myasthenia gravis (MG) Flashcards
3 types of MG
- transient neonatal MG
- juvenile MG
- congenital MG
transient neonatal MG
- temporary, in babies
- mom has MG
- antibodies cross over in utero
- symptoms go away after weeks/months (antibodies replaced with normal function
in transient neonatal MG, are babies at greater risk of developing MG
no
juvenile MG
- typical autoimmune presentation
- lifelong, may go in/out of remission
- watch thymus and autoimmune systems
congenital MG
- autosomal recessive inherited MG
- start at birth, lifelong
infantile botulism causes
- anaerobic bacteria (clostridium botulinum)
- consuming/ingesting the bacteria –> germination –> toxin released
infantile botulism risk is higher in which circumstances
- eating honey
- when there are reptiles as pets
infantile botulism symptoms
- suddenly floopy, acute onset constipation, fixed dilated pupils, respiratory failure
- “floppy”, “loose-limbed” body
- paralysis and difficulty breathing –> fatality
- myasthenic (weakness) presentation
botulism is characterized by ?
- a descending, flaccid paralysis
- can lead to respiratory failure
diagnostic test
- look for antibodies
- repetetive nerve stimulation (fatigue with repetition)
treatment
- immunosuppressants
maintenance
- steroids
- pyridostigmine
long term
- thmectomy
pyridostigmine function
- treat MG
- blocks the breakdown of acetylcholine
botulism mechanism of action
- ingest spores
- germinate in the gut
- produce botulism toxins which bind to calcium channels
- prevent acetylcholine vesicle release into NMJ
botulism treatment
specific immunoglobulins
congenital myasthenic syndromes prevalence
1 in 500,000 in europe
genetic inheritance pattern for congenital myasthenic syndromes
- most autosomal recessive
- some autosomal dominant
where do congenital myasthenic syndromes occur (% in presynaptic, synaptic, postsynaptic)
- 5% presynaptic
- 10% synaptic
- 85% postsynaptic
congenital myasthenic syndromes age of onset
usually birth or infancy
congenital myasthenic syndromes symptoms
- hypotonia, eye issues, voice/swallow changes, facial paresis, muscle fatigueability
- worsens with exacerbation
