04 lecture Neuro-ophthalmology

NEURO OPHTHALMOLOGY; MND
Prof Md Anisur Rahman
Head of the Department
(Ophthalmology). Dhaka Medical
College. Dhaka
9 Sept 2019 (LIONS) 1
anjumk38dmc@gmail.com

Optic Neuritis According to aetiology
Demyelinating. This is by far the most common cause.
Parainfectious, following a viral infection or immunization.
Infectious. This may be sinus-related, or associated with conditions such as
cat-scratch disease, syphilis, Lyme disease, cryptococcal meningitis and herpes
zoster.
Non-infectious causes include sarcoidosis and systemic autoimmune diseases
such as systemic lupus erythematosus, polyarteritis nodosa and other
vasculitides

Demyelinating optic neuritis
Demyelination is a pathological process in which normally myelinated nerve
fibres lose their insulating myelin layer.
The myelin is phagocytosed by microglia and macrophages, subsequent to
which astrocytes lay down fibrous tissue in plaques.
Demyelinating disease disrupts nervous conduction within the white matter
tracts of the brain, brainstem and spinal cord.
Demyelinating conditions that may involve the visual system include the
following:

Demyelinating optic neuritis
• Isolated optic neuritis
• Multiple sclerosis (MS)
• Devic disease (neuromyelitis optica)
• Schilder disease

Isolated optic neuritis
• Isolated optic neuritis with no clinical evidence of generalized
demyelination, although in a high proportion of cases this
subsequently develops

Neuromyelitis optica (also known as Devic’s disease)
Neuromyelitis optica (also known as Devic’s disease) is the occurrence of
transverse myelitis and bilateral optic neuritis.
The disease has been recognised for many years, particularly in Asia.
The majority of cases are associated with an antibody to a neuronal
membrane channel, aquaporin 4.
If changes are seen on brain MRI (this is variable), they are typically high-
signal lesions restricted to periventricular regions.

Neuromyelitis optica (also known as Devic’s disease)
Spinal MRI scans show lesions that are typically longer than three spinal
segments (unlike the shorter lesions of MS).
Clinical deficits tend to recover less well than in MS, and the disease may be
more aggressive with more frequent relapses.
Treatment with older immunosuppressive agents, such as steroids,
azathioprine or cyclophosphamide, and/or plasmapheresis seems to be more
effective than in MS.

Devic disease (neuromyelitis optica)
Neuromyelitis optica spectrum disorder (NMOSD)
Early in the course of the disease, it may be difficult to distinguish between
Devic disease (neuromyelitis optica) and multiple sclerosis because both may
cause optic neuritis and myelitis as symptoms.
However, the optic neuritis and myelitis tend to be more severe in NMOSD;
the brain MRI is more commonly normal, and the spinal fluid analysis does
not usually show oligo clonal bands in NMOSD, which are features that help
distinguish it from MS.

Schilder disease
Schilder disease, a very rare relentlessly progressive generalized
disease with an onset prior to the age of 10 years and death
within 1–2 years. Bilateral optic neuritis without subsequent
improvement may occur

Schilder’s disease
• Schilder’s disease is a very rare, progressive, degenerative,
demyelinating disorder of the central nervous system (CNS) that
usually begins in childhood and young adulthood.
• Schilder’s disease is thought to be a variant of MS.
• As the disease progresses, larger and larger patches of demyelination
occur, interfering with motor movement, speech, personality, hearing
and vision, ultimately affecting the vital functions of respiration, heart
rate, blood pressure.

Schilder’s disease
• Schilder's disease is also known as diffuse cerebral sclerosis,
diffuse cerebral sclerosis of Schilder and myelinoclastic diffuse
sclerosis.

