Duchenne Muscular Dystrophy Flashcards
What is Duchenne Muscular Dystrophy?
Duchenne Muscular Dystrophy is a progressive neuromuscular disorder affecting boys.
Reference: Paediatrics - Lecture Notes [9th Edition], p. 169.
What causes Duchenne Muscular Dystrophy?
Duchenne Muscular Dystrophy is an X-linked recessive disorder caused by deletion of the gene (Xp21) for the protein dystrophin which is a crucial for muscle function.
Reference: Paediatrics - Lecture Notes [9th Edition], p. 169.
How does Duchenne Muscular Dystrophy present?
Age-based
Birth/Early Infancy
Unlikely symptomatic
Mild hypotonia
Toddlers
Lordotic posture (to account for gluteal weakness)
Gower’s sign
Hip waddling (Trendelenberg gait)
Toe walking
Developmental delay
Calf pseudohypertrophy
Later Childhood
Transverse smile
Difficulty walking
Scoliosis (as ambulation is lost)
System-based
Muscles
Distal muscle group power is better preserved.
Contractures in ankles, knees, hips, elbows caused by calcium entry intosarcolemmal membrane.
Respiratory
Ineffective cough
Recurrent chest infections
Aspiration
Nasal voice
Cardiac
Cardiomyopathy
Neurological
Intellectual impairment
Reference: Nelson’s Paediatrics [20th Edition], p. 2976-2977.
How is Duchenne Muscular Dystrophy investigated?
Bloods
Elevated creatinine kinase (15000-35000)
Possibly elevated aspartate aminotransferase
PCR for Dystrophin gene mutation
Muscle Biopsy
Immunocytochemistry more sensitive to cases not picked up by PCR
Echocardiogram
ECG
Chest X-ray
Reference: Nelson’s Paediatrics [20th Edition], p. 2976-2977.
How is Duchenne Muscular Dystrophy managed?
There is no cure for Duchenne Muscular Dystrophy.
Cardiac
Digoxin for decompensation
Respiratory
Prompt treatment of chest infections
Nutrition
Balanced diet avoiding obesity which has deleterious effect on muscle function and strength. Ensure adequate calcium intake to prevent osteoporosis.
Physiotherapy
Delays contractures.
Medical
Steroids may decrease apoptosis of muscle cells.
Reference: Nelson’s Paediatrics [20th Edition], p. 2978.
Which conditions are related to Duchenne Muscular Dystrophy?
Becker Muscular Dystrophy is a similar, but milder dystrophy, affecting the same genetic locus.
Reference: Nelson’s Paediatrics [20th Edition], p. 2976.
What is the prognosis in Duchenne Muscular Dystrophy?
Death usually occurs in late teens. It generally results from respiratory failure heart failure, chest infection, or aspiration.
Reference: Nelson’s Paediatrics [20th Edition], p. 2976.
