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Optic neuritis=INFLAMMATION,INFECTION OR
DEMYELINATION OF OPTIC NERVE
Optic Neuritis - Outline
• Definition
• Classification
▫ Ophthalmoscopic
▫ Aetiological
• Clinical Features
• Investigations
• Principle of Management
CLASSIFICATION:
Can be classified both ophthalmoscopically and
etiologically:
Retrobulbar neuritis
Papillitis (most common)
Neuroretinitis
Demyelinating **
Parainfective
(rubella,mumps&chicken pox)
Infective
(sinusitis.syphilis,cat-scratch fever)
Autoimmune
OPHTHALMOSCOPICALLY
ETIOLOGICALLY
• Retrobulbar neuritis
Optic nerve is affected more posteriorly with no disc swelling.
• Papillitis
Affect optic nerve head (hyperaemia & oedema of optic disc) +
peri-papillary flame-shaped haemorrhages
• Neuroretinitis
Characterized by papillitis with inflammation of the retinal nerve
fiber layer. A macular star figure composed of hard exudates
may present. Least common and most frequently associated with
viral infections and cat-scratch fever, Syphilis and Lyme disease.
Usually self-limiting which resolves 6-12 months.
Neuroretinitis is rarely a manifestation of demyelination.
Ophthalmoscopical Classification
Retrobulbar neuritis Papillitis Neuroretinitis
Optic nerve affected behind the eyeball
Optic nerve head affected Concomitant swelling of optic nerve head (papillitis) and macula (inflammation of retinal nerve fibre layer)
The optic disc appears normal
The condition may be truly described as ‘ the patient sees nothing and the doctor sees nothing.’
Hyperaemia and oedema of the optic disc
May be a/w peripapillary flame-shaped haemorrhages
Macular star (exudates that form around the macula give the appearance of the star)
Most frequent type in adults
Frequently a/w multiple sclerosis (MS)
Most common type in children
Least common type Rarely a manifestation of
demyelination Due to viral infection,cat-
scratch fever
Normal optic disc, primary optic atrophy. The condition may be truly described as ‘ the patient sees nothing and the doctor sees nothing.’
Retrobulbar neuritis
swollen disc with blurring and hyperaemia of disc margin; venous dilation and engorgement ; vitreous haziness because of inflammatory exudates and cells that invaded the vitreous( mild vitritis); Flame-shaped hemorrhages and cotton wool spot (soft exudates) on and around the disc; secondary optic atrophy
Papillitis
Macular star
(Exudates in a star-shaped pattern radiating from the macula)
Neuroretinitis
Diffuse Unilateral Subacute
Neuroretinitis - Nematode
Aetiological Classification (causes)
1. Demyelinating Pathological process: the 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 (plaque) -> distrupts nerve conduction w/in white matter tracts( brain,brainstem,spinal cord)
Ages: 20-50 years old, F:M = 3:2
Most common cause (eg. Multiple sclerosis)
Optic disc is normal (retrobulbar neuritis)
DEMYLINATING DISEASE CAUSES OCULAR PROBLEMS:
1. Isolated optic neuritis
2. Multiple sclerosis
3. Devic disease (neuromyelitis optica) : bilateral optic neuritis -> transverse
myelitis
4. Schilder disease : bilateral; progressive generalised disease (onset prior to
10y/o death within 1-2yrs)
a) visual p/way-> lesion commonly involve optic nerves and cause optic
neuritis
b) Brainstem-> lesions result in gaze palsies, ocular motor cranial nerve
palsies, trigeminal , facial nerve palsies and nystagmus
Multiple sclerosis (MS)
• A remitting idiopathic
demyelinating disease in CNS
• Autoimmune rxn : T-cell
activation => attack&destruct
myelin
2. Parainfectious
Common in children
Occurs d/t exposure of antigens of certain infectious agents eg. measles, mumps, chickenpox, rubella,whoopingcough,glandular fever
Following viral infection, immunization
Usually 1-3 weeks following viral infection with acute severe
visual loss
Usually bilateral papillitis occur
(occasionally: neuroretinitis or the discs may be normal)
Spontaneous recovery within few weeks
May be a/w other neurological features eg. headache, seizures or ataxia (meningoencephalitis)
3. Infectious
Sinus-related optic neuritis
a/w Cat-scratch fever, syphilis, Lyme disease, cryptococcal
meningitis in patients with AIDS and herpes zoster.
