Duchenne Muscular Dystrophy
Definition
- Progressive muscle weakness in young boys
- X-linked recessive
Clinical Features
- Clumsy walking
- Reduced motor skills
- Pseudohypertrophy of the calf (classic) – connective tissue infiltration
- Scoliosis
- Respiratory difficulty in advanced stages
- Gower’s sign:
- Rises by walking hands up thighs to compensate for quadriceps and gluteal weakness
- First affected area is gluteals
Diagnosis
- DNA Testing: Absent Dystrophin protein
- High Creatine Phosphokinase (CPK)
- Muscle Biopsy:
- Absent Dystrophin (diagnostic)
- Connective tissue infiltration and muscle necrosis
Management
Non-Surgical
- Physical Therapy (PT), Occupational Therapy (OT)
- High-dose steroids:
- Prolong ambulation
- Slow scoliosis progression
- Complications:
- Overnight ventilatory support
Surgical
- Controversial due to:
- High anesthetic risks
- Questionable benefit
- Malignant Hyperthermia – intra-operative dantrolene
- Specific Procedures:
- Release of knee contractures: May prolong ambulation by 1–2 years
- Scoliosis:
- Rapid progression as muscles weaken
- Long fusion recommended at >20° curvature to address thoracic compromise
Outcomes
- Unable to walk independently by 10 years
- Wheelchair-bound by 14 years
- Bedridden by 16 years
- Death by cardiopulmonary compromise by 20 years
Becker’s Muscular Dystrophy
Characteristics
- X-linked recessive
- Associated with red/green color blindness
Clinical Features
- Similar to Duchenne but less severe
Diagnosis
- Muscle Biopsy:
- Reduced but not absent Dystrophin
Outcomes
- Survival beyond 22 years is indicative of Becker’s Muscular Dystrophy
Facioscapulohumeral Dystrophy
Clinical Features
- Facial muscle abnormalities
- Shoulder girdle weakness
- Normal Creatine Phosphokinase (CPK)
- Bilateral scapula winging
Management
- Scapulothoracic Fusion: For symptomatic cases
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