Motor

Duchenne Muscular Dystrophy

search

Duchenne Muscular Dystrophy

  • Epidemiology
  1. Exclusively affects males
  • Pathophysiology
  1. X-linked recessive inheritance
  • Symptoms
  1. Difficulty performing Exercises
    1. Climbing
    2. Running
    3. Jumping
    4. Hopping
  • Signs
  1. Symmetric, progressive proximal Muscle Weakness
    1. Affects hip and Shoulder girdle
  2. Palpable Muscle enlargement
    1. Initial muscle hypertrophy
    2. Later fat and connective tissue replace muscle
  • Associated Conditions
  1. Tendon and muscle contractures
  2. Kyphoscoliosis (progressive)
  3. Impaired pulmonary function
  4. Cardiomyopathy
  5. Intellectual Impairment
  • Course
  1. Age 5 years: Onset of symptoms and signs
  2. Age 8-10 years: Leg braces necessary for ambulation
  3. Age 12 years: Nonambulatory
  4. Age 25 years: Survival rare beyond this point
  • Labs
  1. Muscle Enzymes elevated
    1. Creatine Phosphokinase (CPK) increased
    2. Aldolase increased
  2. Electromyogram (EMG)
    1. Myopathy
  3. Muscle Biopsy
    1. Necrotic muscle fibers with regeneration
    2. Fatty replacement of muscle
  4. Electrocardiogram (EKG)
    1. Cardiomyopathy
    2. Deep Q waves across precordium
  • Complications
  1. Respiratory Failure
  2. Respiratory infections
  3. Aspiration Pneumonia
  4. Acute gastric dilatation
  5. Congestive Heart Failure
  6. Cardiac arrhythmia
  • Management
  1. Passive muscle Stretching
  2. Tenotomy
  3. Bracing
  4. Physiotherapy
  5. Mechanical Assistive Devices
  6. Avoid prolonged immobility
  • Reference
  1. Mendell in Wilson (1991) Harrison's IM, p. 2112