Toxic optic neuropathy

A Case of Syphilis with a Rare Finding: Subretinal Hypopyon

PURPOSE

To report clinical features and follow-up of a case with subretinal hypopyon due to syphilis infection.

CASE PRESENTATION

We present a case of syphilis admitted with optic neuritis and treated with intravenous pulse steroids without antibiotics. The patient was referred to the uvea clinic in the follow-up because of decreased vision and the onset of multiple retinitis foci. We determined subretinal hypopyon in the left eye and a positive TPHA test. A significant regression was observed in retinitis and hypopyon with antibiotic therapy.

CONCLUSION

Before starting a steroid treatment, infective etiologies should be considered in patients with optic neuritis. Treating with a high dosage of steroids without antibiotics in syphilis would worsen the clinical features and prognosis.

Toxic and Nutritional Optic Neuropathies—An Updated Mini-Review

Optic neuropathies constitute a group of conditions with various etiologies and might be caused by different factors; we can distinguish the genetic and acquired causes of optic neuropathies. Even though the symptoms are not highly specific, this condition is primarily characterized by unilateral or bilateral vision loss with worsening color detection. The loss may be acute or gradual depending on the causation. In this article, we included a specification of toxic optic neuropathy (TON) mainly triggered by alcohol abuse and also the usage of other substances, including drugs or methanol, as well as intoxication by metals, organic solvents, or carbon dioxide. Nutritional deficiencies, vitamin absorption disorder, and anemia, which usually appear during excessive alcohol intake, and their effect on the etiology of the optic neuropathy have been likewise discussed.

Early-Onset Alcohol Dependence and Multiple Sclerosis: Diagnostic Challenges

Multiple sclerosis (MS) is an inflammatory demyelinating disorder characterized by the progressive disruption of the myelin sheath around the nerve fibres. The early initiation of disease-modifying treatments is crucial for preventing disease progression and neurological damage. Unfortunately, a diagnostic delay of several years is not uncommon, particularly in the presence of physical and mental comorbidities. Among psychiatric comorbidities, the role of alcohol misuse is still under debate. In this paper, we discuss a case of early-onset alcohol dependence and its possible role in delaying the initiation of a specific therapy for MS. The differential diagnosis between idiopathic and secondary neurodegenerative disorders is often challenging. When dealing with patients reporting an early-onset substance abuse (likely to present organic damage), clinicians may be prone to formulate a diagnosis of secondary neuropathy, particularly when facing non-specific symptoms. This case report highlights the need for in-depth medical investigations (including imaging) in the presence of neurological signs suggesting a damage of the central nervous system, prompting a differential diagnosis between idiopathic and secondary neurodegenerative conditions. Indeed, a timely diagnosis is crucial for the initiation of specific therapies positively affecting the outcome.

Alcohol and the Eye

In this article, we present a review of ocular conditions related to alcohol consumption. A search of the literature published from 1952 to March 2020 was performed. The titles and abstracts were screened and the eligible studies were selected. PubMed, ISI Web of Knowledge database, Scopus, Embase, and the Cochrane Library were searched. We categorized the relationship between alcohol intake and ocular conditions by the type of ocular exposure to alcohol. Accordingly, ocular findings following acute alcohol intoxication, optic neuropathy following methanol toxicity, congenital conditions related to maternal alcohol consumption, and ocular disease related to chronic alcoholism are discussed. The main feature of alcohol intoxication in the eye is abnormal eye movement. Acute optic neuropathy secondary to methyl alcohol consumption is a serious ocular disease with permanent vision loss or scotoma. Prenatal exposure to ethanol may end in fetal alcohol spectrum disease, where ocular findings are a constant component. The association between chronic alcohol consumption and increased risks of cataract, age-related macular degeneration, diabetic retinopathy, different types of optic neuropathy, impairment of visual quality, retinal vascular disease, and ocular surface disease has also been reported. Along with detrimental medical and social effects, the role of alcohol consumption in different ocular conditions should be considered, as alcohol-induced visual disturbances may contribute to the heavy burden of alcohol abuse on the healthcare system and overall quality of life.

[Chorioretinal atrophy in pediatric cerebral folate deficiency-a preventable disease?]

