Optic chiasm involvement on MRI with ethambutol-induced bitemporal hemianopia.

While ethambutol optic neuropathy usually causes central or cecocentral scotomas, bitemporal visual field defects also have been reported. The pathogenesis of the bitemporal hemianopia has not been established. This article describes magnetic resonance imaging abnormalities involving the optic chiasm in a patient with bitemporal visual field loss. To our knowledge, these neuroimaging findings have not been previously described in association with ethambutol therapy.

[Bitemporal hemianopia as presenting sign of severe ethambutol toxicity]. / Hémianopsie bitemporale révélatrice d'une atteinte toxique sévère à l'éthambutol.

INTRODUCTION: Optic neuropathy is a severe and well-known complication of ethambutol treatment. If not detected early, it may lead to profound and irreversible vision loss. CASE REPORT: We report the case of a 83-year-old female patient, referred for rapidly progressive, painless, bilateral visual loss, unimproved after bilateral cataract surgery. Automated Humphrey 24-2 visual field demonstrated bitemporal hemianopia associated with bilateral central scotoma. Brain MRI did not demonstrate any compressive lesion in the chiasmal region. However, on T2-weighted sequences, an area of elevated signal intensity appeared within the optic chiasm, enhancing after gadolinium injection. On detailed history, it was noted that the patient had been on ethambutol for the last 18months, for the treatment of a Mycobacterium avium-related pneumonitis. DISCUSSION: The incidence of ethambutol-related toxic optic neuropathy has dramatically decreased since the recommendations for regular follow-up of patients treated with ethambutol. This treatment is classically responsible for bilateral central or ceco-central scotoma due to optic neuropathy, although a few cases of bitemporal hemianopia have been reported in the literature, mimicking a compressive chiasmal lesion. However, none of these cases demonstrated a hypersignal in the optic chiasm on brain magnetic resonance imaging (MRI). CONCLUSION: Bitemporal hemianopia on visual field testing is very suggestive of a chiasmal lesion, which is generally due to a compressive, or more rarely inflammatory, lesion in the sellar region. Toxic chiasmal lesions are rare, but in the absence of any tumoral lesion in the sellar area, a detailed history must be obtained in order to rule out drug toxicity, so as to prevent irreversible visual loss.

Unilateral contrast neurotoxicity as a stroke mimic after cerebral angiogram.

Contrast neurotoxicity (CN) following exposure to iodinated contrast is uncommon, and usually presents as cortical blindness due to bilateral occipital lobe involvement. Unilateral cortical dysfunction due to CN could mimic an acute stroke and has been rarely described. We report the case of an 89-year-old female who developed a transient dense/complete left homonymous-hemianopsia and left-sided tactile extinction after undergoing a right internal carotid (ICA) artery rotational angiogram with a standard high-volume iodinated contrast injection for 3D visualization a 6×4-mm right posterior communicating artery aneurysm with a fetal posterior cerebral artery (PCA) incorporated in the neck. This was associated with transient fullness and loss of gray-white matter differentiation in the right occipital and parietal lobes. The potential mechanism of CN in our case was the injection of a high volume of contrast in the ICA for the rotational angiogram. The presence of a right fetal PCA possibly allowed the contrast to reach the right occipital lobe. CN manifesting as an acute focal neurologic syndrome should be considered in the setting of recent iodinated contrast exposure.

[Hemicentral retinal artery occlusion due to oral contraceptives]. / Hemizentralarterienverschluss bei Einnahme der "Pille"--Mitteilungen über Komplikationen von Kontrazeptiva.

BACKGROUND: Low-dose oral contraceptives can still cause thromboembolic disorders with serious neurologic or ocular disabilities. PATIENT: A 22-year-old woman having used oral contraceptives for several months noticed sudden painless visual loss in her left eye. One tablet of her contraceptive contained ethinylestradiol (0.03 mg) and chlormadinonacetate (2 mg). RESULT: Because of the lower left eye visual field defect, the patient could only read with her right eye. She presented complete left inferior hemianopia, indicating a hemicentral retinal artery obstruction. Visual acuity in both eyes was 20 / 20. The left fundus revealed a distinct retinal edema in the area superior to the optic disc and macula due to vascular disturbances of the superior temporal superior and superior nasal retinal arteries. The right eye was normal. Fluorescein angiography revealed recanalized arteries in the superior retinal area with conspiciously early dye filling as a paradoxical sign. Doppler sonography of the neck and orbital arteries and transesophageal echocardiography (TEE) findings were inconspicious. However, blood examination revealed an elevated thrombin-antithrombin complex and reduced free protein S. CONCLUSION: Coagulopathy can be a side effect of oral contraceptives. Even nowadays, women taking contraceptives risk the danger of vascular occlusions especially if the women suffers from arterial hypertension, diabetes mellitus, have a coagulation anomaly, or if she is a chronic smoker. Before treatment with oral contraceptives commences, a thorough medical examination is necessary. If the family history reveals prominent cardiovascular risk factors, testing for thrombophilia is recommended. Even nowadays, patients should be warned of the risk of visual field defects as a potential side-effect associated with oral contraceptives.

