Optic Neuritis

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Optic neuritis is an inflammation of the optic nerve, which can cause a sudden decrease in vision in one or both eyes. It is often associated with multiple sclerosis (MS) and other autoimmune disorders.

Aetiology

Optic neuritis can be caused by various factors, including:

• Autoimmune diseases such as multiple sclerosis
• Infections (e.g., viral infections like measles, mumps, herpes simplex)
• Immune-mediated diseases (e.g., neuromyelitis optica)
• Idiopathic (no identifiable cause)

Pathophysiology

Inflammation of the optic nerve leads to demyelination, which disrupts the transmission of visual information from the eye to the brain. This can result in visual impairment and, in severe cases, permanent damage to the optic nerve.

Risk Factors

• Gender (more common in females)
• Age (most common between ages 20 and 40)
• Presence of autoimmune diseases
• Genetic predisposition
• Previous episodes of optic neuritis

Signs and Symptoms

Common signs and symptoms of optic neuritis include:

• Sudden vision loss in one eye
• Pain with eye movement
• Colour vision reduction (dyschromatopsia)
• Visual field defects
• Flashing lights (photopsia)

Investigations

• Clinical history and physical examination
• Visual acuity test
• Pupillary light reflex test (relative afferent pupillary defect)
• Ophthalmoscopy to examine the optic disc
• MRI of the brain and orbits with contrast to assess optic nerve and rule out MS
• Blood tests to check for underlying autoimmune or infectious causes

Management

Primary Care Management

• Immediate referral to an ophthalmologist or neurologist: For further evaluation and management
• Pain management: Oral analgesics such as paracetamol or ibuprofen

Specialist Management

• Intravenous corticosteroids: High-dose steroids (e.g., methylprednisolone) to reduce inflammation and hasten recovery
• Oral corticosteroids: Following intravenous treatment to reduce the risk of recurrence (e.g., prednisolone)
• Plasma exchange therapy: For severe or refractory cases
• Treatment of underlying conditions: Such as immunosuppressive therapy for multiple sclerosis or other autoimmune diseases
• Regular follow-up to monitor recovery and manage any complications

References

1. NICE. (2024). Optic Neuritis: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Optic Neuritis. Retrieved from NHS
3. British Medical Journal (BMJ). (2022). Optic Neuritis: Diagnosis and Management. Retrieved from BMJ
4. American Academy of Ophthalmology (AAO). (2021). Clinical Practice Guidelines: Optic Neuritis. Retrieved from AAO
5. Patient.info. (2023). Optic Neuritis: Causes and Treatment. Retrieved from Patient.info

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