Neuropatia óptica tóxica por inalação de metanol / Optic neuropathy toxic after methanol inhalation

Resumo A intoxicação por metanol é um evento considerado raro, principalmente quando feita por via inalatória. Retratou-se neste presente estudo um relato de caso de um paciente que desenvolveu neurite óptica tóxica após exposição ao metanol e ácido acético por via inalatória em seu ambiente de trabalho. Foi descrito sobre as terapias obtidas na literatura, bem como as manifestações clínicas e o manejo a este paciente.

Abstract The methanol toxicity is considered rare event , especially when taken by inhalation . It was portrayed in the present study a case report of a patient who developed toxic optic neuritis after exposure to methanol and acetic acid by inhalation in the workplace . It was described for the therapies from the literature as well as the clinical manifestations and management in this patient.

Optic neuritis due to immunobiologics: first Brazilian case report / Neurite optica por imunobiologico: relato do primeiro caso brasileiro

The change in immunological response obtained by immunobiologics has brought a new paradigm to the treatment of immune-mediated disorders. As a result of their efficacy, there is a positive impact on the quality of life of patients. However, severe side effects, such as demyelination of cerebral or peripheral nerves, have been reported. After review of literature using PubMed and MEDLINE data from 2000 to 2012, we identified the cases correlating the biological uniterms and optic neuritis. This article reports the first Brazilian optic neuritis case associated with the use of immunobiologics. This publication is justified by the rarity of the disease and atypical therapeutical evolution.

A mudança da resposta imunológica, obtida pelos imunobiológicos, trouxe um novo paradigma no tratamento das doenças imuno-mediadas. Pela sua eficácia, trazem impacto positivo na qualidade de vida dos pacientes. Entretanto, efeitos colaterais graves, como desmielinização cerebral ou nos nervos periféricos, foram relatados. Após revisão da literatura usando o banco de dados do PubMed e da MEDLINE de 2000 a 2012, identificamos os casos correlacionando os unitermos biológicos e neurite óptica. Este artigo relata o primeiro caso brasileiro de neurite óptica associado ao uso de imunobiológico. Justifica-se esta publicação pela raridade e pela evolução terapêutica atípica.

Efficacy of PS-VEPS in the detection of subclinical optic neuritis following ethambutol in therapeutic dosage

Ethambutol is an antimicrobial agent used frequently to treat tuberculosis. The most commonly recognized toxic effect of ethambutol is optic neuropathy, which may sometime result in irreversible vision loss. However, early recognition not only prevents this complication, it also increases compliance of the drug. This study was carried out to assess the usefulness of pattern-shift visual evoked potentials [PS-VEPs] in the detection of sub clinical optic neuropathy in patients on ethambutol for the treatment of tuberculosis in the recommended dosage. 30 consecutive patients of tuberculosis were studied before and after two months of ethambutol therapy. Ethambutol was administered in the WHO recommended dosage of 15mg/kg of body weight. All the patients underwent pattern shift visual evoked potential tests, which check the function of the visual pathway from the retina to the occipital cortex. PS-VEP abnormalities were seen in 5 patients [16.7%],out of which prolonged latency was documented in 3 patients [10%],increased latency difference was seen in 1 patient [3.3%] and abnormal amplitude difference was reported in 1 patient [3.3%].Associated psychophysical abnormalities of visual acuity in 2 patients [6.7%] and color vision abnormality in 1 patient [3.3%] were also seen. Our study confirms that during the treatment with ethambutol, PS-VEPs may reveal a surprisingly high percentage of sub clinical optic neuritis even at dosages considered to be safe. This needs attention in terms of patient care and drug compliance

Ocular side effects of antitubercular drugs - a focus on prevention, early detection and management.

Given the increasing prevalence of tuberculosis, antitubercular drugs frequently used are also associated with ocular toxicity. Ethambutol is the most commonly implicated drug. It is generally well tolerated, but known to cause optic neuritis, more specifically retro bulbar neuritis causing blurred vision, decreased visual acuity, central scotomas, and loss of red-green color vision. The exact mechanism of toxicity is not understood. Though optic neuritis due to ethmabutol is generally considered to be reversible upon prompt discontinuation of the drug, there are reports of reversible toxicity, particularly in the elderly population. Isoniazid can rarely cause retro bulbar neuritis. Dose relationship is usually not seen. Streptomycin is known to cause pseudo tumorcerebri. Thiacetazone can produce severe cutaneous reactions including Steven Johnson Syndrome affecting the skin and mucosa including conjunctiva. Educating the patients for early detection of the ocular manifestations and regular follow-ups are very essential.

