Case Study 133 T Sign in Retrobulbar Neuritis

Abstract

CW is a 25-year-old woman who presented with complaints of pain and reduced vision in her left eye for about a week. Examination found visual acuity of 20/20 OD and of 20/60-2 OS with a 3+ afferent pupil defect. The left eye was mildly proptotic. Fundus examination showed a normal right optic disc and moderate edema of the left disc with several focal hemorrhages. Some perivascular sheathing was noted peripherally.

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CW is a 25-year-old woman who presented with complaints of pain and reduced vision in her left eye for about a week. Examination found visual acuity of 20/20 OD and of 20/60-2 OS with a 3+ afferent pupil defect. The left eye was mildly proptotic. Fundus examination showed a normal right optic disc and moderate edema of the left disc with several focal hemorrhages. Some perivascular sheathing was noted peripherally.

Echography of the left orbit revealed increased lucency of subtenon’s space and the optic nerve sheaths with the appearance of a T sign (Fig. 1). A-scan measured the right optic nerve to be 3.2 mm and the left 3.4 mm, which was within normal limits for optic nerve thickness.

Fig. 1

T sign–scleral thickening (large arrow) and adjacent optic nerve thickening (small arrow)

Magnetic resonance imaging scan showed optic nerve sheath enhancement after contrast injection, but no white plaques were noted in the brain as would be expected in demyelinating disease, such as multiple sclerosis. Systemic evaluation found a significantly positive antinuclear antibodies (ANA), which supported the diagnosis of systemic lupus erythematosus. She was treated with high-dose IV steroids with improvement in her vision in the left eye to 20/25. She subsequently experienced recurrences of her optic neuritis with response to steroids, but she began to have similar episodes in the right optic nerve. She eventually suffered some atrophy of both nerves but maintained functional vision.

Idiopathic inflammation at the orbital apex, such as in the Tolosa–Hunt syndrome, can result in reduction of vision in conjunction with motility disturbances. This syndrome usually presents with the abrupt onset of painful ophthalmoplegia involving the third, fourth, and sixth nerves. There is often associated hypesthesia of the skin in the distribution of the first division of the fifth trigeminal nerve.