[Myelin oligodendrocyte glycoprotein antibody positive optic neuritis with anti-N-methyl-D-aspartate receptor encephalitis: a case report]

A 6-year-old girl had binocular vision loss with pain for one week. The patient presented with symptoms such as non-communication, language deterioration, dysphonia, and choking when drinking and eating during the course. The serum myelin oligodendrocyte glycoprotein antibody was positive. Both the serum and cerebrospinal fluid anti-N-methyl-D-aspartate receptor antibody were also positive. The diagnoses were myelin oligodendrocyte glycoprotein antibody positive optic neuritis and anti-N-methyl-D-aspartate receptor encephalitis. High-dose intravenous glucocorticoids were given. Recurrence was not observed during the 15-month clinical follow-up.

[Progress in the treatment of neuromyelitis optica spectrum disorders related optic neuritis]

Neuromyelitis optica spectrum disorders (NMOSD) related optic neuritis (NMOSD-ON) is a common neuro-ophthalmic disease which often results in permanent blindness. NMOSD is characterized by high recurrence rate and poor prognosis. Therefore the two key objectives of the therapeutic approach for patients with NMOSD are treatment of the acute attacks and prevention of the relapses. With the in-depth study of the pathogenesis of NMOSD, new treatments developed for different stages of the disease are emerging. This review gives an update of latest knowledge of NMOSD-ON, emphasizing both current and future therapeutic approaches. (Chin J Ophthalmol, 2020, 56: 539-543).

[Optic nerve subarachnoid space expansion in MR imaging: a etiology study]

Objective: To investigate spectrum of causes in optic nerve subarachnoid space (ONSS) expansion by using Magnetic Resonance Imaging (MRI). Methods: A retrospective study. Twenty-six patients (46 eyes) with ONSS expansion and 20 healthy adults (40 eyes) were recruited in Neuro-ophthalmology Department of Chinese PLA General Hospital from January, 2014 to December, 2015. The diameters were measured on the optic nerve (OND) and optic nerve sheath (ONSD) 2.4 mm behind the globe. ONSS was calculated by the formula of (ONSD-OND)/2. All participants were under went ophthalmologic examinations. The patients' clinical features, MRI and final diagnosis were analyzed. Qualitative data were compared between groups by using chi square test and quantitative data were compared by independent sample t test. Results: There was no statistically significant difference between ONSS group and control group with age, BMI and mean arterial blood pressure (P>0.05). Larger space was found in ONSS group with mean±standard deviation (SD) of (1.9±0.4) mm comparing to the control group with (1.2±0. 2) mm (t=2.879, P<0.01). Bilateral ONSS expansion were found in 20 patients, 15 patients (75%) with cerebral venous sinus thrombosis (CVST), 2 patients (10%) with neurosyphilis, 2 patients (10%) with peri-neuritis and 1 patient (5%) with hydrocephalus. Unilateral ONSS expansion were seen in 6 patients, 4 patients (66.7%) with compressive lesson on anterior visual pathway, 1 patient (16.7%) with fungal infection and 1 patient (16.7%) with peri-neuritis. Conclusions: The CVST patients more frequently presented bilateral ONSS expansion. Unilateral ONSS expansion may indicate compressive lesions located on the anterior visual pathway. (Chin J Ophthalmol, 2016, 52: 911-917).

[Clinical features of neurosyphilis with optic neuritis as an initial finding]

