Transient global amnesia and hippocampal diffusion restriction: an overlooked radiological finding

Transient global amnesia (TGA) is characterized by isolated sudden anterograde amnesia. Diffusion restriction can be observed in the hippocampus on DWI-MRI at varying rates in TGA patients. This study analyzes the prevalence and characteristics of the hippocampal diffusion restriction (HDR), its relationship with vascular risk factors, and the prevalence of lesions overlooked in routine reports. 91 patients diagnosed with TGA at a tertiary hospital between 2011 and 2022 were evaluated retrospectively. The mean age was 64.8 ± 7.3 years, and 63.7% of patients were female. 75.8% of the patients had at least one vascular risk factor. Focal diffusion restriction was detected in 17 patients (18.5%) on DWI-MRI, with only one being extra-hippocampal. 81.2% of HDR was detected when DWI-MRI scan was performed between 12 and 96 h after the onset of symptoms. HDR was detected most when the imaging was performed in 24 to 48 h (p = 0.03). There was no correlation between the duration of symptoms and the detection rates of HDR (p = 0.55). In 9 patients (53% of 17) diffusion restriction was not specified in routine radiology reports. Although focal ischemia, venous flow abnormalities, migraine and epileptic phenomena have been suggested in its etiology, TGA is a clinical condition of which pathophysiology has not been determined clearly. Signal changes observed in DWI-MRI has led to discussions that cerebrovascular etiology may play a role, yet more comprehensive studies are required to prevent and manage TGA. HDRs can be overlooked in routine reports. Therefore, the DWI-MRI images of patients with TGA should be examined vigilantly.

A case report on concomitant reversible cerebral vasoconstriction syndrome and transient global amnesia

Reversible Cerebral Vasoconstriction Syndrome clinically presents as severe headaches with or without neurological deficits accompanied by multilocal caliber variation of the cerebral arteries on imaging studies. Transient Global Amnesia is a benign neurological condition that implies sudden temporary antero- and retrograde amnesia. The exact pathophysiological mechanisms involved in transient global amnesia and reversible cerebral vasoconstriction syndrome remain unclear but suggest similar pathways as both can be triggered by factors that activate the sympathetic nervous system. We herein discuss a potential relationship of the two conditions in a 65-year-old woman that initially presented herself to the emergency department with temporary memory impairment, indicating Transient Global Amnesia. Four days later, the patient revealed a thunderclap headache accompanied by a subarachnoid hemorrhage with transient segmental narrowing of the arteries of the anterior circulation on neuroimaging. In this case report we hypothesize that Reversible Cerebral Vasoconstriction Syndrome might be a potential cause for the clinical symptoms and imaging patterns with Transient Global Amnesia as a possible prodromal stage of Reversible Cerebral Vasoconstriction Syndrome.

Automated CT perfusion analysis reveals medial temporal perfusion abnormalities during transient global amnesia

INTRODUCTION

The underlying pathophysiology of Transient global amnesia (TGA) remains elusive. Reports of perfusion abnormalities in TGA were inconsistent, but semi-automated analysis of perfusion CT (CTP) may improve reliability and precision of perfusion deficit detection.

METHODS

Per institutional protocol, all TGA patients undergo multiphasic contrast-CT with arch to vertex CT angiography, intracranial CT venography, MRI, and EEG upon admission. During the study period consecutive patients diagnosed with TGA underwent CTP during the early acute amnestic phase. We retrospectively reviewed the clinical and radiological findings.

RESULTS

Five patients (3 female. median age 71, range 47-74) fulfilled entry criteria. Automated CTP analysis revealed the absence of an ischemic core (defined by CBF < 30%) or conventionally defined clinically relevant hypoperfusion area (defined by Time-to-maximum (Tmax) >6 s) in any of the patients. However, four of the five patients demonstrated territories of benign oligemia defined as Tmax>4 s in areas supplied by the Posterior Cerebral Artery. Three of these four patients had clear involvement of the bilateral medial temporal lobes. None of the patients had epileptic activity on their EEG. Both CTA and MRI were normal apart for small foci of restricted diffusion in the hippocampus of four patients.

DISCUSSION

Deficits in perfusion were found in the hippocampi of 60% of patients in the acute phase of TGA using automated image analysis software. This method may provide a quick and simple method to detect these abnormalities. These perfusion abnormalities could help solidify the diagnosis at an early stage and may advance our understanding of this elusive syndrome.

Altered cerebellar volumes and intrinsic cerebellar networks in patients with transient global amnesia

This study aimed to investigate the differences in cerebellar volumes and intrinsic cerebellar networks between patients with transient global amnesia (TGA) and healthy controls. We retrospectively enrolled patients with TGA and age- and sex-matched healthy controls. We used three-dimensional T1-weighted imaging at the time of TGA diagnosis to obtain cerebellar volumes, and the intrinsic cerebellar network was calculated by applying graph theory based on cerebellar volumes. The nodes were defined as individual cerebellar volumes, and edges as partial correlations, controlling for the effects of age and sex. The cerebellar volumes and intrinsic cerebellar networks were compared between the two groups. We enrolled 44 patients with TGA and 47 healthy controls. The volume of the left cerebellar white matter in patients with TGA was significantly lower than that in healthy controls (1.0328 vs. 1.0753%, p = 0.0094). In addition, there were significant differences in intrinsic cerebellar networks between the two groups. The small-worldness index in patients with TGA was higher than that in the healthy controls (0.951 vs. 0.880, p = 0.038). In the correlation analysis, the volumes of the right cerebellar cortex and lobules VIIIB were significantly correlated with age in patients with TGA (r = -0.323, p = 0.033; r = -0.313, p = 0.038, respectively). Patients with TGA exhibit alterations in cerebellar volumes and intrinsic cerebellar networks compared with healthy controls. These findings may contribute to a better understanding of the pathophysiology of the TGA.

Involvement of the default mode network in patients with transient global amnesia: multilayer network

INTRODUCTION

We aimed to investigate the alterations in the multilayer network in patients with transient global amnesia (TGA).

METHODS

We enrolled 124 patients with TGA and 80 healthy controls. Both patients with TGA and healthy controls underwent a three-teslar brain magnetic resonance imaging (MRI). A gray matter layer matrix was created using a morphometric similarity network derived from the T1-weighted imaging, and a white matter layer matrix was constructed using structural connectivity based on the diffusion tensor imaging. A multilayer network analysis was performed by applying graph theoretical analysis.

RESULTS

There were no significant differences in global network measures between the groups. However, several regions, related to the default mode network, showed significant differences in nodal network measures between the groups. Multi-richness in the left pars opercularis, multi-rich-club degree in the right posterior cingulate gyrus, and weighted multiplex participation in the right posterior cingulate gyrus were higher in patients with TGA compared with healthy controls (15.47 vs. 12.26, p = 0.0005; 41.68 vs. 37.16, p = 0.0005; 0.90 vs. 0.80, p = 0.0005; respectively). The multiplex core-periphery in the left precuneus was higher (0.96 vs. 0.84, p = 0.0005), whereas that in the transverse temporal gyrus was lower in patients with TGA compared with healthy controls (0.00 vs. 0.02, p = 0.0005).

