Transient Blindness Research Articles

8158 Transient Blindness In Metformin-Associated Lactic Acidosis

Abstract Disclosure: Y. Abouelkheer: None. A. Nasir: None. M. Ibrahem: None. Transient Blindness in Metformin-associated Lactic Acidosis Background: Metformin-associated lactic acidosis (MALA) is a rare side effect of metformin use. MALA can result in acute transient blindness in patients with severe metabolic derangements. Clinical Case: A 62-year-old woman presented with severe diarrhea, poor oral intake, malaise, and vomiting on a background of metformin-treated type 2 diabetes mellitus. Laboratory investigations showed bicarbonate <2 mmol/L, anion gap 48 mmol/L, lactic acid 20.5 mmol/L, serum osmolality 352 mOsm/kg, negative urine toxicology screen, and positive SARS-CoV-2. In the emergency department, the patient developed sudden onset bilateral vision loss. The examination was remarkable for complete vision loss bilaterally in all fields, associated with minimally reactive pupils and spontaneous ocular movements with an otherwise unrevealing neurological examination. Computed Tomography (CT) of the brain with stroke protocol showed no evidence of acute intracranial process. CT angiogram of the brain and neck showed patent intracranial and cervical vasculature without high-grade stenosis, large vessel occlusion, or aneurysm. While receiving medical management with intravenous fluid resuscitation and sodium bicarbonate supplementation, the patient had a spontaneous return of vision with no additional neurological complications or deficits. The severe metabolic derangements were associated with distributive shock, requiring admission to the intensive care unit for urgent hemodialysis, pressor support, empiric antibiotics, and stress-dose steroids. Shortly after the patient’s only hemodialysis session, we noted the resolution of her critical metabolic disturbances, renal failure, and shock state. Laboratory investigations post-dialysis showed bicarbonate 12 mmol/L, anion gap 36 mmol/L, and lactic acid 10.5 mmol/L. Follow-up MRI showed chronic lacunar infarct of the left basal ganglia, and she was discharged home six days later. Conclusion: Transient blindness in MALA can mimic acute neurovascular events. Prompt correction of metabolic derangements can aid in reversing systemic symptoms and blindness. Reference: DeFronzo R, Fleming GA, Chen K, Bicsak TA. Metformin-associated lactic acidosis: Current perspectives on causes and risk. Metabolism. 2016;65(2):20-29. doi:10.1016/j.metabol.2015.10.014 Presentation: 6/2/2024

Postural control depends on early visual experience.

The present study investigated the role of early visual experience in the development of postural control (balance) and locomotion (gait). In a cross-sectional design, balance and gait were assessed in 59 participants (ages 7-43 years) with a history of (a) transient congenital blindness, (b) transient late-onset blindness, (c) permanent congenitally blindness, or (d) permanent late-onset blindness, as well as in normally sighted controls. Cataract-reversal participants who experienced a transient phase of blindness and gained sight through cataract removal surgery showed worse balance performance compared with sighted controls even when tested with eyes closed. Individuals with reversed congenital cataracts performed worse than individuals with reversed developmental (late emerging) cataracts. Balance performance in congenitally cataract-reversal participants when tested with eyes closed was not significantly different from that in permanently blind participants. In contrast, their gait parameters did not differ significantly from those of sighted controls. The present findings highlight both the need for visual calibration of proprioceptive and vestibular systems and the crossmodal adaptability of locomotor functions.

Recurrent Transient Nocturnal Blindness Caused by Forceful Eye Rubbing Parasomnia.

Recurrent Transient Nocturnal Blindness Caused by Forceful Eye Rubbing Parasomnia.

Transient smartphone blindness: A digital lifestyle related physiological phenomenon

Transient smartphone blindness: A digital lifestyle related physiological phenomenon

Retraction: "Sudden transient blindness following ureteroscopy: an uncommon complication of a common procedure (a case report) (Pan African Medical Journal. 2024;47:201. doi: 10.11604/pamj.2024.47.201.42952)".

[This retracts the article DOI: 10.11604/pamj.2024.47.201.42952.].

