Myopathies (Newman)

Question 1

Discuss the importance of monitoring development in children.

Answer 1

A failed screen is simply an indication for a more thorough evaluation. A failed screen is not diagnostic of anything.

Question 2

Name the four general domains of pediatric development.

Answer 2

1. Gross Motor
   
   1. Movements using the large muscles
2. Fine Motor
   
   1. Movements using the hands and smaller muscles, often involving daily living skills.
3. Language
   
   1. Receptive and expressive communication, speech and nonverbal communication.
4. Congnitive/Social-Emotional and Behavioral
   
   1. Attachment, self-ergulation, and interaction with others.

Question 3

Explain the importance of early intervention in children with developmental delay.

Answer 3

The sooner we identify developmental delays and the sooner we intervene, the better the outcome.

Question 4

Which is more concerning: a child who has not yet hit developmental milestones or a child who has hit develpmental milestones and then regresses?

Answer 4

Not hitting developmental milestones can be serious, but hitting milestones and then regressing is even more ominous.

Question 5

List the gross motor developmental milestones that should be seen in a child at 6 months of age.

Answer 5

• sits momentarily

Question 6

List the gross motor developmental milestones that should be seen in a child at 9 months of age.

Answer 6

• pulls up
• cruises
• sits well without support

Question 7

List the gross motor developmental milestones that should be seen in a child at 1 year of age.

Answer 7

• stands momentarily

Question 8

List the gross motor developmental milestones that should be seen in a child at 2 years of age.

Answer 8

• walks up stairs
• kicks ball forward

Question 9

List the gross motor developmental milestones that should be seen in a child at 3 years of age.

Answer 9

• can ride a tricycyle

Question 10

What is a myopathy?

Answer 10

A muscle disease unrelated to any disorder of innervation or neuromuscular junction.

Question 11

Describe the clinical presentation seen in Duchenne Muscular Dystrophy.

Answer 11

• presents in very early childhood
• severe proximal muscle weakness
• neck flexor muscle weakness
• delayed walking, difficulty running, they just can’t “keep up”
• broad-based walking, lordotic gait
• Gowers sign (due to proximal muscle weakness)
• DTR’s diminished, but still present
• hypertrophic calf muscles
  
  • get replaced with fat and connective tissue
• walk on toes
• limited hip flexion
• wheelchair bound around middle school age
• compromised respiratory status
• cardiomyopathy is important to watch for

Question 12

Describe the inheritance pattern seen in Duchenne Muscular Dystrophy.

Answer 12

• X-linked recessive
  
  • carrier mom
  • sons have a 505 chance of getting DMD
  • daughters have a 50% chance of being carriers
    
    • may develop cardiomyopathy, muscle weakness, or muscle cramps

Question 13

Describe the genetic abnormality seen in Duchenne Muscular Dystrophy.

Answer 13

frameshift mutation that results in absence of dystrophin

Question 14

Describe the clinical presentation seen in Becker Muscular dystrophy.

Answer 14

• milder form of muscular dystrophy than DMD
  
  • less severe muscle damage
  • presents later in childhood
• proximal muscle weakness after 5 years of age
• maintenance of independent walking until after age 16 years
• preserve anti-gravity strength of neck flexor muscles
• age of death varies between 4th and 6th decades of life

Question 15

Describe the inheritance pattern seen in Becker Muscular Dystrophy.

Answer 15

x-linked recessive

Question 16

Describe the genetic abnormality seen in Becker Muscular Dystrophy.

Answer 16

in-frame mutation of the dystrophin gene

Question 17

What is Gowers sign?

Answer 17

Describes the way that children pull themselves off the floor when they have severe proximal muscle weakness.

Question 18

Describe the presentation of congenital muscular dystrophies.

Answer 18

• Present at birth or early in infancy
  
  • hypotonia
  • severe muscle weakness (proximal> distal) at birth or shortly after
  • joint contractures
• may present with
  
  • malformations of the eyes and brain
  • cardiomyopathiy
  • rigid spine

Question 19

A preschool boy with muscle weakness, presents with gross motor delay, toe-walking, difficulty walking and climbing stairs, and frequent falls. What should you order first?

Answer 19

• order a serum creatine kinase (CPK). If it is high, then could be a muscular dystrophy.
• Ask further about mother’s family history, especially males on her side

Question 20

Explain the importance of GGTP in differentiating between muscle disease and liver disease.

Answer 20

• Gamma-glutamyl transferase (GGT) is an enzyme that is found in many organs throughout the body, with the highest concentrations found in the liver.
• GGT is elevated in the blood in most diseases that cause damage to the liver or bile ducts.
  
  • if GGT is elevated, think liver disease
  • if GGT normal, think muscular disease

Question 21

Explain the role dystrophin plays in muscular dystrophies.

Answer 21

• Dystrophin connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane.
  
  • absent in DMD
  • reduced in BMD

Question 22

List the major clinical findings of juvenile dermatomyositis.

Answer 22

• generalized muscle weakness
• red or purplish heliotrope rash over the eyelids
• raised erythematous papules over the extensor joint surfaces (Gottren papules)
• thrombi or hemorrhage in peri-ungual capillary beds (around finger nails)

Question 23

What are the symptoms of statin induced myopathy?

Answer 23

• necrotizing, inflammatory myopathy
  
  • muscle weakness
  • pain
  • tenderness

Question 24

Understand what does a serum creatine kinase (CPK) tell you?

Answer 24

high CPK levels can indicate muscle injury/damage

Question 25

What causes mitochondrial disorders?

Answer 25

mitochondrial or nuclear DNA mutaitons

Question 26

What is the clinical course of mitochondrial disorders that cause myopathy?

Answer 26

May be “syndromic” (example: mitochondrial enecephalomyopathy with lactic acidosis ans stroke-like symptoms or MELAS) or “non-syndromic”