Optic neuritis in children--clinical and electrophysiological follow-up

Optic Neuritis in a Pediatric Patient with Kikuchi-Fujimoto Disease: A Case Report and Review of the Literature

Kikuchi-Fujimoto disease (KFD), also known as histiocytic necrotizing lymphadenitis, is a rare, benign, and self-limiting condition characterized by lymph node inflammation. While KFD is rarely associated with ocular manifestations, our case report highlights bilateral optic neuritis in a 13-year-old male patient with KFD. We also provide a comprehensive review of similar cases in the literature.

Clinical electrophysiology of the optic nerve and retinal ganglion cells

Clinical electrophysiological assessment of optic nerve and retinal ganglion cell function can be performed using the Pattern Electroretinogram (PERG), Visual Evoked Potential (VEP) and the Photopic Negative Response (PhNR) amongst other more specialised techniques. In this review, we describe these electrophysiological techniques and their application in diseases affecting the optic nerve and retinal ganglion cells with the exception of glaucoma. The disease groups discussed include hereditary, compressive, toxic/nutritional, traumatic, vascular, inflammatory and intracranial causes for optic nerve or retinal ganglion cell dysfunction. The benefits of objective, electrophysiological measurement of the retinal ganglion cells and optic nerve are discussed, as are their applications in clinical diagnosis of disease, determining prognosis, monitoring progression and response to novel therapies.

What can visual electrophysiology tell about possible visual-field defects in paediatric patients

Recognising a potential visual-field (VF) defect in paediatric patients might be challenging, especially in children before the age of 5 years and those with developmental delay or intellectual disability. Visual electrophysiological testing is an objective and non-invasive technique for evaluation of visual function in paediatric patients, which can characterise the location of dysfunction and differentiate between disorders of the retina, optic nerve and visual pathway. The recording of electroretinography (ERG) and visual-evoked potentials (VEP) is possible from early days of life and requires no subjective input from the patient. As the origins of ERG and VEP tests are known, the pattern of electrophysiological changes can provide information about the VF of a child unable to perform accurate perimetry. This review summarises previously published electrophysiological findings in several common types of VF defects that can be found in paediatric patients (generalised VF defect, peripheral VF loss, central scotoma, bi-temporal hemianopia, altitudinal VF defect, quadrantanopia and homonymous hemianopia). It also shares experience on using electrophysiological testing as additional functional evidence to other tests in the clinical challenge of diagnosing or excluding VF defects in complex paediatric patients. Each type of VF defect is illustrated with one or two clinical cases.

Chromatic visual evoked potentials indicate early dysfunction of color processing in young patients with demyelinating disease

PURPOSE

Chromatic visual evoked potentials (cVEP) primarily reflect the parvocellular visual pathway function, which has been shown to be predominantly affected in demyelinating disease (DD). The purpose of this study was to evaluate cVEP responses and to compare them with other structural and functional findings in young patients with DD.

METHODS

Thirty patients (8-28 years of age) with DD with or without a history of optic neuritis (ON) were investigated. Twenty-five eyes had at least one episode of ON (ON-group) and 35 eyes had no clinically evident episode of ON (nON-group). OCT imaging was performed using a high-resolution spectral-domain OCT (SD-OCT), measuring retinal nerve fiber layer (RNFL) thickness. Pattern reversal electroretinography (PERG) and visual evoked potentials (VEP) were recorded according to the ISCEV standard, and chromatic visual evoked potentials (cVEP) were recorded to isoluminant red-green (R-G) and blue-yellow (B-Y) 7° circle stimuli, composed of horizontal sinusoidal gratings with spatial frequency 2 cycles/°, 90% chromatic contrast and onset-offset (300:700 ms) mode of stimulation. Structural and functional measures were analyzed and compared between the groups.

