Muscular Dystrophies Flashcards
What is muscular dystrophy?
An umbrella term for genetic conditions that cause progressive weakness and wasting of muscles.
What are the most common types of muscular dystrophy?
- Duchennes muscular dystrophy (DMD)
- Beckers muscular dystrophy (BMD)
Name other types of muscular dystrophy.
- Myotonic dystrophy
- Fascioscapulohumeral muscular dystrophy
- Limb-girdle muscular dystrophy
- Emery-dreifuss muscular dystrophy
What is the aetiology of Duchennes and Beckers muscular dystrophy?
- X-linked recessive
- Mostly affect males; females act as carriers
- One third are spontaneous mutations
What are the general clinical features of muscular dystrophy?
- Progressive weakness (starting proximal and moving distally)
- Delayed motor milestones
- Waddling gait
- Gowers sign
What are the examination findings in muscular dystrophy?
- Weakness in proximal and distal leg muscles
- Calf pseudohypertrophy
- Waddling gait
- Tip-toe walking
- Gowers sign
- Hyporeflexia
- Loss of arches of feet
- Difficulty or inability to squat
What is the initial investigation for muscular dystrophy?
Serum creatine kinase (CK) level.
What are the definitive diagnosis methods for muscular dystrophy?
- Genetic analysis
- Muscle biopsy
- Clinical exam findings
What is the initial management for muscular dystrophy?
- Information and support
- Referral to specialists
- Immunisations (including influenza and pneumococcal)
What are some early management strategies for patients still walking?
- Corticosteroids
- Vitamin D and calcium supplements
- Physiotherapy
- Orthoses
- Serial casting of ankles
What management strategies are recommended for later stages when the patient is unable to walk?
- Wheelchair
- Counselling
- Orthopaedic input
- Cardiac and respiratory surveillance
- Advanced planning and palliation
What is the genetic defect associated with Duchennes muscular dystrophy?
Defective dystrophin on the X-chromosome.
At what age do boys with Duchennes MD typically present with symptoms?
3-5 years.
What is the life expectancy for individuals with Duchennes muscular dystrophy?
25-30 years.
What are the characteristics of Beckers muscular dystrophy?
- Very similar to DMD
- Less severely affected dystrophin gene
- Clinical course less predictable
- Symptoms around 8-12 years
What are the typical features of myotonic dystrophy?
- Progressive muscle weakness
- Prolonged muscle contractions
- Cataracts
- Cardiac arrhythmias
What is a typical presentation of prolonged muscle contraction in myotonic dystrophy?
Inability to let go after shaking hands or releasing grip on a doorknob.
