🏥 Stations

🧠 Qbank

📖 Book

😃 More

💳 Pricing

🔒 Dashboard

📖 OSCE Learning

🔒 OSCE Stations

🔒 Qbank

🔐 Membership
Share your insights

Help us by sharing what content you've recieved in your exams


Optic neuritis

Specialties > Ophthalmology

Background knowledge 🧠

Definition

  • Optic neuritis is inflammation of the optic nerve.
  • Leads to demyelination and axonal damage, affecting vision.
  • Can be unilateral or bilateral, though unilateral is more common.

Epidemiology

  • Most common in adults aged 20-45 years.
  • More frequent in females, with a female-to-male ratio of approximately 3:1.
  • Higher prevalence in individuals of Northern European descent.
  • Often associated with multiple sclerosis (MS).

Aetiology and Pathophysiology

  • Autoimmune demyelination is the primary cause.
  • Commonly linked to MS; optic neuritis is often the first symptom.
  • Other causes include infections (e.g., viral, Lyme disease), and autoimmune diseases (e.g., lupus, sarcoidosis).
  • Demyelination disrupts nerve signal transmission, leading to visual impairment.

Types

  • Retrobulbar neuritis: Most common type, where the optic nerve behind the eye is inflamed.
  • Papillitis: Inflammation involves the optic disc (more common in children).
  • Neuroretinitis: Inflammation extends to the retina, often associated with infectious causes.

Clinical Features 🌡️

Symptoms

  • Acute vision loss in one eye, typically developing over hours to days.
  • Pain with eye movement, often preceding visual symptoms.
  • Color vision deficit, particularly red desaturation.
  • Photopsia (flashes of light) may occur.
  • Symptoms often worsen with heat or exercise (Uhthoff’s phenomenon).

Signs

  • Relative afferent pupillary defect (RAPD) present in the affected eye.
  • Visual acuity reduction, often ranging from mild to severe.
  • Fundoscopy may appear normal in retrobulbar neuritis; papillitis shows optic disc swelling.
  • Visual field defects, typically central scotoma.
  • Impaired color vision, particularly for red and green hues.

Investigations 🧪

Tests

  • MRI of the brain and orbits with contrast: Most important test to identify demyelination and rule out other causes.
  • Visual evoked potentials (VEP): Detects slowed conduction in the optic nerve.
  • Lumbar puncture: May show oligoclonal bands, supportive of MS diagnosis.
  • Blood tests: Considered for infectious or systemic autoimmune causes (e.g., ANA, ESR, CRP).

Management 🥼

Management

  • High-dose intravenous corticosteroids (e.g., methylprednisolone) for 3-5 days, followed by oral taper.
  • Monitor for underlying causes, particularly MS; consider starting disease-modifying therapies if diagnosed.
  • Pain management as needed.
  • Patient education on the potential for recurrence and chronicity.
  • Referral to neurology and ophthalmology for ongoing care.

Complications

  • Risk of permanent visual impairment if untreated or recurrent.
  • Development of multiple sclerosis in approximately 50% of patients within 15 years.
  • Recurrence of optic neuritis in the same or contralateral eye.
  • Chronic pain or discomfort in some cases.

Prognosis

  • Good prognosis for visual recovery in most cases, with significant improvement within weeks to months.
  • However, some patients may experience persistent deficits, particularly in color vision.
  • Higher risk of future episodes of optic neuritis or MS in patients with MRI evidence of demyelination.
  • Ongoing neurological monitoring is essential for early detection of MS or other related conditions.

Key Points

  • Optic neuritis is a common initial presentation of MS.
  • MRI is crucial for diagnosis and assessing the risk of MS.
  • Prompt treatment with corticosteroids can hasten recovery.
  • Long-term follow-up is essential due to the risk of recurrence and progression to MS.

No comments yet 😉

Leave a Reply

Ophthalmology