Clinical 16: Cranial Nerves and Opthalmoscopy Flashcards
Which of the cranial nerves can dessicate?
Trochlear - only one to truly decussate
Optic - partially decussate
Facial and hypoglossal - supranuclear UMN fibres which cross over.
How to test for a visual field blind spot?
Cover one eye
Equidistant from patient
Red hat pin
Move laterally slowly from central vision, ask patient to tell you when the pin goes out of vision and when the pin comes back into view.
Compare own blind spot to patients/
Complete the examination - remind not to drive fo 3-4hrs if have mydraitic drops.
Assessment of eye and visions, retinal photgpahy, cranial nerves,
What are some potential causes of ptosis?
Unilateral/bilateral - myasthenia gravis, myotonic dystrohy
Unilateral - 3rd nerve palsy, horner syndrome
Billateral - congential toabes dorsalist (argyll roberston pupil
What is meant by strabismus?
Squint - a condition in which eyes do not align properly with each other when looking at an object.
What is proptosis?
Protrusion of the eyeball
What is meant by lid lag?
A delay in moving the eyelid as the eye moves downwards.
What is anisocoria?
Asymmetry in pupil size
What does PERLA mean when written in patient records?
Pupilar Equal
React to Light and Accomodation
How does unilater trigeminal nerve palsy present?
Open jaw deviates towards the side of the lesion
What is the difference between bulbar palsy and pseudo-bulbar palsy?
Bulbar palsy - a lower motor neuron lesion affecting CN8-12 results in flaccid paralysis of the pharynx and larynx
Pseudo-bulbar palsy - a bilateral upperm motor neuron disorder - spastic paralysis of the parhynx and larynx = airway occlusion emergency.
How shoud you set up for an ophthalmoscope examination?
Darken the room as much as possible
Mydriatic drops may be used to dialte the pupil.
Use light size according to pupil size.
Set dial - compensate for patient and your visual errors.
Position at same level as patient - approach in way to avoid direct face to face contact.
Ask patient to focus on point far away and directly in front of them.
What to do during an opthalmoscope exam?
Check for red light reflex from a short distance away.
Approach close with permission - rest hand on shoulder or head - loop for optic disk.
Follow retinal vessel out to the periphery.
Assess each quadrant of the retina and associated vasculature with a systemic clockwise approach.
Arteries are smaller than the darker vein
Ask briefly to look directly into the light to assess fovea (only few seconds as painful)
What features of the optic disk are we assessing in opthalmoscopy?
Disc colour
Cup:disk ratio
Depth of cup
Sharp or blurred edges
What features of the retina should you be looking at during opthalmoscopy?
Colour
Scars
Haemorrhages
Hard exudates
Cotton wool spots
Ask to look to up down, lieft right to examine peripheriersis
May see evidence of retinal later treatment in peripheries
What should the cup disk ratio of the optic nerve be?
Less than 0.5
