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)