CONCLUSION

We newly find the alterations in the multilayer network in patients with TGA compared with healthy controls, which shows the involvement of the default mode network. These changes may be related to the pathophysiology of TGA.

Prolonged Transient Global Amnesia: Part of the Clinical Spectrum or a Separate Disease Entity?

Background

Transient global amnesia (TGA) is the prototypical neurologic disease for acute-onset reversible amnesia. It is currently defined by resolution of symptoms within 24-hours. In this case report we describe an atypical case of prolonged TGA, emphasizing our current lack of knowledge surrounding this disease entity and its pathophysiology.

Results

A 66-year old female presented acutely with profound anterograde amnesia and variable retrograde amnesia with no inciting event. A thorough workup to exclude alternative causes of amnesia (including computed tomography angiogram and electroencephalogram) was normal. Her magnetic resonance imaging was consistent with TGA, with punctate diffusion restriction changes bilaterally in the hippocampi. She was also mildly hypoxemic with no discernible cause. She was ultimately diagnosed with TGA although her diagnosis remains controversial as her symptoms persisted for 72-hours.

Conclusion

Our patients clinical and imaging features (apart from her protracted time-course and hypoxemia) were in keeping with a diagnosis of TGA. The association of hypoxemia, COVID-19, obstructive sleep apnea, and the development of TGA remains to be elucidated. Although the underlying pathophysiology for TGA is unknown several mechanisms have been postulated including cortical spreading depression and reversible hypoxic-ischemic injury. The time course for symptom resolution, could be an important clue in discerning the pathophysiology of TGA on an individual basis. Importantly, a clinician should not be deterred by amnestic symptoms lasting >24-hours, if the patients clinical/radiologic presentation is consistent with TGA.

Incidence and Risk Factors of Transient Global Amnesia

INTRODUCTION

Transient global amnesia (TGA) is a spontaneously resolving, anterograde amnesia that lasts mostly <24 h and often occurs with retrograde amnesia. The etiology of TGA remains unclear, although in recent decades, many risk factors and preceding events have been identified. There are few up-to-date reports on the TGA incidence in Northern Europe. In this study, we report the incidence and risk factors associated with TGA in Finland.

MATERIALS AND METHODS

The study included all patients with suspected TGA that were referred to Kuopio University Hospital (KUH) in 2017. The hospital catchment area included 246,653 individuals. Risk factors and demographic data were collected from medical records. The TGA incidence rates were calculated as the number of patients with TGA divided by the number of individuals at risk in different age groups.

RESULTS

In 2017, 56 patients were treated for TGA at KUH. Of these, 46 had a first-ever TGA. The most common event preceding TGA was physical effort (n = 28, 50%), followed by emotional stress (n = 11, 19.6%) and water contact or a temperature change (n = 11, 19.6%). The most common comorbidities were hypercholesterolemia (n = 22, 39.3%), hypertensive disease (n = 21, 37.5%), hypothyroidism (n = 11, 19.6%), coronary artery disease (n = 8, 14.3%), and migraine (n = 7, 12.5%). TGA occurred most often in December (n = 9, 16.0%), March (n = 8, 14.3%), or October (n = 8, 14.3%), and least often in November and May (n = 2, 3.6% in both months). The crude incidence of a first TGA in Eastern Finland was 18.6/100,000 inhabitants, and when standardized to the European population in 2010, it was 14.3/100,000 inhabitants. Therefore, the TGA incidence was higher than previously reported in European countries.

DISCUSSION

The most common precipitating factors for TGA were physical effort, emotional stress, and water contact/temperature change. The incidence of TGA was high in the Eastern Finnish population.

Recurrent Episodes of Transient Global Amnesia: A Rare Clinical Entity

Transient global amnesia (TGA) is a syndrome characterized by anterograde amnesia with otherwise intact cognitive function, resolving within 24 h of onset, occurring in the absence of neurological changes. Recurrent episodes remain rare. We report an interesting case of recurrent episodes of TGA in a 63-year-old woman presenting with altered mental status. She had no memory of antecedent events and demonstrated repetitive questioning but retained awareness of self. Physical examination and laboratory diagnostics were unremarkable. Brain magnetic resonance imaging revealed scattered foci of increased FLAIR signal within the bilateral periventricular and subcortical white matter. She was notably diagnosed with TGA a few months prior when she had presented with similar symptoms. During the current hospitalization, she remained alert and fully oriented, with resolution of perseveration. This case emphasizes the recognition of TGA as an important neurological diagnosis, uniquely describes not only the recurrence, but the short interval between recurrent episodes.

Network localization of transient global amnesia beyond the hippocampus

BACKGROUND

Transient global amnesia is common in the older adult, but the cause and mechanism remain unclear. Focal brain lesions allow for causal links between the lesion location and resulting symptoms, and we based on the reported TGA-causing lesions and used lesion network mapping to explore the causal neuroanatomical substrate of TGA.

METHODS

Fifty-one cases of transient global amnesias with DWI lesions from the literature were identified, and clinical data were extracted and analyzed. Next, we mapped each lesion volume onto a reference brain and computed the network of regions functionally connected to each lesion location using a large normative connectome dataset.

RESULTS

Lesions primarily occurred in the hippocampus, and in addition to the hippocampus, there are also other locations of TGA-causing lesions such as the cingulate gyrus, anterior thalamic nucleus (ATN), putamen, caudate nucleus, corpus callosum, fornix. More than 90% of TGA-causing lesions inside the hippocampus were functionally connected with the default mode network (DMN).

CONCLUSION

Structural abnormality in the hippocampus was the most consistently reported in TGA, and besides the hippocampus, lesions occurring at several other brain locations also could cause TGA. The DMN may also be involved in the pathophysiology of TGA. According to the clinical and neuroimaging characteristics, TGA may be a syndrome with multiple causes and cannot be treated simply as a subtype of TIA.

[Transient epileptic amnesia-A rare phenomenon in temporal lobe epilepsies]

BACKGROUND

Transient epileptic amnesia (TEA) is a rare phenomenon in temporal lobe epilepsy that is often unrecognized or misdiagnosed as transient global amnesia (TGA). It is postulated that TEA is due to both ictal and postictal disturbances. Response to antiseizure medication underlines its epileptic nature. In view of the increasing incidence of new-onset epilepsies in old age, an increase in TEA can be expected in the future.

OBJECTIVE

Analysis of TEA features in a monocentric case series.

MATERIAL AND METHODS

A search in our electronic patient data base yielded 10 patients with TEA out of 7899 patients over a period of 8 years. Clinical and paraclinical features as well as findings of additional examinations were retrospectively collected. Data are given as mean ± SD.

