L6: Myopathy Flashcards
(145 cards)
1
Q
Skeletal muscle constitutes the principal organ of locomotion.
A
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2
Q
There is more than 600 separate muscles, this tissue makes up as much as 40% of the weight of adult human beings.
A
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3
Q
- The muscle fibers are attached at their ends to tendon fibers —-> connect with the skeleton.
- By this means, muscle contraction maintains posture and produce movement.
A
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4
Q
Histology of Muscle Fibers
- Types of Muscles
A
Red and White (human muscles are composed of both types)
5
Q
Histology of Muscle Fibers
A
6
Q
- Each lower motor neuron supplies a bundle of muscle fibers but each M.F. is innervated by only one axon.
A
…
7
Q
Def of Motor Unit
A
is a motor neuron and all the muscle fibers it innervates.
8
Q
Examples of Motor Unit
A
- In Ocular muscles: a motor unit contains only 6 to 10 muscle fibers.
- In Gastrocnemius: a motor unit contains as many as 1,800 fibers
9
Q
Physiology of Muscle Fibres & muscle Contraction
A
10
Q
Manifestations of Muscle Diseases
A
11
Q
Def of Progressive Muscular Dystrophy
A
- Group of genetically determined primary degenerative muscular disorders characterized by muscular weakness and wasting (myopathy).
12
Q
Pathogenesis of Progressive Muscular Dystrophy
A
- A defect in muscle fiber plasma membrane → uncontrolled entry of calcium → activates calcium dependent protease → muscle fiber necrosis.
- The missing gene product is a protein called Dystrophin.
13
Q
Pathology in Progressive Muscular Dystrophy
A
14
Q
Classification of Progressive Muscular Dystrophy
A
15
Q
Classification of Progressive Muscular Dystrophy
- X-Linked Recessive
A
- Severe (Duchenne).
- Benign (Becker).
16
Q
Classification of Progressive Muscular Dystrophy
- AD
A
- Facio-scapulo-humeral.
- Scapulo-peroneal.
- Limb girdle.
- Distal.
- Ocular
- Oculo-pharyngeal.
17
Q
Classification of Progressive Muscular Dystrophy
- Autosomal Recessive
A
18
Q
Age in Becker Muscle Dystrophy
A
at 5-20 Years
19
Q
Course of Becker Muscle Dystrophy
A
Slowly progressive and does not shorten life.
20
Q
Sex in Duchenne Muscle Dystrophy
A
Affects Boys & Females are carriers. → due to It is X-linked s
20
Q
Age in Duchenne Muscle Dystrophy
A
- Between 3 -10 years.
- The child appears normal at birth and in the first year of life.
21
Q
Onset of Duchenne Muscle Dystrophy
A
Gradual
22
Q
Course of Duchenne Muscle Dystrophy
A
Rapidly progressive
23
Q
Site affected in Duchenne Muscle Dystrophy
A
Pelvic girdle, then Shoulder girdle muscles.
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CP of **Duchenne Muscle Dystrophy**
25
CP of **Duchenne Muscle Dystrophy**
- Which Side?
Bilateral & Symmetrical
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CP of **Duchenne Muscle Dystrophy**
- Proximal or Distal?
Proximal more than distal
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CP of **Duchenne Muscle Dystrophy**
- Symptoms
- Slow Walking, inability to Run, frequent Falling.
- Difficulty in Climbing stairs, Putting on and Taking off clothes.
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CP of **Duchenne Muscle Dystrophy**
- Shoulders
Sloping shoulders
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CP of **Duchenne Muscle Dystrophy**
- Scapulae
Winging of scapulae
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CP of **Duchenne Muscle Dystrophy**
- Spine & pelvis
- Exaggerated Lumbar Lordosis, protuberant abdomen, pelvis is tilted forward due to: Weak Glutei, so lordosis compensates this tilting and it disappears with sitting.
31
CP of **Duchenne Muscle Dystrophy**
- Muscle Hypertrophy?
32
CP of **Duchenne Muscle Dystrophy**
- Gait
33
CP of **Duchenne Muscle Dystrophy**
- Signs
34
CP of **Duchenne Muscle Dystrophy**
- Ambulation
Ambulation is lost at age of about 10 years.
