Neuroprogressive Disorders Flashcards
(9 cards)
General Pathophysiology: Muscle Disorders (MC)
These disorders are usually caused by ….. ….. (e.g. inherited conditions) or …… processes.
Muscle disorders like muscular dystrophies are classified as primary …., meaning the problem originates within the ….. ….. themselves.
Both the …… …… and muscle fibres are affected, disrupting communication and ….. ……
Loss of key …… ….. (e.g. dystrophin in Duchenne) …… the muscle fibres and makes them more vulnerable to ….. during ….. use.
….. or …… enzymes affect the muscle’s ability to ……. …… and perform …… …… needed for repair and endurance.
The …… (muscle cell membrane) has impaired ……. mechanisms, leading to an accumulation of ……-….. over time.
This ongoing damage causes progressive …… degeneration, ….., and ……
These disorders are usually caused by genetic mutations (e.g. inherited conditions) or autoimmune processes.
Muscle disorders like muscular dystrophies are classified as primary myopathies, meaning the problem originates within the muscle fibres themselves.
Both the neuromuscular junction and muscle fibres are affected, disrupting communication and muscle function.
Loss of key structural proteins (e.g. dystrophin in Duchenne) weakens the muscle fibres and makes them more vulnerable to damage during normal use.
Faulty or missing enzymes affect the muscle’s ability to produce energy and perform cellular functions needed for repair and endurance.
The sarcolemma (muscle cell membrane) has impaired repair mechanisms, leading to an accumulation of micro-damage over time.
This ongoing damage causes progressive muscle degeneration, weakness, and wasting.
General Pathophysiology: Muscle Disorders (MC)
If onset occurs during childhood, the weakness interferes with …… development, often causing …. ….. and ….. ……
Causes major disturbances of movement - …. & …..
If onset occurs during childhood, the weakness interferes with musculoskeletal development, often causing joint contractures and skeletal deformities.
Gait and grasp
Duchenne Muscular Dystrophy & Becker Muscular Dystrophy
Affects what gene? What does it encode?
…..-linked recessive = almost all affected are …..
Onset?
Starts with …. ….. weakness and progresses to …. …..
….. → ……
Pseudo hypertrophy of?
Motor skills/presentation (3)?
…. progressive decline in mobility, …. and ….
Death usual before ….. years due to ….. and …… problems. In DMD most lose ambulation by age ….
DMD gene - which encodes dystrophin (a protein critical for maintaining muscle fibre integrity)
X-linked recessive = almost all affected are male (females can often be carriers without severe symptoms)
Onset 2-5 years
Hip girdle weakness → shoulder girdle - Starts with hip girdle (e.g. glutes, hip flexors), then progresses to shoulder girdle (e.g. deltoids, scapular muscles).
The weakness spreads from proximal (near the centre of the body) to distal (further from the centre).
Pseudo hypertrophy on plantarflexors, quadriceps and deltoids
Waddling gait & difficulty jumping/running
Rapidly progressive decline in mobility, contractures and scoliosis
Death usual before 25 years due to cardiac and respiratory problems. In DMD most lose ambulation by age 12.
Common impairments for Duchenne muscular dystrophy and Becker Muscular dystrophy
Weakness of….
Contractures of….
Other impairments?
- Weakness on hip and knee extensors and dorsiflexors.
- Weakness on abdominals
- Contractures: iliopsoas, hamstrings, plantarflexors, and iliotibial band.
- Balance and gait impairments –> Loss of gait: 10 – 12 yo (usually require a wheelchair)
Becker vs Duchenne
Becker form: same gene, different mutation, milder disease progression
DMD management
- Contracture management
- Daily stretching/Active or Passive ROM particularly for hamstrings, gastroc/soleus and hip flexors. - Aerobic and strengthening/functional activity
- Low impact aerobic activity eg walking
- Task-specific eg STS, reaching in sitting
Avoid eccentric/high-load strengthening = risk of muscle damage due to dystrophin deficiency
- Respiratory physio
- Breathing exercises
- Cough assist
- Inspiratory muscle training
- Chest clearance techniques - Other aids
- Ankle foot orthoses to prevent PF contracture
- Gait aids eg KAFO’s or walkers in early non-ambulant stage to prolong mobility
Note aim is to delay loss of ambulation and joint contracture. Preserve respiratory capacity and prevent secondary complications.
Fascioscapulohumeral dystrophy
- Characterised by weakness of the?
- Caused by gene mutations to ….
- Males/Females affected?
- Onset in ….,
- ….. and ….. progressive
- Course variable
- ….. not involved
- …… longevity possible
Fascioscapulohumeral dystrophy
* Characterised by weakness of the facial muscles, scapular stabilisers, upper arms and lower legs- asymmetrical wasting of facial, pectoral, and shoulder girdle muscles
* Caused by gene mutations (DUX4)
* Both sexes equally affected
* Onset in adolescence
* Mild and slowly progressive
* Course variable
* Heart not involved
* Normal longevity possible
Fascioscapulohumeral dystrophy
- When expressed in muscle tissue, DUX4 protein is toxic, leading to:
- Activation of cell death pathways
- Inhibition of muscle regeneration
- Muscle inflammation and degeneration
Limb girdle dystrophy
- Group of disorders
- …… ….. (90%) or …… (10%)
- Both sexes affected equally
- Onset adolescence or adulthood
- Usually, mild progression
- ….. girdle & …. girdle
- …… impairment
