• Neuromuscular
• Myasthenia Gravis
• Autoimmune disease whereby the body produces IgG antibodies agains ACh receptors
• Try to avoid the use of NDMRs if possible as they are very sensitive. Use dose 1/10 of then usual if you must!
• Presents with ocular, bulbar and proximal muscle weakness
• Relatively resistant to suxamethonium
• Reversal can theoretically provoke a cholinergic crisis
• Predictors of respiratory failure
• Disease duration > 6 yrs
  Daily pyridostigmine dose > 750mg
  Coexisting lung disease
  Pre-op VC of < 2.9L
  Major body cavity surgery
  Bulbar involvement
• Crises - note they are unrelated!
• Cholinergic
• Provoked by administration of anti-cholinesterase leading to muscarinic effects e.g. Bradycardia, salivation, sweating, small pupils, abdominal pain and diarrhoea
• Myasthenic
• Due to relative lack of anti-cholinesterase
  Sudden rapidly worsening weakness
  Can be due to missed meds, surgery, illness
• Guillain-Barre
  Link:../Guillain-barre syndrome
  
• Acute demyelinating myelopathy, 10% mortality, 10% long-term neuro sequale.
• Look for progressive motor weakness, areflexia, facial and bulbar palsy, opthalmoplegia, sensory symptoms, severe girdle pain, autonomic dysfunction.
• Check VC - 25% require ventilatory support if:
  VC <20ml/kg
  Maximal inspiratory pressure <30 cm H₂O
  Maximal expiratory pressure <40 cm H₂O
  Decrease of > 30% in VC
• Look for antiganglioside antibodies
• Characteristically high protein on LP (may be normal in early disease)
• Muscular dystrophies
• Duchenne's muscular dystrophy
• Sex-linked recessive, presents between the ages of 3-5. Causes progressive weakness and life expectancy is about 25 yrs due to respiratory or cardiac failure
• Becker's muscular dystrophy
• Similar inheritance but less severe clinical picture
• Fascioscapulohumeral dystrophy (dominant)
  Limb-girdle dystrophy (recessive)
• Muscular dystrophy
• Clinical features
• Frontal balding
  Cataracts
  Muscle wasting
  Bulbar symptoms
  Restrictive lung defect
  OSAS
  Cor pulmonale
  Aspiration pneumonia
  Cardiomyopathy
  Conduction defects
  Oesophageal dysmotility
  Delayed gastric emptying
  Diabetes
  Hypothyroidism
• Anaesthetic management
• Avoid depolarising NMBDs
  Consider invasive monitoring for cardiomyopathy
  Avoid cold/shivering
  ALL THE ABOVE CAN PRECIPITATE MYOTONIA