Optic Neuritis

Diseases, ,

Diagnosis:

Clinical features with or without imaging or physiological tests

Clinical features:

Painful, loss of vision, & loss of accurate colour vision (dyschromatopsia)
Fundoscopy: swollen optic disc (optic disc edema, this is not papilledema because pressure is normal),
Relative afferent papillary defect

Findings on Investigations:

MRI: T2 fat suppressed, high signal foci in the optic nerve, minimal or no nerve expansion, enhancement post contrast.
Optical coherence tomography OCT: retinal layer thickness is increased in acute optic neuritis.  Retinal layer thickness is decreased by 3 months.

Investigations to consider:

Those for multiple sclerosis, see multiple sclerosis for more details
Lumbar puncture, CSF electrophoresis
MRI
Blood tests:

  • Anti-NMO antibody,
  • VDRL, FTA-ABS, Lyme serology, CMV serology, VZV serology, cryptococcal antigen, measles serology, mumps serology,
  • B1, B12 levels: nutritional deficiency optic neuropathy
  • ESR, CRP, ANA screen, ENA panel (anti- dsDNA, anti-Sm, anti-RNP, SSA, SSB, anti-Jo-1, antitopoisomerase ‘formerly anti Scl-70’, antinucleolar, anticentromere), ANCA (c-ANCA, p-ANCA), Complement C3, C4 and CH50
  • ACE levels: neurosarcoidosis
  • Anti-CRMP5, Anti-CAR (anti-recoverin): cancer associated retinopathy
  • Quantiferon: tuberculosis

Visually evoked response VER: increased latencies, reduced amplitude in >65%
Multifocal VER: more sensitive & specific than VER
CT chest abdomen & pelvis: lung cancer in cancer associated retinopathy
Lymph node biopsy: Bartonella henselae (cat-scratch disease)

Treatment:

Methylprednisolone 1000 mg intravenously daily for 3 -5 days. Some physicians consider following it by prednisolone 1 mg/kg orally X11 days +taper over 4 days.

Causes of optic neuropathy:

Optic neuritis:

  • Multiple sclerosis
  • Neuromyelitis optica
  • Systemic lupus erythematosus, Sjogren’s syndrome, Wegener grandulomatosis, Behcet’s disease inflammatory bowel disease,
  • Neuro-Sarcoidosis
  • Chronic relapsing inflammatory optic neuropathy

Ischemic optic neuropathy:

Infection:

  • Syphilis
  • Lyme disease
  • Tuberculosis
  • Bartonella henselae (cat-scratch disease)
  • CMV
  • VZV
  • Measles, mumps,
  • Cryptococcus

Paraneoplastic:

Noninflammatory:

  • Genetic:
    • Leber’s hereditary optic neuropathy (LHON)
    • Dominant optic neuropathy (Kjers’ type, OPA1 gene, Chr. 3q), Recessive optic neuropathy (X-linked, OPA2),
  • Tobacco-alcohol amblyopia a.k.a. nutritional optic neuropathy
  • B1, B2, B3, B6, or B12 deficiency: nutritional optic neuropathy
  • Compression by internal carotid artery aneurysm at the siphon i.e. infrasellar aneurysm
  • Drugs and toxins: Ethambutol, Chloraphenicol, amiodarone, methanol,
  • Radiation optic neuropathy
  • Traumatic optic neuropathy
  • Neoplastic:

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