DIS - Optic Nerve V - Week 10 Flashcards
List three types of optic neuritis based on the involvement of optic nerve fibres.
Retrobulbar neuritis
Papillitis
Neuroretinitis
Is optic neuritis generally uni- or bilateral?
Unilateral
How does optic neuritis affect vision? What about colour vision and visual fields? How does it affect brightness?
Acute vision loss
Visual field loss
Abnormal colour vision
Abnormal brightness and colour comparison
How long do symptoms worsen for with optic neuritis and when do they peak? Is full recovery expected?
Symptoms worsen for 7-10 days, peaking within 1-2 weeks
May not fully recover
List 6 possible causes of optic neuritis.
Infections Multiple sclerosis Tumours Drug/chemical exposure Post-vaccination Idiopathic
List four infections that can cause optic neuritis.
Meningitis
Syphilis
Viruses
Herpes zoster
Does optic neuritis affect more men or women?
Women twice as often as men
What is the typical age of patients with optic neuritis (range)?
20-45
What is the most common type of optic neuritis?
Retrobulbar
Retrobulbar neuritis is the inflammation of what?
Between the back of the eye and the brain
What four things should you check if you suspect retrobular neuritis?
RAPD
Pain, especially on eye movement
Acute vision loss
Brightness and colour comparison
List an obvious ophthalmic sign of retrobulbar neuritis.
There arent any initially
Is there any disc oedema with retrobulbar neuritis? Explain.
It may become apparent due to axoplasmic stasis
List the four stages of retrobular neuritis progression.
No obvious signs
Mild disc oedema
Loss of RNFL
Optic atrophy
How long until optic atrophy with retrobulbar neuritis?
3-6 months
What is papillitis?
Inflammed area at the optic nerve head
What five things should you check if you supect papillitis?
RAPD Pain, especially on eye movement Acute vision loss Brightness and colour comparison Disc oedema
What is neuroretinitis (3)?
Inflammed optic nerve head and retina, including the macula
What is neuroretinitis often caused by?
Infective diseases
List 6 diseases that can cause neuroretinitis.
Toxoplasmosis Cat-scratch disease Syphilis Lyme disease AIDS Herpes zoster
Is there an association between neuroretinitis and multiple sclerosis?
Not usually
What is visual loss and prognosis like with neuroretinitis?
Can be much more severe with poorer prognosis
-especially if macula is involved
List 8 things to check for if you suspect neuroretinitis.
RAPD Pain Acute vision loss Brightness and colour comparison Disc oedema Macula wing/star Photostress abnormal Retinal thickening, possibly macular oedema
Is RAPD always present with optic neuritis?
Not always, it may not if neuritis is bilateral or a past event indicating for RAPD
Describe how to carry out a photostress test (6).
Determine distance VA for one eye
Occlude the other eye
Hold light source 2-3cm away from the eye
Ask patient to look at it directly for 10 seconds
Remove it and ask to read their best VA line after central scotoma is gone (using their Rx)
Time how long it takes to read it
What does the photostress test measure?
Rate of photoreceptor pigment re-synthesis after bleaching
What does the photostress test probvide an index of (in terms of function, 3)?
Macula function
- photoreceptors
- bruchs membrane
- choroid
What is an abnormal photostress recovery time?
> 50 seconds
What should you do when assessing optic neuritis?
Dilated fundus exam
What should you refer a patient with optic neuritis for (2)? What needs to be ruled out? What is the treatment?
Refer for serology and imaging
Rule out raised ICP as a cause for disc oedema
Systemic steroids
Who should you refer for optic neuritis (3)?
Anyone with recurrence
Children
Teenagers
What do studies suggest of the difference between oral and IV steroids for treating optic neuritis? Note which hastened recovery time and which increased rate of recurrence.
IV hastened recovery
Oral increased rate of recurrence
What is a possible consequence of using IV steroids?
There is some indication it may promote later multiple sclerosis
What does demyelination usually produce?
Retrobulbar neuritis
What is the major cause of multiple sclerosis? List four other causes of demyelination that may be confused for multiple sclerosis.
Demyelination Guillain-barre syndrome Miler fisher syndrome Devics disease Carbon monoxide poisoning
What is the most common acquired chronic neurological condition affecting young adults?
Multiple sclerosis
What is the age range at which multiple sclerosis is diagnosed?
20 to 40
What is multiple sclerosis? What does it interfere with?
Immune system attacks myelin, interfering with nerve impulses and conduction
What is seen in nerves with multiple sclerosis?
Demyelination plaques
What is the most common kind of multiple sclerosis?
Relapsing-remitting MS
- unpredictable attacks that worsen symptoms followed by recovery
- each wave causes more and more disability unless there is remission
What happens with primary progressive MS?
Steady increase in disability without attacks
What happens with secondary progressive MS?
An initial relapsing-remitting MS that begins to have steady decline with no remisison periods
What happens with progressive-relapsing MS?
Steady decline since onset with unpredictable attacks
What is the key requirement for diagnosing multiple sclerosis (2)? Explain each (2). What is this called?
Evidence of CNS damage that is disseminated in time and space
Disseminated in time - damage has occurred at different dates
Disseminated in space - damage has occurred to different parts of the CNS
-mcdonald criteria
What are three things that are assessed for multiple sclerosis?
MRI scans
Clinical symptoms
CSF
What is clinically isolated syndrome?
If the mcdonald criteria are not met
What may cause clinically isolated syndrome (2)?
Single episode of optic neuritis/transverse myelitis/ l’hermittes sign
When Ms is not yet MS and is the first clinical episode
What is CSF-specific marker?
Oligoclonal immunoglobin bands in the CSF
-lab marker for MS
List 9 clinical neurological symptoms of multiple sclerosis.
Fatigue Dizziness Ataxia Vision problems Bladder problems Weakness/numbing/tingling Memory problems Trouble concentrating Uhthoffs sign
What is uhthoffs sign?
Excessive fatiguing
What kind of optic neuritis can multiple sclerosis cause?
Retrobulbar
What region of the RNFL tends to be lost with multiple sclerosis vs glaucoma?
MS - temporal loss
Glaucoma - superior loss
Internuclear ophthalmoplegia is due to a lesion in what part of the brain? What is this due to mostly? Give two other causes.
Lesion of the medial longitudinal fasiculus
- due to Ms mostly
- can also be due to mass or ischaemia
What is internuclear ophthalmoplegia a disorder of?
Conjugate lateral gaze
What are the two hallmark features of internuclear ophthalmoplegia?
Affected eye shows impaired adduction
Contralateral eye can abduct but has nystagmus
Distinguish between anterior and posterior internucelar ophthalmoplegia and how convergence is affected for each.
Posterior - lower brainstem affected, convergence normal
Anterior - upper brainstem affected, convergence affected
What should you do to assess internucelar ophthalmoplegia (3)?
Dilated fundus exam to rule out other retinal causes
Extensive history taking for past events
Check visiion after a brisk walk
What counsel should be given to a patient with internucelar ophthalmoplegia (3)?
Vision loss could be protracted, recurrent
Counsel regarding variable vision over time
Association with MS
Who should a patient with internucelar ophthalmoplegia be referred to and why?
To a neurologist for association with Ms
How are relapses of internucelar ophthalmoplegia managed? Comment on how this may affect MS relapses.
IV steroids can speed recovery without affecting MS relapses