Diagnosis and management of transient smartphone blindness: A literature review

The development of smartphones worldwide has rapidly increased the number of smartphone users. Although smartphones have many benefits, prolonged use causes various visual disorders, of which transient smartphone blindness (TSB) is one of the most important concerns. This study aims to analyse the phenomenon of TSB and explore its etiology, pathophysiology, symptoms, and examination to determine the diagnosis and management. Transient smartphone blindness is a new physiologic phenomenon caused by exposure to a certain level of smartphone bright light and the body posture of the smartphone user. It leads to the use of monocular vision to stare at the smartphone. By exploring recent literature, this study found that patients with TSB experienced retinal photopigment bleaching, which decreased light sensitivity. Typically, the sensitivity returned physiologically after several minutes. Patients with this blindness showed several symptoms. For example, they perceived shapes, outlines, or figures during the blackout. The diagnosis of TSB should be primarily based on a detailed history of smartphone use, with the differential diagnosis based on circumstance or occurrence. This diagnosis is useful to distinguish it from transient ischemic attack (TIA). Transient smartphone blindness is a basic monocular transient loss that does not require therapy or drugs. However, it was found that the reassurance of patients’ condition and suggestions on smartphone use were sufficient for the intervention. With a limited scientific study of TSB, this review is the first to raise the discussion topic. It is expected to help physicians to diagnose TSB significantly. In addition, this study will enrich the literature, particularly on the scientific and clinical mechanisms of recognising TSB for clinical diagnosis and management.

Ondansetron induced blindness: a pharmacovigilance database study

ABSTRACT Background Ondansetron is an antiemetic drug (AED) used to prevent and treat nausea and vomiting. The summary of product characteristics reports a rare risk of transient blindness primarily during IV injections, notably with the concomitant use of chemotherapeutic agents. We aimed to refine the characterization of ondansetron-induced blindness. Research design and methods We performed a descriptive and a case/non-case analysis using VigiBase®. Cases were defined as reports of adverse drug reactions (ADRs) related to blindness: amaurosis, amaurosis fugax, blindness. Non-cases were all other recorded reactions. Reporting risk of blindness-related ADRs was assessed using a disproportionality analysis and expressed as Reporting Odds Ratios (ROR). Results 138,315 ADRs were reported with AEDs, including 136 blindness-related ADRs, among them 44 (32.4%) with ondansetron. For ondansetron users, blindness-related ADRs occurred mainly on the first day. Out of the 25 patients with known outcomes, 18 (72.0%) were recovering or had recovered, 7 (28.0%) patients had not recovered There were no statistical differences in the number of cases for IV or oral users and for users or not of chemotherapeutic agents. Compared with other AEDs, ondansetron was associated with an increase in the reporting risk of blindness-related ADRs (ROR = 4.00 [2.79–5.72], p < 0.001). Conclusions Rarely blindness can occur following intravenous or oral administration of ondansetron.

Analysis of 6 pediatric nephrotic syndrome cases with complications of cerebral sinovenous thrombosis and literature review.

Cerebral venous sinus thrombosis (CVST) is a rare but serious complication of nephrotic syndrome (NS) in children. To investigate the clinical characteristics of CVST in children with NS in order to timely diagnose this complication and reduce poor outcome. Collect and analyze clinical data and magnetic resonance venography (MRV) results of children with NS complicated with CVST. Data of 6 patients with NS complicated with CVST were collected. 4 of the patients were steroid-sensitive nephrotic syndrome (SSNS) and 2 were steroid-resistant nephrotic syndrome (SRNS). The occurrence of CVST was observed within a time frame ranging from 12 days to 3 years following the diagnosis of NS. One patient had two episodes of thrombosis in three years, while the other five patients had only one episode of thrombosis. All patients had proteinuria at the time of episode of thrombosis. All patients presented with headache, and three of them had strabismus, seizures, and transient blindness, respectively. Neurological examination was negative. All patients were diagnosed with CVST by MRV within 3-16 days of the onset of headache. Two patients had TRPC6 gene mutation. All patients had resolution of neurological symptoms after anticoagulation treatment. CVST may occur in the early stages of NS. There is currently a lack of specific diagnostic indicators to reliably identify the presence of CVST in patients with NS. Children with NS who have neurological symptoms should be promptly evaluated with imaging studies. Whether TRPC6 gene mutation is also a risk factor for CVST remains to be further studied.

