Neuro ILAs Flashcards
Explain how you’d assess the direct / indirect light response
Direct = shine light into eye and assess for pupillary constriction Indirect = shine light into one eye and assess for pupillary constriction of the other eye
What is a relative afferent pupillary defect? (Marcus Gunn pupil)
+ how would you assess it?
Direct / indirect light response:
When light shone into the affected eye, small amount of constriction
When light shone into the other eye, normal constriction of both eyes
Swinging flashlight test:
When light shone into the unaffected eye, constriction
When light shone into the affected eye, apparent partial dilation of the pupil - as the pupil is only slightly constricted instead of completely
What are the causes of a Marcus Gunn pupil?
Relevant afferent pupillary defect
- Lesion of optic nerve between retina and optic chiasm - ie optic neuritis
- Severe retinal disease
What is normal visual acuity?
+ what does this figure mean?
6/6
Can read the 6 metre line (bottom line) at correct distance from the chart
What is the visual acuity needed for someone to be legally blind?
+ what does this figure mean?
6/60
They can see an object at a 6 metre distance what a normal person would see at 60 metres
Why would you use a pinhole occluder when testing visual acuity?
To remove refractive errors due to the shape of the lens eg myopia
What are the causes of unilateral visual loss?
Break down into the BRAIN, the BLOOD SUPPLY, and then EYE ITSELF • Optic neuritis • Glaucoma • Uveitis • Giant cell arteritis • Corneal ulcer • Retinal detachment • TIA / stroke • Migraine • Space-occupying lesion • Emboli or something • Cataracts • + these things due to medications
What sort of problem is likely to cause a SUDDEN unilateral loss in vision?
Vascular problem
How would you investigate a patient presenting with unilateral vision loss? (4)
MRI and VEP (visual evoked potential) for optic neuritis
Fluorescein angiography for CRVO – central retinal vein occlusion
Tonometry – to measure the intraocular pressure – for glaucoma
USS – to show vitreous haemorrhage / retinal detachment
What is optic neuritis?
Inflammation of the optic nerve
What are the symptoms / signs of optic neuritis?
SYMPTOMS
Pain on eye movement
Loss of central vision in one eye
Dyschromatopsia (inability to see colours correctly)
Photopsia – flashing lights in one or both eyes
SIGNS Relative afferent pupillary defect (changes in the way the pupil reacts to bright light) Disc swelling (from papillitis)
What are the causes of optic neuritis?
Demyelination - MS, Schilder’s disease, Neuromyelitis optica
Infections - sinusitis, mumps, measles, Lyme disease, meningitis, viral encephalitis
Autoimmune neuropathies - SLE
Compressive neuropathies - meningioma
Inflammatory conditions - sarcoidosis (PAINFUL)
Guillan-Barre
How would you treat optic neuritis?
Mostly recover without treatment
Treat underlying cause
IVMP (IV methylprednisolone - can reduce pain and hasten recovery) / immunoglobulin / interferon
What are the typical presenting symptoms of MS? (7)
Visual loss (optic neuritis)
Pyramidal weakness, spasticity, paraparesis (UMN signs)
Sensory disturbance
Cerebellar symptoms - nystagmus / vertigo / ataxia / tremor / dysarthria
Lhermitte’s sign
Bladder involvement / sexual dysfunction
+ Uhthoff’s phenomenon
If someone has one attack of demyelination, what is it classified as?
Clinically isolated syndrome
