Neuromuscular Disease Flashcards
what does neuromuscular disease affect?
the peripheral nervous syste,
what specific area of the peripheral nervous system is affected by neuromuscular disease?
lower motor neurones that innervate skeletal muscle
what is the effect of neuromuscular disease on muscle function?
causes a reduction in ability to function properly
where along the neuromuscular pathway can be affected by neuromuscular disease?
anywhere along neuromuscular pathway
how do patients with neuromuscular disease present?
weakness and lethargy
muscles are unable to contract properly
describe what happens at the neuromuscular junction
depolarisation of end of neuron at synapse causes opening of Ca2+ channels
Ca2+ fuses with vesicles containing Ach and these then fuse with the pre-synaptic membrane releasing neurotransmitter into the synaptic cleft
Ach crosses the synapse and binds to Na+ channels causing them to open and the post snaptic cell depolarises
what sort of disease is polyradiculoneuritis?
immune mediated disease
what does polyradiculoneuritis affect?
myelin and/or axons
what is the name for diseases which affect myelin or axons?
axonopathy
what is the most common peripheral neuropathy in dogs?
polyradiculoneuritis
what is the presentation of a patient with polyradiculoneuritis?
short-strided gait that progresses to tetraparesis
ambulatory or non-ambulatory
dysphonia
autonomic function remains
are clinical signs of polyradiculoneuritis the same with all patients?
no, they vary depending on patient and severity
what function remains in polyradiculoneuritis patients?
autonomic (BAR, DUDE is normal)
what is tetraparesis?
all 4 limbs become weak and the patient is unable to walk properly / at all
what is dysphonia?
change in voice (bark)
when does recovery from polyradiculoneuritis occur?
1-4 months after signs stabilise
how is polyradiculoneuritis diagnosed?
accurate patient history
physical and neurological exam
electrodiagnostic testing
muscle and nerve biopsies
what tests are used in electrodiagnostic testing?
EMG - electromylogram
NCV - nerve conduction velocity
how is polyradiculoneuritis treated?
intensive nursing care and physiotherapy
is medical treatment for polyradiculoneuritis effective?
medical treatment with corticosteroids shown to have little to no effect
what is myasthenia gravis a disease of?
neuromuscular transmission which affects the neuromuscular junction
what is the name of diseases which affect the neuromuscular junction?
junctionopathy
what are the 2 ways myasthenia gravis may be aquired?
congenital
aquired
what is congenital myasthenia gravis caused by?
reduced number of Ach receptors
what is acquired myasthenia gravis caused by?
immune mediated
what happens during aquired myasthenia gravis to produce symptoms?
antibodies act on Ach receptor and alter it’s function by preventing or changing the binding of Ach to receptors so there are fewer receptors which are effective and so muscles cannot contract normally
how do myasthenia gravis patients present?
muscle weakness or fatigue which is usually more obvious when the patient is exercising
regurgitation commonly seen
what are the 3 possible types of myasthenia gravis?
focal
generalise
acute fulminating
what type of myasthenia gravis is most severe?
acute fulminating
what is focal myasthenia gravis?
affects one muscle group only
what is generalised myasthenia gravis?
muscles all over the body affected
why is regurgitation commonly seen in myasthenia gravis patients?
due to oesophageal dilation/weakness
what is typical behaviour while walking of a patient with myasthenia gravis?
will walk in a slow/stilted manner for a short period and then need to stop to rest
how is myasthenia gravis diagnosed?
presumptive based on history and presentation
thoracic radiographs to show megaoesophagus
edrophonium / tensilon test
are electrodiagnostics usually used to test for myasthenia gravis?
not usually as they are not specific - will be able to rule out some other diseases but not pinpoint myasthenia gravis
what is a edrophonium / tensilon test?
injection of IVdrug
wait for a few seconds and then walk animal forwards
if + the animals will be able to walk normally where they couldn’t before
what is a positive result in edrophonium / tensilon tests?
animal is able to walk forward normally after IV injection
how is myasthenia gravis treated?
anticholinesterase therapy
corticosteroids at immunosuppressive doses alongside
intensive nursing care and support
how do anticholinesterases help patients with myasthenia gravis?
act like tensilon and so increase the Ach available and time spent in synaptic cleft to improve attachment of Ach to receptors and allow normal muscle function
what are the side effects of anticholinesterase therapy?
