Msck - disease of the Skeletal muscle Flashcards

1
Q

immunohesitochemistry used to stain Monocytes

A

NADH-HR

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2
Q

Myosin ATP-ase; pH: 4.3 Vs Myosin ATP-ase; pH: 9.4 for Type I/II muscle fibers

A
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3
Q

Type I vs Type IIA vs Type IIB muscle fibers on Histology

A
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4
Q

Denervation Atrophy invloves ——– fibers

A

Type I and Type II fibers

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5
Q

Disuse Atrophy involves —— fibers

A

Type II fibers only

* unlike Denervation atrophy which involved type I and II

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6
Q

Causes of Disuse Atrophy

A

Prolonged immobilisation
(not using muscles enough so –> muscles break down and decrease in size)

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7
Q

Histology of Denervation Atrophy:
▪ Involvement of ——– fibres
▪ Small and ———- as well as ———-
▪ Fibre ———–, after re-innervation

A

▪ Involvement of both type I and type II fibres
▪ Small and angular fibers as well as target fibres
▪ Fibre type grouping, after re-innervation

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8
Q

Histopatho:
▪ Involvement of both type I and type II fibres
▪ Small and angular fibers as well as target fibres
▪ Fibre Type grouping, after re-innervation

features of?

A

Denervation Atrophy

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9
Q

what do you obsever , what condition causes this?

A

Target fibers caused by Denervation Atrophy

* traget fibers are normally found on type I fibers

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10
Q

Histology of Disuse Atrophy:
——— of type II fibers

A

Angular Atrophy of type II fibers

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11
Q

Muscular Dystrophies examples

A

1) Duchenne Muscular Dystrophy
2) Becker Muscular Dystrophy

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12
Q

CF of muscular dystrophies

A

Progressive muscle wasting and weakness due to degenration of Skeletal muscles

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13
Q

Lab findings of Muscular Dystrophies

A

Increased serum Creatine kinase (CK)

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14
Q

cause of Duchenne muscular dystrophy

A

X-linked disroder –> De novo mutations of the Dystrophin gene (Deficiency of Dystrophyin)

* X-linked recessive

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15
Q

Epi of Duchenne muscular dystrophy

A
  • Male children
  • most common/sever muscular dystrophy
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16
Q

Duchenne muscular dystrophy

Microscopic findings:
- Random variation in muscle fibre ——–
- ———— perimysial and endomysial fibrosis
- Basophilic regenerating myotubes
- Amorphous pink cytoplasm in —————
- Many, irregularly scattered ———–

A
  • Random variation in muscle fibre size
  • moderate perimysial and endomysial fibrosis
  • Basophilic regenerating myotubes
  • Amorphous pink cytoplasm in necrotic msucle
  • Many, irregularly scattered hyaline fibers
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16
Q

Microscopic features:
- Random variation in muscle fibre size
- moderate perimysial and endomysial fibrosis
- Basophilic regenerating myotubes
- Amorphous pink cytoplasm in necrotic msucle
- Many, irregularly scattered hyaline fibers

features of?

A

Duchenne muscular dystrophy

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17
Q

Lab findings of Duchenne Muscular dystrophy

A

Increased serum CK

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18
Q

What do you observe + found in what condition?

A

Many, irregulary scattered Hyaline fibers –> found in Duchenne muscular dystrophy

19
Q

CM of Duchenne muscular dystrophy

A

1) Proximal muscle weakness of the extremities –> immobolization, wasting, muscle contracture (death due to pneumonia)
2)Enalrgement of the calves (Compensatory hypertrophy of distal sites)

20
Q

Cause of Becker Muscular dystrophy

A

Abnormality in Dystrophin caused by segmental deletions within the gene

21
Q

CM of Becker muscular dystrophy

A

similar to Duchenne but less severe

22
Q

Becker muscular dystrophy

Microscopic features:
- —— to —— Endomysial and Perimysial fibrosis
- ——- Hyaline fibers
- Variation in muscle fiber size

A

Microscopic features:
- mild to light Endomysial and Perimysial fibrosis
- No Hyaline fibers
- Variation in muscle fiber size

23
Q

Microscopic features:
- mild to light Endomysial and Perimysial fibrosis
- No Hyaline fibers
- Variation in muscle fiber size

features of?