4. Non-infectious
Sarcoidosis- optic nerve head exhibit lumpy appearance,
inflammatory reaction in vitreous
Systemic autoimmune diseases –retrobulbar neuritis
eg. SLE, polyarteritis nodosa, other vasculitides (vasculitis)
Clinical Features of Optic Neuritis
Clinical Presentations
• Usu. women aged btw 20-40 (mean around 30 years)
• Acute unilateral loss of vision, may progress over a few days,
then slowly improve
• Pain exacerbated on eye movement (retrobulbar neuritis) b/c rectus
contraction pulls on the optic nerve sheath; painless (papillitis)
• Dyschromatopsia (change in color perception) in affected eye
• Flashes of light/ phosphenes (tiny white or coloured flashes or
sparkles) induced by eye movement or loud sounds
• Relapsing( most common)/ Progressive (10%)
• A preceding H/O viral illness in some cases
• Vision loss exacerbated by heat or exercise (Uhthoff
phenomenon).
• 40-70% of patients will have other neurological symptoms
(such as parasthesia, weakness, incontinence, Lhermitte sign)
to suggest a diagnosis of demyelination (multiple sclerosis)
Examinations
• Reduced visual acuity
• Reduced color vision
• RAPD (Relative afferent pupillary defect) : reduced
optic nerve conduction
• Central scotoma
• Normal disc: retrobulbar neuritis ; Swollen disc:
papillitis
Diagnosis
• The diagnosis of optic neuritis is clinical, based on the history
and physical findings.
• Investigations
▫ Brain MRI
▫ Serological tests: ESR, syphilis, antinuclear antibody
(ANA), antineutrophil cytoplasmic antibodies (ANCA)
▫ CSF analysis (lumbar puncture) : Presence of oligoclonal
band, elevated IgG level suggest MS.
Brain MRI
• MRI of the brain and orbits with gadolinium contrast has
become the cornerstone of the evaluation in patients with optic
neuritis
▫ To confirm the clinical diagnosis (look for additional
plaques of demyelination)
▫ Offers very strong prognostic information about the risk of
future demyelinating events and MS
▫ For treatment decision
A gadolinium-enhanced fat-saturated T1-weighted scan will show a bright enhancement of the inflamed optic nerve (upper left red arrow). Additionally, bright spots characteristic of multiple sclerosis may also be seen in the brain (lower right red arrow).
White matter lesions in
brain MRI denote a higher
risk of developing MS
Principle of Management
TREAT THE
UNDERLYING
CAUSE
Management: Demyelinating Optic
Neuritis
• In most cases (mild vision loss, no significant visual field
loss, no enhancing lesions on brain MRI) - no treatment
• Vision slowly recovers over several weeks even w/o treatment
(spontaneously)
• Treatment Indicated
▫ Visual acuity worsen than 6/12
▫ Treatment hasten the recovery process, but no effect on
long-term visual outcome
Regimen
▫ IV corticosteroid (eg. methylprednisolone)
1g daily for 3 days followed by oral steroid as prednisone
(1mg/kg/day) for 11 days and then tapered for 3 days
▫ IM interferon beta-1a
Reducing the development of clinical MS over the
following 3 years in patients at high risk (based on the
presence of subclinical brain MRI lesion)
NB. Oral prednisolone alone is contraindicated b/c it does not affect
the speed of recovery and is a/w a significantly higher recurrence rate.
Corticosteroids S/E
• Mood changes
• Facial flushing
• Weight gain
• Dyspepsia