RESULTS

Both general (G) and temporal (T) RNFL thicknesses were reduced below normal limits in most of the eyes. However, in the ON-group (G: 77.5 ± 20.6, T: 51.4 ± 23.4 µm), the thinning was more significant (p < 0.001) than in the nON-group (G: 95.4 ± 12.1, T: 70.1 ± 11.5 µm). PERG N95 was within normal limits in the nON-group, while it was significantly more affected in the ON-group (7.4 ± 1.0 vs. 5.1 ± 2.0 μV; p < 0.0001). Similarly, also VEP P100 latency and amplitude showed a greater percentage of abnormality in the ON-group, the latency being longer (117.2 ± 16.9 vs. 99.4 ± 4.6 ms; p < 0.0001) and the amplitude lower (9.1 ± 5.1 vs. 16.4 ± 7.5 μV; p < 0.0001). The cVEP N-wave amplitude to R-G and B-Y stimuli was reduced below normal limits in both ON- and nON-groups; however, cVEP to B-Y stimulation were slightly more affected in the ON-group (4.0 ± 3.8 vs. 5.9 ± 3.3 µm; p = 0.02). A positive correlation between cVEP amplitude and RNFL thickness and between cVEP amplitude and PERG N95 amplitude, as well as a strong negative correlation between cVEP amplitude and P100 latency was observed.

CONCLUSIONS

These findings demonstrate that cVEP indicate early abnormality of parvocellular pathway function in eyes with or without a history of optic neuritis and can be used together with other structural and functional parameters to evaluate visual pathway integrity of young patients with DD.

Visual electrodiagnostics and eye movement recording - World Society of Pediatric Ophthalmology and Strabismus (WSPOS) consensus statement

Visual electrodiagnostics and eye movement recording are important additional clinical tools in evaluation, diagnosing and management of ophthalmic and neurological disorders. Due to their objectiveness and non-invasiveness they can play an important role in pediatric ophthalmology. The WSPOS (World Society of Pediatric Ophthalmology and Strabismus) consensus statement gives insight into basic principles and highlights the clinical application of both visual electrodiagnostic tests and eye movement recording.

Pediatric optic neuritis

PURPOSE OF REVIEW

Pediatric optic neuritis may be challenging to diagnose and treat. Significant clinical investigation of optic neuritis occurring in adults guides current clinical practices. Differences in presentation and prognosis exist for pediatric patients with optic neuritis when compared with adults including the risk of developing multiple sclerosis. The aim of this review is to provide an update on latest advances in the diagnosis, treatment and current research concerning pediatric optic neuritis.

RECENT FINDINGS

Limited case series and retrospective reviews constitute much of the data we know about patients with pediatric optic neuritis. Pediatric optic neuritis is included in the spectrum of neuroinflammatory diseases. Testing modalities (ocular coherence tomography and visual evoked potentials) and serologic testing (antibodies against aquaporin-4 and myelin oligodendrocyte glycoprotein) are being investigated for diagnostic and prognostic value. The low incidence of pediatric optic neuritis results in small sample sizes may contribute to conflicting results of different studies.

SUMMARY

Recent advances in diagnostic and serologic testing in pediatric neuritis may offer better diagnosis, treatment and prediction of prognosis. Validation requires well designed prospective research.

Updates and Controversies in the Management of Acute Optic Neuritis

Optic neuritis remains a common diagnosis with controversial management. Although typical optic neuritis is often associated with "good" recovery of visual acuity, patients are often left with persistent impairments of contrast sensitivity, color vision, and visual field. These permanent visual deficits correlate with structural injury to the anterior visual pathway and are closely linked to visual quality of life. High dose corticosteroids are commonly used for patients with acute optic neuritis. However, even several decades after the initial clinical trials, there remains significant controversy regarding the efficacy and utility of this treatment. There is a need for more effective treatments, and many new immunomodulatory and neuroprotective agents have been investigated recently. Atypical optic neuritis, such as that seen with neuromyelitis optica spectrum disorder, often requires more aggressive initial treatment. Thus, it is important for clinicians to have a framework for rapid diagnosis and triage of patients who present with typical or atypical optic neuritis. Lastly, optic neuritis is associated with an elevated long-term risk of developing multiple sclerosis. Some patients may benefit from initiation of medications targeting multiple sclerosis at the time of initial presentation of optic neuritis. Appropriate identification and treatment of patients at highest risk of developing multiple sclerosis may help impact their disease course, while limiting exposure to potential adverse effects in patients who are at lower risk and do not require disease-modifying treatment.