Preserved visual categorical coding in the ventral occipito-temporal cortex despite transient early blindness and permanent alteration in the functional response of early visual regions

Preserved visual categorical coding in the ventral occipito-temporal cortex despite transient early blindness and permanent alteration in the functional response of early visual regions

Case Report: Transient complete blindness after coronary angiography

Transient cortical blindness is a rare complication that can occur after coronary angiography. We report a case of a 53-year-old Caucasian male with a history of multiple cardiovascular risk factors who presented to the emergency room with chest pressure and shortness of breath. He underwent cardiac catheterization and subsequently developed transient bilateral blindness. His vision gradually improved over the next 72 hours without any intervention. This case highlights the importance of considering transient cortical blindness as a potential complication of coronary angiography and the favorable outcome of this condition.

Stimulus-evoked and resting-state alpha oscillations show a linked dependence on patterned visual experience for development

Persistent visual impairments after congenital blindness due to dense bilateral cataracts have been attributed to altered visual cortex development within a sensitive period. Occipital alpha (8–14 Hz) oscillations were found to be reduced after congenital cataract reversal, while participants performed visual motion tasks. However, it has been unclear whether reduced alpha oscillations were task-specific, or linked to impaired visual behavior in cataract-reversed individuals. Here, we compared resting-state and stimulus-evoked alpha activity between individuals who had been treated for dense bilateral congenital cataracts (CC, n = 13, mean duration of blindness = 11.0 years) and age-matched, normally sighted individuals (SC, n = 13). We employed the visual impulse response function, adapted from VanRullen and MacDonald (2012), to test for the characteristic alpha response to visual white noise. Participants observed white noise stimuli changing in luminance with equal power at frequencies between 0 and 30 Hz. Compared to SC individuals, CC individuals demonstrated a reduced likelihood of exhibiting an evoked alpha response. Moreover, stimulus-evoked alpha power was reduced and correlated with a corresponding reduction of resting-state alpha power in the same CC individuals. Finally, CC individuals with an above-threshold evoked alpha peak had better visual acuity than CC individual without an evoked alpha peak. Since alpha oscillations have been linked to feedback communication, we suggest that the concurrent impairment in resting-state and stimulus-evoked alpha oscillations indicates an altered interaction of top-down and bottom-up processing in the visual hierarchy, which likely contributes to incomplete behavioral recovery in individuals who experienced transient congenital blindness.

Savremeni tretman pacijenata sa karotidnom stenozom

Narrowing of the carotid arteries, carotid stenosis, (CS) is a frequent manifestation of atherosclerosis. It can be associated with other diseases of peripheral blood vessels, stenotic occlusive or aneurysmal, but also coronary arteries. Almost 15% of ischemic strokes are caused by this disease, which shares common risk factors with other atherosclerotic manifestations (age, male gender, hypertension, diabetes, smoking). The disease is progressive and with progression comes the progression of the degree of stenosis, the volume and morphological characteristics of the plaque. As these features progress, they increase the risk of clinical manifestations. Ischemic stroke, transient ischemic attack or transient blindness in the ipsilateral eye (amaurosis fugax) are the only clinical manifestations that can be directly related to carotid stenosis. Ischemic changes in the brain parenchyma, which can be seen on magnetic resonance imaging or computed tomography, are also associated with carotid stenosis. All the mentioned parameters are taken into account when making decisions about further treatment. Available drug therapy includes antiplatelet and statin therapy with control of risk factors (body weight correction, smoking cessation) and associated diseases (hypertension, diabetes, etc.). Invasive treatment includes carotid endarterectomy (CEA) as vascular or carotid stenting (CAS) as endovascular treatment. KEA is performed under local or general anesthesia, increasingly under local anesthesia, and after accessing the carotid arteries through a cervicotomy, they are clamped, the flow is interrupted, and after the artery is opened, plaque removal and endarterectomy are performed. In addition to the anesthesiological management of the patient and the performance of the surgical technique, the monitoring of cerebral perfusion during clamping is an important technical detail in these operations. KAS is performed through a percutaneous transfemoral approach under local anesthesia when a stent is implanted in the carotid artery at the site of the carotid stenosis. To perform this procedure, adequate access is required in terms of the quality of the femoral and iliac blood vessels, i.e. the aortic arch. KAS was introduced into practice much later, and in the last 20 years, there has been a significant improvement both in terms of performance and technology with the development of modern stents and the materials used in their installation. A special contribution to this technique was the introduction of embolization protection. KAS is a complementary method to CEA and an individual approach to the patient enables the choice of method, taking into account the advantages and disadvantages of one and the other method. When it comes to symptomatic patients, CEA certainly has a significantly greater advantage and when the use of CAS should be avoided. Complications of both methods are general, local and neurological, with the latter being the most important. Current recommendations state that performing these procedures is beneficial for the patient if the risk of neurological complications is less than 3% in asymptomatic patients, or less than 6% in symptomatic patients. At the Clinic for Vascular and Univascular Surgery of the Clinical Center of Serbia, in the last fifteen years, almost 9.000 procedures have been performed due to carotid stenosis, of which about 10% (960) were CAS. We opt for this method in patients who are at cardiorespiratory risk for CEA or in whom access to the carotid bifurcation is difficult. All, the CEA procedures are performed under conditions of the cervical block. The improvement of patient stratification and the use of artificial intelligence should in the future help doctors decide on the method of examination and treatment of these patients.