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CP of **Duchenne Muscle Dystrophy**
- Reflexes
Reflexes are lost → With increasing weakness and progressive muscle atrophy
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CP of **Duchenne Muscle Dystrophy**
- No .......
No fasciculations, sphincter disturbance, sensory changes.
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CP of **Duchenne Muscle Dystrophy**
- which Muscles are involved?
38
CP of **Duchenne Muscle Dystrophy**
- Speech
Delayed speech: development may occur.
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CP of **Duchenne Muscle Dystrophy**
- IQ
May be affected
40
Age in **Facio-Scapulo-Humeral Type**
starts in the 2nd decade
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Course in **Facio-Scapulo-Humeral Type**
Benign, arrest is common.
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Incidence of **Facio-Scapulo-Humeral Type**
Females are less severely affected than males.
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CP of **Facio-Scapulo-Humeral Type**
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CP of **Facio-Scapulo-Humeral Type**
- Transverse Smile
Elevators > Retractors
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Incidence of **Scapulo-Peroneal Type**
Rare Syndrome
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CP of **Scapulo-Peroneal Type**
Like Facioscapulohumeral but with no facial affection.
47
Inheritance of **Limb-Girdle Ms Dystrophy**
- Autosomal recessive in 90%,
- Autosomal dominant in 10%.
- Sporadic cases were reported
48
Age in **Limb-Girdle Ms Dystrophy**
Starts at 3rd Decade
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Course of **Limb-Girdle Ms Dystrophy**
Slowly Progressive
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CP of **Limb-Girdle Ms Dystrophy**
- More commonly starts in Shoulder Girdle more than Pelvic Girdle
- There may be enlarged calf muscles mildly.
- Usually limited for years before spread
- Severe disability occurs after about 20 years.
51
Inheritance of **Congenital Type Ms Dystrophy**
Autosomal recessive
52
CP of **Congenital Type Ms Dystrophy**
- Characterized by congenital or early infantile onset of weakness with variable CNS involvement including ocular.
- Epilepsy is common and although mental development is normal,
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MRI in **Congenital Type Ms Dystrophy**
white matter abnormalities
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Inheritance of **Distal Myopathy**
Some Are Autosomal Dominant & Some Are Autosomal Recessive
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Onset of **Distal Myopathy**
- Some begin in 4th - 6th decade
- Some patients show onset in childhood or early adult life-
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Age in **Occular Type Ms Dystophy**
Before 30 years
57
CP of **Occular Type Ms Dystophy**
1. External opthalmoplegia,
2. Progressive bilateral ptosis
3. Orbicularis oculi affection.
4. No pupillary changes
5. No diplopia (gradual bilateral symmetrical affection).
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Age in **Occulo-Pharyngeal Type**
Around 40 years old.
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CP of **Occulo-Pharyngeal Type**
Similar to ocular type but with dysphagia.
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Investigations in **Progressive Muscular Dystrophy**
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Investigations in **Progressive Muscular Dystrophy**
- EMG
Diminished duration and amplitude of motor action potential.
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Investigations in **Progressive Muscular Dystrophy**
- Urine
- Diminished creatinine
- Appearance of creatine.
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Investigations in **Progressive Muscular Dystrophy**
- Serum Enzymes
Increase and that's used to detect
- Female carriers and
- Preclinical diagnosis in males.
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Investigations in **Progressive Muscular Dystrophy**
- Muscle Bx
...
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TTT of **Progressive Ms Dystophy**
65
TTT of **Progressive Ms Dystophy**
- Steroids
It is now accepted that it prolongs ambulation
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TTT of **Progressive Ms Dystophy**
- Myoblast Transfer
Injecting the muscle with a huge number of myoblasts will give a transient improvement (but cost exceeds benefit).
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Def of ****Myotonic Disorders****
A group of M. disorders characterized by delayed relaxation of skeletal muscles after voluntary, mechanical or electrical stimulation.
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What Improves **Myotonic Disorders**?
