Management of Becker and Duchenne Muscular Dystrophy
Multidisciplinary care is the cornerstone of management for both Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), with glucocorticoids being the pharmacological mainstay for DMD to slow disease progression and improve motor function. 1
Diagnostic Approach
Genetic Testing
- Precise genetic diagnosis is the gold standard and should be actively sought in all cases
- Mutation-specific therapies are in development, making genetic diagnosis increasingly important
- Diagnostic testing should include:
- Initial screening with CK levels
- Genetic testing for DMD gene mutations
- Muscle biopsy (if genetic testing is inconclusive) to assess dystrophin levels
Clinical Differentiation
- DMD: More severe phenotype with symptom onset before age 5, loss of ambulation by age 13
- BMD: Milder phenotype with later onset, preserved ambulation into teens or adulthood
- BMD patients typically have dystrophin levels >40% of normal 2
Pharmacological Management
Glucocorticoid Therapy
- Primary pharmacological intervention for DMD
- Initiation typically between 5-15 years of age (average ~8 years)
- Options:
- Prednisone: Most studied steroid for DMD
- Deflazacort: Similar benefits with possibly fewer side effects
- Benefits:
- Increases muscle mass
- Retards muscle deterioration
- Preserves pulmonary function
- Maintains ambulation longer
- Requires monitoring for side effects:
- Weight gain
- Behavioral changes
- Growth retardation
- Bone fragility
- Adrenal suppression
Respiratory Management
Assessment and Monitoring
- Regular pulmonary function testing (FVC, MIP, MEP, PCF)
- Sleep studies to detect nocturnal hypoventilation
- Monitoring for signs of respiratory insufficiency
Interventions
- Airway clearance techniques
- Assisted coughing when PCF falls below 270 L/min
- Noninvasive ventilation for nocturnal hypoventilation
- Consideration of tracheostomy for severe respiratory failure
Scoliosis Management
- Nearly all DMD patients develop scoliosis after losing ambulation
- Surgical intervention recommended when Cobb angle reaches 30-50 degrees
- Preoperative pulmonary and cardiac evaluation essential
- No absolute contraindications based on pulmonary function 1
Cardiac Management
Assessment
- Echocardiogram at diagnosis or by age 6 years
- Regular cardiac monitoring (ECG, echocardiogram, Holter)
- Maximum 24 months between evaluations
Interventions
- ACE inhibitors for early cardiac involvement
- Beta blockers for progressive cardiomyopathy
- Heart failure medications as needed 1
Rehabilitation Management
Physical Therapy
- Preventive measures to maintain muscle extensibility
- Minimize contracture development
- Appropriate exercise and activity programs
- Provision of adaptive devices as needed
Orthopedic Management
- Regular monitoring of spine and joints
- Surgical intervention for contractures in specific situations
- Positioning devices for wheelchair users
- Foot position management for optimal wheelchair positioning 1
Psychosocial Management
Assessment
- Screening for emotional adjustment and coping
- Neurocognitive function evaluation
- Speech and language development assessment
- Screening for autism spectrum disorders
- Evaluation of social support systems
Interventions
- Designation of a care coordinator as point of contact
- Development of individualized education plans
- Psychotherapy as needed:
- Parental management training for behavioral issues
- Individual therapy for depression, anxiety, or OCD
- Pharmacological interventions for psychiatric symptoms
- Social interaction support:
- Peer education about DMD/BMD
- Social skills training
- Modified/adapted sports and activities 1
Transition of Care
- Encouraging self-advocacy in medical care
- Facilitating transfer to adult medical care teams
- Developing educational and vocational opportunities
- Planning for independent living where possible
End-of-Life Care Considerations
- Palliative care for pain management and emotional support
- Guidance for treatment and medical decisions
- Hospice care for end-stage patients 1
Common Pitfalls and Caveats
Delayed Diagnosis: Failure to recognize early signs can delay appropriate interventions.
Inadequate Multidisciplinary Approach: Management requires coordination across specialties including neurology, pulmonology, cardiology, orthopedics, and rehabilitation.
Underutilization of Glucocorticoids: Despite evidence supporting their use, steroids remain controversial and not uniformly prescribed.
Reactive Rather Than Proactive Care: Anticipatory care is essential to prevent complications rather than treating them after they occur.
Neglecting Psychosocial Aspects: Behavioral and learning issues are common but often overlooked in medically-oriented care structures.
Poor Transition Planning: Inadequate planning for transition from pediatric to adult care can lead to gaps in management.
Failure to Address Family Needs: Parents of children with DMD have increased rates of depression, underscoring the need for whole-family support.