Duchenne's

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