Week 2 - Neuro 1.2 Flashcards
What 3 things should be examined when suspecting optic atrophy?
• Comparison of colour of 2 discs
- Subtle Pallor; watch if pseudophakia
• Evaluation of surface vasculature of disc
- Thin or absent capillary net
• Assessment of retinal nerve fibre layer
- dropout may precede atrophy, loss of normal glistening appearance, most likely superior than inferior first
What is optic atrophy? And how long for it to appear? What separates unilateral from bilateral?
• Pale (chalky white) disc appearance with sharp margins
• Damage to retinal ganglion cells at any level
• Lesion in optic pathway anterior to lateral geniculate body
- Anterior to chiasm - unilateral; Posterior to chiasm - bilateral
• 4 to 6 weeks to appear from time of axonal damage
What are the two types of optic atrophy?
• Primary Vs secondary
What is Primary optic atrophy and its causes?
No adjacent swelling of ON head
Causes:
• Retrobulbar neuritis
• Compression by tumour or aneurysm
• Hereditary optic neuropathies
• Toxic and nutritional optic neuropathy
What is secondary optic atrophy?
Proceeded by swelling of ON head
How is Primary and Secondary optic atrophy managed?
Primary:
• Retrobulbar neuritis; needs scan for MS
• Compression by tumour or aneurysm; emergency referral
• Hereditary optic neuropathies; H&S to check if any in family has it, referral
• Toxic and nutritional optic neuropathy; Depends on problem, different for diet/drugs/alcohol, GP/referral
Secondary:
• Swelling of ON head; depends on cause or swelling on ON head
What is Optic Disc Oedema?
• Swelling of nonmyelinated nerve fibres from impaired axoplasmic flow
- Evidence of acute / evolving pathology
• Blurred disk margins
What terms can be used to describe the appearance on record card?
• Elevated appearance of nerve head
• Filling of cup
• Retinal vessels drape over disc margin
• Blurring of margin
• RNFL oedema - greyish appearance obscuring vessels
• Hyperaemia
• Retinal venous dilation and toruosity
• Peripapillary haemorrhages/exudates
What are the different types of peripapillary haemorrhages and exudates?
• Dot-Blot haemorrhages
• Flame shaped haemorrhages
• Exudates
• Cotton wool spots
What are the differences between the two retinal haemorrhages?
Flame shaped haemorrhages:
• from superficial pre-capillary arterioles
• in NFL
Dot-blot haemorrhages:
• from venous end of capillaries
• in middle retinal layers
What are the differences between the two main types of Oedema?
• Oedema
- Diffuse: caused by extensive leakage
- Localised: focal leakage
Between OPL and INL, may later involve IPL and NFL
What are hard exudates?
• Caused by oedema
- Chronic localised oedema
• Located at junction of normal and oedematous tissue
• Lipoprotein and macrophages
• Mainly in OPL
- Get spontaneously absorbed as oedema recovers
What are cotton wool spots?
• Accumulation of neuronal debris in NFL
• Disruption of axial flow of neurons
What are the 4 causes of optic oedema, and their subcategories?
• Papilloedema (acute and chronic)
• Ischaemia
- Arteritic anterior ischaemic optic neuropathy (AION)
- Non-Arteritic Anterior Ischaemic optic neuropathy (NAION)
- Posterior Ischaemic optic neuropathy
• Inflammation
- Optic Neuritis (demyelinating, infectious, non-infectious)
- Neuroretinitis
• Diabetic papillopathy
What is Papilloedema? What is physiological cause?
• Raised intracranial pressure
• Pressure is transmitted to the optic nerve
• Optic nerve sheath acts as a band to impede axoplasmic transport so there is a build up of material at the lamina cribrosa
• BILATERAL
What causes raises intracranial pressure?
