Neuromuscular Conditions Flashcards
what is myasthenia gravis
autoimmune condition where there is antibodies to post-synaptic acetylcholine receptors
antibodies in myasthenia gravis
anti-AchR antibodies
characteristic presentation of the muscle weakness in myasthenia gravis
weakness that gets worse with muscle use and improves with rest
- symptoms minimal in the morning, worse at end of day
which muscles are first affected in myasthenia gravis
eye muscles
- ptosis
- diplopia
symptoms of myasthenia gravis
proximal limb weakness facial weakness weak swallow slurred speech ptosis, diplopia jaw fatigue
what is myasthenia gravis linked to
thymomas / thymus hyperplasia
treatment of myasthenia gravis
oral pyridostigmine (acetylcholinesterase inhibitor)
immunosuppression with prednisolone
thymectomy
what is Lambert Eaton syndrome
antibodies to pre-synaptic calcium channels causing proximal muscle weakness + weakness of eye/facial muscles
what is Lambert Eaton strongly associated with
small cell lung cancer
what is myotonia?
where is the defect?
myotonia = failure of muscle relaxation after use
defect in chloride channel
what is myotonic dystrophy
autosomal dominant chloride channelopathy
symptoms of myotonic dystrophy
distal weakness sternocleidomastoid / facial muscle weakness cataracts cardiomyopathy male frontal baldness
presentation of polymyositis
symmetrical proximal muscle weakness
muscle + point pain
what is raised in polymyositis
CK
antibody in polymyositis
Anti-Jo antibody
diagnostic investigation for polymyositis
muscle biopsy
treatment of polymyositis
prednisolone
what is inclusion body myositis
slowly progressive inflammatory myopathy
presentation of inclusion body myositis
slowly progressive asymmetrical weakness
affects finger flexors
- thumb sparing
affects pharyngeal muscles
- dysphagia
what is rhabdomyolysis
damage to skeletal muscle causes leakage of large quantities of toxic intracellular contents into plasma
symptoms of rhabodomyolysis
myalgia
muscle weakness
myoglobinuria
what drug causes neuromuscular junction dysfunction
curare
- blocks action potential – no muscle contraction – no respiration
what causes botulism
clostridium botulinum bacteria
- found in soil
symptoms of botulism
rapid onset weakness without sensory loss
who typically gets botulism
IV drug users
what is a myasthenic crisis
complication of myasthenia gravis
- acute worsening of symptoms
- triggered by illness / drugs
what drugs can trigger a myasthenic crisis
beta blockers
lithium
phenytoin
gentamicin, quinolone
treatment of restless leg syndrome
ropinerole (dopamine agonist)
symptoms of restless leg syndrome
uncontrollable urge to move legs
parasthesias e.g crawling / throbbing sensations
treatment of myasthenia crisis
IV immunoglobulins + plasmaelectropheresis
