Neurological Causes of Visual Loss Flashcards
What are common neurological causes of visual loss?
Optic neuritis, anterior ischaemic optic neuropathy (AION), stroke, pituitary tumours, and papilloedema.
What is optic neuritis?
Inflammation of the optic nerve causing visual loss, pain with eye movement, and sometimes colour desaturation.
What are the symptoms of anterior ischaemic optic neuropathy (AION)?
Sudden, painless monocular vision loss, often with an afferent pupillary defect and disc swelling.
What is papilloedema?
Swelling of the optic disc due to raised intracranial pressure, often causing transient visual obscurations.
What are common visual symptoms of a stroke?
Homonymous hemianopia, visual neglect, or cortical blindness.
What is the pathophysiology of optic neuritis?
Inflammation causes demyelination of the optic nerve, disrupting signal transmission to the brain.
What are the risk factors for anterior ischaemic optic neuropathy (AION)?
Hypertension, diabetes, atherosclerosis, and giant cell arteritis.
What is the main cause of papilloedema?
Increased intracranial pressure due to conditions such as a brain tumour, hydrocephalus, or idiopathic intracranial hypertension.
What are the visual field changes in optic neuritis?
Central scotoma (central visual field defect).
What are the visual field changes in a stroke?
Homonymous hemianopia (loss of the same side of the visual field in both eyes).
What is a pituitary tumour’s effect on vision?
Bitemporal hemianopia due to compression of the optic chiasm.
What is the role of MRI in optic neuritis?
To assess for optic nerve inflammation and rule out multiple sclerosis.
What is the treatment for optic neuritis?
High-dose intravenous corticosteroids can be used to hasten recovery, especially in severe cases.
What are the clinical signs of papilloedema on fundoscopy?
Blurred optic disc margins, elevated optic disc, and venous congestion.
What is the differential diagnosis for visual loss with a neurological cause?
Optic neuritis, stroke, multiple sclerosis, brain tumours, and papilloedema.
What is the afferent pupillary defect (APD), and when is it seen?
A relative APD is seen in conditions like optic neuritis and AION, where one optic nerve is impaired.
What is the management of anterior ischaemic optic neuropathy (AION)?
Treat underlying conditions such as hypertension or diabetes and investigate for giant cell arteritis if suspected.
What is the role of visual field testing in neurological vision loss?
To identify specific field defects that indicate the site of the lesion, such as hemianopia or scotomas.
What systemic conditions are associated with optic neuritis?
Multiple sclerosis and other autoimmune conditions.
What is cortical blindness?
Bilateral visual loss due to damage to the visual cortex, with preserved pupillary reflexes.
How does idiopathic intracranial hypertension (IIH) affect vision?
Causes papilloedema, leading to transient visual obscurations and potential permanent vision loss if untreated.
What are the symptoms of bitemporal hemianopia?
Loss of peripheral vision in both eyes, typically caused by optic chiasm compression from a pituitary tumour.
Why is urgent treatment important in giant cell arteritis-related AION?
Delay in treatment can lead to permanent vision loss in both eyes and systemic complications.
What investigations are needed for papilloedema?
Brain imaging (CT/MRI) and lumbar puncture to assess intracranial pressure.
What is the prognosis for optic neuritis?
Vision usually improves within weeks to months, but recurrent episodes may occur in multiple sclerosis.
