MS clinical exam

• Optic nerve (CN II):

  • fundoscopy for optic neuritis
  • most common initial presentation of MS
  • demyelination of the optic nerve
  • enlarged central blind spot, pain with eye movement, impaired colour vision
  • relative efferent pupillary defect
  • Acute = blurring of the optic disc
  • previous episode = disc pallor
• Optic neuritis causes a relative afferent pupillary defect which can be seen with the pendular swinging light test

  • The pupil of the healthy eye will constrict as light is shone on it, exhibiting a normal direct light reflex. The contralateral pupil will also constrict as there is a normal consensual light reflex. 
  • When the light is then swung to the affected eye, the previously constricted pupil will dilate
  • no afferent signal being transmitted by the inflamed optic nerve
• occulomotor (CN III), trochlear (CN IV), abducens (CN VI):

  • internuclear ophthalmoplegia
  • failure of abduction of the affected eye during horizontal eye movement
  • nystagmus of the non-affected eye
  • diplopia
• trigeminal nerve (CN V):

  • facial parasthesia
  • weakness of the muscles of mastication
• Facial nerve (CN VII):

  • weakness of facial muscles of expression
  • forehead sparing - can mimic an acute stroke
• Glossopharyngeal (CN IX), vagus (CN X), and hypoglossal (CN XII):

  • loss of motor function to tongue and pharynx
  • speech and swallowing problems
• Accessory nerve (CN XI):

  • loss of motor function to sternocleidomastoid and trapezius
  • neck weakness and hypertonia
• Cerebellar signs:

  • nystagmus - towards lesion
  • intention tremor
  • dysarthria - scanning speech
• Peripheral NS signs:

  • sensory - abnormal sensation and romberg’s test positive
  • motor - hypertonia, decreased power, hyperreflexia and clonus
• A positive romberg‘s test indicates dorsal column involvement in the spinal cord - affects proprioception
• MS is one of the most common causes of internuclear ophthalmoplegia - impaired adduction of the ipsilateral eye with nystagmus of the abducting eye

  Due to damage to the interneuron between CN VI and CN III