Cerebral folate deficiency (CFD) results in neurological alterations and a massive degeneration of the choroid/retina if left untreated, which limit the visual field and visual acuity. This article reports the case of a female patient with CFD, who developed autistic personal characteristics prior to reaching school age and first started to speak at the age of 3 years. At the age of 6 years she was presented because of unclear reduced visual acuity in the right eye. At that time mild bilateral peripheral chorioretinal atrophy was present, which subsequently became more pronounced. Additionally, a centrally emphasized chorioretinal atrophy further developed. Visual acuity of both eyes progressively deteriorated until stagnating at 0.1 at the age of 14 years. The causal assignment of the findings of the patient was not possible for many years. Choroideremia was excluded by molecular genetic testing (CHM gene with no mutations) and gyrate atrophy was ruled out by a normal ornithine level. The existence of a mitochondrial disease was almost completely excluded by exome sequencing. After the onset of further nonocular symptoms, e.g. neuromuscular disorders, electroencephalograph (EEG) alterations and autistic disorder, intensified laboratory diagnostics were performed in the treating pediatric hospital. Finally, an extremely low level of the folic acid metabolite 5‑methyltetrahydrofolate was detected in the cerebrospinal fluid (CSF) leading to the diagnosis of CFD. High-dose substitution treatment with folic acid was subsequently initiated. After excluding the presence of a pathogenic mutation of the FOLR1 gene for the cerebral folate receptor 1, a high titer blocking autoantibody against cerebral folate receptor 1 was detected as the cause.

Linezolid-Induced Toxic Optic Neuropathy

To report a case of linezolid-induced toxic optic neuropathy. Clinical examination and imaging are presented over a 4-month interval from initial presentation to subsequent follow-up of 4 months after discontinuation of linezolid. The patient was found to have optic neuropathy as demonstrated by clinical presentation and examination. Upon discontinuation of linezolid, the patient's visual acuity, visual fields, and color vision significantly improved. Linezolid has previously been reported to cause toxic optic neuropathy and retinopathy. We hereby describe a tuberculosis patient with linezolid-associated toxic optic neuropathy. Our report aims to describe the ocular side effects of linezolid use to enhance awareness.

Optic Nerve Degeneration and Reduced Contrast Sensitivity Due to Folic Acid Deficiency: A Behavioral and Electrophysiological Study in Rhesus Monkeys

Purpose

The purpose of the research was to elucidate the role of folic acid (B9) deficiency in the development of nutritional optic neuritis and to characterize the neurophysiological consequences of optic nerve degeneration in the cortical visual system.

Methods

A combined behavioral and electrophysiological approach was applied to study luminance contrast sensitivity in two macaque monkeys affected by nutritional optic neuritis and in two healthy monkeys for comparison. For one monkey, a follow-up approach was applied to compare visual performance before onset of optic neuropathy, during the disease, and after treatment.

Results

Optic nerve degeneration developed as a consequence of insufficient dietary intake of folic acid in two exemplars of macaque monkeys. The degeneration resulted in markedly reduced luminance contrast sensitivity as assessed behaviorally. In one monkey, we also measured visual activity in response to varying contrast at the level of single neurons in the cortical visual system and found a striking reduction in contrast sensitivity, as well as a marked increase in the latency of neuronal responses. Prolonged daily folate supplementation resulted in a significant recovery of function.

Conclusions

Folic acid deficiency per se can lead to the development of optic nerve degeneration in otherwise healthy adult animals. The optic nerve degeneration strongly affects contrast sensitivity and leads to a distinct reduction in the strength and velocity of the incoming signal to cortical visual areas of the macaque brain, without directly affecting excitability and functional properties of cortical neurons.

Ethambutol toxic optic neuropathy: A case report and review

This article presents a case of ethambutol toxic optic neuropathy determined during the routine optometric examination of a 66-year-old man. Ethambutol is an established drug for the treatment of tuberculosis, but has significant side effects, notably optic neuropathy. The prognosis for vision restoration is unpredictable, with the possibility of permanent vision loss. Treatment cessation is the only option to limit ocular damage; therefore, the early recognition of ethambutol optic neuropathy by optometrists is essential.