RESULTS

All 10 patients were diagnosed with temporal lobe epilepsy. The mean age at manifestation of TEA was 59.1 ± 6.7 years, the diagnosis was made with a delay of 21.9 ± 26.3 months. The TEA lasted on average 56 ± 37 min, and 16 ± 9.9 TEA episodes per year were reported by the patients; out of the 10 patients 6 reported that TEA usually occurred upon awakening. In 9 of 10 patients, there was evidence of typical seizure symptoms or other semiological elements during TEA. Interictal neuropsychological disturbances of temporal functions were seen in 8 of 10 patients and evidence of depressive disorder in 6 of 10 patients. Video EEG recordings revealed epileptiform activity during sleep in 4 patients over the left and in 2 patients over both temporal regions. In 3 patients, magnetic resonance imaging displayed typical alterations of the temporomesial structures (in 2 patients on the left and in 1 the right side). Antiseizure medication improved seizure control in 7 of 10 patients (seizure freedom in 6 patients), 3 patients were lost to follow-up.

DISCUSSION

TEA is rare, occurs in older adults and is correctly diagnosed after about 2 years. Thorough assessment of additional symptoms and circumstances, the recurrent occurrence as well as typical EEG and imaging findings of temporal lobe epilepsy enables the distinction between TEA and TGA.

Transient global amnesia with unexpected clinical and radiological findings: A case series and systematic review

BACKGROUND

Transient global amnesia (TGA) represents a benign neurological syndrome of unknown pathophysiology, often accompanied by vanishing hippocampal punctate diffusion-weighted imaging lesions (HPDL). The literature suggests that TGA may present with unusual features. This study analyses atypical clinical and radiological manifestations of patients with TGA and/or HPDL.

METHODS

We retrospectively reviewed patients with atypical clinical or radiological presentations of TGA and/or HPDL in three neurology centers. We also performed a systematic review of literature using predefined search terms. Results were classified as: A) Atypical clinical manifestations of TGA (such as amnesia with additional manifestations, or only non-amnesic manifestations); B) Atypical radiological manifestations of clinically typical TGA.

RESULTS

We identified 83 patients: 18 in our centres (median age 63.5 years, 39% female) and 65 in the literature. In group A, 43 patients presented atypical clinical manifestations such as TGA with added transitory cognitive or sensory-motor deficits, seizures, headaches, but also non-amnesic presentations associated with HPDL and incidental HPDL without symptoms. In group B, 40 patients with typical clinical TGA showed extra-hippocampal punctate diffusion lesions (E-HPDL) which disappeared on follow-up imaging. Using clinical and radiological manifestations, we classified these patients into different categories describing a "TGA-PDL spectrum".

CONCLUSIONS

TGA may have atypical clinical manifestations despite typical neuroimaging and patients with typical TGA may show vanishing extra-hippocampal punctate diffusion lesions. TGA, related clinical manifestations, and vanishing punctate diffusion lesions should be considered part of a larger "TGA-PDL spectrum", allowing for better diagnosis of typical and atypical cases and stimulating further studies.

Pathophysiological insight into transient global amnesia from quantitative electroencephalography

Transient global amnesia (TGA) is recognized as a benign memory disorder, with characteristic clinical and imaging features. However, the pathophysiology of TGA remains elusive. This study aims to elucidate the pathophysiological changes underlying TGA by exploring the brain activities. In total, 215 patients with TGA (age: 61.8 ± 7.8 years; women: 146) with MRI (within 7 days) and EEG studies (within 90 days) were recruited. Quantitative EEG (QEEG) power spectra and network analysis were performed by the artificial intelligence EEG analysis platform (iSyncBrain®). Subgroup analyses were conducted for different clinical groups, based on symptom duration, EEG timing after onset, and cytotoxic lesions on the MRI. Compared with 252 age- and sex-matched subjects (age: 64.5 ± 8.3 years, women: 182), TGA patients showed a global decrease in absolute power in all band waves, a relative decrease in alpha waves, a relative increase in theta waves, and atypical compensation activity. These QEEG changes were observed regardless of having cytotoxic lesions in MRI and they were significant up to 1 week after symptom onset. Network analysis showed that TGA was more activated than normal controls in alpha1 band-waves, exhibiting a compensatory process. TGA results in prolonged and widespread alterations of brain activity and connectivity. QEEG provide insight into pathophysiology of TGA.

The remains of the day: neuropsychological findings in postacute transient global amnesia

INTRODUCTION

Current clinical diagnostic criteria of transient global amnesia (TGA) require the episode to completely resolve within 24 h. Small case series investigating the neuropsychological profiles obtained during the first days after TGA are inconclusive, with some suggesting the persistence of memory deficits.

METHODS

In this retrospective observational study, neuropsychological data of 185 TGA patients obtained during the first days following an attack were analysed. Data of cognitive functions assessed in at least 50 patients were evaluated and dichotomised according to z-values as "impaired" or "unimpaired". Moreover, the results of magnetic resonance imaging (MRI) were collected.

RESULTS

Neuropsychological assessment was performed within the first 3 days after TGA in 158 (85.4%) of all patients. The majority of patients showed no significant neuropsychological sequelae in the postacute phase of TGA. However, Mini-Mental Status Examination showed impairment in 22.6% of 159 patients, and we found subtle reductions of patients' performance in tests of verbal long-term memory and executive function in 16.3-24.6% of patients. Patients with hippocampal diffusion-weighted imaging (DWI) lesions performed significantly worse in a verbal recognition task than those without DWI lesions.

DISCUSSION

Our findings reflect subtle performance reductions in different cognitive domains in a small subgroup of TGA patients. This implies that the gradual resolution of subclinical symptoms may take longer than the 24 h required as maximum episode duration by current diagnostic criteria.

[Memory Loss - a Case of Sudden Amnesia]

Memory Loss - a Case of Sudden Amnesia Abstract. Transient global amnesia (TGA) is a clinical diagnosis with typical signs of an anterograde and retrograde amnesia. The underlying mechanisms are yet unknown, different hypotheses are being discussed. Ultimately there is a temporary dysfunction of the hippocampi. Consistent with this, transient uni- or bilateral punctiform hyperintense lesions may be found on DWI-MRI sequences, usually without correlation on FLAIR-weighthed MR-images. Symptoms usually resolve within twenty-four hours. There is no need for a specific therapy. A prophylactic therapy, such as antithrombotic treatment, is not indicated. The prognosis is usually good, the risk of a recurrence is about 18%.

Recurrent amnesia caused by early seizures after hippocampal infarction: a case report

Background

We report the case of a patient with recurrent episodes of disturbed memory suggestive of transient epileptic amnesia, and a focal hippocampal lesion typically associated with transient global amnesia. We argue how careful consideration of clinical, electrophysiological and imaging findings can resolve this apparent contradiction and lead to a diagnosis of early symptomatic post-stroke seizures that links brain structure to function in a new, clinically relevant way.

Case presentation

A 70-year-old patient was identified in clinical practice in our tertiary care centre and was evaluated clinically as well as by repeated electroencephalography and magnetic resonance imaging. The presenting complaint were recurrent episodes of short-term memory disturbance which manifested as isolated anterograde amnesia on neurocognitive evaluation. EEG and MRI revealed predominantly right frontotemporal spikes and a punctate diffusion-restricted lesion in the left hippocampus, respectively. Both symptoms and EEG changes subsided under anticonvulsant treatment with levetiracetam.

Conclusions

Our report contributes to the current discussion of clinical challenges in the differential diagnosis of transient memory disturbance. It suggests that focal diffusion-restricted hippocampal lesions, as seen in TGA, might be ischemic and thus highlights the importance of considering post-stroke seizures as a possible cause of transient memory disturbance.

