Trans 054 Approach to Myopathy

Question 1

refers to a clinical disorder of the skeletal muscles. Abnormalities of muscle cell structure and metabolism lead to various patterns of weakness and dysfunction. In some cases, the pathology extends to involve cardiac muscle fibers, resulting in a hypertrophic or dilated cardiomyopathy.

Answer 1

Myopathy

Question 2

The first goal in approaching a patient with a suspected muscle disease is to determine____________

The second goal is to determine the __________

Answer 2

site of the lesion/ pattern of weakness.

cause of the myopathy.

Question 3

in evaluation of myopathy,

The third goal is to determine ___________.

Answer 3

whether a specific treatment is available and if not, to optimally manage the patient’s symptoms to maximize his or her functional abilities and enhance quality of life.

Question 4

In adulthood presentation, what are under muscular dystrophy?

Answer 4

o Limb-girdle
o Facioscapulohumeral
o Becker
o Emery-Dreifuss

Question 5

In adulthood presentation what are under Inflammatory myopathies ?

Answer 5

o Polymyositis
o Dermatomyositis
o Inclusion body myositis
o Viral [HIV]

Question 6

In adulthood presentation what are under, metabolic myopathies?

Answer 6

o Acid maltase deficiency 
o Lipid storage diseases 
o Debrancher deficiency 
o Phosphorylase b kinase deficiency 
o Mitochondrial myopathies

Question 7

In adulthood presentation what are under Endocrine myopathies?

Answer 7

o Thyroid
o Parathyroid
o Adrenal
o Pituitary disorders

Question 8

In adulthood presentation what are under Toxic myopathies?

Answer 8

o Alcohol 
o Corticosteroids 
o Local injection of narcotics 
o Colchicine 
o Chloroquine 
o Statins

Question 9

what does this presentation suggests regarding the pattern of weakness?

Difficulty climbing stairs, arising from a low chair or toilet, or getting up from a squatted position.

Answer 9

Proximal lower extremities:

Question 10

what does this presentation suggests regarding the pattern of weakness?

trouble lifting objects over their head and brushing their hair.

Answer 10

Proximal upper extremities:

Question 11

what does this presentation suggests regarding the pattern of weakness?

difficulty opening jars, inability to turn a key in the ignition.

Answer 11

Distal upper extremities:

Question 12

what does this presentation suggests regarding the pattern of weakness?

Tripping due to foortdrop

Answer 12

Distal lower extremities:

Question 13

if there is constant weakness, what are some diff diagnosis?

acute

chronic c slow progresssion

non progressive weakness

Answer 13

inflammatory myopathies (dermatomyositis and polymyositis).

o most muscular dystrophies
o Inclusion Body Myositis (IBM1)

o congenital myopathies

Question 14

can occasionally have an acute monophasic course with complete resolution of strength within weeks or months.

• Patients with periodic paralysis or metabolic myopathies can have recurrent attacks of weakness over many years,

Answer 14

polymyositis

Question 15

Periodic paralysis is characteristically provoked by

Answer 15

exercise or ingestion of a carbohydrate meal followed by a period of rest.

Question 16

Patients with para-myotonia congenita frequently report that _________ may precipitate their symptoms of muscle stiffness

Answer 16

cold exposure

Question 17

what are X linked myopathies?

Answer 17

o Duchenne
o Becker
o Emery-Dreifuss

Question 18

Autosomal Dominant myopathies

Answer 18

o Facioscapulohumeral 
o Limb-girdle 
o Oculopharyngeal muscular dystrophy 
o Myotonic dystrophy 
o Periodic paralysis 
o Para-myotonia congenita 
o Thomsen disease 
o Central core myopathy

Question 19

Autosomal Recessive myopathies?

Answer 19

o Limb-girdle
o Metabolic myopathies
o Becker myotonia

Question 20

Maternal Transmission myopathy?