Multiple sclerosis (MS)
Multiple sclerosis (MS) is an important cause of long term
disability in adults.
The aetiology is idiopathic.
There is evidence that both genetic and environmental factors
play a causative role

An immune hypothesis is supported by increased levels of
activated T lymphocytes in the CSF and increased
immunoglobulin synthesis within the CNS.
Initial CNS inflammation in MS involves entry of activated T
lymphocytes across the blood–brain barrier

These recognise myelin-derived antigens on the surface of the
nervous system’s antigen-presenting cells, the microglia, and
undergo clonal proliferation
The resulting inflammatory cascade releases cytokines and
initiates destruction of the oligodendrocyte–myelin unit by
macrophages.

Histologically, the resultant lesion is a plaque of inflammatory
demyelination, most commonly in the periventricular regions of the
brain, the optic nerves, and the subpial regions of the spinal cord.
This begins as a circumscribed area of disintegration of the myelin
sheath, accompanied by infiltration by activated lymphocytes and
macrophages, often with conspicuous perivascular inflammation. After
the acute attack, gliosis follows, leaving a shrunken grey scar

Presentation
It is more common in women than men (twice). It is typically in
the third–fourth decades, generally with relapsing/remitting
demyelination that may switch later to an unremitting pattern,
and less commonly with progressive disease from the outset.

Systemic features
Spinal cord, e.g. weakness, stiffness, sphincter disturbance, sensory loss.
Brainstem, e.g. diplopia, nystagmus, dysarthria, dysphagia.
Cerebral, e.g. hemiparesis, hemianopia, dysphasia.
Psychological, e.g. intellectuel décline, dépression, euphoria.
Transient features, e.g. the Lhermitte sign (pronounced Ler-meets)
(electrical sensation on neck flexion) and the
Uhthoff phenomenon (sudden worsening of vision or other symptoms on
exercise or increase in body temperature).

Ophthalmic features
Common.
Optic neuritis (usually retrobulbar),
Internuclear ophthalmoplegia, nystagmus.
Uncommon.
Skew deviation,
ocular motor nerve palsies, hemianopia.
Rare: Intermediate uveitis and retinal periphlebitis.

Investigation
Lumbar puncture shows oligo clonal bands on protein
electrophoresis of cerebrospinal fluid in 90–95%.
MRI almost always shows characteristic white matter lesions
(plaques)
VEPs are abnormal (conduction delay and a reduction in
amplitude) in up to 100% of patients with clinically definite MS.

Multiple sclerosis. T2-weighted
axial MR image showing
characteristic periventricular
plaques

In T1 image with gadolinium
enhancement, recent lesions (A arrows)
show enhancement, suggesting active
inflammation (enhancement persists for
4 weeks); older lesions (B arrows)
show no enhancement but low signal,
suggesting gliosis
A
B

Clinical features of demyelinating optic neuritis:
Symptoms
Subacute monocular visual impairment.
Usual age range 20–50 years (mean around 30).
Some patients experience tiny white or coloured flashes or sparkles
(phosphenes).
Discomfort or pain in or around the eye is present in over 90% and
typically exacerbated by ocular movement.
Frontal headache and tenderness of the globe may also be present.

Clinical features of demyelinating optic neuritis: Signs
Visual acuity (VA) is usually 6/18–6/60, but may rarely be worse.
Other signs of optic nerve dysfunction particularly impaired colour
vision and a relative afferent pupillary defect.
The optic disc is normal in the majority of cases (retrobulbar neuritis);
the remainder show papillitis
Temporal disc pallor may be seen in the fellow eye indicative of
previous optic neuritis.

Clinical features of demyelinating optic neuritis:
Visual field defect
Diffuse depression of sensitivity in the entire central 30° is the most
common.
Altitudinal/arcuate defects and focal central/centrocaecal scotomas
Focal defects are frequently accompanied by an element of
superimposed generalized depression.
Course. Vision worsens over several days to 3 weeks and then begins
to improve. Initial recovery is fairly rapid and then slower over 6–12
months.