• Relates to Cerebrospinal fluid - CSF
- produced in centre of brain; choroid plexus, to provide cushion/buffer for brain
- occupies subarachnoid space
- if problem along that pathway; this will raise the CSF, causing papilloedema
What can cause a disruption of CSF and therefore raised intracranial pressure?
• Intracranial mass
• Hydrocephalus (dilation of ventricles)
• Central nervous system infection e.g Meningitis
• Trauma
• Infiltration e.g. leukaemia, sarcoidosis
• Benign intracranial hypertension
What is Benign intracranial hypertension?
• Raised ICP in the absence of an intracranial mass, lesion or hydrocephalus and normal CF constituents
• Not life threatening but permanent, often severe, visual damage (fields more than VA)
What is the most common symptom of papilloedema, especially in the early stages?
• Occasionally asymptomatic
• Headaches
- “muzzy headed” at start, then develop into extreme pain; hospital at 6 weeks
- Characteristic in morning, waking up px
- generalised or localised
- Worse when pressure increases: moving head, bending over, coughing etc
• Very rarely is a headache absent
Apart from headaches, what are other systemic symptoms of papilloedema?
• Nausea and vomiting
- Often projectile
- May partially/temporarily relieve headache
- Could occur at time of headache onset or earlier (up to few months)
• Deterioration of consciousness
- From slight (drowsy) to dramatic
• Pulsatile tinnitus
What are the visual symptoms of papilloedema?
• Visual symptoms often absent
• Transient visual loss
• Horizontal diplopia (6th nerve palsy)
• Constriction of visual field
• Altered colour perception
• Reduced VA in later stages
What are the four stages if Papilloedema?
• Acute/early
• Acute/established
• Chronic
• Atrophic
What are the symptoms and examinations if acute/early papilloedema?
• Symptoms
- Headache
- Nausea and vomiting
- Vision normal and no visual symptoms
• Examination
- VA usually normal
- Colour vision usually normal
- Pupil responses normal
How might the disc appear in acute/early papilloedema and what terms might describe it?
• Hyperaemia
• Dilatation of capillary net
• Oedematous retinal nerve fibre layer seen as obscuration of disc edge and vessels
• Mild elevation
What absent spontaneous venous pulsation?
• If SVP present, papilloedema unlikely
• absence of SVP does not confirm papilloedema as 20% of normal individuals don’t have this
• Loss of previous SVP more indicative of papilloedema
What are the symptoms and examinations of acute/established papilloedema?
Symptoms
As early stage but includes:
• Transient visual disturbance, lasting seconds
Examination
As early stage but includes:
• Visual fields: enlargement of blind spot
How does the fundus appear for acute/established papilloedema?
As early, but includes:
• Severe hyperaemia
• Moderate elevation, enlarged optic nerve head and retinal folds
•Peripapillary flame shaped haemorrhages and cotton wool spots
• Hard exudates in macular fan with temporal part missing
What are the symptoms and examinations of chronic papilloedema?
Symptoms
• Vision variable, fields restricted
Examination
• Gradual deterioration in optic nerve function
• VA variable
• Visual fields:
- nasal loss
- arcuate defect
- generalised depression
• central loss a late finding
What is the disc appearance of chronic papilloedema?
• Pale due to axonal loss
• Marked elevation of discs
• Absence of cotton wool spots and haemorrhages
• Optociliary shunt vessels / collateral vessels
- Pre-existing venous channels
- Chronic central retinal vein obstruction
- Refractile bodies at disc due to chronic lipid rich exudation
• High water marks
What are the symptoms/examinations and optic disc appearance of Atrophic Papilloedema
(secondary optic atrophy)
• Symptoms/examination
VA, fields etc severely reduced
• Optic disc appearance
Pale/grey optic nerve
Possibly mild elevation, indistinct margins
Management if Papilloedema?
• Same day referral to ophthalmologist
• Treatment of cause
What are the differential diagnosis for raised discs?