Optical coherence tomography and visual evoked potentials in pediatric MS

Objective:

To determine the relative ability of optical coherence tomography (OCT) and pattern-reversal visual evoked potentials (pVEPs) to detect visual pathway involvement in pediatric-onset MS.

Methods:

Pediatric-onset MS participants (onset <18 years) and healthy controls (HCs) underwent OCT (Cirrus HD-OCT) and pVEPs. Retinal nerve fiber layer (RNFL), ganglion cell layer to inner plexiform layer (GCL-IPL), and P100 pVEP latency were measured. Generalized estimating equation models were used to compare the groups, adjusting for age and intereye correlations.

Results:

Twenty-four pediatric MS participants, 14 with a history of remote (>6 months) optic neuritis (ON) in one eye (8 participants) or both the eyes (6 participants), and 24 HCs were enrolled. RNFL thinning (<83 μm, 2 SDs below HC eyes) occurred in 50% of ON eyes vs 5% of non-ON eyes. Prolonged VEP latency (>109 msec) occurred in 58% of ON eyes and 55% of non-ON eyes. A clinical history of ON predicted RNFL (p < 0.001) and GCL-IPL thinning (p = 0.011), whereas prolonged pVEP latency in children with MS occurred independent of ON history.

Conclusions:

OCT and pVEPs provide complementary but distinct insights. OCT is sensitive to retinal changes in the context of clinical ON, whereas pVEPs are useful to detect disseminated lesions of the visual pathway in children with MS.

Pediatric Optic Neuritis

Optic neuritis is rare in children in comparison to adults, but accounts for approximately 25% of pediatric acute demyelinating syndromes. Features of pediatric optic neuritis that differ from adults include a higher rate of bilaterality, poor visual acuity on presentation, and papillitis. Diagnostic work-up includes brain magnetic resonance imaging, lumbar puncture, and blood tests to exclude infectious and inflammatory disorders. Pediatric optic neuritis may occur following infection or vaccination, or in association with a systemic demyelinating process such as acute disseminated encephalomyelitis, neuromyelitis optica, or multiple sclerosis. Treatment is controversial, but most practitioners administer corticosteroids. Most children with optic neuritis experience full visual recovery. The recently launched Pediatric Optic Neuritis Prospective Data Collection Study (PON1) aims to provide estimates of visual acuity outcome and assess the potential to recruit for a future pediatric optic neuritis treatment trial.

Visual electrophysiology in the clinical evaluation of optic neuritis, chiasmal tumours, achiasmia, and ocular albinism: an overview

BACKGROUND AND METHODS

In routine clinical evaluation of optic neuritis and chiasmal tumours, pattern electroretinography and visual evoked potentials (VEPs) to pattern-reversal stimulation are useful examinations. Similarly, in achiasmia and ocular albinism, VEPs to flash and pattern-onset stimulation provide relevant information.

RESULTS

The role of visual electrophysiology in these diseases is to assess potential dysfunction of the visual pathway: (a) at the acute stage of optic neuritis, to determine the magnitude of conduction block of the optic nerve fibres; (b) at the clinical recovery stage of optic neuritis, to determine optic nerve conduction delay due to demyelination, and to follow possible remyelination; (c) at the recovery of optic neuritis when visual acuity does not normalise, to define loss of optic nerve fibres and retrograde degeneration of retinal ganglion cells; (d) in tumours at the chiasm, to detect abnormal conduction along the crossed and/or uncrossed fibres; and (e) in achiasmia or albinism, which are both congenital disorders associated with nystagmus, to detect achiasmia and absence of or reduced optic nerve fibre decussation at the chiasm, or to detect ocular albinism and excess of optic nerve fibre decussation at the chiasm. In optic neuritis, two recent examinations have been used to detect retrograde axonal degeneration: photopic negative response of the electroretinogram, to assess dysfunction of ganglion cell axons; and optic coherence tomography, to measure thinning of the retinal nerve fibre layer. In optic neuritis, multifocal VEPs provide a promising clinical examination, because this can show areas that are associated with normal or abnormal optic nerve fibre function.

