Disorders Chiasm• 3 SECTIONor Nerve Optic Acquired

Paraneoplastic Optic Neuropathy

Key Facts

•Subacute visual loss in one eye or both in a patient with lung cancer

•Caused by autoimmune destruction of optic nerve(s) as the result of crossreaction to tumor antigens (molecular mimicry)

•Much less common than infiltrative optic neuropathy and less common than paraneoplastic retinopathy

•History of lung cancer typical but evidence of metastasis is uncommon

•May also have other paraneoplastic neurologic manifestations (ataxia and encephalopathy)

•Optic discs appear normal or swollen

•Diagnosis confirmed by finding paraneoplastic antibody (CRMP-5) or other antibodies in blood, but paraneoplastic antibody screen often negative

•Treatment of underlying cancer may produce visual improvement

Clinical Findings

•Subacute monocular or binocular visual loss

•Optic discs appear normal or swollen

•May also have ataxia and mental status changes

Ancillary Testing

•Body imaging may show signs of lung cancer

•Brain imaging usually normal

•Paraneoplastic antibody screen usually negative, but CRMP-5 antibody may be found

Differential Diagnosis

•Infiltrative (neoplastic) optic neuropathy

•Optic neuritis

•Ischemic optic neuropathy

Treatment

•High-dose corticosteroid, plasmapheresis, or intravenous immunoglobulin

•Treatment of underlying cancer

Prognosis

•Treatment may sometimes produce visual improvement, which may also occur spontaneously

•Treatment of underlying cancer may improve visual outcome

Fig. 3.43 Paraneoplastic optic neuropathy autopsy fi ndings. Microscopic section of the optic nerve shows prominent spongiosis (S) and perivascular lymphocytic infiltrate (arrow) (hematoxylin and eosin). (After Sheorajpanday R

et al. J Neuroophthalmol 2006; 26:168–172, with permission.)

Neuropathy Optic Paraneoplastic

Disorders Chiasm• 3 SECTIONor Nerve Optic Acquired

Diabetic Papillopathy

Key Facts

•Nerve fiber bundle visual loss associated with chronic optic disc swelling in patients with insulin-dependent or non–insulin-dependent diabetes mellitus

•May be indolent form of anterior ischemic optic neuropathy

•Visual loss monocular or binocular, subacute or chronic, and usually mild

•Optic discs have distinctive appearance of diffuse swelling with surface telangiectasia

•Often confused with papilledema or diabetic optic disc neovascularization

•Diabetic retinopathy need not be present

•Optic disc findings usually resolve spontaneously within a year

•Visual loss may not recover fully

•There is no treatment

Clinical Findings

•Subacute or chronic visual loss, monocular or binocular

•Visual acuity and/or visual field loss (nerve fiber bundle defects) typically mild

•Diffuse optic disc edema with surface telangiectasia in one or both eyes

•Diabetic retinopathy either absent or mild

Ancillary Testing

•Fluorescein angiography shows leakage within disc substance (not into vitreous, as seen in diabetic neovascularization)

•Brain and orbit imaging is negative

•Lumbar puncture, indicated in bilateral cases, shows normal opening pressure and cerebrospinal fluid constituents

Differential Diagnosis

•Papilledema

•Congenitally elevated optic disc(s)

•Ischemic optic neuropathy

•Proliferative diabetic retinopathy

•Optic neuritis

•Hypertensive optic neuropathy

•Infiltrative optic neuropathy

Treatment

• Good control of blood sugar is recommended but no evidence of efficacy

Prognosis

•Visual loss may resolve spontaneously

•Optic disc abnormalities eventually resolve to normal or pallor after many months

•Neovascularization of optic disc may occur soon afterward