• Compression
• Infiltration
• Congenital optic neuropathies (Leber’s optic neuropathy)
• Toxic optic neuropathies (methanol poisoning)
• Traumatic optic neuropathy
What other conditions could cause APPEARANCE of a raised disk (optic neuropathy without swelling)
• Optic disc drusen
• Tilted optic disc
• Myelinated nerve fires
• Hypermetropic crowded disc
What Intraocular diseases could cause APPEARANCE of a raised disk (optic neuropathy without swelling)
• Central retinal vein occlusion
• Posterior uveitis
• Posterior scleritis
• Hypotony
What is anterior ischaemic optic neuropathy? (AION)
• Most common optic neuropathy over 50 years
• Represents ischaemic damage to optic nerve head
What is the carotid artery and its divisions?
• comes from heart
• External carotid artery supplies face
• Internal carotid artery supplies brain/eyes etc
What are the divisions of the internal carotid?
• Ophthalmic artery divides into multiple branches:
- Central retinal artery
- posterior ciliary artery : PCA, feeds choroid. Around 6-12 in total.
What type of vision loss do you get with anterior ischaemic optic neuropathy? (AION)
Visual loss (both types)
• Painless, monocular visual loss over hours to days
• Altitudinal defects most common
• Reduced central vision
Relative afferent pupillary defect
Optic disc oedema present from onset
What are the two subtypes of Anterior ischaemic optic neuropathy?
• Arteritic anterior ischaemic optic neuropathy (AAION)
• Non-Arteritic Anterior ischaemic optic neuropathy (NAION)
what is Arteritic anterior ischaemic optic neuropathy (AAION) caused by?
• 5-10% of AION cases
• Occurs in older patients
• Caused by Giant Cell Arteritis (GCA)
- Inflammatory and thrombotic occlusion of short posterior ciliary arteries causing optic nerve head infarction
What percentage of (AAION) have systemic symptoms, and how is it related to GCA?
• Variable, no systemic symptoms in 20%
• Giant Cell Arteritis
Granulomatous necrotizing arteritis
Affects large and medium sized arteries, especially:
• superficial temporal artery
• ophthalmic artery
• posterior ciliary artery
• proximal vertebral artery
- 5-10% of GCA have AAION
What are the AAION systemic symptoms?
• Usually 60-80years old
• Tender, hardened, non pulsatile temporal artery
• Scalp tenderness, especially on brushing hair
• Jaw claudication (pain on speaking or chewing, almost pathognomonic)
• Proximal muscle weakness (typically shoulders), may occur 1st
What affects on health might AAION cause to a patient?
• Reduced appetite
- Unexplained weight loss
- Unexplained lethargy, malaise, depression
As a result of all the systemic conditions
What are the visual symptoms of AAION?
• Sudden, profound, visual loss
- Usually unilateral (initially)
• May be proceeded by transient visual obsurcations, flashing lights
• Periocular pain
What will you find during the fundus examination AAION?
• Severe visual loss
• Pale swollen disc
• Cotton wool spots (retinal ischaemia)
• Over 1-2 months, swelling resolves leaving optic atrophy
How is AAION managed in practice?
• If in community, immediate (same day) referral to ophthalmologist
• Treatment aimed at preventing blindness of 2nd eye
How is AAION managed in ophthalmology?
• Immediate therapy is essential
• Confirmed with immediate blood results (
• Temporal artery biopsy confirms diagnosis
• Usually overnight stay in hospital, High dose systemic steroids (IV usually)
• Blood tests aid in tapering of steroids which is done in response to serial blood tests and symptoms
• Patients may remain on oral steroids for years (average 1-2yrs)
What is the prognosis of AAION?
• Visual loss usually permanent
• Prompt administration of steroids may allow partial visual recovery In 25% of cases 2nd eye affected despite treatment, this could be within days
What is Non-Arteritic Anterior Ischaemic Optic Neuropathy (NAION) and its risk factors?