CONCLUSIONS

Visual electrophysiology defines function of the visual pathway and is relevant: (1) in optic neuritis, when visual acuity does not recover well; (2) in tumours of the chiasm with normal visual fields, as in paediatric patients who cannot adequately perform perimetry; and (3) in children with congenital nystagmus and suspected achiasmia or ocular albinism.

Chromatic visual evoked potentials in young patients with demyelinating disease

The purpose of this study was to evaluate color vision in young patients with demyelinating disease both clinically and electrophysiologically. Thirty young patients (8-28 years, mean age 19 years) with demyelinating disease with or without a history of optic neuritis (ON) were investigated. Color vision was evaluated clinically with the Ishihara test and the Farnsworth-Munsell 100 hue (FM 100 hue) test and electrophysiologically with chromatic visual evoked potentials (cVEPs). Color deficiency axis and error score (ES) obtained with the FM 100 hue test were analyzed. cVEPs to isoluminant red-green (R-G) and blue-yellow (B-Y) stimuli were recorded. The stimulus was a 7 deg circle composed of horizontal sinusoidal gratings with a spatial frequency of 2 cycles/deg and 90% chromatic contrast. Onset-offset mode of stimulation (ON:OFF=300∶700  ms) was used. Since the majority of the patients were adults (>18  years), the negative wave (N wave) of the cVEP respones is the prominent part and therefore was analyzed. Sixty eyes were studied-22 with at least one episode of ON (ON group) and 38 without any clinically evident episode of ON (nON group). The average ES in the ON group was 179.18±171.8, whereas in the nON group it was 87.60±65.34. The average N-wave latency in the ON group was 144±44  ms for the R-G stimulus and 146±56  ms for the B-Y stimulus, whereas in the nON group, it was 117±13  ms for the R-G stimulus and 121±22  ms for the B-Y one. The average N-wave amplitude in the ON group was 9.3±7.1  μV for the R-G stimulus and 5.1±3.9  μV for the B-Y one, whereas in the nON group, it was 10.8±8.3  μV for the R-G stimulus and 6.4±4.3  μV for the B-Y one. A significant difference between the ON and the nON group was found: in the ON group, ES was higher (p=0.01) and N-wave latency was longer (p=0.01) compared with those in the nON group. The study showed that color vision is expectedly more affected in the ON group, but also often in the nON group, which may indicate increased parvocellular visual pathway vulnerability in demyelinating diseases.

Clinical profile of Malay children with optic neuritis

Limited data are available on optic neuritis in Asian children. Clinical profiles tend to vary with different races. We aimed to determine the clinical manifestations, visual outcomes, and etiologies of optic neuritis in Malaysian children, and discuss the literature of optic neuritis in Asian children. A retrospective study involving 14 children with optic neuritis was performed at Hospital Universiti Sains Malaysia between July 2005 and January 2010 (follow-up, 18-60 months). Clinical features, laboratory results, possible etiologies, and visual acuity after 1 year were studied. Females were predominant (mean age at presentation, 11.1 years). All patients manifested bilateral involvement. Swollen optic discs were observed in 92.9% of eyes; 60.7% of patients demonstrated a visual acuity of 6/60 (or 20/200) or worse on presentation, whereas 14.3% remained at 6/60 (or 20/200) or worse, 1 year after their attack. Cecocentral scotoma comprised the most common visual field defect. Infection contributed to 50.0% of cases; 14.3% progressed to multiple sclerosis during follow-up, with no evidence of recurrent optic neuritis. The clinical profiles and etiologies of optic neuritis in Malay children differ slightly compared with other optic neuritis studies of Asian children. The frequency of progression to multiple sclerosis is relatively lower.