Verbal commands help the execution of endogenous movements in anarchic hand.

Patients with anarchic hand (AH) syndrome exhibit involuntary but seemingly purposeful controlesional upper limb movements. Here we report on the case of a patient (AC) presenting with a right AH following a left medial frontal lesion. Previous literature indicated that endogenous movements, particularly in the presence of distractors, are impaired in AH, whereas exogenous movements are spared. In this study we examined exogenous and endogenous (or sequential) movements using a new experimental procedure. Our main aim was to investigate whether the ability to perform sequential movements improves under verbal command as anecdotally observed in patients with AH. Results showed that the performance of AC's right AH was impaired in sequential tasks and that this impairment was improved by verbal command. The observed reduction in errors in sequential tasks under external verbal command was coupled with a compensatory increase in response times.

Visual field defect as a presenting sign for hemorrhagic stroke caused by sildenafil.

Herein, we describe the presenting symptoms, history, ophthalmic examination, visual fields and brain magnetic resonance imaging of a patient who developed left homonymous hemianopia due to right occipital lobe hemorrhage after ingestion of sildenafil citrate (Novagra Forte). To the best of our knowledge, association of homonymous hemianopia with sildenafil usage has not been reported before.

Vigabatrin and epilepsy: lessons learned.

PURPOSE: The risk factors for visual field loss attributable to vigabatrin (VAVFL) are equivocal. This multinational, prospective, observational study aimed to clarify the principal/major factors for VAVFL. METHODS: Interim analysis of three groups with refractory partial epilepsy, stratified by age (8-12 years; >12 years) and exposure to vigabatrin (VGB). Group I comprised participants treated with VGB for >or=6 months, Group II participants previously treated with VGB for >or=6 months who had discontinued the drug for >or=6 months and Group III those never treated with VGB. Perimetry was undertaken at least every six months, for up to 36 months; results were evaluated masked to drug exposure. RESULTS: Based upon 563 participants in the locked data set, 432 yielded one or more Conclusive visual field examinations. For Group I, the frequency of VAVFL at the last Conclusive examination was 10/32 (31.2%) for those aged 8-12 years and 52/125 (41.6%) for those aged >12 years. For Group II, the proportions were 4/39 (10.3%) and 31/129 (24.0%). No cases resembling VAVFL manifested in Group III. VAVFL was associated with duration of VGB therapy (Odds ratio [OR] 14.2; 95% CI 5.0 to 40.5); mean dose of VGB (OR 8.5; 95% CI 2.2 to 33.2); and male gender (OR 2.1; 95% CI 1.2 to 3.7). VAVFL was more common with static than kinetic perimetry (OR 2.3, 95% CI 1.3 to 4.2). CONCLUSIONS: The therapeutic benefit of VGB is counteracted by the progressive accrual of the risk of VAVFL with continued exposure and with increase in mean dose.

Delayed neuropsychiatric syndrome in a child following carbon monoxide poisoning.

Here, we report the case of a five-year-old boy with carbonic monoxide (CO) poisoning. The patient initially recovered after the initiation of hyperbaric oxygen (HBO) therapy, but lethargy as well as visual and gait disturbances appeared two days later. Left hemiparesis and mood lability also subsequently appeared. Slow frontal activity was noted on electroencephalography, while fluid-attenuation inversion recovery and diffusion-weighted magnetic resonance imaging (MRI) revealed high signal-intensity lesions in the hippocampus and deeper layers of the occipital and frontal cerebral cortex. The neurological symptoms subsided gradually during the 10-day course of HBO therapy, but the left-hand paresis and quadrantic hemianopsia persisted, in association with impaired attention, slow mental processing, and incontinence. Lesions in the globus pallidum were noted on follow-up MRI at 14 days, and cortical lesions became evident as linear, low signal-intensity areas on T1-weighted imaging 4 months after presentation. Delayed neuropsychiatric syndrome in CO poisoning is rare in childhood, although children should be carefully monitored after CO exposure. The finding of cortical laminar necrosis in this patient is quite atypical in CO poisoning, and suggests a broader and previously nonpredicted pathomechanism in this condition.