Chronobiology of transient global amnesia

INTRODUCTION

The etiology of transient global amnesia (TGA) is still a matter of debate. Based, among others, on the observation of a close temporal relation between certain events and subsequent TGA episodes, recent proposals discuss the relevance of stress-associated processes impacting on hippocampal functioning. Circadian, infra- and ultradian rhythmicity has been found to play a relevant role in the multifactorial pathomechanisms of various disorders but has not been thoroughly studied in TGA.

METHODS

Data of patients with a final diagnosis of TGA were collected in Mannheim, Germany (06/1999-01/2018, n = 404), and in the Kansai district, Japan (04/2006-03/2018, n = 261). Chronological patterns of TGA occurrence were determined.

RESULTS

Significant circadian rhythmicity of TGA occurrence with bimodal peaks (mid-morning, late afternoon) was found for the entire population (p = 0.002) and for either sub-cohort (Mannheim: p = 0.003, Kansai: p = 0.007). This finding was confirmed for either sex (women: p = 0.004, men: p = 0.004) and different age groups (< 65 years: p = 0.0009, ≥ 65 years: p = 0.003). There was no variation according to day of the week, month or season, but the proportion of patients with a weekday episode was significantly higher in the Mannheim cohort (p = 0.002).

DISCUSSION

We identified a robust circadian rhythm in TGA occurrence which remarkably applied to either of the two study sites located on different continents and which was independent of sex and age. In light of abundant evidence of circadian rhythmicity of both, components of the human stress response system and memory, chronobiological analyses may provide an opportunity to further uncover the mechanisms underlying TGA.

Clinical manifestation and imaging characteristics of transient global amnesia: patent foramen ovale as an underlying factor

Transient global amnesia is not rare, but its etiology remains unknown. Cerebral ischemia is a suspected cause because high signal intensity is observed on diffusion-weighted brain magnetic resonance imaging; however, previous studies have not established it as a cause. Of the 128 patients (114 females) enrolled in this study, 82 (64.6%) experienced extreme stress before transient global amnesia. The number of female patients with patent foramen ovale was more than that of males. The patent foramen ovale-positive group had fewer vascular risk factors and fewer old ischemic lesions on fluid-attenuated inversion recovery magnetic resonance imaging than the patent foramen ovale-negative group. Brain magnetic resonance imaging confirmed that high signal intensity was more likely to be detected on the initial diffusion-weighted imaging when there was an old lesion detected by fluid-attenuated inversion recovery. Furthermore, a longer period from symptom onset to brain magnetic resonance imaging was associated with a positive initial diffusion-weighted imaging result. It is difficult to attribute one underlying mechanism to all the transient global amnesia cases. This study confirmed that transient global amnesia patients with patent foramen ovale had lesser vascular risk factors and showed fewer old lesions on fluid-attenuated inversion recovery magnetic resonance imaging than those without. These results suggest that transient global amnesia may be caused by a paradoxical embolus rather than ischemia due to traditional vascular risk factors in patients with patent foramen ovale.

Acute coronary syndrome and transient global amnesia with sumatriptan

Triptans are potent serotoninergic vasoconstrictors. They are generally avoided in elderly patients age greater than 65 or in patients with a history of CAD. Although there are reported cases of Acute Coronary Syndrome (ACS) or Transient Global Amnesia (TGA) in patients after ingesting therapeutic doses of triptan or dihydroergotamine, this is the first case report, up to our knowledge, of a patient, who had no previous cardiac history, that was diagnosed with both ACS and TGA. A 59-year-old woman with a long-standing history of migraine, gastroesophageal reflux disease, and hypothyroidism, presented to the Emergency Department (ED) complaining of amnesia, chest pain, and left arm numbness after ingesting a single dose of oral sumatriptan approximately 1-2 h prior to arrival. She had no recollection of the events that occurred after taking sumatriptan. No acute laboratory abnormalities were found except for an elevated troponin, which continued to trend upwards. Her EKG had no ST-T wave abnormalities. She was diagnosed with Acute Coronary Syndrome (ACS), non-ST elevation MI. She had a negative noncontrast CT head. Neurology was consulted for her amnesia and diagnosed her with Transient Global Amnesia (TGA). They recommended discontinuing sumatriptan and beginning topiramate as a prophylactic therapy. There is an increasing number of reports delineating sumatriptan's adverse effects. Emergency medicine physicians should promptly recognize the toxic effects and adverse reactions from triptans. Sumatriptan-induced vasoconstriction may lead to cardiac and cerebral ischemic events.

Frequency of silent brain infarction in transient global amnesia

Background and purpose

To determine the frequency and distribution pattern of acute DWI lesions outside the hippocampus in patients clinically presenting with Transient Global Amnesia (TGA).

Methods

Consecutive patients clinically presenting with TGA between January 2010 and January 2017 admitted to our hospital were retrospectively evaluated. All patients fulfilled diagnostic criteria of TGA. We analyzed imaging and clinical data of all patients undergoing MRI with high-resolution diffusion-weighted imaging within 72 h from symptom onset.

Results

A total of 126 cases were included into the study. Fifty-three percent (n = 71/126) presented with one or more acute lesions in hippocampal CA1-area. Additional acute DWI lesions in other cortical regions were found in 11% (n = 14/126). All patients with DWI lesions outside the hippocampus presented with neurological symptoms typical for TGA (without additional symptoms.)

Conclusions

In a relevant proportion of clinical TGA patients, MRI reveals acute ischemic cerebral lesions. Therefore, cerebral MRI should be performed in patients with TGA to identify a possible cardiac involvement and to detect stroke chameleons.

Diagnostic Yield of Diffusion-Weighted Brain Magnetic Resonance Imaging in Patients with Transient Global Amnesia: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate the diagnostic yield of diffusion-weighted imaging (DWI) in patients with transient global amnesia (TGA) and identify significant parameters affecting diagnostic yield.

MATERIALS AND METHODS

A systematic literature search of the MEDLINE and EMBASE databases was conducted to identify studies that assessed the diagnostic yield of DWI in patients with TGA. The pooled diagnostic yield of DWI in patients with TGA was calculated using the DerSimonian-Laird random-effects model. Subgroup analyses were also performed of slice thickness, magnetic field strength, and interval between symptom onset and DWI.

RESULTS

Twenty-two original articles (1732 patients) were included. The pooled incidence of right, left, and bilateral hippocampal lesions was 37% (95% confidence interval [CI], 30-44%), 42% (95% CI, 39-46%), and 25% (95% CI, 20-30%) of all lesions, respectively. The pooled diagnostic yield of DWI in patients with TGA was 39% (95% CI, 27-52%). The Higgins I² statistic showed significant heterogeneity (I² = 95%). DWI with a slice thickness ≤ 3 mm showed a higher diagnostic yield than DWI with a slice thickness > 3 mm (pooled diagnostic yield: 63% [95% CI, 53-72%] vs. 26% [95% CI, 16-40%], p < 0.01). DWI performed at an interval between 24 and 96 hours after symptom onset showed a higher diagnostic yield (68% [95% CI, 57-78%], p < 0.01) than DWI performed within 24 hours (16% [95% CI, 7-34%]) or later than 96 hours (15% [95% CI, 8-26%]). There was no difference in the diagnostic yield between DWI performed using 3T vs. 1.5T (pooled diagnostic yield, 31% [95% CI, 25-38%] vs. 24% [95% CI, 14-37%], p = 0.31).