A

Becker Muscular dystrophy

24
Q

Cause of Facio-scapulo-humoral muscular dystrophy

A

Autosomal Dominant Disorder

25
Q

CM of Facio-scapulo-humoral muscular dystrophy

A
  • Slowly progressive, non-disabling course
  • Sequential involvement of muscles of the face, scapular area and humerus
26
Q

Facio-Scapulo-Humoral muscular dystrophy involves?

A

Sequential involvement of muscles of the face, scapular area and humerus

27
Q

Microscopic features:
- severely atrophic fibers
- Marked variation of musclel fiber size
- Grossly hypertrophied fibers
- Prominant intertitial fibrosis

features of?

A

Facio-Scapulo-Humorla muscular Dystrophy

28
Q

cause of Limb Gridle Dystrophy

A

Autosomal recessive Disorder

29
Q

what muscles are affected by Limb Gridle Dystrophy

A

proximal muscles of the shoulder,
pelvic girdle (bony pelvis) or both

30
Q

Microscopic features:
- Variation in muscle fiber size
- Greatly Hypertrophied fibers
- Endomysial fibrosis
- Atrophic fibers

features of?

A

Limb Gridle dystrophy

31
Q

Cause of Myotonic Dystrophy

A

AD inheritance –> Trinucleotide repeat (CTG) disorder (repeats in Myotonin protein kinase gene)

32
Q

Myotonic dystrophy is an AD disorder –> Trinucleotide repeat —– (repeats in ———— gene)

A

AD inheritance –> Trinucleotide repeat (CTG) disorder (repeats in Myotonin protein kinase gene)

33
Q

CF of Myotonic Dystrophy

A

1) Muscle weakness w/ Myotonia (inability to relax muscles once contracted)
2) Cataracts
3) Testricular Atrophy
4) Baldness (males)

34
Q

Myotonic Dystrophy

Microscopic features:
Many of the small fibres with a ————

A

Many of the small fibres with a central nucleus

35
Q

Congenital Myopathies are disorders characterised by —————– (marked hypotonia at birth)

A

characterised by floppy infant syndrome (marked hypotonia at birth)

36
Q

Lab findings in Congenital Myopathies

A

Normla serum CK

37
Q

The 3 types of Congenital Myopathies

A

➢ Central Core Disease
➢ Nemaline Myopathy
➢ Mitochondrial Myopathies

38
Q

* Congenital myopathy

Patho of Central core disease:
Loss of ———— and other organelles in the ———- portion of type —- muscle fibres

A

Loss of mitochondria and other organelles in the central portion of type I muscle fibres

39
Q

CM of central core disease

A

Muscle weakness and hypotonia (Decreased muscle tone)

40
Q

Microscopic findings:

features of?

A

Central core disease

41
Q

Microscopic findings:
Tangles of small rod-shaped granules (“Rod bodies”), predominantly in type I fibres

feature of?

A

Nemaline Myopathy

42
Q

Distinctive micro featurs of Nemaline Myopathy

A

“Rod bodies” in type I fibers

43
Q

CM of Nemaline Myopathy

A

Variable clinical presentation; from mild, non- progressive disease to severe weakness → Death from respiratory failure

44
Q

Cause of Mitochondrial Myopathies

A

Non-Mendelian inheritance
Maternally transmitted mitochondrial DNA abnormalities

45
Q

Microscopic features:
“Ragged red” appearance of muscle fibres
▪ Various mitochondrial enzyme or co-enzyme defects (detected by immuno-histochemistry -NADH-TR)

features of?

A

Mitochondrial Myopathies

46
Q

Distinctive micro features found in Mitochondrial Myopathies

A

“Ragged Red” appearance of muscle fibers