Central
Scotoma
centrocaecal
scotoma

• Fixation: Part of visual field corresponding to fovea centralis
• Central field: Portion of visual field within 30° of fixation
• Bjerrum’s area: Central visual field within 20-30° of fixation
• Centrocecal scotoma: a horizontal oval defect in the visual field
situated between and embracing both the fixation point and the
blind spot

Arcuate scotoma or Bjerrum’s scotoma: A small, bow-shaped (arcuate) visual
field defect that follows the arcuate pattern of the retinal nerve fibers; does not
cross the horizontal median.
Ring or Double arcuate scotoma: Two arcuate scotomas join together to form a
Ring or Double arcuate scotoma. This defect is seen in advanced stages of
glaucoma.
Seidel's scotoma: is a sickle-shaped scotoma that is a superior or inferior
extension of the blind spot. It occurs in some patients with glaucoma.

Prognosis
More than 90% of patients recover visual acuity to 6/9 or better.
Subtle parameters of visual function, such as colour vision, may
remain abnormal.
A mild relative afferent pupillary defect may persist.
Temporal optic disc pallor or more marked optic atrophy may ensue.
About 10% develop chronic optic neuritis with slowly progressive or
stepwise visual loss.

04 lecture Neuro-ophthalmology

Treatment
Indications for steroid treatment. When visual acuity within the first
week of onset is worse than 6/12, treatment may speed up recovery by
2–3 weeks and may delay the onset of clinical MS over the short term.
Therapy does not influence the eventual visual outcome and the great
majority of patients do not require treatment.
Steroid regimen. Intravenous methylprednisolone sodium succinate 1 g
daily for 3 days, followed by oral prednisolone (1 mg/kg daily) for 11
days, subsequently tapered over 3 days.

Treatment
Oral prednisolone may increase the risk of recurrence of optic neuritis if used
without prior intravenous steroid.
Immunomodulatory treatment (IMT) reduces the risk of progression to
clinical MS in some patients, but the risk versus benefit ratio has not yet been
fully defined with the options available, which include interferon beta,
teriflunomide and glatiramer. A decision should be individualized, based on
risk profile

Parainfectious optic neuritis
Optic neuritis may be associated with viral infections such as measles,
mumps, chickenpox, rubella, whooping cough and glandular fever, and
may also occur following immunization.
Children are affected much more frequently than adults. Presentation
is usually 1–3 weeks after a viral infection, with acute severe visual
loss generally involving both eyes.
Bilateral papillitis is the rule; occasionally there may be a
neuroretinitis or the discs may be normal.

Parainfectious optic neuritis
The prognosis for spontaneous visual recovery is very good, and
treatment is not required in the majority of patients.
However, when visual loss is severe and bilateral or involves an
only seeing eye, intravenous steroids should be considered, with
antiviral cover where appropriate.

Infectious optic neuritis:
Sinus-related optic neuritis
It is uncommon and is sometimes characterized by recurrent
attacks of unilateral visual loss associated with severe headache
and spheno-ethmoidal sinusitis.
Possible mechanisms include direct spread of infection,
occlusive vasculitis and mucocoele.
Treatment is with systemic antibiotics and, if appropriate,
surgical drainage.

Cat-scratch fever (benign lymphoreticulosis) is usually caused by
Bartonella henselae inoculated by a cat scratch or bite.
Numerous ophthalmological features have been described,
notably neuroretinitis.
Syphilis may cause acute papillitis or neuroretinitis during the
primary or secondary stages.

Lyme disease (borreliosis) is a spirochaetal infection caused by
Borrelia burgdorferi transmitted by a tick bite. It may cause
neuroretinitis and occasionally acute retrobulbar neuritis, which
may be associated with other neurological manifestations and
can mimic MS.
Cryptococcal meningitis in patients with acquired
immunodeficiency syndrome (AIDS) may be associated with
acute optic neuritis, which may be bilateral

Varicella zoster virus may cause papillitis by spread from
contiguous retinitis (i.e. acute retinal necrosis, progressive
retinal necrosis) or associated with herpes zoster ophthalmicus.
Primary optic neuritis is uncommon but may occur in
immunocompromised patients, some of whom may subsequently
develop viral retinitis.

