Neuro 1.2 Flashcards
1
Q
Optic Atrophy
A
- atrophy - wasting away of the ON
- generally causes pale coloured nerve
2
Q
Features of Optic Atrophy
A
- Pale (chalky white) disc appearance with sharp margins
- Damage to retinal ganglion cells anywhere along the pathway
- Lesion anterior to chiasm – unilateral optic atrophy
- Lesion posterior to chiasm – bilateral optic atrophy
- Takes around 4-6 weeks to appear from time of axonal damage
3
Q
Primary and Secondary Optic Atrophy
A
- Atrophy (paleness of the ONH) with no adjacent swelling of the ONH
- Atrophy preceded by swelling of the ONH
4
Q
Management of Optic Atrophy
A
- Depends on cause
- Each cause covered in later cards
5
Q
Optic Disc Oedema
A
- Swelling of nonmyelinated nerve fibres (at point of ONH) from impaired axoplasmic flow (reduced flow down nerves as swollen)
- Is evidence of acute/evolving pathology, something happening now to ONH
6
Q
OD Oedema Appearance
A
- Elevated appearance of ONH
- Filling of cup
- Retinal vessels drape over disc margin
- Blurring of margin
- RNFL oedema – greyish appearance that obscures vessels
- Hyperaemia
- Retinal venous dilatation & tortuosity
- Peripapillary haemorrhages & exudates
7
Q
Causes of Optic Disc Oedema (LEARN!)
A
- Papilledema (acute & 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
8
Q
Causes of a Raised Optic Disc (LEARN!)
A
- Not swollen but very similar appearance
- Compression
- Infiltration
- Congenital optic neuropathies (Leber’s optic neuropathy)
- Toxic optic neuropathies (methanol poisoning)
- Traumatic optic neuropathy
9
Q
Causes of APPEARANCE of a Raised Optic Disc (LEARN!)
A
- Optic disc drusen
- Tilted optic disc
- Myelinated nerve fibres
- Hypermetropic crowded disc
- Intraocular disease
- CRVO
- Posterior uveitis
- Posterior scleritis
- Hypotony
10
Q
Causes of Optic Disc Oedema
A
- Papilledema (acute & 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
11
Q
Papilledema
A
- Swollen OD secondary to raised intracranial pressure - leads to raised CSF
- Pressure is transmitted to the ON
- ON sheath acts as a band to impede axoplasmic transport so there is a build-up of material at the lamina cribrosa
- Swelling of the ONH results
- BILATERAL, may be asymmetrical
12
Q
Papilledema - Causes
A
- Intracranial mass (benign or cancerous tumour)
- Hydrocephalus (dilation of ventricles)
- CNS infection (e.g. Meningitis)
- Trauma
- Infiltration (e.g. leukaemia, sarcoidosis)
- Benign intracranial hypertension
- Raised ICP in the absence of an intracranial mass, lesion or hydrocephalus and normal CSF constituents (absence of all other causes)
- Not life threatening but permanent, often severe, visual damage (fields more than VA)
13
Q
Papilledema - Symptoms
A
- Occasionally asymptomatic
- Headaches
- Can be ‘muzzy headed’ at start and then develop into extreme pain, usually presenting at hospital within 6 weeks
- Characteristically in morning, waking up px
- Generalised or localised
- Worse when pressure increases (moving head, bending over, coughing)
- Very rarely, headache absent
- Nausea and vomiting
- Often projectile
- May temporarily relieve headache
- Could occur at time of headache or earlier (up to few months)
- Deterioration of consciousness
- From slight (drowsy) to dramatic
- Pulsatile tinnitus (ringing in the ears)
- Vision
- Visual symptoms often absent
- Transient visual loss
- Horizontal diplopia (6th nerve palsy)
- Constriction of VF (pressure building up and pressing on nerves)
- Altered colour perception
- Reduced VA in later stages
14
Q
Papilledema - Stages
A
- Acute/early
- Acute/established
- Chronic
- Atrophic
15
Q
Acute Papilledema - Examination
A
- VA usually normal
- CV usually normal
- Pupil responses normal
16
Q
Acute Papilledema - Disc Appearance
A
- Hyperaemia
- Dilation of capillary net
