Some studies have found TGA patients to have higher vascular risk factors and greater frequency of carotid atherosclerosis, suggesting an atherosclerotic embolic event as a cause. Ischaemia from thromboembolism constitutes a contrasting hypothesis on pathogenesis. Support for this comes from the observation that many TGA cases are precipitated by Valsalva-like activities, particularly physical or emotional stressors, which would temporarily cause thoracic-pressure elevation. One hypothesis is that retrograde venous flow leads to venous congestion, possibly due to increased thoracic pressure or jugular valve incompetence, which in turn causes a transient ischemia due to hypoperfusion. Multiple mechanisms have been proposed for the aetiology of TGA. Other patients might develop long-lasting memory problems, especially those with recurrence. For instance, memory and executive function impairment may objectively last up to five days post-TGA onset, despite patients subjectively reporting normal memory. It is hypothesized that, as these neurons are in locations vital for memory consolidation, small lesions may significantly impair memory function, though any effects on prognosis are unknown. Diffusion-weighted imaging (DWI) on magnetic resonance imaging (MRI) provides specific, consistent findings of 1–5 mm focal lesion in the hippocampal CA-1 sector, which resolve 7–10 days after onset of TGA, with no long-term structural changes. Imaging investigations are used to support the clinical diagnosis of TGA. While TGA occurs as a single event for many, estimates of recurrence have ranged from 2.9 to 26.3%, but some studies were retrospective. The estimated minimum annual incidence of TGA is 3.4 per 100,000, though this is likely to be much higher as some people will not present to the hospital and others will be misdiagnosed. Meta-analysis has found no predominance for either gender. Typically, it occurs in individuals aged 50–80 years, with decreased incidence in younger and older populations. Transient global amnesia (TGA) presents as sudden onset anterograde amnesia, with some features of retrograde amnesia, without residual cognitive impairment, of duration < 24 h. We have found that depression, previous head injury and family history of dementia may predict TGA recurrence. ConclusionsĭWI lesions were not significantly associated with outcomes (recurrence, subjective memory impairment, dementia). DWI lesions were observed in 24 patients and were located anywhere within the hippocampus. Of 15 patients with confirmed recurrent TGA, two developed dementia and four subjective memory impairment. recurrent, 15.4% vs 46.7%, p = 0.01) and family history of dementia (isolated vs. Risk factors associated with recurrence were head injury (isolated vs. Eighty-four patients had possible comorbidities or risk factors for TGA, though no single risk factor was ubiquitous. ResultsĪmong precipitating events, physical activities inducing Valsalva-like manoeuvres were most common, followed by emotional stress. Fifteen of 93 (16%) patients experienced a recurrence of TGA. Patients were followed from 2004 to 2016. We evaluated clinical history, family history and magnetic resonance diffusion-weighted imaging (DWI) studies of 93 prospective patients with TGA. We attempted to determine risk factors for TGA, as well as prognostic factors that may cause recurrence. Aetiology of transient global amnesia (TGA) remains uncertain, though many have been proposed, including ischaemic, migrainous or epileptic pathologies.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |