Aetiology
X linked recessive
Lack of dystrophin
Epidemiology
1:3500
Boys only
Decreased intellectual capacity / average IQ 80 - 90
Present
Delay in walking
- test CPK in any boy not walking by age 18 months
Toe walking
Parents have noticed waddling gait and stiff feet
Signs
Gower's
- have trouble rising from floor
- rear in the air first
- use arms to walk up legs
Proximal muscle weakness
- symmetrical
Calf hypertrophy
- pseudohypertrophy
Toe walking
Lumbar lordosis
Investigation
Creatinine Phosphokinase / CPK
- normal < 200
- DMD > 5000
Muscle biopsy
- absent dystrophin protein
- definitive diagnosis
NHx
Loss of independent walking by 10 years
Rapid scoliosis progression by 14 years
Wheelchair bound by 15 years
Death in late teens (<20 years) due to respiratory infection
Management
Non operative Management
Physiotherapy / occupational therapy
Prevent contractures
- hip adduction / tendoachilles
AFO's
Steroids
Concept
- prolongs walking
- improves strength
- delays scoliosis
- improves respiratory function
Begin
- age 7 or 8
Complications
- AVN
- mood swings
- cataracts
- short stature
- Cushingoid features
Operative Management
Scoliosis
Bracing not effective / can compromise respiratory function
Need early posterior fusion when scoliosis 20o
Malignant Hyperthermia
All patients high risk
- must be screened preoperatively
- give prophylactic dantrolene
- avoid inhalational anaesthetics / suxamethonium
Contractures
SEML's
- hip adductors
- T achilles
- T posterior