Answer 20

Mitochondrial Myopathy

Question 21

Selective atrophy of the quadriceps and forearm flexor muscles is highly suggestive of

Answer 21

inclusion body myositis

Question 22

may have profound atrophy of the anterior or posterior lower extremity compartments

Answer 22

Distal myopathies

Question 23

what can cause hypertrophy

Answer 23

o LGMD2C-2F, LGMD2I, (LGMD 2G in 50% of pt)
o Myotonia congenita
o Amyloidosis o Sarcoidosis, and
o Hypothyroid myopathy

Question 24

wha can cause Pseudohypertrophy

Answer 24

Duchenne and Beckers MD

Question 25

muscular enlargement through deposition of fat rather than muscle fibre

Answer 25

Pseudohypertrophy

Question 26

what can cause scapular winging

Answer 26

o Facioscapulohumeral muscular dystrophy (FSHD3) o LGMD1B (laminopathy), LGMD2A (calpainopathy), LGMD2c-2f (sarcoglycanopathies)

Question 27

The most common pattern of muscle weakness in myopathies

Answer 27

Pattern 1 proximal limb girdle weakness

Question 28

This pattern of weakness is seen in most hereditary and acquired myopathies and therefore is the least specific in arriving at a particular diagnosis

Answer 28

proximal limb girdle weakness

Question 29

The involvement is usually, although not invariably, symmetrical.
• more commonly a feature of neuropathies

Answer 29

Distal Weakness

Question 30

This pattern of weakness affects the periscapular muscles of the proximal arm and the anterior compartment muscles of the distal lower extremity (scapuloperoneal distribution)
• The scapular muscle weakness is usually characterized by scapular winging.
• Weakness can be very asymmetrical.

Answer 30

PROXIMAL ARM/DISTAL LEG WEAKNESS

Question 31

• The facial muscles are usually spared.
• Involvement of other muscles is extremely variable.
• The weakness is often asymmetrical between the two sides, which is uncommon in most myopathies.

Answer 31

DISTAL ARM/PROXIMAL LEG WEAKNESS

Question 32

• This pattern is essentially pathognomonic for inclusion body myositis (IBM).

Answer 32

DISTAL ARM/PROXIMAL LEG WEAKNESS

Question 33

The combination of ptosis, ophthalmoplegia (without diplopia), and dysphagia should suggest the diagnosis of

Answer 33

oculopharyngeal dystrophy

Question 34

Ptosis and ophthalmoplegia without prominent pharyngeal involvement is a hallmark of

Answer 34

many of the mitochondrial myopathies.

Question 35

Ptosis and facial weakness without ophthalmoplegia is a common feature of

Answer 35

myotonic dystrophy

Question 36

Identify is this is a Ptosis s Ophthalmoplegia or Ptosis C Ophthalmoplegia?

Myotonic dystrophy

Answer 36

without

Question 37

Identify is this is a Ptosis s Ophthalmoplegia or Ptosis C Ophthalmoplegia?

• Congenital myopathies
o Centronuclear myopathy
o Nemaline myopathy
o Central core myopathy

Answer 37

without

Question 38

Identify is this is a Ptosis s Ophthalmoplegia or Ptosis C Ophthalmoplegia?

• Oculopharyngodistal myopathy

Answer 38

with

Question 39

Identify is this is a Ptosis s Ophthalmoplegia or Ptosis C Ophthalmoplegia?

• Neuromuscular junction disease (myasthenia gravis, Lambert-Eaton, botulism)

Answer 39

with

Question 40

Identify is this is a Ptosis s Ophthalmoplegia or Ptosis C Ophthalmoplegia?

Desmin (myofibrillary) myopathy

Answer 40

without

Question 41

what pattern of weakness?

• ‘‘dropped head syndrome’’
• Involvement of the neck flexors is variable.
• Isolated neck extension weakness represents a distinct muscle disorder called isolated neck extensor myopathy.
• Prominent neck extensor weakness:
• amyotrophic lateral sclerosis and
• myasthenia gravis.