Objective: To study the characteristics of neurosyphilis with optic neuritis as an initial finding. Methods: Retrospective analysis of clinical data and laboratory testing results of 16 cases (27 eyes) with optic neuritis as an initial finding of neurosyphilis from October 2010 to March 2015 in General Hospital of People's Liberation Army was made. Results: Six-teen patients (12 males, 4 females) were collected, the median age of patients was 47 (range 33 to 65) years ,the mean age was (49.63±9.05) years. Treponema pallidum particle agglutination assay (TPPA) analysis was positive in all of the patients and rapid plasma reagin (RPR) test was positive in 14 patients (2 patients did not test). Lumbar puncture was requested and performed for all patients. Cerebrospinal fluid (CSF) TPPA analysis was positive in 16 patients and RPR test was positive in 12 patients. The CSF white blood cell counting increased in 9 (56.3%) patients and 10(62.5%)patients presented with increased CSF protein level. Both eyes were involved in 11 patients (68.8%). Relative afferent papillary defect was positive in 11 patients. Twenty-seven eyes were affected in 16 patients, and among them 7 eyes' pupil diameter were 2.5 mm or less. Incipient visual acuity was less than 0.1 in 22 eyes. The slit lamp examination showed vitreous opacity in 12 eyes and visible cells in 6 eyes among 27 eyes. Fundus examination found that 6 eyes had papillary edema and 15 eyes had pallordisc among 27eyes. Electro-retinogram (ERG) was tested in 24 eyes, and 18 eyes were abnormal. Visual evoked potential (VEP) were performed in 26 eyes (flash VEP in 22 eyes, pattern VEP in 4 eyes), and all were abnormal. Fourteen eyes were tested by 30-2 perimetry, and 6 eyes had diffuse visual field defect, 2 eyes had peripheral visual field defect, 4 eyes had quadrant defect and 2 eyes had center scotoma. Fundus fluorescence angiography was done in 16 eyes and choroidal hyper-fluorescent dots were found in posterior pole in 4 eyes. All patients were treated with antibiotic medicines, among them 10 cases in the General Hospital, and 6 cases in the other hospitals. During 15 months follow-up after discharge, visual acuity of 17 eyes recovered to 0.5 and above. Conclusion: Syphilitic optic neuritis is a condition that manifests with severe visual loss and tends to involve both eyes, Some patients have a smaller pupil diameter. Due to the particular infective routes of the disease, patients often conceal their sexual history. The manifestations of ocular syphilis are complicated and easy to misdiagnose or undiagnose. Clinical manifestations combining with the detailed history taking, serum and cerebrospinal fluid examination can guide to an accurate diagnosis and prevent from permanent vision loss. (Chin J Ophthalmol, 2016, 52: 898-904).

Magnetic resonance imaging retinal oximetry: a quantitative physiological biomarker for early diabetic retinopathy?

AIMS

To assess the efficacy of using magnetic resonance imaging measurements of retinal oxygenation response to detect early diabetic retinopathy in patients with Type 2 diabetes.

METHODS

Magnetic resonance imaging was conducted during 100% oxygen inhalation in patients with Type 2 diabetes with either no diabetic retinopathy (n = 12) or mild to moderate background diabetic retinopathy (n = 12), as well as in healthy control subjects (n = 12). Meanwhile, changes in retinal oxygenation response were measured.

RESULTS

In the healthy control group, levels of retinal oxygenation response increased slowly during 100% oxygen inhalation. In contrast, they increased more quickly and attained homeostasis much earlier in the groups with background diabetic retinopathy (at the 20-min time point) and with no diabetic retinopathy (at the 25-min time point) than in the healthy control group (at the 42-min time point). Furthermore, levels of retinal oxygenation response in the group with background diabetic retinopathy increased more than that of the group with no diabetic retinopathy, which in turn increased more than that of the healthy control group. There are statistically significant differences between the group with background diabetic retinopathy and the healthy control group at 6-, 8-, 10-, 15-, 20- and 25-min time points (P < 0.05). According to the normal range of the healthy control group by setting fundus photography results as 'gold standard' in our research, the sensitivity, specificity, positive predictive value, negative predictive value and receiver operating characteristic area for reporting the early indications of utility of diabetic retinopathy were 83.33%, 58.33%, 50%, 87.5% and 0.774, respectively.

CONCLUSIONS

The results indicate that magnetic resonance imaging is a potential screening method and probably a quantitative physiological biomarker to find early diabetic retinopathy in patients with Type 2 diabetes.