Internal carotid and vertebral artery dissections - a comparison of clinical, radiological and prognostic characteristics.

To examine whether baseline characteristics, potential risk factors, clinical symptoms, radiological presentation, and long-term outcomes differ between internal carotid artery dissection (ICAD) and vertebral artery dissection (VAD). Cervical artery dissection (CeAD) is a major cause of cerebral ischaemia in young adults. Its clinical course is highly variable, resulting in challenges in making a proper diagnosis. We performed a retrospective analysis of 31 patients (mean age 42.2 years) with CeAD (18 with ICAD, 13 with VAD) treated in our neurology department from 2008 to 2018. Appropriate imaging confirmed the diagnosis of CeAD. Patients with ICAD presented Horner syndrome significantly more often (44.4% vs 7.6%; p = 0.04). Patients with VAD more often had ischaemic events (ischaemic stroke, TIA or transient blindness) (84.6% vs 44.6%; p = 0.0032). Ischaemic stroke was more severe in patients with ICAD [(median NIHSS 6, interquartile range 4-12) vs VAD (median NIHSS 4, interquartile range 1.5-5.5), p = 0,03]. Occlusion occurred more often in patients with VAD (69.2% vs 22.2%; p = 0.013). Most patients had a favourable outcome (mRS 0-2). In a series of patients with CeAD, we observed significant differences between VAD and ICAD in terms of clinical symptoms and radiological features.

Acute intermittent porphyria presenting with posterior reversible encephalopathy syndrome: A case report

Acute intermittent porphyria (AIP) is an inborn error caused due to inherited deficiency of porphobilinogen (PBG) deaminase leading to increased levels of aminolevulinic acid and PBG. AIP is rarely associated with posterior reversible encephalopathy syndrome (PRES). This association is important because drugs used in the management of seizures may worsen an attack of AIP. We report the case of a 10-year-old male child with AIP, who presented with encephalopathy and transient blindness of cerebral origin.

Transient blindness associated with mild encephalitis/encephalopathy with a reversible splenial lesion (MERS): a case report and review of literature