• 90% of AION cases
• Occlusion of short posterior ciliary arteries causing infarction of optic nerve head
• Typically in 55-70yrs (average 60yrs), younger compared to AAION
• Structural “crowding” of the disc when cup is small/absent
Common risk factors include:
• diabetes
• hypertension
• high cholesterol
• smoking
What are NAION symptoms?
• Sudden, painless loss of vision
• Unilateral
• Visual impairment on wakening (nocturnal hypotension?)
• Lack of systemic symptoms
What do you find during the examination of NAION?
• VA: Moderate to severe reduction in VA in most px 30% have normal or slightly reduced VA
• Visual fields: Commonly inferior altitudinal defect
• Dyschromatopsia: Proportional to amount of VA loss
Most px have no further visual loss although in a small number, visual loss continues for about 6 weeks
What would you find during the Fundus examination of NAION?
• Disc oedema diffuse or segmental
• Disc hyperaemic with focal telangiectasia on disc surface
• Often a few peripapillary splinter-shaped haemorrhages
• Atrophy within 3-8 weeks of onset
• Contralateral eye usually small with absent cup - “disc at risk”
How is NAION managed?
• In community, difficult to differentiate from other causes of swollen disc and AAION
• Treat underlying cause
• Prophylaxis ? Aspirin is frequently given but does not appear to reduce risk in fellow eye
What is the NAION prognosis, progression and risk factors for progression?
• Most px: no further visual loss, some Px visual loss continues for about 6 weeks
• Some recovery (e.g. 2 lines) in 31% at 2 years
• Chance of other eye being affected is 15% over 5yrs
• Risk factors for other eye are:
- poor VA in 1st eye
- diabetes
• Pseudo-Foster Kennedy syndrome if contralateral eye affected
- Unilateral disc swelling with contralateral optic atrophy in absense of mass compressing nerve
What are the differences in Arteritic vs non/arteritic for:
age, sex, associations, VA, Disc, ESR, CRP, fluorescein angiography, prognosis and treatment?
• age: Mean 70 vs 60 yrs
• sex : F > M vs F=M
• associations: Headaches, tenderness vs none
• VA: 60% of cases - <6/60 vs >6/60
• Disc: Pale vs hyperaemic disc odema
• ESR: Mean 70 vs mean 20-40
• CRP: Elevated vs normal
• prognosis: Rarely improves vs 31% improves
- Fellow eye >50% vs 10-20%
• treatment: systemic steroids vs none
What is posterior ischaemic optic neuropathy and its causes?
• Much rarer than AION
• Obstruction of plial artery/capillary plexus leading to ischaemia to retrolaminar part of the optic nerve
Causes:
• After surgical procedure, e.g. of spine
- Arteritic (similar to AAION)
- Non-arteritic (similar to NAION)
Diagnosis after ruling out other causes (compression, inflammation)
What are 3 causes optic neuritis?
• Infection of the optic nerve
• Inflammation of the optic nerve (non-infectious)
• Demyelination of the optic nerve (most common)
What are some causes of infection of optic nerve? (optic neuritis)
• local infection e.g. sinus, syphillis, Lyme disease, Herpes zoster, cat-scratch disease
• viral infection e.g. chicken pox, whooping cough, glandular fever, measles, mumps
• Following an immunisation
What are some causes of inflammation of optic nerve? (non-infectious)
• Sarcoid
• Autoimmune
What is Demyelination of optic neuritis and some causes?
• Demyelination disrupts nerve conduction within brain, brainstem and spinal chord sparing peripheral nerves
Causes:
• Multiple sclerosis (most common)
• Isolated optic neuritis with no other demyelination, but that may subsequently develop
• Devic disease or Schilder disease, both rare and bilateral optic neuritis
What other symptoms may brain stem demyelination lesions cause?
• cranial nerve palzies
• gaze palsies
• facial nerve palsies
• nystagmus
What is multiple sclerosis (MS) and its statistics with optic neuritis?
