OSCE/Thinking about the brain

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Contents

Neurological symptoms

  • Balance, unsteadiness, falls
  • Loss of vision
  • Hearing problems
  • Visual disturbance
  • Dysphagia
  • Dysphasia
  • Headache
  • Paraesthesia
  • Nausea
  • Photophobia
  • In a talkie with patients remember to check patient expectations etc
  • Impairment due to pain - somehow ask about this rather than pain scale
  • Today's comms is just psychosocial
    • Perception of health/disease
  • Acknowledge problems like a boss

Cranial nerve exam

  • 12 cranial nerves, but we examine
    • Eyes: CNII, CNIII. CNIV, CNVI
    • Face: V, VII
    • Hearing: VIII


CNII

Visual acuity with Snellen chart, and check visual fields. They can do it with contacts or glasses (not checking for refractive errors). Normally you use a much bigger chart, with 6m away. If there's 1-2 errors, that's the correct line. The mini one must be done at 1m, finding the lowest one they can read. Recording it: the top reading is 6. The bottom reading is the number of the smallest line. Results will be Good (6/6 or 6/5) or bad (6/24, 6/18 etc). The number for denominator is written near each line (tells you how far away a normal person would be to see that resolution). Each eye has nasal and temporal visual fields. Need to upper and lower halves for each (i.e. four quadrants).

  1. Observation: ptosis, assymmetry
  2. "Do you wear glasses or contacts?"
  3. Cover left eye, put card at an arm's distance, get them to read the bottom line. Then do the other eye, reading backwards
  4. Put hands half way in between the two of you. Get them to cover their right eye, and you cover your own left eye, then move your fingers in from periphery. You swap hands over your same eye while they're on the same eye and try again. This is to compare their sight to yours. Remember the information from optic nerves crosses over (what you see on temporal part, maps to nasal part of retina).
  5. Repeat above for the other eye.
  6. Get them to look straight at you and then point with either hand to which finger you're moving, and you blink with your hands left and right and from top to bottom; checking for neglect (can be due to damage of visual association cortex).
  7. Check pupils are even on both sides
  8. Without glasses: Observe their eyes, use a torch in the dark, shine torch in eye while they look straight ahead (do it twice for each eye, bringing the light inwards from laterally).
    • Constriction of pupil = 3rd nerve (in the one eye you're looking at)
    • When you do it the second time, the pupil constricts on the other eye as well (because the optic nerve fibres cross in their path)
  9. With glasses (if needed): Get them to look in the distance, then again at your finger, and then repeat; watch their eyes (accommodation). Close up, should see: eyes converge, pupils constrict (can't see the lens constricting with naked eye)
  10. Checking how eyes move (nerves 3, 4 and 6). Get them to follow your finger with their eyes, move to side then up and down, do on both sides. Check for double vision.
    • H shape
    • Look for nystagmus (flicking at the extremes of eyes) and double vision.
    • Want to make sure it looks the same both sides
    • If they have double vision, do each eye separately
  11. There's another one - check in the guide
  • Nasal light --> temporal retina --> optic nerve --> switch side in optic chiasm --> optic tract --> optic radiation --> visual cortex (occipital lobe)
    • Whereas temporal ones go to ipsilateral side of occipital lobe
    • Therefore shining light in, half the fibres go to one side of brain, and half go to the other side of the brain. There is a reflex in the third nerve on both sides causing constriction on both sides
    • Therefore constriction in only one eye would be abnormal
    • 2nd nerve gets sensory information, 3rd nerve carries out motor function of pupillary constriction
    • This is the direct and indirect light reflex
  • Need to be able to work out, if there's a visual field abnormality, what part of the optic pathway is damaged. It's in the notes.

Nerve 5

Trigeminal branches: ophthalmic, maxillary and mandibular branches. Sensation in the face. Check each of these 3 areas. 5th nerve also does the muscles of mastication (feel in the temporal and mandibular regions). Mostly sensory with a bit of motor.

  1. Look at their face; you need a tissue
  2. Check if they can feel you touching tissue on their neck (gently). Touch their face with tissue on both sides
  3. Feel their temporalis as they clench their teeth
  4. Feel their masseter as they clench their teeth
  5. Test power of jaw, with their mouth slightly open as you push up to try and close their mouth
  6. Tap hammer on your finger on their jaw (jaw jerk - if they have an upper motor neuron lesion of 5th nerve, there would be a strong jaw jerk, normally nothing happens)

Nerve 7

Facial nerve: muscles of facial expression (purely motor)

  1. Wrinkle forehead
  2. Frown
  3. Close eyes as tight as you can (try to open them)
  4. Smile, show teeth
  5. Push out cheeks

Nerve 8

  1. Check hearing. Rub fingers together on either side of ear, and get them to point to which side you're rubbing, if they can hear it
  2. Check hearing using tuning fork (512 Hz); should be able to hear it in the midline.
    • Weber test: Put tuning fork on centre of forehead - if they can hear it, see if they can hear louder on one side than the other. Sensorineural loss: then affected ear is poorer. Conductive loss: affected ear is louder.
    • Rinne test: Put the tuning fork on mastoid process and get them to tell tou when they stop hearing it
      • Then switch it to air conduction
      • Normal person: air conduction > bone conduction; should still be able to hear it
      • If sensorineural: then result will be the same as normal
      • If conduction loss: then they won't be able to hear in air conduction.
  3. Repeat it on the other side