CONCLUSION

The pooled diagnostic yield of DWI in TGA patients was 39%. DWI obtained with a slice thickness ≤ 3 mm or an interval between symptom onset and DWI of > 24 to 96 hours could increase the diagnostic yield.

Significance of serum neuron-specific enolase in transient global amnesia

Neuron-specific enolase (NSE) is a glycolytic enzyme, which is associated with neuronal cell dysfunction in the brain. This study evaluated the role of serum NSE levels of patients with transient global amnesia (TGA). In addition, the relationship between serum NSE levels and the clinical features of TGA was explored. Forty-eight patients with TGA were prospectively included, and their serum NSE levels were measured. We investigated serum NSE levels in patients with TGA. In addition, we analyzed the differences in clinical characteristics between patients with elevated and normal serum NSE levels. Of the 48 patients with TGA, 16 patients (33.3%) had elevated serum NSE levels (25.0 ± 11.5 ng/mL), whereas 32 patients (66.7%) showed normal serum NSE levels (12.8 ± 2.1 ng/mL). The patients with elevated serum NSE levels exhibited higher levels of cognitive impairment than those with normal serum NSE levels (4/16 vs. 1/32, p = 0.036). The serum NSE levels showed a relatively high discrimination (AUC 0.684) between patients with and without cognitive impairment, with 80.0% sensitivity and 74.4% specificity at a cut-off value 17.3 ng/mL. A third of all patients with TGA carry elevated serum NSE levels, which suggests that the neuronal cell dysfunction could be associated with TGA pathogenesis. In addition, it might be correlated with cognitive impairment.

Sex-related differences in stressful events precipitating transient global amnesia - A retrospective observational study

INTRODUCTION

Physically or emotionally charged events have consistently been reported as precipitating an episode of transient global amnesia (TGA). In conjunction with evidence of hippocampal involvement from neuroimaging, this has promoted the hypothesis that TGA is a stress-related disorder.

METHODS

In this retrospective observational study, medical records of 389 patients with TGA were analysed regarding documented precipitating events, which were classified according to previously suggested criteria. Moreover, comorbidities and results of magnetic resonance imaging were collected.

FINDINGS

In our cohort of TGA patients, 231 were female (59.4%). A precipitating factor was identified in 266 patients (68.4%). Of these, 136 patients (51.1%) reported physical triggers, the most common being physical exertion (64.0%). Another 122 patients (45.9%) presented with an emotional trigger, most frequently classified as an interpersonal conflict (42.7%). In 8 cases (2.1%), TGA was preceded by a medical procedure. Emotional triggers were more often experienced by women (37.2% vs 22.8%, p = 0.003), while physical stressors were more often present in men (30.7% vs 41.1%, p = 0.035). Women had a significantly higher number of hippocampal MRI lesions than men (mean 1.13 vs 0.92; p = 0.042).

CONCLUSION

Our data suggest a female predominance in TGA occurrence and a sex-related difference in susceptibility to certain triggering events in TGA patients. In light of recent research on sex-specific differences in vulnerability to stress, these findings support the hypothesis that this might be a significant contributing factor in the pathogenesis of TGA.

Self-awareness in Transient Global Amnesia: distinguishing the effects of transient memory disorder vs. pre-existing vulnerability factors

Numerous evidences suggest the existence of relationships between the impairment of episodic memory, acute stress exposure and variations in self-awareness (SA). Here, we examined 27 patients presenting transient global amnesia (TGA), a clinical condition which combines episodic amnesia and high anxiety, thanks to state and trait questionnaires of SA. We observed variation of SA depending on the stage of TGA (acute, recovery and follow-up). We also found preexisting differences in patient's awareness of their own image when the precipitating event was physical, encouraging us to give more consideration to the social determinants of stress in physiological cascade of TGA.

Did Ribot describe transient global amnesia in the nineteenth century?

Some recent authors have claimed that Théodule-Armand Ribot described transient global amnesia in the nineteenth century in his monograph, Diseases of memory, An examination of this work was undertaken to determine whether or not this claim is true. Whilst Ribot cites Koempfen's thorough report of a case of transient amnesia, dating from 1835, this does not conform to current understanding of transient global amnesia.

Transient global amnesia and focal diffusion weighted imaging lesions in mesiotemporal region: A ten-year experience

OBJECTIVE

To determine prevalence and characteristics of mesiotemporal diffusion weighted imaging (DWI) lesions in transient global amnesia (TGA), and to determine prevalence of "missed" DWI lesions on routine radiological reporting.

METHODS

This is a retrospective study of patients with TGA admitted to a tertiary care hospital over ten years. Patients with TGA, who underwent magnetic resonance imaging (MRI) of the brain within one week of index event, were included in this study. MRI's were reviewed by two independent raters. Clinical data and other investigations were collated.

RESULTS

Of the 55 patients of TGA, 19 (35 %) had hyperintense DWI lesions with concordant apparent diffusion coefficient (ADC) hypointensity in the mesiotemporal region. Fifteen out of 19 (79 %) had unilateral lesions (6 left, 9 right). Twelve out of 19 DWI lesions were reported at the time of index scan. The false negative reporting rate was 36.8 %. DWI slice thickness (5 mm versus 3 mm), MRI machine strength (1.5 versus 3 T) and time interval from symptom onset to MRI brain (>24 h versus ≤ 24 h) were not significantly different between patients with or without DWI lesions and as well between patients with DWI lesions missed and initially reported at the time of index scan.

CONCLUSION

Punctuate DWI mesiotemporal lesions in TGA are prone to under-reporting. These lesions need to be categorically searched for at the time of reporting MRI Brain.

A case of transient global amnesia with hippocampal infarction due to infective endocarditis

Transient global amnesia (TGA) is an uncommon disease characterized by sudden onset anterograde amnesia that typically improves within 24 hours. A 35-year-old woman presented with complete disruption of memory that had started on the previous day. She had fever and heart murmur and was diagnosed as having infective endocarditis with Staphylococcus lugdunensis, a coagulase-negative staphylococcus. Septic embolizations were found in the spleen and kidney on CT scan. The patient underwent aortic valve replacement. MRI susceptibility-weighted imaging showed a dotted low intensity area in the right hippocampus. Recently, etiology of TGA is reported to be related to hippocampal disorder. We report a rare case of TGA with hippocampal infarction due to septic embolism from infective endocarditis.

Effective connectivity alteration according to recurrence in transient global amnesia

PURPOSE

This study aimed to evaluate alterations in structural covariance network and effective connectivity of the intrahippocampal circuit in patients with transient global amnesia (TGA). We also investigated whether there were differences of them according to recurrence.

