Muscle and Nerves Disease Flashcards
state some symptoms of muscle disease
weakness short of breathe cardiopathy poor feeding in infants cramp pain myoglobinuria
what is myoglobinuria ?
is the presence of myoglobin in the urine, usually associated with rhabdomyolysis or muscle destruction. Myoglobin is present in muscle cells as a reserve of oxygen.
state three signs of muscle disease
- wasting/hypertrophy
- normal/reduced tone and reflexes
- motor weakness
what is the function of muscle ?
convert chemical energy to physical energy
what are the four components of the muscle contraction process?
- excitation contraction coupling
- contractile mechanism
- structural components
- energy system
could someone with muscle disease have a headache when they walk up in the morning?
yes because their intercostal muscles aren’t working properly so would have increased retention of CO2
what is myotonia ?
when the muscles contract but can’t relax again so are stiff
what does stiff muscles result in?
hypertrophy of muscles
is lack of reflexes usually due to muscles or nervous system?
nervous system
what investigations should be done for muscle diseases ?
- History and examination
- CK - blood test for enzyme in muscles
- EMG
- Muscle biopsy
- Genetic testing
what three things are usually tested for in a muscle biopsy ?
muscle structure
biochemistry
inflammation
what is the EMG test?
electromyography
- measures electrical activity in response to a nerve’s stimulation of the muscle. The test is used to help detect neuromuscular abnormalities.
what are the five classifications of muscle disease ?
Muscular dystrophies Channelopathies Metabolic muscle disease Inflammatory muscle disease Congenital myopathies
out of the 5 classifications of muscle disease, which one is not hereditary ?
inflammatory muscle disease
what is the cell membrane which surrounds muscle called?
sarcolemma
what causes muscular dystrophies ?
when one protein controlling contraction isn’t functioning properly
give some examples of muscular dystrophies
Duchenne’s MD Becker’s MD Facioscapulohumeral MD Myotonic dystrophy Limb-Girdle MD
is myotonic dystrophy hereditary ?
yes
- it gets worse throughout generations
is limb girdle MD a single disease?
no
- it is a spectrum of diseases caused by about 30 gene mutations
is channelopathies common?
no
what is the cause of channelopathies ?
disorders of Ca, Na and Cl channels
- therefore the muscle can’t function properly
what happens to the muscle during Paramyotonia congenita and Myotonia congenita?
can’t relax properly
give three causes of metabolic muscle disease
- disorder of carbohydrate metabolism
- disorder of lipid metabolism
- mitochondrial myopathies
what substance is broken down first in the body to get energy?
carbohydrate
after carbohydrates have been broken down with is then broken down to provide energy in the body?
lipids
if muscles aren’t provided with energy/ATP what occurs?
the muscle can’t contract as the muscle needs ATP to relax and to release the myosin form the actin
give two examples of inflammatory muscle disease
Polymyositis
Dermatomyositis
do inflammatory muscle disease run in families ?
no
do inflammatory muscle disease start suddenly?
yes
- over a few days or few weeks
what two symptoms are common with inflammatory muscle diseases?
painful and weak muscles
purple rash around eyes and rash behind elbows and finger with dermatomyositis
what age range are more likely to have inflammatory muscle disease?
can affect any age
what affect can inflammatory muscle diseases have on the heart?
can affect the conducting system and cause arrhythmias
would the CK of inflammatory muscle disease be increased or decreased ?
increased CK
what investigations should be done for inflammatory muscle disease ?
EMG
Biopsies
CK blood test
what is the treatment of inflammatory muscle disease ?
immunosuppression
what does the enzyme acetylcholinesterase do?
breaks down ACh in the synaptic cleft to stop APs being stimulated
what is the common disorder of the neuromuscular junction called?
myasthenia gravis
what is the main clinical sign of myasthenia gravis?
muscles get tired quickly
what are the main symptoms of myasthenia gravis ?
limb weakness ptosis chewing weakness slurred talking after a few sentences/words SOB diplopia
what causes myasthenia gravis ?
- the antibody binds to the ACh receptors are the post ganglionic terminal
- therefore, less ACh can bind and trigger APs to be fired
- therefore, initial contraction is present but continued contraction can’t be maintained
what are 3 treatment options for myasthenia gravis ?
immunosupressors
acetylcholinesterase inhibitor
steroids
what 5 investigations can be done for myasthenia gravis ?
AChR ab Anti MuSK ab EMG/repetitive stimulation Tensilon test CT chest
what does the tension test involve ?
- Short acting inhibtor of acetylcholinesterase
- Will relieve symptoms for 1 min
- Used for a diagnositic test
what doe the repetitive stimulation test involve ?
Send lots of APs to tire out the muscle and the contraction will get less and less every time
what conditions are associated with myasthenia gravis in young and older people?
young = thymic hyperplasia
older = malignant thymoma
what surgical option is there for treatment of myasthenia gravis ?
thymectomy
what sensory axons are larger ?
- pain/temperature
- proprioception/vibration
proprioception/vibration
state two causes of lesion of an individual peripheral nerve ?
compression
inflammation (vasculitic)
state three causes of spinal root disease
- degenerative spine disease
- inflammation
- infiltration
give some examples of disease which cause inflammation in spinal roots?
lymes disease
shingles
HIV
give the two main causes of peripheral nerve disease
- alcohol
- diabetes
what investigations can be done for nerve disease?
blood tests - LFTs, glucose genetic analysis NCS lumbar puncture nerve biopsy
what is a good way to determine whether a nerve disease condition is hereditary or not?
the feet will not be normal if it is hereditary because development wouldn’t have been normal
a cause of nerve disease can be inflammatory demyelination. give an example of an acute and chronic example…
acute = Guillain Barre Syndrome
chronic = CIDP
what symptoms would be seen if a nerve root was damaged ?
muscle wasting and weakness
dermatomal sensory change
reflex change
what symptoms would be seen if a individual nerve was damaged ?
wasting and weakness in innervated muscle
specific sensory change
what clinical sign would be seen with UMN disease?
brisk reflexes
increased tone
what clinical sign would be seen with LMN disease?
muscle wasting
muscle weakness
muscle fasciculations
does UMN diseases sometimes have mixed symptoms which may indicate a LMN disease?
yes
why might a UMN disease have symptoms of a LMN disease?
because UMN diseases may involve the anterior horn head of the lower motor neuron so muscle wasting may also be seen
what type of muscle disease is amyotrophic lateral sclerosis ?
motor neuron disease
what are the clinical signs of amyotrophic lateral sclerosis ?
starts in one limb progressively moving over to contralateral limb then starts to involve breathing and swallowing
- muscle weakness and atrophy
what is the prognosis from symptom onset?
3-5yrs
what is the prognosis from diagnosis ?
2-3yrs
how many patients with motor neuron disease will have died within 14 months of diagnosis ?
50%
what is the treatment options for motor neuron disease?
medication
- riluzole (trials)
supportive
- physical therapist
- Non Invasive Ventilation
- Percutaneous endoscopic gastrostomy
