What is the recommended treatment approach for a young patient with Duchene muscular dystrophy and progressive muscle weakness?

Recommended Treatment Approach for Duchenne Muscular Dystrophy

Start daily glucocorticoid therapy immediately with prednisone 0.75 mg/kg/day (maximum 40 mg/day) as the cornerstone of treatment, unless pre-existing weight or behavioral issues favor deflazacort 0.9 mg/kg/day, and maintain this therapy even after loss of ambulation to reduce mortality and preserve cardiac and pulmonary function. 1

Pharmacological Management: Glucocorticoids

Initiation Timing and Dosing

• Begin glucocorticoids during the plateau phase (typically age 4-8 years) when motor skills stop progressing but before clear decline begins 1
• Do not start in children under 2 years who are still gaining motor skills 1
• Prednisone 0.75 mg/kg/day is first-line unless weight gain or behavioral problems are present 2, 1
• Deflazacort 0.9 mg/kg/day should be used when pre-existing weight or behavioral concerns exist 2, 1
• Increase dose incrementally with growth up to maximum weight of 40 kg (prednisone 30 mg/day or deflazacort 36 mg/day) 2

Critical Pre-Treatment Requirements

• Complete all recommended immunizations and establish varicella immunity before starting glucocorticoids 1
• Provide families with a steroid emergency card listing considerations for acute illness, fracture, infection, or surgery/anesthesia 1

Managing Side Effects Without Abandoning Therapy

If side effects become unmanageable or intolerable, follow this stepwise approach rather than stopping treatment entirely:

• First step: Reduce daily dose by 25-33% and reassess in 1 month 2, 1
• Second step: If still problematic, reduce an additional 25% (minimum effective daily dose is approximately 0.3 mg/kg/day) 2
• For weight gain/behavior issues specifically: Switch from prednisone to deflazacort 1
• Last resort before abandonment: Consider 10/10 or 10/20 intermittent schedule 2

Do not abandon glucocorticoid therapy without attempting at least one dose reduction and change to alternative regimen 1, as this deprives patients of proven mortality and morbidity benefits 1

Continue Beyond Loss of Ambulation

• Maintain glucocorticoids even when non-ambulatory to retard scoliosis progression, slow decline in pulmonary function, and possibly prevent heart failure 2

Cardiac Management

Prophylactic Cardioprotection

• Initiate ACE inhibitors or ARBs by age 10 years (barring contraindications) for proven mortality benefits 1
• Add β-adrenergic blockade after ACE inhibitor/ARB initiation, especially with ventricular dysfunction or elevated heart rate 1

Respiratory Management

Monitoring and Intervention

• Perform regular pulmonary function monitoring 1
• Assess for sleep hypoventilation with sleep studies or nocturnal oximetry 1
• Arrange preoperative pulmonologist evaluation at least 2 months before any surgery 1
• Noninvasive ventilation has proven survival benefits and improved quality of life in non-ambulatory patients 3

Multidisciplinary Monitoring Schedule

Regular Assessments

• Routine clinic appointments every 6 months 1
• Physical and occupational therapy assessments every 4 months 1
• Emotional adjustment screening at every clinic visit using standardized rating scales 1
• Comprehensive neuropsychological assessment at diagnosis 1

Glucocorticoid Side Effect Monitoring

Monitor at each visit for: 2

• Blood pressure (as percentile for height and sex)
• Weight gain and cushingoid features
• Behavioral changes (hyperactivity, mood swings)
• Glucose intolerance (urine dipstick)
• GERD symptoms
• Bone health with annual DEXA scans
• Annual 25-hydroxy vitamin D levels (supplement if <32 nmol/L)
• Annual ophthalmological examination for cataracts
• Fracture history

Orthopedic Management

• Consider surgical intervention for scoliosis when Cobb angle reaches 30-50 degrees 1
• No absolute pulmonary function contraindications exist for surgery; patients with FVC as low as 20% of predicted have had good outcomes 1

Nutritional and Bone Health

• Dietitian should assess calcium and vitamin D intake 2
• Supplement with vitamin D3 if level is <32 nmol/L 2
• Consider bisphosphonates such as pamidronate for bone demineralization 2

Therapies to Avoid

Do not use the following due to insufficient evidence: 1

• Coenzyme Q10, carnitine, amino acids, fish oil, vitamin E, or green tea extract
• Oxandrolone (anabolic steroid)
• Botulinum toxin A for contracture treatment/prevention

Common Pitfalls to Avoid

• Starting glucocorticoids too early (before plateau phase in children under 4 years still gaining skills) exposes patients to unnecessary side effects without clear benefit 1
• Abandoning glucocorticoids prematurely due to side effects without attempting dose reduction or alternative regimens deprives patients of proven mortality and morbidity benefits 1
• Failing to provide steroid emergency card puts patients at risk during acute illness or surgical procedures 1
• Stopping glucocorticoids after loss of ambulation eliminates benefits for cardiac, pulmonary, and scoliosis outcomes 2