1. Exercise (Repetition of movement)
2. Calcium
3. Warmth
4. Quinine and Procainamide.
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What Worsens **Myotonic Disorders**?
1. Rest
2. Cold
3. Potassium
4. Prostigmine.
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Types of **Myotonic Disorders**
1. Myotonic Dystrophy
2. Myotonia congenita
3. Paramyotonia congenita
4. Myotonia paradoxica
5. Acquired myotonia
6. Chondrodystrophic myotonia (Schwartz-Jample syndrome)
71
Age in **Myotonic Dystrophy**
20 - 50 Years
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Incidence in **Myotonic Dystrophy**
Male › female
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CP of **Myotonic Dystrophy**
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Age in **Myotonia Congenita**
1st & 2nd Decade
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Incidence of **Myotonia Congenita**
- Female more than male.
- Autosomal recessive & less frequently autosomal dominant
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CP of **Myotonia Congenita**
- Present since birth (Difficult Suckling).
- Generalized muscular hypertrophy and stiffness.
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PPT Factors for **Paramyotonia Congenita & Myotonia Paradoxica**
- Precipitated only by exposure to cold
- Exacerbated by exercise
78
**Acquired Myotonia** is associated with .....
Occurs with polymyositis and some cases of polyneuropathy.
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Another Name of **Chondrodystrophic Myotonia**
Schwartz-Jample Syndrome
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CP of **Chondrodystrophic Myotonia**
- AR
- Dwarfism
- Myotonia
- Skeletal deformities
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Prognosis of Myotonic Disorders
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Prognosis of Myotonic Disorders
- Myotonia Congenita
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Prognosis of Myotonic Disorders
- Myotonia Dystrophica
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Prognosis of Myotonic Disorders with anasethia
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TTT of **Myotonic Disorders**
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TTT of **Myotonic Disorders**
- Genetic Counseling
- Female carrying the gene may be asymptomatic but still at risk of having a child with sever congenital form of the disease so antenatal diagnosis based on chorionic villus sampling is needed.
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TTT of **Myotonic Disorders**
- ECG
regular
88
TTT of **Myotonic Disorders**
- Chest Infections
may be reduced by influenza and pneumococcus vaccination.
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TTT of **Myotonic Disorders**
- Anesthetia
The patient must carry a warning card explaining hazards.
90
TTT of **Myotonic Disorders**
- Cataract
Treated surgically.
91
TTT of **Myotonic Disorders**
- Drugs
- Procainamide (500 mg t.d.s.) & Phenytoin (100 mg t.d.s.)
- They are theoretically contraindicated because of their potential action on cardiac conduction but practically few problems have been reported.
92
TTT of **Myotonic Disorders**
- Speech therapy
to correct swallowing and dysarthria.
93
Def of **Myasthenia Gravis**
- Disorder of transmission of the myoneural junction characterized clinically by fatigability on repetition of muscular activity which may be relieved by rest and or cholinergic drugs.
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Pathogenesis of **Myasthenia Gravis**
It is due to an autoimmune process in which antibodies against acetylcholine receptors cause a disordered conduction in neuromuscular junction.
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Pathology of **Myasthenia Gravis**
96
Sex in **Myasthenia Gravis**
Female: male = 2: 1
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Age in **Myasthenia Gravis**
Mean age of onset: 26y in Females, 30y in Males.
98
**Myasthenia Gravis** is closely related to ......
- Thyrotoxicosis
- Rheumatoid arthritis
- M.S. (Multiple sclerosis)
- SLE. (Systemic Lupus Erythematosus)
- Biliary cirrhosis
- Cancer
99
CP of **Myasthenia Gravis**
...
100
Onset of **Myasthenia Gravis**
Gradual
101
Course of **Myasthenia Gravis**
progressive with remissions.
102
CP of **Myasthenia Gravis**
- site
Only skeletal muscles (smooth muscles are not involved).
103
CP of **Myasthenia Gravis**
- Symptoms
104
CP of **Myasthenia Gravis**
- Descending march
105
CP of **Myasthenia Gravis**
- Fluctiations in Myasthenia
106
CP of **Myasthenia Gravis**
- Muscle Bulk Affection
No
107
CP of **Myasthenia Gravis**
- smooth Musce affection
No
108
CP of **Myasthenia Gravis**
- Smile?
