Paraneoplastic Optic Neuropathy
- Subacute optic neuropathy indirectly related to an underlying cancer
- Clinical manifestations are caused by an autoimmune cross-reaction to tumor antigens (“molecular mimicry”)
- Much less common than infiltrative (neoplastic) optic neuropathy and less common than paraneoplastic retinopathy
- Source of cancer may be known or occult
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Core clinical features
- Subacute typically binocular visual loss
- Optic discs typically appear elevated
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Tip: the vitreous is always inflamed!
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Possible accompanying clinical features
- Altered mental state
- Ataxia
- Tremor
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Imaging features
- Brain imaging is usually normal
- Body imaging or blood tests may show cancer
- Paraneoplastic CRMP-5 antibody may be found, but the paraneoplastic screen is often negative
- Infiltrative (neoplastic) optic neuropathy
- Optic neuritis
- Ischemic optic neuropathy
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Tip: reject this diagnosis if there is no vitreous inflammation!
- Exclude alternative causes of vitritis
- Order a blood panel for paraneoplastic antibodies
- Search for cancer if not already known
- Treat the optic neuropathy with high-dose corticosteroids, plasmapheresis, or intravenous immunoglobulin if a cancer is found
- Treat the underlying cancer
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Tip: treatment of the underlying cancer is more effective in restoring vision than is anti-inflammatory treatment
- Treatment is rarely effective in restoring vision