Optic Neuropathies -DDx

Inflammatory

Ischaemic Optic Neuropathy

Arteritic

Non-arteritic

Compressive (or infiltrative)

Compressive

Infiltrative

Toxic/Nutritional/Drugs

Hereditary

Isolated

Associated with other disorders

 

Optic Neuropathies -DDx

DDx:

       Inflammatory (optic neuritis)

       Vascular – Ischaemic optic neuropathy

       Compressive/Infiltrative

       Hereditary

o    Isolated

o    Syndromic

       Toxic/nutritional

       Traumatic

       Raised ICP

       Glaucoma

       Anomalous optic nerve

 

Inflammatory

See Optic Neuritis

Ischaemic Optic Neuropathy

Arteritic

See GCA and PMR

Non-arteritic

Anterior (AION)

       Occlusion of the small vessels supplying the anterior portion of the optic nerve

       Exact cause is still controversial

       Often likely to be caused by a compartment syndrome of the anterior disc

Risk factors

       Small crowded disk (Disk at risk)

       Optic nerve head drusen

       Anomalous disk

       Severe papilloedema

       Severe hypotension

       Severe anaemia

       Hypercoaguable disorders

       Radiation

       Acute intraocular hypertension

       Association with standard vascular risk factors

 

Treatment

       No proven treatment

       Control vascular risk factors

       Avoid triggers that could affect the other eye – in particular avoid hypotension

       Aspirin trials equivicol – probably no harm

       Steroid trials negative (although controversial – some argue minor improvement)

       Operative decompression trialled – no benefit

 

PION

       Typically altitudinal or arcuate defect inferiorly

       Rare (Arteritic PION is much more common))

       Presumed risk factors:

       Severe hypotension

       Severe anaemia

       Hypercoaguable disorders

       Radiation

Compressive (or infiltrative)

       Painless, progressive visual loss

       Usually pale nerve (sometimes swollen)

 

Traumatic

Surgery is appropriate if there is ongoing compression (e.g. from bone fragment)

IONTS – steroids in traumatic optic neuropathy trial

No evidence of effectiveness

Particularly avoid if concurrent head injury (increased mortality in CRASH trial)

 

 

Compressive

Neoplastic

       Optic nerve sheath meningioma

       Sphenoid wing meningioma

       Pituitary tumours

       Craniopharyngioma

       Intraorbital tumour

 

Non-neoplastic

Thyroid eye disease

Orbital pseudotumour

       Orbital haemorrhage

       Ophthalmic artery aneurysm

       Internal artery compression

       Fibrous dysplasia

       Paget disease

 

Infiltrative

Neoplastic

       Optic nerve glioma

       Metastasis

       Lymphoma

       Meningeal carcinomatosis

Non-neoplastic

Sarcoidosis

 

Toxic/Nutritional/Drugs

       Progressive, symmetrical, central visual lsoss

       Disc often normal or slight swelling

       Progressive, bilateral, symmetica, central visual loss

       Dyschromatopsia

       Cecocentral scotomas

       Normal or pale nerve (often pale temporal first)

Causes:

       B12 deficiency

       Tobacco use (Cigars >cigarettes)

       Methanol

       Ethylene glycol

       Medications

o    Ethambutol (Dose related , early dyschromatopsia)

o    Amiodarone (Disc oedema, mimics AION)

o    Linezolid,

o    Disulfiram

       Organic solvents

       Lead

        

 

 

Hereditary

Isolated

Leber Hereditary Optic Neuropathy

       Bilateral, sequential, painless central visual loss

       Male >> female, age 15-35

       Hyperaemic optic nerve acutely

       Cecocentral scotomas

       Pale optic nerve late

       Poor visual prognosis

       ECG – cardiac abnormalities

       Mitochondiral DNA mutation, maternal inheritance

Dominant Optic Atrophy (Kjer)

       Bilateral slowly progressive painless visual loss

       Usually presents in childhood

       Autosomal dominant, somatic mutation for mitochondrial protein

Associated with other disorders

       DIDMOAD

       Friedreich Ataxia

       Spinocerebellar ataxia

       Charcot-Marie Tooth (HSMN type VI)