletal changes (kyphoscoliosis) - may involve mm of face, pharynx, neck - m. degeneration (late onset) - ^serum creatine kinase
49
What causes scoliosis in congenital myopathies?
lack of postural tone
50
What is the best indicator of muscular breakdown on lab findings?
^serum creatine kinase
51
What is the etiology of Central nuclear myopathy?
autosomal recessive or dominant mutations of dynamin 2
52
What are the clinical manifestations of Central nuclear myopathy?
facial & extraocular involvement (**bilateral ptosis**)
53
What is ptosis?
drooping of upper eyelid
54
What is the function of dynamin 2?
endocytosis, membrane function & actin assembly
55
Describe the histologic appearance of Central nuclear myopathy?
single, centrally located nucleus in skeletal m cells
56
Central nuclear myopathy primarily affects ____ fibers
type I

NYCC MSP (44 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions