Transient global amnesia and migraine in twin sisters

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.

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 < 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.

Transient Global Amnesia Triggered by Migraine in a French Tertiary-Care Center: An 11-Year Retrospective Analysis

OBJECTIVE

The etiology of transient global amnesia (TGA) remains unclear, and flow disturbances in the mesial temporal lobes secondary to venous congestion have been proposed as a potential cause. The occurrence of TGA during a migraine attack is a rare condition.

METHODS

This 11-year retrospective study in one French center describes patients' characteristics, type of migraine, investigations, treatment with vasoconstrictor during the TGA/migraine attack, and outcome in patients who had TGA during a migraine attack.

RESULTS

Among 8821 new patients, 6 cases of TGA occurring during a migraine attack were identified. For a majority of patients, TGA occurs after the beginning of the attack. TGA always occurs during a severe migraine attack, with vomiting or vomiting efforts. Vomiting or vomiting efforts always precede a TGA episode.

CONCLUSIONS

TGA occurring during a migraine attack is rare. Since a Valsalva maneuver, such as forceful vomiting, is frequently described at the origin of the attack, blocking venous return through the superior venous cava may allow brief retrograde transmission of high venous pressure from the arms to the cerebral venous system, resulting in venous ischemia to the diencephalon or mesial temporal lobes and causing TGA.

Involvement of AMPA receptors in CSD-induced impairment of LTP in the hippocampus

OBJECTIVE

To investigate the alteration of hippocampal long-term plasticity and basal synaptic transmission induced by repetitive cortical spreading depressions (CSDs).

BACKGROUND

There is a relationship between migraine aura and amnesia attack. CSD, a state underlying migraine attacks, may be responsible for hippocampus-related symptoms. However, the precise role of CSD on hippocampal activity has not been investigated.

METHODS

Male Wistar rats were divided into CSD and control groups. Repetitive CSDs were induced in vivo by topical application of solid KCl. Forty-five minutes later, the ipsilateral hippocampus was removed, and hippocampal slices were prepared for a series of electrophysiological studies.

RESULTS

Repetitive CSDs led to a decrease in the magnitude of long-term potentiation in the hippocampus. CSD also reduced hippocampal synaptic efficacy, as shown by a reduction in post-synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor responses. In contrast, the post-synaptic N-methyl-d-aspartate receptor responses remained unchanged. In addition, there were no changes in paired-pulse profiles between the groups, indicating that CSD did not induce any presynaptic alterations.

CONCLUSION

These findings suggest that a reduction of post-synaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor responses is the mechanism responsible for impaired hippocampal long-term potentiation induced by CSD.

Genetic epidemiology of migraine and cluster headache

Migraine. The present genetic epidemiological survey of migraine was based on semi-structured interviews by a physician. The operational diagnostic criteria of the International Headache Society were used. Three thousand males and 1,000 females aged 40 were drawn from the Danish National Central Person Registry. They received a questionnaire by post regarding migraine and the response rate was 87%. People with self-reported migraine and a random sample reporting no migraine were invited to a headache interview and physical and neurological examination. Those not reacting to the invitation were interviewed by telephone. The participation of the interview was 87%. Kappa was 0.77 validating self-reported migraine against a clinical interview by a physician. Non-responders did not differ from responders regarding migraine. The lifetime prevalence of MO and MA was 9.3% and 6.3% in males and 20.1% and 9.6% in females. People with MA were included as probands in the family study. An equivalent number of probands with MO and probands who had never had migraine were random samples of the people with MO) and those who had never had migraine, respectively. First-degree relatives and spouses were interviewed blindly by a physician. The 378 probands had 1,109 first-degree relatives and 229 spouses. Compared with the general population, the first-degree relatives of probands with MO had a 1.9-fold increased risk of MO and a 1.4-fold increased risk of MA, after standardization for sex and age. The first-degree relatives of probands with MA had a 3.8-fold increased risk of MA and no increased risk of MO. The first-degree relatives of probands who had never had migraine had no increased risk of either MO or MA. Spouses to pro-bands with MC) had a 1.5-fold increased risk of MO, while spouses to probands with MA had no increased risk of MA. The familial patterns indicate that MO and MA are distinct entities. The familial occurrence suggests that MO is caused by a combination of genetic and environmental factors, while MA is determined mainly or exclusively by genetic factors. The complex segregation analysis supports the importance of genetic factors and suggests multifactorial inheritance without generational difference in both MO and MA, but genetic heterogeneity cannot be excluded.

