37. Duchenne Muscular Dystrophy

Question 1

Outline the pathophysiology and aetiology of Duchenne Muscular Dystrophy

Answer 1

Mutation in the DMD gene changes the DMD RNA so that it no longer codes for functional dystrophin protein, muscle gets replaced by fibroadipose

More common in boys

Question 2

How does Duchenne Muscular Dystrophy present?

Answer 2

• Progressive muscle weakness
• Frequent falls
• Difficulty rising from a lying or sitting up position
• Trouble running and jumping
• Waddling gait
• Walking on the toes
• Large calf muscles
• Muscle pain and stiffness
• Learning disabilities

Question 3

How should suspected Duchenne Muscular Dystrophy be investigated?

Answer 3

Bloods = CK

Electromyography

Genetic testing

Muscle biopsy

ECG, ECHO

Lung function testing

Question 4

Outline the ideal Mx of Duchenne Muscular Dystrophy

Answer 4

No cure

Eteplirsen = morpholino antisense oligomer which triggers excision of exon 51 (to slow or prevent the progression)

Corticosteroids = slow progression

HF = ACEi, beta-blockers

Knee-ankle-foot orthoses

Gene therapy

Question 5

What are the possible complications of Duchenne Muscular Dystrophy?

Answer 5

Eventually need to use a wheelchair

Shortening of muscles or tendons around joints (contractures) - limit mobility

Eventually require ventilator

Scoliosis

HF

Dysphagia, aspiration pneumonia