METHODS

We enrolled 88 patients with TGA and 50 healthy controls. We classified patients with TGA into two groups: the single event group (N = 77) and recurrent events group (N = 11). We performed volumetric analysis using the FreeSurfer program and structural covariance network analysis based on the structural volumes using a graph theoretical analysis in patients with TGA and healthy controls. The effective connectivity of the intrahippocampal circuit was also evaluated using structural equation modeling.

RESULTS

There were no significant differences between patients with all TGA events/a single TGA event and healthy controls with regard to global structural covariance network. However, patients with recurrent events had significant alterations in global structural covariance network with a decrease in the small-worldness index (0.907 vs. 0.970, p = 0.032). In patients with all events/a single, there were alterations in effective connectivity from the entorhinal cortex to CA4, only. However, in patients with recurrent events, there were alterations in effective connectivity from the subiculum to the fimbria as well as from the entorhinal cortex to CA4 in bilateral hemispheres.

CONCLUSION

Our study revealed significant alterations in structural covariance network and disruption of the intrahippocampal circuit in patients with TGA compared to healthy controls, which is more prominent when amnestic events recurred. It could be related to the pathogenesis of TGA.

An image is not always worth a thousand words: an image mimic of transient global amnesia

Transient global amnesia (TGA) is a neurological syndrome with rather distinctive brain MRI features, namely hyperintense lesion in hippocampus on diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR) sequences. Post-traumatic amnesia is another amnestic syndrome which can also show hyperintense lesions in brain MRI due to cytotoxic oedema caused by traumatic brain injury. We present a case of a patient with post-traumatic amnesia with a brain MRI image mimic of TGA.

Prevalence of Mimics and Severe Comorbidity in Patients with Clinically Suspected Transient Global Amnesia

BACKGROUND

Transient global amnesia (TGA) is a syndrome featuring acute anterograde amnesia as the most striking clinical symptom. Its etiology is still a matter of debate. Most neurological guidelines allow the diagnosis on the basis of clinical criteria only; a more extensive evaluation is recommended only for patients with "red flags" like severe headache, nausea or vomiting, or metabolic abnormalities. The aim of our study was to assess the frequency of a severe underlying disease or alternative diagnoses (mimics) in patients fulfilling the clinical criteria.

METHODS

We evaluated the medical records and the imaging data of an unselected consecutive cohort of patients with suspected TGA over a 7-year period. All patients were hospitalized and received a neurological workup including brain imaging, color-coded duplex sonography of the brain supplying arteries, electroencephalography, and laboratory studies of blood and (in selected cases) cerebrospinal fluid.

RESULTS

163 patients with 166 episodes of suspected TGA were hospitalized (3 patients twice). After the workup, the diagnosis of TGA was confirmed in 148/166 (89.2%) episodes ("simple TGA"). Eighteen patients (10.8%) either had an alternative diagnosis or a severe comorbidity that was assumed to have had an impact on the occurrence of the amnestic episode ("complicated TGA/mimic"). The most important differential diagnosis was stroke (11 patients, 6.6% of all TGA suspects and 61.1% of the complicated TGA/mimic group). Other mimics were transient epileptic amnesia (2 patients) and steroid-induced delirium (1 patient). Important comorbidities that had not been obvious at the time of presentation were severe sleep apnea (2 patients), triptan overuse (1 patient), and an involuntary amlodipine intoxication during TGA.

CONCLUSION

As approximately every tenth patient with suspected TGA either had an alternative diagnosis or a severe comorbidity, which had not been obvious at the time of admission, we consider in-patient treatment of all suspected TGA cases as appropriate, preferably in the setting of a stroke unit, as ischemic stroke was the by far most important diagnosis mimicking TGA.

Migraine in transient global amnesia: a meta-analysis of observational studies

BACKGROUND

PURPOSE: Although many studies have investigated the relationship between transient global amnesia (TGA) and migraine, to date, no meta-analysis has confirmed the existence and size of their association.

METHODOLOGY

Literature search involved MEDLINE, EMBASE, CENTRAL and PsycINFO. Observational controlled studies including TGA patients (Caplan, Hodges and Warlow) were retrieved. Quality evaluation was based on the Newcastle-Ottawa scale. The prevalence of migraine was compared in TGA patients vs. healthy controls (HC), as well as in TGA against TIA individuals. Data from case-control, cross-sectional and cohort studies were pooled separately.

RESULTS

Literature search yielded 1178 articles, 12 of which were included in the present meta-analysis. Results from case-control (ten), cohort (one) and cross-sectional (one) studies were compatible with an association between TGA and migraine. The nationwide inpatient cross-sectional study was of lesser value due to its inpatient orientation. The high-quality, population-based, retrospective cohort (158,301 participants per group) determined a higher relative-risk (RR) of TGA for migraine vs. non-migraine individuals [RR = 2.48, 95%confidence-interval (95% CI) = (1.32, 4.87)]. Sensitivity testing based on stricter diagnostic criteria strengthened the estimated association [RR = 3.84, 95% CI = (1.57, 9.38)]. Additionally, pooled data from eight case-control studies (700 TGA, 746 HC) yielded similar results [Odds-Ratio, OR = 2.51, 95% CI = (1.85, 3.41)], with the association mainly driven by the three high-quality studies, rather than the five articles of moderate quality. Finally, pooled findings from four case-control studies of moderate-quality revealed a higher prevalence of migraine among TGA compared to TIA patients [OR = 1.82, 95% CI = (1.22, 2.73)].

CONCLUSIONS

A significant association between TGA and migraine was established. The underlying connecting mechanism remains undetermined, yet.

Increased incidence of transient global amnesia during the Covid-19 crisis?

Since the beginning oft he Covid-19 pandemic we have observed an increased incidence of transient global amnesia, possibly related to emotional stress as a trigger factor.

Transient global amnesia following carotid artery stenting: A case report

Transient global amnesia (TGA) is a neurological disorder characterized by sudden onset of anterograde and retrograde amnesia. TGA following angiography is rare and its possible etiologies have not been determined definitively. Herein, I report a case of TGA after carotid artery stenting with DWI findings, which, to date, has not been reported. The patient was a 71-year-old man who developed TGA following carotid artery stenting. Diffusion-weighted imaging demonstrated a focal restricted diffusion lesion in the left medial temporal lobe. Left carotid artery stenting was performed via the common femoral artery, and the procedural course was uneventful. However, the patient suffered an amnestic event 1 hour after the procedure. DWI performed 1 hour after amnesia onset revealed a small punctate restricted diffusion lesion in the left hippocampus. One day later, his amnesia spontaneously resolved. Although TGA after endovascular procedure is rare and usually has a favorable prognosis, clinicians and interventionists should be aware of this rare complication.

Acute amnestic syndromes

Acute amnestic syndromes are usually rare clinical events occurring in emergency situations. Etiological diagnosis can be challenging and underlying causes diverse. They can be transient and totally reversible, or accompanied by other neurological symptoms resulting in serious and irreversible brain damage. Pathophysiology of these syndromes mainly corresponds to structural or functional alteration of memory circuits, including those in the hippocampus. One of the most frequent forms is transient global amnesia (TGA), characterized by sudden onset of anterograde amnesia lasting less than 24  hours, in the absence of other neurological signs or symptoms. Another acute and transient memory disorder is transient epileptic amnesia (TEA), due to focal crisis activity. Stroke injuries occurring at strategic memory-related sites can also present as sudden episodes of amnesia. In addition to neurological etiologies, amnesia may be a symptom of a psychiatric disorder (dissociative amnesia). Traumatic brain injuries, autoimmune encephalitis and acute toxic metabolic disorders can also cause amnesia and should be included among the differential diagnoses. In this review, we summarize the most relevant clinical findings in acute amnestic syndromes, and discuss the different ancillary tests needed to establish a correct diagnosis and management as well the best treatment options. Relevant anatomical and pathophysiological aspects underlying these conditions will be also be presented.