Pediatric optic neuritis and risk of multiple sclerosis: meta-analysis of observational studies

PURPOSE

To determine the relationships among age, unilateral versus bilateral simultaneous presentation, magnetic resonance imaging (MRI) lesions, and the risk of multiple sclerosis (MS) in children with optic neuritis.

METHODS

A systematic literature review and meta-analysis were performed by the use of a MEDLINE search to identify published studies containing individual patient data for children with optic neuritis. Age, laterality (unilateral vs bilateral simultaneous optic neuritis), presence of brain MRI abnormalities, and development of MS were recorded. Logistic regression was used to determine the relationships among these parameters.

RESULTS

Fourteen studies met inclusion criteria. Data for 223 patients (age range 2-17.8 years) were analyzed. Unilateral optic neuritis occurred more frequently in older children but was not associated with an increased risk of MS, after adjusting for age (odds ratio [OR] = 1.9, P = 0.11; 95% confidence interval [CI], 0.9-4.3). For every 1-year increase in age, the odds of developing MS increased by 32% (OR = 1.3, P = 0.005; 95% CI, 1.1-1.6, adjusted for the presence of MRI lesions). The risk of MS was greater in children with abnormal brain MRI scans at presentation compared with normal MRIs (OR = 28.0, P < 0.001, 95% CI, 6.3-125.1, adjusted for age).

CONCLUSIONS

The relationship between unilateral and bilateral optic neuritis and the development of MS is dependent on age. Older children and those with brain MRI abnormalities at presentation, are at greater risk for MS. Long-term follow-up of children with optic neuritis is needed to establish the true risk for the development of MS.

The role of visual evoked potentials in the differential diagnosis of functional visual loss and optic neuritis in children

This study aims to determine whether visual evoked potentials can aid the diagnosis of functional visual loss and differentiate it from optic neuritis in children. The medical records and visual evoked potentials of 72 patients registered in the neurophysiological database of our Institution in the period 2000-2009, with diagnoses of functional visual loss or optic neuritis were reviewed retrospectively. In 61 children, visual evoked potentials confirmed the diagnosis: 49 functional visual loss and 12 optic neuritis. Visual evoked potentials were normal in all patients but 1 in the functional visual loss group, while all were abnormal in the optic neuritis group. Overlapping clinical features occurred between the 2 groups as well as prevalent severe visual loss, relative afferent pupillary defect, and papillitis in optic neuritis. Visual evoked potentials are of value in confirming clinical suspicion of functional visual loss, particularly when clinical overlap with optic neuritis occurs.

When do asymmetrical full-field pattern reversal visual evoked potentials indicate visual pathway dysfunction in children?

Our study aimed to find out the association between full-field pattern reversal visual evoked potential (pVEP) transoccipital asymmetries and half-field pVEP transoccipital distributions in children. Over a six-month period, 46 patients (mean age: 9 years 9 months) had both monocular full-field and half-field pVEPs to test checks subtending 50 min of arc in a 35 degree full-field and 0-17.5 degree lateral half-field. Silver-silver chloride electrodes placed at Oz, O1 and O2 were referred to Fz. Monocular full-field data were categorised according to the degree of transoccipital asymmetry. Half-field data were measured and summated to see whether they explained any full-field asymmetry. In this cohort of 46 patients, eight (17%) patients had symmetrically distributed monocular full-field pVEPs for each eye. Four of these patients had normal half-field pVEP distributions for each eye, but the other four showed a half-field deficit in one or both eyes. Of the 38 patients with asymmetrically distributed full-field pVEPs in at least one eye, 17 (44%) patients showed a half-field deficit, 20 (53%) showed responsive, but symmetrically distributed half-field responses, and one patient (3%) showed typical half-field distributions. Half-field pVEPs can help explain full-field asymmetries and should be attempted in any child able to co-operate with testing and in whom visual pathway dysfunction is suspected.