Synopsis
Recognise major inherited dystrophy patterns, use genomic confirmation rather than phenotype alone, and anticipate respiratory, cardiac, swallowing, endocrine, anaesthetic and family risks across the life course.
- Muscular dystrophies are genetically diverse disorders causing progressive muscle degeneration; age at onset, distribution, contractures, cardiac involvement and inheritance guide the initial differential.
- Duchenne muscular dystrophy usually presents in early childhood with delayed motor milestones, calf pseudohypertrophy, Gowers manoeuvre and very high creatine kinase due to absent dystrophin.
- Becker dystrophy results from partially functional dystrophin and is often milder or later, but cardiomyopathy can be disproportionate to skeletal weakness.
Key red flags
Syncope, palpitations, orthopnoea, recurrent chest infection, morning headache or daytime somnolence can signal conduction disease or nocturnal hypoventilation.
Investigation priorities
Detect muscle membrane injury and common mimics.
Management branches
Progressive muscle weakness, myotonia or a suggestive family history is identified.
- Map facial, scapular, axial, proximal and distal weakness, contractures, calf size and myotonia while checking sensation, reflexes, cardiac and respiratory symptoms.
- Construct a three-generation pedigree and obtain CK, ECG and targeted systemic tests, referring to a neuromuscular and clinical genetics service.
Key medicines
Prednisolone or deflazacort in Duchenne dystrophyA paediatric neuromuscular specialist chooses the current daily or intermittent weight-based regimen, titrating for function, growth and adverse effects.
MexiletineFor disabling myotonia, specialists select a divided oral dose after baseline cardiac assessment and titrate according to the current BNF and local protocol.