Sibling Ethambutol Optic Chiasmopathy

Ethambutol is utilised in the treatment of Mycobacterium avium and Mycobacterium tuberculosis infection. The authors report two siblings who developed the adverse effect of ethambutol-induced optic chiasmopathy, with recovery following cessation of ethambutol. Discussion explores potential genetic predisposition to development of this condition and its resolution. Ethambutol optic neuropathy (EON), Leber's hereditary optic neuropathy (LHON), and other optic neuropathies of mitochondrial origin share a common pathophysiology. Consequently, the authors postulate treatments utilised in LHON, including vitamin B supplementation and idebenone, may have benefit in EON. This article presents concepts for further research, suggesting a potential genetic susceptibility to EON and its treatment.

Pathological Confirmation of Optic Neuropathy in Familial Dysautonomia

Clinical data suggest that optic neuropathy and retinal ganglion cell loss are the main cause of visual decline in patients with familial dysautonomia, but this has not previously been confirmed by pathological analyses. We studied retinas and optic nerves in 6 eyes from 3 affected patients obtained at autopsy. Analyses included routine neurohistology and immunohistochemistry for neurofilaments, cytochrome c oxidase (COX), and melanopsin-containing ganglion cells. We observed profound axon loss in the temporal portions of optic nerves with relative preservation in the nasal portions; this correlated with clinical and optical coherence tomography findings in 1 patient. Retinal ganglion cell layers were markedly reduced in the central retina, whereas melanopsin-containing ganglion cells were relatively spared. COX staining was reduced in the temporal portions of the optic nerve indicating reduced mitochondrial density. Axonal swelling with degenerating lysosomes and mitochondria were observed by electron microscopy. These findings support the concept that there is a specific optic neuropathy and retinopathy in patients with familial dysautonomia similar to that seen in other optic neuropathies with mitochondrial dysfunction. This raises the possibility that defective expression of the IkB kinase complex-associated protein (IKAP) resulting from mutations in IKBKAP affects mitochondrial function in the metabolism-dependent retinal parvocellular ganglion cells in this condition.

Optic pathway degeneration in Japanese black cattle

Degeneration of the optic pathway has been reported in various animal species including cattle. We experienced a case of bilateral optic tract degeneration characterized by severe gliosis in a Japanese black cattle without any obvious visual defects. To evaluate the significance, pathological nature and pathogenesis of the lesions, we examined the optic pathway in 60 cattle (41 Japanese black, 13 Holstein and 6 crossbreed) with or without ocular abnormalities. None of these animals had optic canal stenosis. Degenerative changes with severe gliosis in the optic pathway, which includes the optic nerve, optic chiasm and optic tract, were only observed in 8 Japanese black cattle with or without ocular abnormalities. Furthermore, strong immunoreactivity of glial fibrillary acidic protein was observed in the retinal stratum opticum and ganglion cell layer in all 5 cattle in which the optic pathway lesions could be examined. As etiological research, we also examined whether the concentrations of vitamin A and vitamin B12 or bovine viral diarrhea virus (BVDV) infection was associated with optic pathway degeneration. However, our results suggested that the observed optic pathway degeneration was probably not caused by these factors. These facts indicate the presence of optic pathway degeneration characterized by severe gliosis that has never been reported in cattle without bilateral compressive lesions in the optic pathway or bilateral severe retinal atrophy.

Selective retinal ganglion cell loss in familial dysautonomia

To define the retinal phenotype of subjects with familial dysautonomia (FD). A cross-sectional study was carried out in 90 subjects divided in three groups of 30 each (FD subjects, asymptomatic carriers and controls). The study was developed at the Dysautonomia Center, New York University Medical Center. All subjects underwent spectral domain optical coherence tomography (OCT) and full neuro-ophthalmic examinations. In a subset of affected subjects, visual evoked potentials and microperimetry were also obtained. We compared the retinal nerve fiber layer (RNFL) thickness from OCT between the three groups. OCT showed loss of the RNFL in all FD subjects predominantly in the maculopapillary region (63 % temporally, p < 0.0001; and 21 % nasally, p < 0.005). RNFL loss was greatest in older FD subjects and was associated with decreased visual acuity and color vision, central visual field defects, temporal optic nerve pallor, and delayed visual evoked potentials. Asymptomatic carriers of the FD gene mutation all had thinner RNFL (12 % globally, p < 0.005). OCT and clinical neuro-ophthalmological findings suggest that maculopapillary ganglion cells are primarily affected in FD subjects, leading to a specific optic nerve damage that closely resembles mitochondrial optic neuropathies. This raises the possibility that reduced IKAP levels may affect mitochondrial proteins and their function in the nervous system, particularly in the retina.