BackgroundMild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinical-radiological syndrome that can be related to infectious and non-infectious conditions. The most prominent neurological symptoms are disturbance of consciousness, abnormal speech, delirious behavior, seizures, muscle weakness, ophthalmoplegia, facial nerve paralysis and headache. Here we report the case of a child with MERS presenting with the unusual symptom of bilateral transient blindness.Case presentationA 4-year-old female patient, with a history of fever, abdominal pain, loss of appetite and cough lasted for a few days, experienced 3 episodes of transient bilateral loss of vision with difficulty in walking. Her physical examination showed absence of focal neurological and meningeal irritation signs, although responsiveness was slightly impaired. The ophthalmologic evaluation, including a fundus oculi examination, was negative.The electroencephalogram showed slow activity in the temporo-occipital regions, more evident in the right hemisphere. A lumbar puncture was performed and cerebrospinal fluid analysis revealed normal glycorrhachia, cell counts, protein levels and IgG index.Magnetic resonance imaging of the brain showed a signal alteration in the splenium of the corpus callosum, without contrast enhancement. This finding was suggestive of a reversible cytotoxic lesion. Empiric antiviral treatment with acyclovir and intravenous dexamethasone was initiated. Polymerase chain reaction search for neurotropic viral nucleic acid sequences in the cerebrospinal fluid was negative, while a low number of HHV-6 DNA copies was detected in the blood.Electroencephalograms were repeated in the following days, showing a progressive normalization of the pattern. The child was discharged without symptoms after 10 days of treatment with oral corticosteroids. After 40 days, brain magnetic resonance imaging showed a complete normalization of the signal alteration in the splenium of the corpus callosum.ConclusionTransient blindness was reported as an initial symptom of MERS in a few children. To date, there is no evidence of effective treatment methods. Nonetheless, MERS diagnosis provides pediatricians with valuable prognostic information in order to reassure patients and their families about the good outcome of this disease.

Angioplasty and carotid artery stenting: clinical and morphological factors affecting long-term outcomes

Aim. To identify clinical and morphological factors affecting the longterm outcomes of endovascular angioplasty and carotid artery stenting.Material and methods. The analysis included 198 patients after carotid artery stenting between 03.2014 and 05.2018. There were following inclusion criteria: (1) 50% of symptomatic or 70% of asymptomatic carotid artery stenosis of according to NASCET (North American Symptomatic Carotid Endarterectomy Trial) criteria; (2) follow-up for each patient for at least 1 year. Using the univariate and multivariate logistic regression, risk factors associated with adverse events were determined.Results. The incidence of major adverse events during the 12-month follow-up was 9,6% (n=19), including 4 (2%) major and 6 (3%) minor strokes, 7 (3,5%) cases of transient ischemic attack; one (0,5%) patient had transient blindness and one (0,5%) died in the long-term follow-up period due to acute cerebrovascular accident in the target arterial territory. Also, 11 (5,6%) patients had restenosis &gt;50% after 12-month follow-up. Multivariate analysis showed that long-term outcomes were significantly affected by: age &gt;70 years (odds ratio (OR)=1,27, 95% confidence interval (CI): 1,07-1,61 (p=0,01); using of open-cell stents (OR=1,02, 95% CI: 1,01-1,03 (p=0,034)); contralateral stenosis (OR=1,28, 95% CI: 1,05-1,57 (p=0,01); lesion length &gt;15 mm (OR=1,46, 95% CI: 1,12-1,89 (p=0,01)); residual stenosis &lt;30% (OR=1,38, 95% CI: 1,09-1,49 (p=0,012)); complicated atherosclerotic plaque (OR=1,78, 95% CI: 1,21- 2,34 (p=0,007)). The development of in-stent restenosis was significantly influenced by factors such as the residual stenosis &gt;&lt;30% (OR=1,26, 95% CI: 1,1-1,65; p=0,017) and severe plaque calcification (OR=1,24, 95% CI: 1,04-1,31; p=0,02). Conclusion. The results obtained indicate the need for more careful preparation for endovascular intervention. Such factors as the use of open-cell stents, contralateral stenosis, lesion length &gt;&lt; 30% (OR=1,38, 95% CI: 1,09-1,49 (p=0,012)); complicated atherosclerotic plaque (OR=1,78, 95% CI: 1,21- 2,34 (p=0,007)). The development of in-stent restenosis was significantly influenced by factors such as the residual stenosis &lt;30% (OR=1,26, 95% CI: 1,1-1,65; p=0,017) and severe plaque calcification (OR=1,24, 95% CI: 1,04-1,31; p=0,02).Conclusion. The results obtained indicate the need for more careful preparation for endovascular intervention. Such factors as the use of open-cell stents, contralateral stenosis, lesion length &gt;15 mm, and residual stenosis &lt; 30% may be associated with an increased risk of adverse events.

