Publication Exclusive: Pediatric patient presents with acute onset of vision loss

An 8-year-old Asian boy presented with vision loss in the right eye for 1 day. He described a central area of vision loss with intact peripheral vision. At the onset of the vision loss, he had a mild headache that resolved. He did not have any eye pain or diplopia, and there were no changes in the left eye. He had no other neurologic changes and no recent illnesses or vaccinations. He was otherwise healthy.

Examination

Visual acuity with myopic correction was count fingers at face in the right eye and 20/20 in the left eye. There was an abnormal optokinetic nystagmus (OKN) response in the right eye. The patient’s pupils had been dilated by the referring physician but reportedly had a 2+ afferent pupillary defect, which was confirmed the day after presentation. Extraocular motility was full without pain or nystagmus. Ishihara color plate testing was decreased in the right eye to 0/10 and normal in the left eye. Anterior and posterior segment examinations were unremarkable with the exception of mild nasal elevation of the right optic nerve head.

What is your diagnosis?

Acute onset of decreased vision

Acute onset of decreased vision in a child with a normal exam may lead to a diagnosis of functional vision loss after careful exam and follow-up. In this patient with acute unilateral vision loss, however, an abnormal OKN response and relative afferent pupillary defect were also present. Given these findings, the possibility of a retrobulbar lesion causing an optic neuropathy was considered.

The differential diagnosis for optic neuropathy can be divided into several categories: ischemic, compressive, infiltrative, traumatic, mitochondrial and inflammatory (optic neuritis). Despite the lack of other neurological changes, given the acute onset and severity of vision loss, the patient’s presentation was concerning for optic neuritis associated with neuromyelitis optica (NMO) or multiple sclerosis. Leber’s hereditary optic neuropathy, post-infectious optic neuritis and a retrobulbar compressive lesion were also in the differential.

Management

The patient was admitted to the hospital for further work-up and started on intravenous methylprednisolone. The following labs were sent: CBC, ESR, Lyme titers, ACE, VDRL, FTA-ABS, QuantiFERON Gold and NMO antibody. A lumbar puncture was performed and cerebrospinal fluid sent for cell count, protein and oligoclonal bands. All labs were negative. An MRI of the orbit, brain and spine with gadolinium and fat suppression revealed intracanalicular right optic nerve enhancement and a few scattered nonspecific foci of T2/FLAIR hyperintense signals involving the subcortical white matter of the bilateral frontal lobes (Figure 1). A diagnosis of right retrobulbar optic neuritis was made.

Click here to read the full publication exclusive, Grand Rounds at the New England Eye Center, published in Ocular Surgery News U.S. Edition, August 25, 2015.