Facilitated sprouting in a peripheral nerve injury

During regeneration of injured peripheral nerves, local conditions may influence how regenerative axon sprouts emerge from parent axons. More extensive lesions might be expected to disrupt such growth. In this work, we discovered instead that long segmental crush injuries facilitate the growth and maturation of substantially more axon sprouts than do classical short crush injuries (20 mm length vs. 2 mm). At identical distances from the proximal site of axon interruption there was a 45% rise in the numbers of neurofilament labeled axons extending through a long segmental crush zone by 1 week. By 2 weeks, there was a 35% greater density of regenerating myelinated axons in long compared with short crush injuries just beyond (5 mm) the proximal injury site. Moreover, despite the larger numbers of axons, their maturity was identical and they were regular, parallel, associated with Schwann cells (SCs) and essentially indistinguishable between the injuries. Backlabeling with Fluorogold indicated that despite these differences, the axons arose from similar numbers of parent motor and sensory neurons. Neither injury was associated with ischemia. Both injuries were associated with rises in GFAP (glial acidic fibrillary protein) and p75 mRNAs, markers of SC plasticity but p75, GFAP and brain-derived neurotrophic factor mRNAs did not differ between the injuries. There was a higher local mRNA level of GAP43/B50 at 7 days following injury and a higher sonic hedgehog protein (Shh) mRNA at 24 h in long crush zones. GAP43/B50 protein and SHH protein both had prominent localization within regenerating axons. Long segmental nerve trunk crush injuries do not impair regeneration but instead generate greater axon plasticity that results in larger numbers of mature myelinated axons. The changes occur without apparent change in SC activation, overall nerve architecture or nerve blood flow. While the mechanism is uncertain, the findings indicate that manipulation of the nerve microenvironment can induce substantial changes in regenerative sprouting.

Insulin as an in vivo growth factor

Insulin peptide has been identified to promote regeneration of axons in culture and in some in vivo model systems. Such actions have been linked to direct actions of insulin, or to cross occupation of closely linked IGF-1 receptors. In this work, we examined insulin support of peripheral nerve regenerative events in mice. Systemic insulin administration accelerated the reinnervation of foot interosseous endplates by motor axons after sciatic nerve transection and enhanced recovery of functional mouse hindpaw function. Similarly, insulin accelerated the regeneration-related maturation of myelinated fibers regrowing beyond a sciatic nerve crush injury. That such benefits might occur through direct signaling on axons was supported by immunohistochemical studies of expression with an antibody directed to the beta insulin receptor (IR) subunit. The proportion of sensory neurons expressing IRbeta increased ipsilateral to a similar sciatic crush injury in the L4 and L5 dorsal root ganglia. Insulin receptors, although widely expressed in axons, were also preferentially and intensely expressed on axons regrowing just beyond a peripheral nerve crush injury zone. The findings indicate that insulin imparts a substantial impact on regenerating peripheral nerve axons through upregulation of its expression following injury. Although the findings do not exclude insulin coactivating IGF-1 receptors during regeneration, its own receptors are present and available for action on injured nerves.

Local sensory ganglion ischemia induced by endothelin vasoconstriction: vulnerability of diabetic neurons and microvessels

In some disorders of the peripheral nervous system, it is relevant to understand how sensory neurons respond to selective ganglion ischemia. Sensory dorsal root ganglia may be susceptible to ischemic damage and irretrievable neuron loss because of their metabolic requirements. In diabetes, heightened sensitivity to ischemia associated with elevated endothelin levels might render ganglia particularly vulnerable. In this work, we created a model of local sensory ganglion ischemia by generating intense local vasoconstriction from applied endothelin-1 (ET). In this model, we compared relative vulnerability of L5 ganglia microvessels and neurons to ET in streptozotocin-induced diabetic rats and nondiabetic controls. Diabetic ganglia had reductions in baseline core ganglion blood flow (GBF) measured using microelectrode hydrogen clearance polarography and ET induced particularly profound declines. Serial GBF measurements made using a laser Doppler flowmetry probe also indicated that diabetic ganglia exposed to ET had a marked prolongation in its action. Neuron perikarya and proximal axon segments were more vulnerable in diabetes. Neurons exhibited loss of neurofilament labeling, dissolution of the neurons, replacement of neurons with "nests of Nageotte," displacement of nuclei to the periphery of perikarya, and nuclear labeling with TUNEL. Both intraganglionic axons and downstream sural sensory axons developed evidence of axonal degeneration. Local endothelin-induced vasoconstriction of microvessels supplying dorsal root ganglia provides a selective model of ischemia. Diabetic vessels and neurons, exposed to a greater depth and duration of ischemia from endothelin, are especially vulnerable.