- Oedematous RNFL seen as obscuration of disc edge and vessels
- Mild elevation
- Absent spontaneous venous pulsation (SVP):
- If SVP present, papilledema unlikely
- Absence of SVP does not confirm papilledema as 20% of normal individuals don’t have this
- Loss of previous SVP more indicative of papilledema
17
Q
Established Papilledema - Examination
A
- VA normal or reduced
- VF’s - enlargement of blind spot
- Plus transient visual disturbance (vision goes and comes), lasting seconds
18
Q
Established Papilledema - Fundus Appearance
A
(AS PREV STAGE BUT ALSO INCLUDES…)
- Severe hyperaemia
- Moderate elevation, enlarged ONH and retinal folds
- Peripapillary flame shaped haemorrhages and cotton wool spots
- Hard exudates in macular fan (fan-shaped appearance around the macula) with temporal part missing
19
Q
Chronic Papilledema - Examination
A
- VA variable
- Visual fields:
- Nasal loss
- Arcuate defect
- Generalised depression (function of nerves has generally reduced)
- Central loss a late finding
- Gradual deterioration in ON function
20
Q
Chronic Papilledema - Disc Appearance
A
- Pale due to axonal loss (been there for a while, paleness takes 4-6 weeks)
- Marked elevation of discs
- Absence of cotton wool spots and haemorrhages
- Optociliary shunt vessels/collateral vessels
- Pre-existing venous channels start dilating up to try and supply blood to damaged areas
- Chronic CRVO
- Refractile bodies (yellow lipid exudates) at disc
- High water mark (like water arriving on beach shore and leaving) - Sclera starts to bend
21
Q
Atrophic Papilledema - Examination
A
- VA severely impaired
22
Q
Atrophic Papilledema - Disc Appearance
A
- Pale/grey ON
- Permanent effect on nerves which are damaged
- Possibly mild elevation, indistinct margins
23
Q
Papilledema Management
A
- Same day referral to ophthalmologist
- Treatment of cause
24
Q
Anterior Ischaemic Optic Neuropathy (AION)
A
- Most common optic neuropathy over 50 years
- Represents ischaemic damage to ONH
25
Q
AION - Symptoms and Signs
A
- Visual loss (both types)
- Painless, monocular visual loss over hours to days
- Altitudinal defects most common
- Reduced central vision
- RAPD
- OD oedema present from onset
26
Q
Arteritic AION
A
- 5-10% of AION cases
- Occurs in older px’s
- Caused by GCA
- Inflammatory and thrombotic occlusion of short PCA’s causing ONH infarction
- Variable, no systemic symptoms in 20%
27
Q
Arteritic AION - Giant Cell Arteritis
A
- Variable, no systemic symptoms in 20%
- 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
28
Q
Arteritic AION - Symptoms
A
- Systemic
- Usually 60-80 yrs old
- Tender, hardened, non-pulsatile temporal artery
- Scalp tenderness, especially on brushing hair
- Jaw claudication (pain on speaking or chewing, almost pathognomonic - very indicative of condition)
- Proximal muscle weakness (typically shoulders), may occur 1st
- Reduced appetite
- Unexplained weight loss
- Unexplained lethargy, malaise, depression
- Visual
- Sudden, profound, visual loss
- Usually unilateral (initially)
- May be proceeded by transient visual obscuration’s, flashing lights
- Periocular pain
29
Q
Arteritic AION - Visual Examination
A
- Severe visual loss
- Pale swollen OD (may appear pale initially due to blood supply being lost, complete optic atrophy not present until 4-6 weeks after
- Cotton wool spots (retinal ischaemia)
- Over 1-2 months, swelling resolves leaving optic atrophy
30
Q
Arteritic AION - Management
A
- Immediate, same day referral to ophth
- Treatment aimed at preventing blindness of other eye
- As px could get a blockage somewhere else and get a stroke
Management by ophth
- Immediate therapy essential
- Confirmed with immediate blood results
- Temporal artery biopsy confirms diagnosis
- Usually overnight stay in hospital
