• Broad term for leukodystrophy-like diseases
  
• Characterized by dysfunction of the white matter of the brain
• Caused by imperfect growth or development of the myelin sheath
• Made up of at least ten different chemicals
• Each of the leukodystrophies is the result of a defect in the gene that controls the production or metabolism of one (and only one) of the component molecules of myelin
• Can refer specifically to any of these diseases:
• Progressive multifocal leukoencephalopathy
• Toxic leukoencephalopathy
• Leukoencephalopathy with vanishing white matter
• Leukoencephalopathy with neuroaxonal spheroids
• Reversible posterior leukoencephalopathy syndrome
• Megalencephalic leukoencephalopathy with subcortical cysts
• Hypertensive leukoencephalopathy

• http://www.radiologyassistant.nl/en/483910a4b6f14
• Do an un-enhanced CT first
• So you don't confuse contrast for blood
  
• Early CT signs
• Loss of grey/white matter differentiation
• Hyperdense artery
• Due to thrombus
• Some thrombi may look different to others
• Sulcal effacement
• Mass effect
• Can use "stroke window" to enhance grey/white contrast
• Infarct covering >1/3 of the MCA territory are likely to undergo haemorrhagic transformation

• ADC = Apparent Diffusion Coefficient
• In the acute phase T2WI will be normal, but in time the infarcted area will become hyperintense
• The hyperintensity on T2WI reaches its maximum between 7 and 30 days, then fades
• DWI is already positive in the acute phase and then becomes more bright with a maximum at 7 days
• DWI in brain infarction will be positive for approximately for 3 weeks after onset
  
• In spinal cord infarction DWI is only positive for one week
• ADC will be of low signal intensity with a maximum at 24 hours and then will increase in signal intensity and finally becomes bright in the chronic stage

• Use the patient's words!
• "Jerky vision", not "Oscilloptia"
• Distinguish SYMPTOM from EXAMINATION FINDING
• e.g. Nystagmus => Oscilloptia
• First check HEAD POSTURE
• They'll turn their head to reduce the use of the weak muscle
• But a CN III palsy will cause a complete ptosis so they won't need to :)
• Check smooth horizontal movement first
• 1 m away
• Keep within the binocular field
• Go slow
• Pause at the sides
• Use something coloured
• NB comes from occipital lobe, so you need an object!
• Can't do it voluntarily
• If they have diplopia then the OUTSIDE image is the false one

Cranial nerves

• Bilateral innervation to the forehead is to protect eye closure
• => Best test is to screw the eyes up
• Smiling is a extrapyramidal pathway (emotive)
• => Doesn't accurately test CN function
• Trigeminal nerve => Muscles of mastication
• All have bilateral cortical representation
• Swallowing has bilateral cortical representation
• But takes a few days to kick in e.g. after a stroke
• La-la-la-la-la-la-la-la-la is good to check for a pseudobulbar palsy
• (Results from an UML lesion to the corticobulbar pathways in the pyramidal tract)
• SCREW EYES and PURSE LIPS
• Facial nerve
• Taste in front of tongue (corda tympani)
• Laccrimal ducts (greater superficial petrosal nerve)
• Stapedius muscle
• => Hyperacusis (raised sensitivity to LOUD noise)
• cf stethoscope test
• Bell's phenomenon
• Blink reflex
• Eyelids down, but also eyeball up
• => Can test even with ptosis
• Inspect the tongue AT REST
• As you would for other muscles
• Check movements later
• Check palatal deviation by looking at the median raphe, not the uvula
• Deviation
• Tongue is pushed to the weak side
• Raphe is pulled to the strong side
  

• Dehydration is the commonest cause of venous stroke
• Esp. in kids
• Neck pain + Neurological deficit => Carotid dissection
• Esp. if young
• Bulbar palsy refers to impairment of CN IX, X, XI and XII which occurs due to a lower motor neuron lesion
  
• Either at nuclear or fascicular level in the medulla oblongata or from lesions of the lower cranial nerves outside the brainstem
• DHx: Give dose and WHEN STARTED
• Skin popping => Clostridium botulinum
• Don't forget handedness and job
• 70% of diagnosed TIAs weren't TIAs
  
• Torticollis
• Stiff neck associated with muscle spasm
• Usually SCM + splenius capitus
• Treat with Botox
• Ophthalmic branch goes all the way up to the ear-to-ear line