Factors determining recurrence in transient global amnesia

Background

Aetiology of transient global amnesia (TGA) remains uncertain, though many have been proposed, including ischaemic, migrainous or epileptic pathologies.

Methods

We attempted to determine risk factors for TGA, as well as prognostic factors that may cause recurrence. We evaluated clinical history, family history and magnetic resonance diffusion-weighted imaging (DWI) studies of 93 prospective patients with TGA. Patients were followed from 2004 to 2016. Fifteen of 93 (16%) patients experienced a recurrence of TGA.

Results

Among precipitating events, physical activities inducing Valsalva-like manoeuvres were most common, followed by emotional stress. Eighty-four patients had possible comorbidities or risk factors for TGA, though no single risk factor was ubiquitous. Risk factors associated with recurrence were head injury (isolated vs. recurrent, 16.7% vs. 53.5%, p &lt; 0.01), depression (isolated vs. recurrent, 15.4% vs 46.7%, p = 0.01) and family history of dementia (isolated vs. recurrent, 20.5% vs. 46.7%, p = 0.03). Of 15 patients with confirmed recurrent TGA, two developed dementia and four subjective memory impairment. DWI lesions were observed in 24 patients and were located anywhere within the hippocampus.

Conclusions

DWI lesions were not significantly associated with outcomes (recurrence, subjective memory impairment, dementia). We have found that depression, previous head injury and family history of dementia may predict TGA recurrence.

Concomitant reversible cerebral vasoconstriction syndrome and transient global amnesia

BACKGROUND

Reversible cerebral vasoconstriction syndrome (RCVS) is a common cause of thunderclap headache (TCH), mainly recurrent, sometimes associated with seizures and/or neurological deficit. Association with amnesia is exceptional. We report a case series of RCVS concomitant with transient global amnesia (TGA) and propose pathophysiologic hypotheses.

METHODS

We retrospectively reviewed clinical and radiological features of patients diagnosed with confirmed concomitant RCVS and TGA between 2012 and 2018 in two specialized institutions.

RESULTS

Two women aged 67 and 53, and a 64-year-old man had a first thunderclap headache triggered by an acute emotional stress, rapidly followed by TGA. Amnesia resolved within a few hours and RCVS was proven for all, with complete resolution of vasospasms within 3 months. All three patients had excellent outcome.

CONCLUSIONS

RCVS and TGA can occur simultaneously, which suggests common mechanisms such as aberrant responses to physical or emotional stress and cerebral vasoconstriction.

Emergency department visits for transient global amnesia alone or in association with substance abuse

OBJECTIVES

To study the epidemiology of emergency department visits for transient global amnesia (TGA) by itself or associated with substance abuse or sexual assault.

MATERIAL AND METHODS

Retrospective study of cases treated from January to December 2018. Data for all patients with TGA were extracted, and cases were classified as associated with substance abuse (TGASUB), sexual assault (TGASEX), or neither (TGAONLY).

RESULTS

A total of 287 TGA cases were found: 169 (58.9%) were TGASEX, 62 (21.6%) TGAONLY, and 56 (19.5%) TGASUB. Two hundred eighteen (76%) were female and 69 (24%) were male. Ages ranged from 16 to 90 years; 174 (60.6%) were under the age of 30 years. Two hundred one patients (72.8%) reported consuming alcohol; and 105 (49.1%) were positive on testing (mean blood alcohol concentration, 0.74 g/L; maximum, 3.9 g/L. Twenty patients (7.1%) reported using cannabis, and 39 (17.3%) had positive test results; 14 reported using cocaine (4.9%) and 28 (12.4%) tested positive; 5 (1.7%) reported using amphetamines and 20 (8.8%) tested positive. Fifty-eight (20.1%) had symptoms of intoxication. Four were admitted in coma. A computed tomography scan was ordered for 66 patients (23%), 7 patients were hospitalized, and none died.

CONCLUSION

The prevalence of TGA is higher if cases of substance abuse and sexual assault are counted. Toxicolgy testing changes the epidemiology of TGA in emergencies.

Resting-state connectivity alterations during transient global amnesia

While the pathophysiology of transient global amnesia (TGA) is not understood, due to the specific nature of the clinical deficits, transient dysfunction in the medial temporal lobe, especially in the hippocampus, is assumed; however, concomitant disturbances in other brain regions and in executive function have been postulated. In this study, a cohort of 16 patients was prospectively recruited from the emergency department for resting-state functional MRI (fMRI) during the acute stage of TGA, as confirmed by a standardized neuropsychological assessment. Twenty age- and sex-matched controls, as well as twenty patients with a history of TGA, were recruited for comparison. Functional data were processed using independent component analysis (ICA), allowing the complete automatic (data-driven) identification of spontaneous network dynamics. We documented a severe disturbance in anterograde episodic long-term memory in all patients. Group-based ICA of resting-state data in acute TGA patients versus that of controls and patients with a past TGA episode demonstrated reduced FC mainly of structures belonging to the executive network (EN), but also the hippocampus, confirming its pathophysiological involvement in the disorder, as well as areas belonging to the salience network and other subcortical regions. No significant differences were found when comparing connectivity in patients with a history of TGA and controls. Our findings strengthen previous empirical and theoretical accounts of hippocampal and executive dysfunction in TGA. The disruption of frontal, parietal and insular control regions, together with disruption in the hippocampus, provides a new interpretation for the pathophysiology and neuropsychological profile of this neurological disorder on a large-scale network level

•

During TGA connectivity is reduced in areas within and outside the executive network, including the hippocampus.

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Relevant hubs within the salience network and subcortical regions are also involved.

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The acute stage of TGA is interpreted on a large-scale network level.

Enhanced cortisol secretion in acute transient global amnesia

INTRODUCTION

Stress-related transient inhibition of memory formation in the hippocampus has been hypothesized as one of the underlying pathomechanisms of transient global amnesia (TGA). TGA episodes, during which patients cannot encode and recall new information (anterograde amnesia affecting episodic long-term memory), are frequently preceded by a psychologically or physically stressful event.

METHODS

We measured salivary cortisol during acute TGA in 14 patients, as well as cortisol day-profiles and the effect of experimental exposure to stress (using the socially evaluated cold pressor test) on cortisol levels during the subacute phase. We assessed psychiatric comorbidity as well as depression, trait anxiety and chronic stress. These findings were compared with data of 20 healthy controls.

