What is the management approach for Becker muscular dystrophy?

Management of Becker Muscular Dystrophy

Becker Muscular Dystrophy (BMD) requires a multidisciplinary management approach focused on glucocorticoid therapy, early cardiac intervention, regular respiratory monitoring, and comprehensive rehabilitation to improve outcomes and quality of life. 1

Diagnosis and Initial Assessment

• Genetic testing is essential for confirming BMD diagnosis and guiding appropriate management 1
• Initial comprehensive assessment should include:
  • Muscle strength and range of motion evaluation (repeat every 6 months)
  • Cardiac function assessment via echocardiogram
  • Pulmonary function testing
  • Bone density scan (DEXA)
  • Serum creatine kinase muscle isoforms (typically elevated) 1

Medication Management

Glucocorticoid Therapy

• First-line treatment that slows decline in muscle strength and function:
  • Prednisone/prednisolone (0.75 mg/kg/day) or
  • Deflazacort (0.9 mg/kg/day) 1
• Continue glucocorticoid therapy even when non-ambulatory to:
  • Retard scoliosis progression
  • Slow decline in pulmonary function
  • Potentially delay heart failure 1
• Common pitfall: Discontinuing glucocorticoids prematurely due to side effects; instead, manage side effects while maintaining therapy 1

Cardiac Medications

• Early cardiac therapy with ACE inhibitors as first-line treatment, even with normal cardiac function
• Angiotensin receptor blockers (ARBs) as alternative if ACE inhibitors not tolerated
• Add beta-blockers based on cardiac function 1
• Early intervention for left ventricular dysfunction is critical, as cardiac involvement can remain asymptomatic until late stages 1, 2

Bone Health

• Vitamin D supplementation if levels are low (<32 nmol/L)
• Ensure adequate calcium intake
• Consider bisphosphonates (e.g., pamidronate) if fracture risk is high 1

Cardiac Care

• Regular cardiac monitoring with echocardiogram is essential, as cardiac involvement may be asymptomatic 1
• Early referral for cardiac transplantation in severe cardiomyopathy cases 2
• Female carriers require cardiac monitoring, as they may develop dilated cardiomyopathy in their fifth decade 1, 3

Respiratory Management

• Regular pulmonary function testing to monitor disease progression 1
• Early introduction of nocturnal ventilation may provide cardiac benefits beyond respiratory support 1
• Initiate discussion about mechanical ventilation options before urgent need arises 1

Rehabilitation and Physical Therapy

• Regular physical therapy to maintain muscle extensibility and minimize contractures
• Appropriate exercise within tolerance limits
• Adaptive devices for mobility and function as needed 1
• Custom orthotic insoles to improve biomechanics and reduce pressure points:
  • Shock-absorbing insoles
  • Properly fitted footwear with seamless internal lining 1

Orthopedic Care

• Monitor for scoliosis and joint contractures
• Consider surgical options for contractures in specific situations
• Ensure proper wheelchair positioning with appropriate foot support 1

Nutritional Management

• Regular monitoring of weight gain
• Nutritional assessment for both underweight and overweight concerns
• Attention to potential swallowing difficulties with dietary modifications as needed 1

Psychosocial Support

• Assessment and intervention for coping strategies
• Promotion of independence and social development
• Support for function and participation in daily activities
• Family support and early intervention for developmental concerns
• Educational support through individualized education programs
• Preparation for transition to adult services 1

Palliative Care

• Pain management and emotional support
• Hospice care when appropriate for end-stage patients 1

Prognostic Considerations

• Disease progression is variable and influenced by specific DMD gene mutations 4, 5
• Despite childhood onset, independent walking is typically maintained into the third decade 2
• Specific mutations like exon 45-49 deletions are associated with earlier loss of ambulation, while exon 45-55 and exon 48 deletions correlate with later loss of ambulation 4

Common Pitfalls to Avoid

• Neglecting cardiac care in asymptomatic patients
• Overlooking respiratory support needs
• Focusing only on muscle strength while ignoring other affected systems
• Discontinuing glucocorticoids prematurely despite side effects 1