Non-infectious optic neuritis: Sarcoidosis
Optic neuritis affects 1–5% of patients with neurosarcoid.
It usually develops during the course of established systemic disease.
The optic nerve head may exhibit a lumpy appearance suggestive of
granulomatous infiltration and there may be associated vitritis.
The response to steroid therapy is often rapid, though vision may decline if
treatment is tapered or stopped prematurely, and some patients require long-
term low-dose therapy.
Methotrexate may also be used as an adjunct to steroids or as monotherapy in
steroid-intolerant patients.

Sarcoid granuloma of the optic nerve head with overlying vitreous haze

Autoimmune
Autoimmune optic nerve involvement may take the form of
retrobulbar neuritis or anterior ischaemic optic neuropathy
Some patients may also experience slowly progressive visual
loss suggestive of compression.
Treatment is with systemic steroids and other
immunosuppressants.

Neuroretinitis
Neuroretinitis refers to the combination of optic neuritis and
signs of retinal, usually macular, inflammation.
Cat-scratch fever is responsible for 60% of cases.
About 25% of cases are idiopathic (Leber idiopathic stellate
neuroretinitis).
Other notable causes include syphilis, Lyme disease, mumps and
leptospirosis.

Diagnosis
Symptoms & Signs
Symptoms. Painless unilateral visual impairment, usually
gradually worsening over about a week.
Signs
VA is impaired to a variable degree.
Signs of optic nerve dysfunction are usually mild or absent, as
visual loss is largely due to macular involvement.

Papillitis associated
with peripapillary and
macular oedema.
Signs

A macular star typically
appears as disc swelling
settles; the macular star
resolves with a return to
normal or near-normal visual
acuity over 6–12 months.
Signs

Venous engorgement and splinter haemorrhages may be present
in severe case.
Fellow eye involvement occasionally develops.

Optical coherence tomography (OCT) demonstrates sub- and
intraretinal fluid to a variable extent.
Fluorescein angiography (FA) shows diffuse leakage from
superficial disc vessels.
Blood tests may include serology for Bartonella and other causes
according to clinical suspicion

Treatment
This is specific to the cause, and often consists of antibiotics.
Recurrent idiopathic cases may require treatment with steroids
and/or other immunosuppressants.

Ischaemic Optic Neuropathy
• Ischaemic Optic Neuropathy typically manifest with sudden loss
of vision and are categorize by the involved portion of the optic
nerve and aetiology:
• Optic nerve head: Anterior ION (AION) either non-arteritic
(NAION) or arteritic (AAION)
• Retrobulbar optic nerve to chiasma: Posterior ION (PION) from
hypotension, arteritis or shock/severe blood loss

Non-arteritic anterior ischaemic optic
neuropathy
• Non-arteritic anterior ischaemic optic neuropathy (NAION) is by
far the most common cause of unilateral AION, accounting for
around 95% of cases. The majority of patients are age > 50
years and present with sudden unilateral, painless, altitudinal
loss of vision but are typically younger than those who develop
arteritic ION caused by occlusion of the short posterior ciliary
arteries resulting in partial or total infarction of the optic nerve
head.

• The aetiology of NAION is still widely debated. A compartment-like syndrome
incited by micro-infarcts may be causative, as the majority of NAION patients
have small crowed “disk at risk” (cup disc ratio <0.2) and a higher
preponderance of vascular risk factors including
• hypertension (very common), diabetes mellitus, hyperlipidaemia, collagen
vascular disease, antiphospholipid antibody syndrome,
hyperhomocysteinaemia, sudden hypotensive events, cataract surgery, sleep
apnoea syndrome and erectile dysfunction, tobacco smoking

04 lecture Neuro-ophthalmology

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