Muscle and nerve disease Flashcards
Which parts of the NS pathway can be affected?
- Muscle
- The Neuromuscular junction
- The peripheral nerve
- The Anterior horn cell
- The Upper motor neurone
What happens at the level of the muscle
chemical energy converted into mechanical energy
Symptoms of muscle disease
- Weakness of muscles
- Shallow breathing (muscles of respiration)
- Poor swallowing
- Cardiomyopathy
- Stiffness, cramping, pain, myoglobinuria (blood in urine due to break down of myoglobin)
Signs of muscle disease
- Muscle wasting/hypertrophy
- Normal or reduced tone
- Normal or reduced reflexes
- Motor weakness- Not sensory
Symptoms of muscle disease in babies
- Poor sucking
- Floopy
- Inability to thrive
Investigation of muscle disease
- Examination
- Creatinine kinase
- EMG: elctromyopgraphy- measures electrical activity in skeletal muscles
- Muscle biopsy
- Genetic testing
Congenital muscle disease examples
- Structural: muscular dystrophies
- Contractile: congenital myopathies
- Coupling: channelopathies
- Energy: Enzymes/ mitochondria
Acquired muscle disease
- Metabolic
- Endocrine
- Inflammatory
- Iatrogenic (medication)
What are muscle dystrophies
Disease which interferes with the contractile system of the muscle
- Can be either in the young or the old
- Progressive
- Lead to cell degeneration
- Genetic
Examples of muscle dystrophies
- Duchenne’s
- Beckers
- Facioscapuhumeral
- Myotonic dystrophy
- Limb girdle MD
What are Channelopathies and how do they present?
- Interfere with the movement of Calcium/ Sodium/ Potassium and Chloride
- They present periodic paralysis
Examples of channelopathies
- Familial hypotonic periodic paralysis ( All)
- Paramyotonia congenital (Na)
- Myotonia congenita (Cl)
What are Metabolic muscle disease
Diseases associated with the production of energy
- Disorders associated with the breakdown of carbohydrates
- Disorders associated with the breakdown of Fats
- Mitochondrial myopathies/ cytopahties
Two types of metabolic muscle disease
Those which occur at rest and those which only occur during exercise
Inflammatory muscle disease examples
- Polymyositis
- Dermamyositis: presents with characteristic rash
Investigation for inflammatory muscle disease
-HIGH CK
-EMG: indicated inflammation and myopathies
-BIOPSY:
In polymyotisis: CD8
In Dermomyositis: CD4, humeral- mediated and B cells
Treatment for inflammatory muscle disease
Immunosuppresion
Pathology of Myasthenia gravis
Cholinesterase prevents the Ach neurotransmitter from binding to the post synaptic membrane
Symptoms of myasthenia gravis
- Weakness of limbs
- Weakness of eyelids (Proptosis)
- Weakness of muscles of mastication
- Weakness of GI muscle- problems talking (Slurred speech)
- Weakness of muscles of respiration- SOB
- Diplopia
Investigation of myasthenia gravis
- Ach Receptor antibodies
- Anti muscarinic antibodies
- Neurophysiology
- CT of chest - may present with a thymoma
Treatment for myasthenia gravis
- For symptoms : Acetylcholineresterase inhibitor
- Immunosuppression (predinosole)
- Immunoglobulin/ plasma exchange
- Thymectomy if presents with thymoma
Where does the peripheral nerve form
where motor and sensosoru nerve fuse in the anterior root horn
What type os axons can be affected?
- Sensory
- Motor
- Autonomic
- Nerve sheath
Investigations with PND
- Blood tests
- Genetic analysis
- Nerve conduction studies
- Lumbar punture: for CSF analysis
- Nerve biopsy (only done when severe or when severe treatment is about to be carried out)
Types of PND
- Root disease
- Individual nerve
- Generalised peripheral nerve neuropathy
Signs and symptoms of root disease
-Myotomal wasting and weakness
-Change in reflexes
-Dermatomal sensory change
N.B. Myotomes are groups of muscle fibres which are all innervated by the same spinal nerve
Signs and symptoms of individual nerve disease
- Wasting and weakness of innervated muscles
- Specific Sensory changes
Types of generalised peripheral neuropathy
Axonal or demyelinating
Causes of generalised peripheral neuropathy?
- Hereditary
- Metabolic e.g. diabetes, B12, renal dysfunction
- Toxic : drugs
- Infectious: HIV, lyme, leprosy
- Malignancy
- Inflammatory demyelinating
- when acute: Gullain bare syndrome (autoimmune attack)
- when chronic: chronic inflammatory polyneuropathy]
where do GND symptoms start and why?
- Symptoms start distally and move proximally- therefore the longest nerves are the ones which are affected first
- This because energy is generated in the nucleus and carried along the nerve
What is the most common anterior horn disease
MND
amyotrophic lateral sclerosis
Signs and symptoms of MND
- Usually develops in the limbs, then moves to bulbar and then to respiratory
- LMN: muscle weakness, muscle fasciculations, wasting
- UMN: Increased tone, reflexes
- No sensory involvement
- In 10% cognitive decline
Prognosis and diagnosis of MND
Prognosis
- 3-5 years from onset of symptoms
- 2-3 years from diagnosis
- 50% die within 14 months of diagnosis
Diagnosis
- Combination of UMN and LMN symptoms
- EMG
Treatment for MND
- Supportive: Nasogastric feeding tube, Non-invasive ventilation, Physio, OT
- Riluzole: used to slow down progression of disease
- Palliative
Types of MND and what they affect
- ALS: affects the anterior horn and the motor cortex- affects LMN and UMN
- BULBAR PALSY: affects cranial nerves IX to XII- affects speech
- PERIPHERAL LATERAL SCLEROSIS: affects the motor cortex- so mainly affects UMN
- ANTERIOR HORN CELL: affects the anterior horn- mainly LMN