• MS is an inflammatory, demyelinating disease of the central nervous system (CNS)
• Multiple exacerbations characterised by variable CNS involvement
- Exacerbations are separated in time and anatomical location
• Optic neurotis : 15-20% MS px
• 50% of those with MS with get optic neuritis
• If have optic neuritis, over 10yrs MS risk is 38%
What is optic neuritis and its symptoms?
• Infection, inflammation or demyelination of the optic nerve
Symptoms:
• Monocular visual impairment
• Subacute: develops over several days to 2 weeks
• Discomfort, exacerbated by eye movements which precedes visual loss in majority of cases
• Globe tenderness
What visual, field and fundus defects can be found during examination of optic neuritis?
Visual:
• VA 6/18-6/60 (or worse)
• RAPD
• Reduced colour vison / red desaturation
• Reduced contrast sensitivity
Field defects:
• Generalised depression
• Nerve fibre bundle defects
• Central loss
Fundus examination
• Normal in most cases (retrobulbar neuritis)
• Could get swollen disc
What are symptoms/signs of neuroretinitis? (type of optic neuritis)
• Acute loss of vision (usually painless)
• Disc edema which is diffuse, spreads to involve around fovea at plexiform layer
• Star pattern of exudates at macula
What are some causes if neuroretinitis?
• Demyelination rare
• 66% secondary to cat-scratch disease
• Syphilis
• Lyme disease
• Viruses
How is optic neuritis managed? (in practice and in hospital)
• In community, difficult to differentiate from other causes of swollen disc
• Most need no medical treatment
• Intravenous steroids followed by oral course speed recovery by 1 - 2 weeks
• Oral steroids alone associated with increased recurrence rate
• Corticosteroids have no long term effect on visual outcome
• If relapsing-remitting MS, immunomodulatory therapy for reducing morbidity
If a patient has optic neuritis, and is suspected for MS, how is it managed?
• If suspect MS, MRI scan:
• Look for periventricular white matter lesions
Assesses risk of future MS
• No lesions: 25% risk at 15 years
• >1 lesion: 72% at 15 years
• Overall risk if no scan: 50%
Unresolving cases with other signs should raise suspicion of other underlying cause
•Blood tests - inflammatory markers, infective serum tests
• CSF
• Chest X-ray
What is the prognosis of optic neuritis?
• Recovery between 1 month- 6 months
- 75% recover to 6/9 or better
• May be permanent loss of colour perception and contrast sensitivity
- due to Optic atrophy after optic neuritis
• Pseudo-Foster Kennedy syndrome
- If contralateral eye affected
What is diabetic papillopathy and its causes/associations?
• Optic disc swelling in diabetic patient
• Diagnostic and therapeutic challenge
• Rare
• Pathogenesis unclear: Caused by capillary damage?
• Associations with small cup/disc ratio and rapid reduction in glycemia
• Vascular leakage and edema of the nerve fibres
Causes:
• Chronic ischaemia and secondary nerve swelling
What are the symptoms and what is found during the examination techniques of diabetic papillopathy?
Symptoms:
• Usually asymptomatic or with mild symptoms
Examination:
Va:
• Unilateral
• VA 6/12 or better
• Mild or no RAPD
Visual field:
• Enlargement of blind spot
• Constriction or altitudinal loss in severe cases frequently found
What is found during the fundus examination of diabetic papillopathy?
• Mild disc edema with hyperaemia
• Telangiectasis (dilated capillaries) which could be confused with neovascularisation (new blood vessels)
How is diabetic papillopathy managed and what’s its prognosis/risk to develop into?
Management:
• In community, difficult to differentiate from other causes of swollen disc
• Little evidence that treatment is successful
Possibly corticosteroids/steroids
Prognosis:
• Visual prognosis good: 6/12 or better
• May take 6 months or longer for oedema to resolve
• 5 to 15% progress to non-arteritic ischaemic optic neuropathy
