What is the management approach for Becker muscular dystrophy?

Management Approach for Becker Muscular Dystrophy

A multidisciplinary care team with coordinated interventions focusing on regular cardiac and respiratory monitoring, early cardiac therapy, and preventive rehabilitation measures is essential for managing Becker muscular dystrophy to reduce morbidity and mortality. 1

Diagnosis and Assessment

• Genetic testing is crucial for confirming BMD diagnosis and guiding appropriate management 2, 1
• Initial comprehensive assessment should include:
  • Muscle strength and range of motion evaluation
  • Cardiac function assessment via echocardiogram
  • Pulmonary function testing
  • Bone density scan (DEXA)
  • Serum creatine kinase muscle isoforms (typically elevated) 2, 1

Cardiac Management

• Regular cardiac monitoring every 6-12 months regardless of symptoms 1
• Early cardiac therapy:
  • ACE inhibitors as first-line therapy even with normal cardiac function
  • Angiotensin receptor blockers (ARBs) if ACE inhibitors not tolerated
  • Addition of beta-blockers based on cardiac function 1
• Early intervention for left ventricular dysfunction is critical as cardiac involvement can remain asymptomatic until late stages 2
• Female carriers require cardiac monitoring as they may develop mild to moderate dilated cardiomyopathy in their fifth decade 2, 3

Respiratory Management

• Regular pulmonary function testing
• Early discussion about mechanical ventilation options before urgent need arises 1
• Monitoring for signs of respiratory insufficiency, especially in advanced disease

Musculoskeletal Management

• Regular physical therapy to maintain muscle extensibility and minimize contractures 1
• Appropriate exercise within tolerance limits
• Adaptive devices for mobility and function as needed
• Custom orthotic insoles to improve biomechanics and reduce pressure points 1
• Monitoring for scoliosis and joint contractures 1
• Proper wheelchair positioning with appropriate foot support when needed

Pharmacological Therapy

• Consider glucocorticoid therapy:
  • Options include prednisone/prednisolone (0.75 mg/kg/day) or deflazacort (0.9 mg/kg/day)
  • May slow decline in muscle strength and function
  • Continue even when non-ambulatory to retard scoliosis progression and slow decline in pulmonary function 1, 4
• Vitamin D supplementation if levels are <32 nmol/L 1
• Adequate calcium intake for bone health 1
• Consider bisphosphonates if fracture risk is high 1

Follow-up and Monitoring

• Regular clinic appointments every 6 months 1
• Specialist physical and occupational therapy assessments every 4 months 1
• Monitor for glucocorticoid side effects if on steroid therapy:
  • Weight gain
  • Cushingoid features
  • Behavioral changes
  • Hypertension
  • Glucose intolerance
  • Cataracts
  • Bone demineralization 1

Psychosocial Support

• Assessment and intervention for coping strategies
• Promotion of independence and social development
• Educational support through individualized education programs
• Preparation for transition to adult services
• Development of educational and vocational opportunities 1

Common Pitfalls to Avoid

1. Neglecting cardiac care - Even asymptomatic patients require regular cardiac monitoring and intervention 1
2. Overlooking respiratory support - Early introduction of nocturnal ventilation may have benefits beyond respiratory support 1
3. Focusing only on muscle strength - Management must address all affected systems (cardiac, respiratory, orthopedic, psychosocial) 1
4. Underestimating disease variability - BMD has significant phenotypic variability based on specific mutations, with some patients showing more severe progression than others 5, 6

Prognosis

• BMD is slowly progressive with significant phenotypic variability 4
• Independent walking is typically maintained into the third decade or later 4
• Specific DMD gene mutations can predict clinical severity:
  • Patients with del45-49 show earlier loss of ambulation
  • Patients with del45-55, del48, and del48-49 show later loss of ambulation
  • del45-55 and del48 are associated with decreased odds of developing pathological left ventricular ejection fraction 5

The management of BMD requires a coordinated approach with regular monitoring and early intervention to address all aspects of the disease, with particular attention to cardiac care which significantly impacts mortality and morbidity.