Answer 41

prominent neck extensor weakness

Question 42

what are myopathies with prominent neck extensor weakness?

Answer 42

• Isolated neck extensor myopathy”
• Polymyositis “
• Dermatomyositis “
• Inclusion body myositis “
• Carnitine deficiency “
• Facioscapulohumeral dystrophy “
• Myotonic dystrophy “
• Congenital myopathy “
• Hyperparathyroidism

Question 43

elevated in the majority of myopathies but may be normal in slowly progressive myopathies.

Answer 43

Creatine kinase

Question 44

the CK level is invariably at least 10 times (and often up to 100 times) normal.

Answer 44

Duchenne Dystrophy

Question 45

The CK level may not be elevated in

Answer 45

o corticosteroid administration,  
o collagen diseases,  
o alcoholism  
o hyperthyroidism  
o profound muscle wasting 

If there are no muscles, the CK would not be elevated because there no muscles to be destroyed. This is why in late stages of Duchenne dystrophy, CK levels would be normal.

Question 46

• Confirm localization
• Can be a guide as to which muscle to biopsy.
• rule/out neuropathy, NMG disease, MND.

Answer 46

electrophysiological studies

Question 47

are typically normal in patients with myopathy.

Answer 47

Nerve Conduction Studies (NCS)

But abnormal in patients with neuropathy

Question 48

o Brief duration,
o small-amplitude
o Early recruitment
 Will show abnormality in patients with myopathy

Answer 48

Needle EMG examination: motor units

Question 49

Muscles that are severely weak (MRC grade 3 or less) should [not be/ be] biopsied, since the results are likely to show only evidence of end stage muscle disease

Answer 49

not be

Question 50

muscles that have recently been studied by needle EMG should be avoided because of the possibility of artifacts created by needle insertion. T or F?

Answer 50

True

Question 51

Biopsies should generally be taken from muscles that demonstrate MRC grade ______ strength

Answer 51

grade 4

Question 52

muscle of choice in mm biopsy?

Answer 52

biceps, vastus lateralis

Question 53

why should the gastrocnemius be avoided in muscle biopsy?

Answer 53

The gastrocnemius should be avoided since its tendon insertion extends throughout the muscle and inadvertent sampling of a myotendinous junction may cause difficulty with interpretation.

Question 54

histopathology of myopathies?

Answer 54

Typical myopathic abnormalities include:
o central nuclei,
o both small and large hypertrophic round fibers,
o split fibers, and
o degenerating and regenerating fibers.
o Chronic myopathies frequently show evidence of increased connective tissue and fat.

Question 55

• characterized by: o the presence of mononuclear inflammatory cells in the endomysial and perimysial connective tissue between fibers and occasionally around blood vessels (perivascular)

Answer 55

inflammatory myopathies

Question 56

• In addition, perifascicular atrophy, characterized by atrophy of fibers located on the periphery of a muscle fascicle, is a common finding.
• Inflammatory cell invasion of nonnecrotic fibers is not prominent.
• Deposition of the C5b-9 or membrane attack complex on or around small blood vessels

Answer 56

dermatomyositis

Question 57

• Variability in fiber size,
• Scattered necrotic and regenerating fibers,
• Endomysial inflammation with invasion of non-necrotic muscle fibers

Answer 57

polymyositis

Question 58

• Endomysial inflammation with invasion of non-necrotic muscle fibers • small groups of atrophic fibers, • eosinophilic cytoplasmic inclusions, and muscle fibers with one or more rimmed vacuoles lined with granular material • Amyloid deposition is evident on Congo red staining. • TDP-43 positive • Ubiquitin positive • Electron microscopy demonstrates 15-nm to 21-nm cytoplasmic and intranuclear tubulofilaments

Answer 58

inclusion body myositis?

Question 59

• The typical muscle histopathology is “ragged red’’ fibers
• Subsarcolemmal accumulation of abnormal mitochondria stains red.
• Best seen with modified– Gomori trichrome stain

Answer 59

mitochondrial disorder