[Severe ocular side effects with Topamax]. / Toxicidad oftalmológica severa por Topamax.

CASE REPORTS: We describe 2 patients who developed ocular side effects during treatment with topiramate. One was a 16-year-old woman with generalized seizures who developed a homonymous hemianopia after using topiramate 125 mg per day for 12 weeks, and the other was a 24-year-old epileptic female who developed a bilateral maculopathy after using topiramate 150 mg per day for 8 weeks. DISCUSSION: We identified two severe ocular adverse reactions from topiramate. Both reactions necessitated discontinuing the treatment, but the topiramate-associated maculopathy was irreversible.

Toxicidad oftalmológica severa por Topamax / Severe ocular side effects with Topamax

Caso clínico: Se describe una mujer de 16 años conepilepsia severa que desarrolló una hemianopsiahomónima izquierda después de tomar topiramato125 mg durante 12 semanas y una mujer epilépticade 24 años que presentó una maculopatía bilateraldespués de tomar 150 mg de topiramato durante 8semanas.Discusión: Se identifican dos reacciones ocularesadversas al topiramato. Ambas precisan retirar eltratamiento, aunque la maculopatía por topiramatoes irreversible

Case reports: We describe 2 patients who developed ;;ocular side effects during treatment with topiramate. ;;One was a 16-year-old woman with generalized ;;seizures who developed a homonymous hemianopia ;;after using topiramate 125 mg per day for 12 ;;weeks, and the other was a 24-year-old epileptic ;;female who developed a bilateral maculopathy after ;;using topiramate 150 mg per day for 8 weeks. ;;Discussion: We identified two severe ocular adverse ;;reactions from topiramate. Both reactions necessitated ;;discontinuing the treatment, but the topiramate- ;;associated maculopathy was irreversible

Ethambutol-associated optic neuropathy.

INTRODUCTION: Ethambutol is used in the treatment of tuberculosis, which is still prevalent in Southeast Asia, and can be associated with permanent visual loss. We report 3 cases which presented with bitemporal hemianopia. CLINICAL PICTURE: Three patients with ethambutol-associated toxic optic neuropathy are described. All 3 patients had loss of central visual acuity, colour vision (Ishihara) and visual field. The visual field loss had a bitemporal flavour, suggesting involvement of the optic chiasm. TREATMENT: Despite stopping ethambutol on diagnosis, visual function continued to deteriorate for a few months. Subsequent improvement was mild in 2 cases. In the third case, visual acuity and colour vision normalised but the optic discs were pale. OUTCOME: All 3 patients had some permanent loss of visual function. CONCLUSIONS: Ethambutol usage is associated with permanent visual loss and should be avoided if possible or used with caution and proper ophthalmological follow-up. The author postulates that in cases of ethambutol associated chiasmopathy, ethambutol may initially affect the optic nerves and subsequently progress to involve the optic chiasm.

Methanol poisoning--case report.

The aim of this paper is to present a case of 46-yr-old man, poisoned with methanol, treated with ethanol and haemodialysis. According to history, he was alcoholic, but without any others complaints, except mild hypertension. During the clinical course of methanol poisoning ECG revealed pathological Q wave and ST segment elevation in leads II, III, aVF, without increased cardiac enzymes activity. As a sequel of acute methanol poisoning irreversible bitemporal loss of vision was confirmed four months after poisoning. Cardiologic examination at the same time confirmed past acute coronary episode.

Delayed ischemic stroke associated with methamphetamine use.

A 19-year-old woman had right occipital infarction 3 months after she had injected methamphetamine. No other possible causes of stroke could be found in this case. Magnetic resonance angiography revealed beading of the right posterior cerebral artery, which suggested vasculitis. Her symptoms were right-sided headache, left superior quadrant hemianopia, and left hypesthesia, which gradually improved without any treatment. Methamphetamine has been known to cause hemorrhagic and ischemic stroke relatively soon after administration. We report here that methamphetamine may also cause chronic cerebral vasculitis and delayed ischemic stroke.