Synopsis
Localise childhood weakness, identify respiratory and bulbar emergencies, recognise Duchenne muscular dystrophy early and organise creatine kinase, genetic confirmation, corticosteroid, cardiac, respiratory and family care.
- Localise weakness by onset, proximal or distal distribution, symmetry, fatigability, reflexes, sensation, cranial and bulbar signs and upper motor-neurone features.
- Duchenne muscular dystrophy usually becomes apparent between two and five years with delayed milestones, Gowers manoeuvre, waddling, toe walking, falls and calf pseudohypertrophy.
- First-line testing for a boy with unexplained motor delay or proximal weakness is serum creatine kinase; a very high result demands urgent neuromuscular referral, not repeated observation.
- Confirm dystrophinopathy with molecular genetic testing, starting with methods that detect exon deletions or duplications and then sequencing when required; biopsy is reserved for unresolved cases.
- A normal newborn period does not exclude Duchenne, and language or learning difficulty may precede obvious weakness because dystrophin isoforms are expressed in brain.
- Corticosteroids prolong ambulation and preserve respiratory and upper-limb function; the neuromuscular team selects daily or intermittent prednisolone or deflazacort and monitors toxicity.
- Cardiac surveillance begins before symptoms and uses ECG plus echocardiography or cardiac MRI; cardioprotective therapy is introduced through the specialist protocol.
- Serial forced vital capacity, sleep study when indicated, cough assessment, vaccination and assisted cough or non-invasive ventilation prevent crisis better than waiting for resting hypoxaemia.
- Avoid succinylcholine and alert anaesthesia to dystrophinopathy because hyperkalaemic arrest and anaesthesia-associated rhabdomyolysis can occur.
- Offer genetic counselling, carrier testing through clinical genetics, education support, bone protection, physiotherapy, psychosocial care and timely transition as one coordinated pathway.
Key red flags
Loss of previously acquired motor skills, rapid progression or weakness after a normal early course requires urgent neurological assessment.
Weak cough, recurrent aspiration, sleep-disordered breathing, morning headache or inability to lie flat suggests respiratory muscle failure even with normal oxygen saturation.
Duchenne clues include delayed walking, Gowers manoeuvre, frequent falls, waddling gait, toe walking and calf enlargement in a preschool boy.
Markedly raised transaminases with no liver explanation should prompt creatine kinase because muscle releases AST and ALT.
Weakness with areflexia progressing over days suggests Guillain-Barré syndrome, while bladder change, sensory level or brisk reflexes suggests spinal cord disease.
Children with dystrophinopathy have anaesthetic-associated rhabdomyolysis and hyperkalaemia risk; avoid succinylcholine and ensure specialist anaesthetic planning.
Investigation priorities
Detect muscle-fibre injury in a child with objective weakness, Gowers manoeuvre or delayed motor milestones.
Management branches
A child has delayed motor skills, falls or loss of function.
- Observe play, floor rise, run and stairs before formal power, reflex and sensory examination.
- Screen bulbar, respiratory, cardiac and bladder symptoms to identify emergency localisation.
- Request creatine kinase promptly for objective proximal weakness or Gowers manoeuvre.