D UCHENNE ’ S M USCULAR D YSTROPHY Kate Chipchase Vts teaching Feb 2012 ST2

B ACKGROUND Most common muscular dystrophy Affects 1 in 4000 male infants Inherited X-linked recessive Approx 1/3 cases are new mutation Deletion of chromosome material on short arm of X chromosome This area codes for dystrophin which maintains integrity of muscle cell wall. Proximal muscle weakness

P RESENTATION May present with difficulty walking, climbing, running and jumping Waddling gait Average age of diagnosis is 5.5 years Calf muscle may look bulky Symptoms usually start between ages 1-3 Can have mild learning difficulties First presentation may be with developmental delay Selective atrophy of muscle eg pectoralis major Clumsy and slower than peers

G OWER ’ S SIGN

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P ROGNOSIS Progressive muscle atrophy Often wheelchair bound by mid-teens Life expectancy – late teens to early 20s due to respiratory failure and associated cardiomyopathy

D IAGNOSIS CK ( * higher than normal) Muscle biopsy Genetic testing

C OMPLICATIONS Mobility Osteoporosis Contractures – commonly at ankle Scoliosis Nutrition – may be over weight early in disease due to steroid treatment, may be malnourished in later stages due to swallowing problems Breathing problems Cardiomyopathy

M ANAGEMENT Contractures major issue – passive stretching and night splints may help Achilles tendon surgery Steroids Appropriate exercises to help maintain muscle power and mobility, may help delay onset of scoliosis Braces may be needed for scoliosis management Regular health checks to look for complications Respiratory aids may improve symptoms of nocturnal hypoxia

F URTHER INFO AND PATIENT SUPPORT Inside I’m Dancing - film 2004

R EFERENCES Patient.co.uk Illustrated textbook of paediatrics (Lissauer, Clayden)