GI signs, excessive salivation, lacrimation
what condition are myasthenia gravis patients at great risk of?
aspiration pneumonia
why are myasthenia gravis patients at risk of aspiration pneumonia?
increase in muscle weakness increases likelihood of reflux
what is polymyositis?
immune mediated inflammatory myopathy
what causes polymyositis?
infiltration of inflammatory cells into the skeletal muscle so muscle doesn’t function as well
what is polymyositis caused by?
idiopathic but can be associated with systemic disease
what are the 2 types of polymyositis?
focal
diffuse
what is focal polymyositis?
one muscle group affected
what is diffuse polymyositis?
large muscles or lots of muscle groups affected
how do polymyositis patients present?
exercise intolerance and stiffened gait as the muscles cannot work as normal muscle weakness muscle atrophy dysphonia dysphagia regurgitation
are signs of polymyositis consistent in the beginning of the disease?
no - often wax and wane
how is polymyositis diagnosed?
criteria not well defined diagnosis of exclusion as there are no specific tests clinical history biochemistry electrodiagnostic testing muscle biopsy
what biochemisty parameter is likely to be elevated in polymyositis patients?
creatinine kinase - found during muscle breakdown
how is polymyositis treated?
corticosteroids at immunosuppressive doses
intensive nursing care and support are vital
what drug may be used alongside steroids to treat polymyositis?
Azothrioprine
why may Azothrioprine be needed alongside steroids in treatment of polymyositis?
if patients cannot tolerate steroid side effects as a lower steroid dose can be given
what are the side effects of corticosteroids?
polyphagia
polydipsia
oedema
weight gain
what is the risk of aspiration pneumonia in polymyositis patients?
high due to megaoesophagus
what is the pressure sore risk like for polymyositis patients?
medium due to loss of muscle coverage
what is the contracture risk like in polymyositis patients?
low
what is the aspiration pneumonia risk like for polyradiculoneuritis patients?
low as autonomic function remains
what is the pressure sore risk like for polyradiculoneuritis patients?
high
what is the contracture risk like for polyradiculoneuritis patients?
high in the young and medium in adults due to recumbancy
what is the aspiration pneumonia risk like for myasthenia gravis patients?
high due to mega oesophagus
what is the pressure sore risk like for myasthenia gravis patients?
low
what is the contracture risk like for myasthenia gravis patients?
none
who is the team involved in the care of the neuromuscular patient?
patient
owner
nurses
vet
what is aspiration pneumonia?
inhalation of GI contents into the lungs usually due to regurgitation
what is the result of aspiration on the lungs?
pulmonary damage
inflammatory response
what are the clinical signs of aspiration pneumonia?
coughing
tachypnoea
harsh lung sounds
crackles on auscultation
what is the most common complication in patients with myasthenia gravis?
aspiration pneumonia
how is aspiration pneumonia treated?
careful and close monitoring of patients early administration of antibiotics IVFT O2 therapy supportive care respiratory physiotherapy if clinician wishes walking and turning patients regularly feeding balls of food from height severe cases may need to go onto mechanical ventilation
is respiratory physiotherapy of use in aspiration pneumonia patients?
evidence varies - depends on clinician
how often should aspiration pneumonia patients be turned?
every 4-6 hours
what should animals with aspiration pneumonia be fed?
no liquid or dry food due to aspiration / irritation risk
balls of soft food
fed at height
keep raised after eating
what may severe aspiration pneumonia cases need?
mechanical ventilation as unable to oxygenate properly
what is a common complication for recumbent patients?
pressure sores
what does recumbancy lead to?
increased pressure over bony prominences which leads to ischemia and necrosis
what are the stages of pressure sores?
stage 1 - 4
describe a stage 1 pressure sore
lightly pigmented
skin intact
describe a stage 2 pressure sore
skin is broken
describe a stage 3 pressure sore
larger and deeper wound
has broken through fat below the skin
describe a stage 4 pressure sore
large and deep
through the muscle to bone
necrosis
infection
what areas of the animals body are at particular risk of pressure sores?
elbows hips stifle carpus tarusu
how can pressure sores be prevented?
thick padded bedding
turn every 2-4 hours
donut bandage on areas of concern to reduce pressure
porous bedding
incontinence pads to remove moisture
non-slip floors
physiotherapy
monitor patients closely
checklist to maintain treatment level across shifts
express / catheterise bladder to prevent urine scaulding
how are pressure sores treated?
prevention better than cure
myasthenia gravis patients are especially prone
bandages and commercial boots may be useful
debride sores if necessary
use antibiotics if infection suspected
what is muscle contracture?
adaptive shortening of muscle
adaptive shortening of soft tissues
inelasticity of soft tissues
what leads to muscle contracture?
recumbancy and immobilisation
how is muscle contracture treated?
intensive physiotherapy
what is involved in intensive physiotherapy to treat muscle contracture?
massage
PROM - passive range of motion
properoceptive exercises
neuromuscular stimulator
what must be considered when treating neuromuscular patients?
temperament client expectations client limits disease processes previous injuries / surgeries other medical conditions
what respiratory techniques may be used on aspiration pneumonia patients?
vibration - shaking patients sides
coupage - cupped hands tapping on the chest from caudal to cranial