Neuritis retrobulbar inducida por amiodarona: caso clínico / Amiodarone induced retrobulbar neuritis: report of 1 case

We report a 66 years old male, with an ophtalmologic history of long sightedness, admitted to the hospital due to paroxysmal atrial fibrillation crises in the context of a coronary heart disease. He was treated with iv amiodarone, receiving a total dose of 6 g in 72 hours. After the third day of treatment, the patient noticed a correction of his long sightedness and 24 h later, he complained of blurred vision and orbital frontal headache. Visual field examination revealed a concentric retraction of visual field and a centrocecal scotoma in both eyes. Amiodarone was withdrawn and dexametasone treatment was begun. Three days after amiodarone discontinuation, sight improved and visual field returned to normal. Although retrobulbar neuritis has been associated to various drugs, amiodarone has not been considered as a possible agent

Visual evoked responses in ethambutol induced optic neuritis.

Pattern evoked responses were recorded in 46 patients of tuberculosis on ethambutol and 16 healthy subjects. Deterioration in visual acuity was documented in two patients (4.3%). P100 latency was delayed in 16 cases (34.8%), while in 12 patients (26.1%) both latency and amplitude were affected. A cut off latency value of > or = 140 ms was associated with ophthalmological findings. The incidence of subclinical toxicity as detected by visual evoked response (VER) was higher in older subjects, patients on higher doses of ethambutol (> or = 20 mg/kg/day) and longer duration of treatment. Of two cases with objective ocular signs, one who reported for follow up after two months had recovered completely after stopping ethambutol. Recording of VER is an extremely useful objective test for subclinical optic nerve damage.

Visual evoked responses in tuberculous children on ethambutol therapy.

Visual evoked responses (VERs) were recorded in 47 children, aged 3-13 years with tuberculosis, treated with ethambutol (20 mg/kg/day) as a part of the antitubercular regimen. VERs were evoked by monocular whole field stimulation, the stimulus being provided by a black and white checker-board pattern reversed every 560 msec and recorded before the commencement, 2, 4, 6, 9 and 12 months of therapy and between 3 to 6 months after stopping the drug. In the first 6 months of therapy the mean values of latency ranged from 92.8 to 101.3 msec in the 3 to less than 6 years age group and 88.5 to 100.3 msec in children 6-13 years of age. Between 6-12 months of therapy the mean values of latency were between 93.3 to 101.0 msec in the 3 to less than 6 years age group and 96.0 to 101.5 msec in the older group. Between 3-6 months after stopping therapy the means of latency ranged from 92 to 96 msec. The differences were not statistically significant at any point of time. Thus, children do not seem to be at greater risk for developing ethambutol inducted optic damage as compared to adults. Ethambutol in the above stated dose may, therefore, be recommended for inclusion in antitubercular chemotherapy in pediatrics without undue fear of subclinical toxicity.

Atrofia óptica pós-neurite induzida pelo etambutol, isoniazida e drogas correlatas / Optic atrophy induced by Ethambutol isoniazid and others drugs

O autor apresenta um caso de uso de drogas anti-microbianas usadas na quimioterapia da tuberculose que levou a uma atrofia óptica pós-neurite em ambos os olhos em uma paciente de 58 anos, do sexo feminino, branca, natural de Alegrete, RS

Ethambutol toxic neuroretinopathy in Bangladesh

Ethambutol is considered to have a relative lack of toxicity. In Bangladesh, out of a total of 350 patients receiving ethambutol [25 mg to 35 mg/kg daily] for tuberculosis, 20 [5.71%] developed neuroretinal toxicity. Ten [50%] of these patients had peripheral, four [20%] central, and six [30%] mixed visual field defects. Thirteen [65%] patients recovered, with or without additional treatment, after ethambutol was stopped, but seven [35%] had irreversible damage. In several of the patients who recovered, the visual improvement began only when hydroxycobalamin was administered following the discontinuation of ethambutol. One woman mistakenly received cyanocobalamin instead of hydroxycobalamin, leading to optic atrophy and an irreversible visual loss in her. We would like to warn against the use of cyanocobalamin in patients on ethambutol