Neuro-ophthalmology Illustrated Chapter 8 – Optic Neuropathies 7

Neuro-ophthalmology Illustrated Chapter 8 – Optic Neuropathies 7

Questions:
85. How long after radiation does radiation optic neuropathy devel
86. What are the characteristics of radiation optic neuropathy?
87. In which race is arteritic ischemic optic neuropathy most commonly seen?
88. What is the typical age of onset of arteritic ischemic optic neuropathy?
89. What are the usual systemic symptoms associated with arteritic ischemic optic neuropathy?
90. Can visual loss be the only symptom of arteritic ischemic optic neuropathy?
91. Is visual loss in arteritic ischemic optic neuropathy usually severe?
91. What should recurrent episodes of transient monocular visual loss or transient diplopia suggest in an individual over 50?
93. Other than giant cell arteritis, what are causes of arteritic AION and PION?
94. In presumed arteritic ischemic optic neuropathy, should the results of a temporal artery biopsy be obtained before starting high dose systemic corticosteroid therapy?

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Questions with answers:
85. How long after radiation does radiation optic neuropathy develop?
Radiation optic neuropathy may develop a few months to years after radiation.

86. What are the characteristics of radiation optic neuropathy?
It is characterized by rapidly progressive, painless loss of vision that is most often posterior (without disk edema).  MRI shows marked enhancement of the affected optic nerve. Prognosis is poor, and there is currently no treatment with proven benefit (steroids and hyperbaric oxygen are sometimes tried with only anecdotal success).

87. In which race is arteritic ischemic optic neuropathy most commonly seen?
Arteritic ischemic optic neuropathy is most often seen in older Caucasian patients.

88. What is the typical age of onset of arteritic ischemic optic neuropathy?
The 70s and 80s.

89. What are the usual systemic symptoms associated with arteritic ischemic optic neuropathy?
Headache, scalp tenderness, jaw claudication, polymyalgia rheumatica, fatigue, and weight loss.

90. Can visual loss be the only symptom of arteritic ischemic optic neuropathy
Yes.

91. Is visual loss in arteritic ischemic optic neuropathy usually severe?
Yes, with acuities reduced to no light perception, light perception only, or hand motion.

91. What should recurrent episodes of transient monocular visual loss or transient diplopia suggest in an individual over 50?
In arteritic ischemic optic neuropathy (giant cell arteritis), visual loss may be preceded by recurrent episodes of transient monocular visual loss or transient diplopia.

93. Other than giant cell arteritis, what are causes of arteritic AION and PION?
Systemic vasculitis: systemic lupus erythematosus, periarteritis nodosa, and Churg-Strauss syndrome.

94. In presumed arteritic ischemic optic neuropathy, should the results of a temporal artery biopsy be obtained before starting high dose systemic corticosteroid therapy?
No, systemic corticosteroid therapy should be instituted immediately upon presumed diagnosis and should not be delayed awaiting the performance or the results of a temporal artery biopsy.

The information below is from Neuro-ophthalmology Illustrated-2nd Edition. Biousse V and Newman NJ. 2012. Thieme

8.5.5 Radiation Optic Neuropathy
Radiation optic neuropathy is a subacute optic neuropathy in patients previously treated with radiation therapy to the brain, skull base, or orbit. It is most common in patients with skull base tumors or with pituitary tumors and craniopharyngiomas (in whom radiation was administered close to the optic nerve or chiasm). It is thought to be an ischemic disorder of the optic nerve from radiation-induced vasculopathy.

Radiation optic neuropathy may develop a few months to years after radiation. It is characterized by rapidly progressive, painless loss of vision that is most often posterior (no disc edema). MRI shows marked enhancement of the affected optic nerve. The prognosis is poor, and there is currently no treatment with proven benefit (steroids and hyperbaric oxygen are sometimes tried, with only anecdotal success).

8.5.6 Arteritic Anterior and Posterior Ischemic Optic Neuropathy

AION is the most common ophthalmic manifestation of giant cell arteritis, and giant cell arteritis is the most common cause of PION.

Pearls
Suspect and rule out giant cell arteritis in all patients older than age 50 presenting with an ischemic optic neuropathy (ION).

Characteristics
Arteritic ischemic optic neuropathy is most often seen in older Caucasian patients, typically in their 70s and 80s. It is usually associated with systemic symptoms, such as headache, scalp tenderness, jaw claudication, polymyalgia rheumatica, fatigue, and weight loss. However, visual loss can be the only manifestation of the disease (so-called occult forms of giant cell arteritis).
Visual loss in arteritic ION is usually severe, with acuities reduced to no light perception, light perception only, or hand motion. It is often bilateral and can be associated with a concurrent retinal or choroidal infarction. Visual loss may be preceded by recurrent episodes of transient monocular visual loss or transient diplopia.


Diagnosis
Elevation of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) is highly suggestive of the disease. The diagnosis is proven by finding granulomatous inflammation with giant cells and disruption of the internal elastic lamina on biopsy of a superficial temporal artery. In the absence of treatment, vision deteriorates, and there is a high risk of involvement of the second eye within days or weeks.
In arteritic AION, the visual loss is profound. The optic nerve appears pale, even acutely, at the time of visual loss. The peripapillary retina is often pallid, suggesting associated choroidal and retinal ischemia. Cotton wool spots are common and indicated use ocular ischemia when associated with AION (▶Fig. 8.25).

Causes
Causes of arteritic AION and PION are giant cell arteritis and systemic vasculitis other than giant cell arteritis, such as systemic lupus erythematosus, periarteritis nodosa, and Churg–Strauss syndrome.

Treatment
Arteritic AION and PION require emergency treatment to prevent complete blindness. Systemic corticosteroid therapy should be instituted immediately upon presumed diagnosis and should not be delayed awaiting results of the temporal artery biopsy.

Reference: 1. Neuro-ophthalmology Illustrated-2nd Edition. Biousse V and Newman NJ. 2012. Thieme

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