- High dose systemic steroids
- Px’s may remain on oral steroids for years (average 1-2yrs) to prevent future attack
31
Q
Arteritic AION - Prognosis
A
- Visual loss usually permanent
- Prompt administration of steroids may allow partial visual recovery
- In 25% of cases 2nd eye affected despite treatment, could be within days
32
Q
Non-Arteritic AION
A
- 90% of AION cases
- Occlusion of short PCA’s causing infarction of ONH
- Typically in 55-70 yrs, younger compared to AAION
- Structural ‘crowding’ of the disc when cup is small/absent
33
Q
Non-Arteritic AION - Risk Factors
A
- Diabetes
- Hypertension
- High cholesterol
- Smoking
34
Q
Non-Arteritic AION - Symptoms
A
- Sudden, painless loss of vision
- Unilateral (papilledema would be bilateral)
- Visual impairment on wakening (nocturnal hypotension - BP reduces overnight, HR slows etc)
- Lack of systemic symptoms
35
Q
Non-Arteritic AION - Examination
A
- VA
- Moderate to severe reduction in VA in most px (6/24, 6/36)
- 30% have normal or slightly reduced VA (6/12)
- Visual fields
- Commonly inferior altitudinal defect
- Dyschromatopsia - reduced CV
- Proportional to amount of VA loss
- After initial visual loss, most px have no further visual loss (although in a small number, visual loss continues for about 6 weeks)
36
Q
Non-Arteritic AION - Fundus Examination
A
- Disc oedema diffuse or segmental
- Disc hyperaemic with focal telangiectasia clustered on disc surface (general dilation of capillaries causing them to appear as small, red or clusters - often spidery which attempt to help with blood supply to that area which is lacking)
- Often a few peripapillary splinter-shaped haemorrhages
- Atrophy within 3-8 weeks of onset
- Contralateral eye usually small with absent cup - ‘disc at risk’
37
Q
Non-Arteritic AION - Management
A
- Refer to ophth
- In community, difficult to differentiate from other causes of swollen disc and AAION without appropriate blood tests
- Treat underlying cause
- Prophylaxis? Aspirin is frequently given but does not appear to reduce risk in fellow eye
38
Q
Non-Arteritic AION - Prognosis
A
- Most px have no further visual loss although in a small number, 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 (lower than arteritic)
- Risk factors for other eye are:
- poor VA in 1st eye
- diabetes
- Pseudo-Foster Kennedy Syndrome - unilateral disc swelling with contralateral optic atrophy in absence of mass compressing nerve
39
Q
Arteritic vs Non-Arteritic
A
Arteritic…Non-arteritic
Age Mean 70 years…Mean 60 years
Sex F > M…F = M
Associations Headache, tenderness, etc…Usually none
Visual Acuity <6/60 in >60%…>6/60 in >60%
Disc / fundus Pale disc oedema…Hyperaemic disc oedema
ESR Mean 70…Mean 20-40
CRP Elevated…Normal
Fluorescein Angiography Disc and choroid delay…Disc delay
Natural History Rarely improves…31% improve
Fellow eye >50%…Fellow eye 10 – 20%
Treatment Systemic steroids…None
40
Q
Posterior Ischaemic Optic Neuropathy
A
- Much rarer than AION
- Obstruction of plial artery/capillary plexus leading to ischaemia to retrolaminar part of the ON
- After surgical procedure, e.g. of spine
- Arteritic (similar to AAION)
- Non-arteritic (similar to NAION)
- Diagnosis after ruling out other causes (compression, inflammation)
41
Q
Optic Neuritis
A
- Inflammation, infection or demyelinating process of the ON (Kanski)
Retrobulbar neuritis - inflammation behind the ONH
42
Q
Optic Neuritis - Causes
A
- Infection of the ON
- Caused by local infection e.g. sinus, syphilis, Lyme disease, HZO
- Following a viral infection e.g. chicken pox, whooping cough, measles, mumps
- Following an immunisation
- Inflammation of the ON (non-infectious)
- Sarcoid
- Autoimmune
- Demyelination of the ON (most common)
43
Q
Optic Neuritis - Demyelination
A