FINDINGS

Nine patients reported a precipitating stressor and all 14 developed typical hippocampal lesions on follow-up MRI. During TGA, salivary cortisol levels were more than 3-fold higher compared to time-matched day levels. While there was no difference in mean cortisol levels of the diurnal rhythm, we found a significant interaction between groups during experimental stress exposure (p = 0.049) with the TGA group revealing a higher cortisol increase. The TGA group reported higher levels of depressive symptomatology (CES-D) and higher scores of chronic stress (TICS) compared with the control group and there was a significant correlation between cortisol increase during TGA and the results of self-rating according to the CES-D (r = 0.615; p = 0.004), as well as to the STAI (r = 0.702; p = 0.001).

CONCLUSION

Our findings of enhanced secretion of cortisol in acute TGA patients correlating with symptoms of depression and anxiety and a persisting hyperreactivity to experimental stress in the subacute phase support the hypothesis that stress might be significant for the pathogenesis of TGA.

Transient epileptic and global amnesia: Real-life differential diagnosis

OBJECTIVE

Transient epileptic amnesia (TEA) is an underestimated condition in emergency clinical setting, where most of transient amnesic episodes tend to be classified as transient global amnesia (TGA). We designed this study to evaluate the actual frequency of TEA in a real-life scenario and to highlight the features that can help clinicians distinguishing it from TGA.

METHODS

We retrospectively collected clinical data of 83 patients who accessed our emergency ward for an abrupt onset of amnesic disorder, initially interpreted as TGA. All patients underwent neurological evaluation, magnetic resonance imaging (MRI) scan, and standard 21-channel scalp electroencephalography (EEG) recording (standard EEG [st-EEG]). Moreover, patients with borderline epileptiform abnormalities on st-EEG or with normal st-EEG but high clinical suspicion for TEA underwent a 16-channel 24-hour ambulatory EEG (24-h EEG). Clinical features, neurophysiological, and neuroimaging data were analyzed and compared in the two groups (TEA and TGA).

RESULTS

Diagnosis of TEA, according to Zeman's criteria, was made in 15 patients (18%). From a clinical point of view recurrence (p < .001) and atypical symptoms such as confusion or language disorder (TGA plus manifestations), appear to be key elements in order to discriminate between TEA and TGA (80% of patients with TEA vs 7.8% of patients with TGA; p < .001). In our sample, duration of the episodes did not significantly differ between TGA and TEA, even though it is usually described as shorter for TEA. This result could be related with a prolonged postictal state in these patients. The analysis of st-EEG results evidenced low sensitivity for interictal epileptiform abnormalities (IEAs) detection (52.3%), with not conclusive data in distinguishing TEA from TGA. On the contrary, 24-h EEG showed IEAs in all patients with epilepsy, mostly during sleep, suggesting an essential diagnostic role of long-lasting EEG recording for TEA. Finally, structural abnormalities were more frequent in patients with TEA (26.6%). In the group with TGA, the only imaging alteration found was diffusion weighted imaging (DWI) hippocampal hyperintensity.

CONCLUSION

Our findings show that in a real-life clinical scenario, TEA is frequent but often overlooked. However, simple clinical data and widely available neurophysiological examinations can truly help to effectively distinguish TEA from TGA.

Medical Procedure-Related Transient Global Amnesia

BACKGROUND

Transient global amnesia (TGA) is an interesting clinical syndrome characterized by sudden memory loss for recent events and an inability to retain new memories usually lasting several hours and recovering spontaneously. We conducted a literature search of medical procedure-related TGA and its predisposing conditions.

METHODS

We performed PubMed searches using the keyword "transient global amnesia" combined with "procedure," "test," "therapy," or various other individual medical procedures. In addition, we described 2 cases of gastroscopy-related TGA.

RESULTS

Eighty-nine patients with medical procedure-related TGA in 49 articles were summarized. The most common procedure was cerebral angiography (n = 45), followed by coronary angiography (n = 10) and general anesthesia (n = 9). After categorization, neurological procedures were most common (n = 46, 51.7%), followed by cardiac (n = 17, 19.1%), anesthetic (n = 11, 12.4%), gastrointestinal (n = 4, 4.5%), and pulmonary (n = 2, 2.2%) procedures.

CONCLUSIONS

Diverse cases of medical procedure-related TGA have been reported in the literature. Valsalva-associated activities, emotional stress with anxiety, and acute pain were predisposing conditions. An understanding of medical procedure-related TGA may be important for clinicians who perform such medical procedures.

Transient global amnesia: Minor inconvenience or early warning sign?

Transient global amnesia (TGA) is a clinical diagnosis and is often a diagnosis of exclusion. However, despite the benign nature of this condition, it has been associated with underlying life-threatening medical conditions (e.g., myocardial infarction, dissecting aortic aneurysm, arrhythmias). Our case report highlights the importance of early recognition of those with cardiovascular risk factors who present with acute onset altered mental status to look for underlying medical comorbidities.

Unilateral or bilateral punctate hippocampal hyperintensities on DW-MRI: seizures, amnesia, or both?

The presence of small hippocampal hyperintense lesions on diffusion-weighted (DW) MRI can respond to different etiologies and represents a challenge where clinical judgment is imperative, since therapeutic approach may be quite different.We here report three patients with similar neuroradiological findings, i.e., hyperintense punctate hippocampal lesions on diffusion-weighted MRI sequences, yet of different origin. The first one presented with isolated amnesia (transient global amnesia), the second one with amnesia and seizures, and the third one with seizures.Thus, hippocampal punctate lesions appear after transient global amnesia, but the same pattern may be present after seizures, either focal-onset or generalized seizures. This peculiar radiological MRI pattern could indicate a pathogenic link between transient global amnesia (TGA) and seizures which should be further studied.

Tako-tsubo cardiomyopathy with transient global amnesia and cerebellar embolic stroke triggered by existential fear

BACKGROUND

Embolic stroke is a complication of Tako-Tsubo-cardiomyopathy (TTC), transient left ventricular dysfunction mimicking myocardial infarction without coronary culprit lesion explaining the whole left ventricular dysfunction. Transient global amnesia (TGA) is characterized by sudden onset of anterograde amnesia without compromise of other neurologic functions.

CASE REPORT

A 57 years old female was admitted because of sudden confusion and loss of her memory after emotional stress. TGA was diagnosed. Because of chest pain and laboratory tests indicating myocardial ischemia, she underwent coronary angiography which was normal. Within the following 24h her memory improved. She complained about severe vertigo and cerebral magnetic resonance imaging showed a recent ischemia in the left cerebellum.

CONCLUSIONS

TGA is not a disease for the neurologists exclusively but also cardiac comorbidities have to be considered and cardiologists should be involved in the acute care of these patients in order not to overlook life-threatening diseases.

[CME - Transient Global Amnesia]

Transient global amnesia (TGA) is a neurological condition which is still a diagnostic challenge for clinicians. Diagnostic clues are an acute onset of a disturbance of memory, a lack of other focal neurological deficits, and repetitive questioning of the patients about time and circumstances. Although the signs and symptoms are quite typical, making the diagnosis of TGA might still be challenging, depending on the patient’s characteristics. Taking a precise history from the patient and his/her next of kin is seminal. This article discusses the typical clinical presentation, pathophysiological hypotheses, the diagnostic clues and the most important differential diagnoses.