Demyelinating optic neuritis

Question 1

What are the systemic features of multiple sclerosis?

Answer 1

• 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. intellectual decline, depression, euphoria
• Transient features, e.g. Lhermitte sign, Uhthoff phenomenon

Question 2

What are symptoms of multiple sclerosis?

Answer 2

• Subacute monocular (unilateral) visual impairment
• 20-50 years (mean around 30), young females more commonly affected
• Discomfort/pain in/around eye present in > 90%, typically exacerbated by ocular movement; it may precede or accompany the visual loss and usually lasts for a few days
• Frontal headache and tenderness of the globe may also be present
• Intermediate uveitis/granulomatous anterior uveitis (associated with MS)
• Prodromal flu-like illness may accompany optic neuritis

Question 3

what are the investigations for multiple sclerosis?

Answer 3

• Lumbar puncture (LP): shows oligoclonal bands on protein electrophoresis of CSF in 90-95%
• MRI brain & orbit/anterior visual pathway (paraventricular white matter plaques radiating outwards from corpus callosum is highly suggestive of MS)

Question 4

what are the occular signs of multiple scerosis?

Answer 4

Decreased visual acuity
Impaired colour vision (profound, disproportionate to decrease in VA)

RAPD

Optic disc is normal in majority of cases (retrobulbar optic neuritis), remainder may show papillitis (optic disc swelling). Fellow eye may show disc pallor (indicative of previous optic neuritis)

Visual field defects

• Diffuse depression of sensitivity in entire central 30’ is most common
• Altitudinal/arcuate defects and focal central/centrocaecal scotomas are also frequent

Question 5

What is Uhthoff’s phenomenon?

Answer 5

worsening of neurologic symptoms with an increase in temperature (e.g. exercise, hot shower)

Question 6

what is lhermitte’s sign?

Answer 6

electrical sensation that runs down the back and into limbs, elicited by bending neck forward

Question 7

what is pulfrich effect?

Answer 7

lateral motion of an object interpreted as having a depth, looks as if they are moving in an elliptical fashion (due to a relative difference in signal conduction between 2 eyes)

Question 8

what is the management?

Answer 8

Treatment only serves to speed up recovery; the end outcome is the same whether or not the patient is treated, therefore treatment is not necessary.

Indications for steroid treatment

• When VA within first week of onset worse than 6/12, treatment may speed up recovery by 2-3 weeks. This may be relevant for patients with poor vision in the fellow eye, or those with occupational requirements.
• Oral steroids in standard doses (1 mg/kg) had no effect on the rapidity of recovery and were associated with a higher recurrence rate, making them contraindicated in patients with acute optic neuritis, a recommendation that has been widely adopted.
• Intravenous corticosteroid treatment was shown to be safe and to be associated with minimal adverse effects.