13

Optic Disc Edema

with a Macular Star Figure

CASE NO. 13

An 11-year-old boy presents with acute unilateral loss of vision OD. He had recently received a new kitten as a gift from his grandmother and he had been playing with the cat over the previous two weeks and received a few scratches. The past medical, surgical, family, and social history are unremarkable. He had mild flu-like symptoms one week prior to the visual loss but had no headache, lethargy, fever, lymphadenopathy or other neurologic symptoms or signs. The left eye was asymptomatic.

On exam, the patient’s visual acuity was 20/200 OD and 20/20 OS. The pupils were 5 mm OU and both pupils were reactive to light but there was a right relative afferent pupillary defect. Goldmann visual field testing showed a dense central scotoma OD but was normal OS. Slit lamp biomicroscopy, motility, and intraocular pressure measurements were normal OU. The fundus exam was normal OS. The patient was seen by an outside eye doctor who noted optic disc edema OD and made the diagnosis of “optic neuritis” and told the patient’s family that the boy might have “multiple sclerosis.” A cranial MRI was performed and was normal. The patient was seen three weeks later in the eye clinic and had the fundus findings shown in Fig. 13.1.

Optic disc edema with a macular star (ODEMS) is a descriptive term encompassing a heterogeneous group of disorders. The condition has subsequently been called Leber’s stellate maculopathy,

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Emergencies in Neuro-Ophthalmology: A Case Based Approach

Fig. 13.1. Right eye fundus photograph shows marked disc edema, inferior peripapillary hemorrhage, and a full blown macular star figure.

Leber’s idiopathic stellate neuroretinitis, or simply neuroretinitis. This syndrome is characterized by swelling of the optic disc, peripapillary and macular hard exudates which often occur in a star pattern, and, often, vitreous cells. Because the macular exudate likely results from primary optic nerve disease and not a true retinitis, we prefer the term idiopathic optic disc edema with a macular star (ODEMS) for idiopathic cases and use the term neuroretinitis when the optic disc swelling and a macular star are associated with retinitis, especially if an infectious cause is documented.

Patients are usually children or young adults, with the average age of onset of 20 to 40 years. Men and women are affected equally. Most cases are unilateral but bilateral involvement has been noted to occur in up to a third of the cases. Most patients present with acute unilateral loss of vision. The condition is often painless, but retrobulbar pain, pain on eye movement, or associated headache may occur. A nonspecific “viral” illness precedes or accompanies the visual loss in approximately half of the cases.

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Optic Disc Edema with a Macular Star Figure

The clinical characteristics of ODEMS include:

•Age at onset: Childhood to young adult (6–50 years)

•Gender: Men = women

•Bilateral involvement: 5%–33%

•Pain: Occasional

•Antecedent viral illness: Approximately 50%

•Initial visual acuity: Variable (20/20 — light perception)

•Dyschromatopsia: Often prominent

•Visual field testing: Central, cecocentral, arcuate, or altitudinal defects; possible generalized constriction

•Relative afferent pupil defect present; but may be absent if bilateral involvement

•Optic disc swelling present with subsequent optic atrophy

•Macular star present but may take 1–2 weeks to develop

•Vitreous cells common (90%)

Optic disc edema is the earliest sign of ODEMS and may be severe. The disc edema tends to resolve over two weeks to two months but in some patients optic atrophy ensues. Optic disc edema is associated with leakage of disc capillaries with the fluid spreading from the disc through the outer plexiform layer of the retina. The serous component of the fluid accumulation in Henle’s layer is reabsorbed, and the lipid precipitate forms a macular star. The macular star may be present at the onset of visual loss or may only be noted after one to two weeks following development of the disc edema. The macular star may even be observed only after the disc swelling has started to resolve. Patients with acute disc swelling with a normal macula should thus be re-examined within two weeks to investigate for the presence of a macular star, especially as it is of prognostic importance for the patient’s subsequent risk of developing multiple sclerosis. Fluorescein angiography typically shows leakage from the optic disc in the midto late phases with abnormal permeability of the deep capillaries in the optic nerve head but no perifoveal leakage.

Most cases of ODEMS are “idiopathic” and thought to be the result of a nonspecific viral infection or some immune-mediated process.

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Emergencies in Neuro-Ophthalmology: A Case Based Approach

In general, ODEMS is usually a benign, self-limited inflammatory process. However, a number of infectious agents and inflammatory diseases have been reported to cause ODEMS and neuroretinitis. It appears that syphilis, cat scratch disease, Lyme disease, and perhaps toxoplasmosis are the most common causes of ODEMS and neuroretinitis in cases where an etiologic agent can be identified. Infectious agents should be aggressively sought in cases of ODEMS and neuroretinitis because appropriate antibiotic treatment might be indicated. We recommended special emphasis on recent patient travel history (Lyme endemic areas), consumption of unpasteurized or uncooked foods (toxoplasmosis), sexually transmitted disease exposure (syphilis), and animal contacts (cat scratch).

There is no proven treatment for idiopathic ODEMS. Steroids have been used in some cases with unclear effect. If a specific infectious agent is discovered, than appropriate antibiotics should be considered. However, the data is limited.

Dr. Lee. I agree with Dr. Brazis that the term “neuroretinitis” should be reserved for infectious causes of ODEMS to avoid confusion. The main emergency considerations for optic disc edema with a macular star (ODEMS) are to exclude the mimics of infectious neuroretinitis. Patients with bilateral optic disc edema with a macular star figure might not have infectious neuroretinitis and instead might have disc edema from malignant hypertension or papilledema. I personally recommend considering imaging for bilateral cases especially if there is no vitreous cell seen or if the history is not compatible with an infectious exposure. Although cat scratch neuroretinitis is the most common etiology in my experience for the presentation of unilateral optic disc edema with a macular star figure, it is not clear from the evidence that treatment makes any difference in outcome. Nevertheless, I generally treat patients with serologic confirmation of Bartonella related neuroretinitis.

Course. Bartonella henselae IgM titers were positive and acute and convalescent IgG titers showed a titer elevation at 1:2048. The patient was treated with oral antibiotics and two months later had complete

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