Neuromuscular Disease Supplementary Flashcards
What are 3 causes of presynaptic neuromuscular disorders?
abnormality of calcium, sodium or magnesium
botulism
lambert eaton myasthenic syndrome
What organism is present in soil & can infect through food, wounds or heroin use?
Clostridium botulinum
How does the botulinum toxin disrupt the NMJ and how does it present?
cleaves presynaptic proteins involved in vesicle formation & blocks vesicle docking
presents as rapid onset weakness without sensory loss
What is the treatment for botulism?
Supportive, will improve
Lambert Eaton Myasthenic Syndrome has a strong association with large cell carcinoma. True/false?
False - small cell carcinoma
How does Lambert Eaton Myasthenic Syndrome disrupt the NMJ?
antibodies to presynaptic calcium channels causes less vesicle release
What is the treatment for Lamber Eaton Myasthenic Syndrome?
3-4 diaminopyridine
What is the classic presentation of Myasthenia Gravis?
bilateral facial weakness
extraocular weakness, facial and bulbar weakness
limb weakness proximal
struggling to chew, hold head up
At what point do symptoms tend to start with myasthenia gravis?
When ACh receptors are reduced to about 30%
75% of Myasthenia Gravis patients have hyperplasia or thymoma. True/false?
True
What are the 2 peak ages of incidence for myasthenia gravis?
females in 3rd decase
males in 6th and 7th decades
How is diagnosis for myasthenia gravis made?
clinical: fatiguability doing task
diplopia, ptosis, head drop that comes and goes
Investigations: serum AChR antibodies and single fibre EMG & CT chest
What are the acute treatment options for myasthenia gravis?
acetylcholinesterase inhibitor (pyridosigmine) intravenous immunoglobulin plasma exchange thymectomy
What is the long term treatment for myasthenia gravis?
immunomodulating with steroids, steroid sparing agents (azathiprine/mycophenolate)
What is the drug you MUST avoid in myasthenia gravis?
Gentamicin
____ surrounds a muscle fibre and ____ surrounds 20-80 muscle fibres as a fascile and ____ surrounds an individual muscle.
Endomysium
Perimysium
Epimysium
What protein most commonly causes neuromuscular disease?
Dystrophin
What are the 4 main symptoms of muscle disease?
myalgia
muscle weakness
wasting
hyporeflexia
Fasciculations are usually a sign of disease of the muscle not the motor neurone. True/false?
False - usually sign of disease of motor neurone
Myotonia is associated with disorders of what channel?
Chloride
Give an example of disease for each pathology of muscle:
- acute inflammation and fibre necrosis
- genetically determine metabolic failure
- infiltration by inflammatory tissue
- immunological damage
- ion channel disorders
- acute inflammation and fibre necrosis: polymyositis
- genetically determined metabolic failure: muscular dystrophies
- infiltration by inflammatory tissue: sarcoidosis
- immunological damage: myasthenia
- ion channel disorders: hereditary myotonias
What are investigations for muscle problems?
- blood tests: CK, ALT, lactate indicates mitochondria problems, antibodies
- biopsy
- MRI
What degenerative immune mediated muscle disease presents as slowly progressive weakness with characteristic thumb sparing?
Inclusion body myositis
Myotonic dystrophy is autosomal dominant and is a trinucleotide repeat disorder with anticipation. True/false?
True
Name four organisms that can cause muscle problems.
coxsacchie
trpanosomiasis
cistercercosis
borrelia
What 2 common drugs can cause myopathies?
statins
steroids
What are 4 main potential causes of rhabdomyolysis?
crush injuries
toxins
post convulsions
extreme exercise
How do rhabdomyolysis patients present?
Triad of myalgia, muscle weakness and myoglobinuria