Tobacco-alcohol amblyopia: A rare complication of prolonged alcohol abuse

Tobacco-alcohol amblyopia is rare, however, extremely disabling complication seen in patient with alcohol dependence syndrome, which if not addressed properly and at the right time may lead to persisting deficits. We here report a patient of alcohol-dependence syndrome who presented with significant diminution of vision bilaterally in the background of excess alcohol consumption.

The effect of smoking on the symptoms and progression of multiple sclerosis: a review

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disorder of the central nervous system with characteristic demyelinating lesions and axonal loss. MS accounts for the most common cause of neurological disability in young adults in the Western world. The clinical manifestations and the course of MS are highly variable. The early stage of the disease is usually characterized by attacks of neurological dysfunction with complete or incomplete recovery, however, with time disability accumulates in many patients. MS is believed to result from an interplay between susceptibility genes and environmental factors, one of which is smoking. Smoking, a worldwide epidemic, can be regarded as an important risk factor for MS particularly because of its modifiable nature in the quest to prevent or temper the disease course in MS as well as providing possible insights into MS pathogenesis. There are also reports that smoking may influence the symptoms and disease progression in patients with MS. The purpose of this article is to review the effects of smoking on MS symptoms and progression. We conclude that (1) although there are some early reports on worsening of MS symptoms by smoking, the existing evidence is insufficient to thoroughly assess the effects of smoking on the myriad of MS symptoms and (2) smoking seems to adversely influence disease progression in MS patients. We also discuss the potential biological mechanisms linking smoking and MS.

Folic acid deficiency optic neuropathy: a case report

Introduction

Nutritional optic neuropathies are uncommon and can be associated with gradual visual loss and optic atrophy or sudden vision loss and optic disc swelling.

Case presentation

A 44-year-old woman presented with a 4-week history of progressive visual loss and was noted to have bilateral retrobulbar optic neuropathy. No other clinical abnormality was noted. Investigations revealed severe folate deficiency with normal vitamin B12 levels. Her alcohol and tobacco consumption was moderate and subsequent correction of folate levels with oral supplementation has led to improvement in her visual acuity.

Conclusion

This case highlights an unusual presentation of folic acid deficiency that may present to the general physician.

Nutritional optic neuropathies

Nutritional deficiency may be the cause of a genuine optic neuropathy, sometimes associated with involvement of the peripheral nervous system. Nutritional optic neuropathies are usually bilateral, painless, chronic, insidious and slowly progressive. Most often, they present as a non-specific retrobulbar optic neuropathy. The differential diagnosis with other causes of optic nerve involvement, in particular of toxic origin, may be particularly difficult. Nutritional deficits are often associated with toxic effects from alcohol and tobacco; therefore, the separation of the nutritional and toxic components is often illusory and artificial. The pathophysiological mechanisms involved in nutritional -- and toxic -- optic neuropathies affect biochemical pathways involved in cell energetic production, correction of oxidative stress and quenching of free radicals. The recognition of these mechanisms could provide future therapeutic alternatives. Currently, the treatment is limited to the intensive use of vitamins with variable results in individual cases, and to the implementation of preventive measures, when feasible.

Ciprofloxacin-induced toxic optic neuropathy

A case of bilateral toxic optic neuropathy that developed in the setting of prolonged oral ciprofloxacin use for the treatment of chronic osteomyelitis is described. The patient experienced progressive, bilateral and symmetrical visual loss, central scotomas and loss of colour vision over a 2-month period. The visual symptoms improved immediately upon cessation of ciprofloxacin with a gradual and near complete recovery over several years.

Optic neuropathy related to hydrogen peroxide inhalation

Optic neuropathy related to toxins is a complex, multifactorial disease potentially affecting individuals of all ages. We report a case of presumed toxic optic neuropathy secondary to H2O2 exposure. This has not been previously reported, and the temporal relationship of the exposure to the optic neuropathy is compelling, although not definite, evidence of a causal relationship.