- Demyelination disrupts nerve conduction within brain, brainstem and spinal cord, spares peripheral nerves
44
Q
Optic Neuritis - Demyelination (Causes)
A
- Multiple sclerosis (most common)
- Only diagnosed as MS if 3 or more demyelination lesions
- Isolated optic neuritis with no other demyelination, but that may subsequently develop
- Devic disease or Schilder disease, both rare and produce bilateral optic neuritis
- Brain stem demyelinating lesions may also cause:
- CN palsies
- Gaze palsies
- Facial nerve palsies
- Nystagmus
45
Q
Optic Neuritis - Demyelination (MS)
A
- 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 neuritis is the presenting feature in 15-20% of those with MS
- 50% of those with MS will get optic neuritis at some point
- If optic neuritis present, the overall 10 year risk of MS is 38%
46
Q
Optic Neuritis - Demyelination (Symptoms)
A
- Monocular visual impairment
- Subacute - develops over several days to 2 weeks
- Discomfort, exacerbated by eye movements which comes before visual loss in most cases
- Globe tenderness
47
Q
Optic Neuritis - Demyelination (Examination)
A
- Reduced VA (6/18 - 6/60)
- RAPD (affects amount of light being transmitted by one eye, that pupil will dilate when same light is shone in other eye)
- Reduced CV
- Reduced CS
- VF defects
- Generalised depression
- Nerve fibre bundle defects
- Central loss
48
Q
Optic Neuritis - Demyelination (Fundus Examination)
A
- Normal in most cases
- If px experiencing retrobulbar neuritis (inflammation behind ON)
- Could get swollen disc
49
Q
Neuroretinitis
A
- A feature of optic neuritis
- optic neuritis including macular and ONH involvement
- macular star often forms
50
Q
Neuroretinitis - Signs and Symptoms
A
- Acute loss of vision (usually painless)
- Disc oedema which is diffuse, spreads to involve around fovea at plexiform layer
- Star pattern of exudates at macula
51
Q
Neuroretinitis - Causes
A
- Demyelination rare
- 66% secondary to cat-scratch disease
- Syphilis
- Lyme disease
- Viruses
52
Q
Neuroretinitis - Management
A
- 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
53
Q
Neuroretinitis - Prognosis
A
- Recovery within 1 month, lasting up to 6 months
- 75% recover to 6/9 or better
- May be permanent loss of colour perception and contrast sensitivity
- Will have optic atrophy after optic neuritis
- Pseudo-Foster Kennedy syndrome may be present
- If contralateral eye affected
- Unilateral disc swelling with contralateral optic atrophy in absence of mass compressing nerve
54
Q
Diabetic Papillopathy
A
- OD swelling in a diabetic patient
- Difficult to diagnose (very rare)
- Pathogenesis unclear
- Caused by capillary damage?
- Associations with small C:D ratio and rapid reduction in glycemia
- Vascular leakage and oedema of the nerve fibres
- Chronic ischaemia and secondary nerve swelling
- Does not result in full blown ischaemic optic neuropathy
- Usually diagnosed on examination rather than on symptoms
55
Q
Diabetic Papillopathy - Symptoms
A
- Usually asymptomatic or with mild symptoms
- Usually diagnosed on examination rather than on symptoms
56
Q
Diabetic Papillopathy - Examination
A
- 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 on fundus examination
57
Q
Diabetic Papillopathy - Fundus Examination
A
- Mild disc oedema with hyperaemia
- Telangiectasia (dilated capillaries) which could be confused with neovascularisation (new BV’s)
58
Q
Diabetic Papillopathy - Management
A
- In community, difficult to differentiate from other causes of swollen disc
- Emergency referral to ophth
- Little evidence that treatment is successful
- Possibly corticosteroids/steroids
59
Q
Diabetic Papillopathy - Prognosis
A
- Visual prognosis good: 6/12 or better
- May take 6 months or longer for oedema to resolve
- 5 to 15% progress to Non-Arteritic AION (diabetes is a risk factor)
