Purpose
Syphilis can affect any part of the eye, including the optic nerve. Patients can have disc edema without visual compromise, which has been attributed to papilledema from raised intracranial pressure or optic perineuritis from optic nerve sheath inflammation. However, these attributions were proposed before MRI was largely available. We performed a retrospective, clinical observational study to better understand the mechanism of optic disc edema in neurosyphilis.
Methods
We reviewed all patients seen at the University of Iowa from 2010 to 2014 with a diagnosis of neurosyphilis affecting the optic nerve, which revealed three patients with optic disc edema. The visual acuity, fields, OCT, fundus photos, lumbar puncture, and MRI results were examined to determine the mechanism of the optic disc edema. Neurosyphilis was confirmed with reactive VDRL in the CSF.
Results
One patient had unilateral optic disc edema and two patients had bilateral optic disc edema. The visual fields showed enlargement of the blind spots only, except for one eye of a patient who had concomitant chorioretinitis and trace optic disc edema resulting in a cecocentral scotoma. All three patients denied symptoms of raised intracranial pressure. The opening pressure was normal in the two patients who had it measured; the opening pressure in the patient with unilateral disc edema was not measured. MRI of the orbits demonstrated no optic nerve sheath enhancement in any of the patients.
Conclusions
With modern diagnostic imaging, we were able to demonstrate a lack of optic nerve sheath enhancement in three patients with optic disc edema and preserved visual function, suggesting papillitis may be a better term than optic perineuritis in many cases of isolated disc edema from neurosyphilis.