Transient global amnesia in a young child

Unprovoked and unexplained sudden loss of memory and inappropriate behaviour in a 5 year old child is described as fitting into the clinical picture of 'transient global amnesia'. The likely pathophysiology of this condition is discussed with some support for Fisher's suggestion of 'hippocampal-fornical' dysfunction.

Transient global amnesia

Transient global amnesia (TGA) is a transient, benign neurological syndrome, characterized by global loss of memory, preserved consciousness and self-awareness, associated with some behavioral changes (in particular, repetitive questioning). It generally resolves within 24 h. Mild brain stem symptoms can often be demonstrated during the attack, but major neurological abnormalities never occur. The only sequel is a permanent amnesic gap for the duration of the episode. The episode is often preceded by typical precipitating events, such as physical activity, emotional stress, acute pain, comprising haemodynamic changes of the body. The diagnosis is easy provided one is acquainted with the syndrome. The prevalence of vascular risk factors is low and the risk for stroke is not increased. Although much evidence indicates the possibility of a causative ischaemia in the inferomedial parts of the temporal lobes, an atherothrombo-embolic TIA is not the cause of TGA, and TGA is unrelated to cerebrovascular disease in general. In the author's view, the cause of TGA is a transient ischemic attack (TIA) but a haemodynamic one of the vertebrobasilar system, producing a transient dysfunction of inferomedial parts of the temporal lobes, regions that are particularly sensitive to impaired blood supply. For a full pathogenetic explanation of TGA, clarification of the underlying mechanisms is a prerequisite. This touches on the genesis of migraine and Leao's spreading depression phenomenon. The term 'amnesic TIA' would reflect the pathogenesis more appropriately.

The genetics of migraine without aura and migraine with aura

Studies of twins, spouses and familial aggregation strongly suggest that migraine without aura (MO) and migraine with aura (MA) are genetically determined. The mode of inheritance is most likely multifactorial in both MO and MA. However, autosomal dominant inheritance with reduced penetrance cannot be excluded in either MO or MA. At present the only evidence for genetic heterogeneity of MA is familial hemiplegic migraine with slowly progressive ataxia. This phenomenon can also be explained by linkage of different genes. All existing studies have been characterized by one or more of the following methodologic shortcomings: selection of probands from clinic populations, information obtained by questionnaire, family history obtained through probands, insufficient description of the attacks, lack of distinction between MO and MA. Useful strategies for future studies of migraine genetics are discussed.

Syndromes of transient amnesia: towards a classification. A study of 153 cases

Of 153 patients presenting with acute transient amnesia, 114 fulfilled the proposed strict diagnostic criteria for transient global amnesia (TGA). The prognosis of this group was excellent with the exception of a small subgroup (7%), largely identifiable because of atypically brief or recurrent attacks, who developed epilepsy of temporal lobe type on follow up. Computerised tomography (CT) scans performed on 95 patients were normal, evidence for covert alcoholism was lacking and there was a familial incidence of approximately 2%. By contrast, the group of 39 patients who did not meet the criteria for TGA had a significantly worse prognosis with a high incidence of major vascular events. The groups could not be distinguished on the basis of behavioural characteristics during the attack. The following classification was proposed: 1) pure TGA--attacks fulfilling the strict criteria, and of more than one hour in duration which do not require detailed investigation, 2) probable epileptic amnesia--attacks of less than an hour or rapidly recurrent, 3) probable transient ischaemic amnesia, a minority of cases with additional focal neurological deficits during the attack.