Retractors of mouth angle › elevators → Vertical or snarling smile.
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What induces remission of **Myasthenia Gravis**?
Pregnancy
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Dx of **Myasthenia Gravis**
111
Dx of **Myasthenia Gravis**
- Clinical Fatigue Test
Inducing fatigue by asking the patient to:
- Count to 50 (will induce dysarthria) or
- Maintain looking up (will precipitate ptosis).
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Dx of **Myasthenia Gravis**
- Prostigmine test
1.5 mg Prostigmine + 0.5 mg Atropine IM → Improve myasthenia.
113
Dx of **Myasthenia Gravis**
- EMG
Repetitive stimulation test shows:
- Diminished amplitude after repeated stimulation (decremental response).
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Dx of **Myasthenia Gravis**
- Tensilon Test
2 mg IV followed, if no idiosyncrasy, by 8mg → improve myasthenia after a minute.
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Dx of **Myasthenia Gravis**
- Most Sensitive Test
Detection of Anti-Ach R Antibodies
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Dx of **Myasthenia Gravis**
- Chest tomogram
to detect Thymoma or Thymic Hyperplasia.
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Dx of **Myasthenia Gravis**
- Thyroid Function Tests
...
118
Dx of **Myasthenia Gravis**
- tests for Collagen Disorders or Cx
...
119
TTT of **Myasthenia Gravis**
120
TTT of **Myasthenia Gravis**
- Anticholinestrase
- Mestinon
- Prostigmine: titrate until adequate response.
121
TTT of **Myasthenia Gravis**
- Prednisone
- 50 mg daily then taper to 5-10 mg per day as a maintenance dose.
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TTT of **Myasthenia Gravis**
- Azathioprine
2mg/ Kg/day.
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TTT of **Myasthenia Gravis**
- Plasmapharesis
to get rid of harmful antibodies.
124
TTT of **Myasthenia Gravis**
- IVIG
0.4 gm/ Kg/day divided over five successive days.
125
TTT of **Myasthenia Gravis**
- Thymectomy
Obligatory for Thymoma or Thymic hyperplasia.
126
Def of **Crises in Myasthnia**
Severe deterioration in a myasthenic patient which necessitate Mechanical Ventilation.
127
Types of **Crises in Myasthnia**
128
Types of **Crises in Myasthnia**
- Myasthenic Crises
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Types of **Crises in Myasthnia**
- Cholinergic Crises
130
Managment of **Crises**
131
Managment of **Crises**
- Tensilon test
For differentiation (it will improve only the myasthenic crisis)
132
Managment of **Crises**
- Avoid ......
- Aminoglycosides
- Ampicillin
- Phenytoins
- Propranolol
- Morphine
- Barbiturates (has a neuromuscular blocking effect)
133
Managment of **Crises**
- Re-introduction of Drugs
134
age in **Neonatal Myasthenia**
Seen in infants from a myasthenic mother
135
Etioogy of **Neonatal Myasthenia**
It is due to antibodies from the mother serum.
136
TTT of **Neonatal Myasthenia**
- Recovers spontaneously (1 week - 3 months after delivery).
- The infant need treatment with anti cholinesterase for short duration
137
Def of **Congenital Myasthenia**
Genetically determined non-auto-immune disorder.
138
Pathogenesis of **Congenital Myasthenia**
- Mutation affecting one of A.Ch.R. subunits
- Mutation affecting the end plate protein.
139
Incidence of **Congenital Myasthenia**
- Rare disease
- Begin in infancy (floppy infant).
140
CP of **Congenital Myasthenia**
141
Etiology of **Lambert-Eaton Syndrome (Myasthenic-Myopathic)**
142
CP of **Lambert-Eaton Syndrome (Myasthenic-Myopathic)**
143
TTT of **Lambert-Eaton Syndrome (Myasthenic-Myopathic)**
1. Tumour treatment often improves the picture.
2. Prednisolone and azathioprine often induces remission → In absence of tumor
3. Plasma exchange and IVIG are effective.