Venous sinus stenting improves cerebral autoregulation in a patient with venous sinus stenosis: a case report

BackgroundVenous sinus stenosis (VSS) is a type of cerebral venous vascular disease. Cerebral autoregulation is an indicator of cerebral arterial function. The cerebral circulatory system is composed of the venous system and arterial system. Impaired venous function may affect arterial function. Thus, cerebral venous stenosis may influence cerebral autoregulation.Case presentationIn this case, a 50-year-old woman with transient blindness and headache was admitted to the hospital. The patient was diagnosed with VSS. A stent was placed at the stenosis. The stent released the intravenous pressure and remitted the patient’s symptoms. Measurements of dynamic cerebral autoregulation (dCA) were performed at 3 time points: before stenting, after stenting, and 3 months later. The dCA gradually improved after stenting.ConclusionVSS may have an influence on cerebral autoregulation, and effective treatment improves cerebral autoregulation in patients with VSS.

Bronchial Artery Embolization, an Increasingly Used Method for Hemoptysis; Treatment and Avoidance.

Objectives:Hemoptysis is an alarming symptom. It may cause some severe life-threatening complications. Hypertrophic and fragile bronchial artery causes hemoptysis and occurs mostly in bronchiectasis, sarcoidosis, active or sequelae tuberculosis, aspergilloma, lung cancer or cystic fibrosis. Bronchial artery embolization is one of the angiographic methods used in diagnosis and treatment for years performed by radiologists. Hemoptysis is used mostly in patients with hemoptysis. Using this method, surgical management with high mortality and morbidity rates can be avoided or better conditions for surgery can be provided via stopping hemorrhage before surgery. We aim to share the experiences of our hospital about patients who underwent bronchial artery embolization and compare our results with the literature.Methods:Thirty-nine patients (29 male, 10 female) underwent angiography-aiming embolization. Pathologies were hemoptysis in 37 patients, Castleman disease in two patients. Embolization was performed in 33 patients; 31 for hemoptysis, two for Castleman disease. Bilateral embolization was performed in six patients.Results:Computed tomography (CT) was helpful in diagnosing the side of bleeding in 91.8% of the patients with hemoptysis. Bronchoscopy was diagnostic in 53% of patients. Polyvinyl alcohol (n=27) was mostly used for embolization. Hemoptysis recurred in six patients (19.3%). All were managed successfully, of four with re-embolization. One major complication, transient blindness, was observed.Conclusion:Bronchial artery embolization is minimally invasive, more tolerable compared to surgery can be managed with high success and lower complication rates, especially hemoptysis and in some other situations. It provides time for evaluating the underlying disease and delaying surgery for elective conditions. That is why this method has been used increasingly.

A rare phenomenon: blindness in acute pancreatitis

Background: Acute pancreatitis generally leads to complement activation, which mediates tissue injury and inflammatory cascades. Retinopathy associated with pancreatitis is rare but run a rapid course independent of disease activity leading to vision loss. Case Presentation: We present a case of 39-year-old man who had transient blindness associated with acute pancreatitis. Conclusion: This a rare presentation associated with pancreatitis which can lead to complete vision loss if left undetected and untreated.

Reversible Acute Blindness in Suspected Metformin-Associated Lactic Acidosis

Metformin is commonly used for the treatment of type 2 diabetes mellitus. Renal insufficiency is one of the contraindications for its use. Inadvertent prescription in patients with renal insufficiency may lead to metformin-associated lactic acidosis (MALA), which is associated with a high risk of mortality. Consequently, the early recognition and management of MALA is essential. We present the case of a 68-year-old man who had reversible blindness resulting from severe lactic acidosis. On presentation, he was alert, oriented, and had no complaints except mild abdominal discomfort and blindness. He denied any history of trauma or drug abuse. The results of the laboratory studies showed severe metabolic acidosis with a high anion gap and increased levels of serum creatinine. There were no predisposing ocular or neurologic lesions that could have induced the blindness. Although the blood levels of methanol, ethanol, and metformin were not estimated, correction of acidosis and hemodialysis led to a complete recovery. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Rarely, transient blindness may occur in patients with fatal severe metabolic acidosis. Evaluation for the presence of metabolic acidosis and a detailed medical history are essential in the management of acute blindness in such patients.