Welcome to PracticeUpdate! We hope you are enjoying temporary access to this content.
Please register today for a free account and gain full access
to all of our expert-selected content.
Already Have An Account? Log in Now
Mimics and Severe Comorbidity in Clinically Suspected Transient Global Amnesia
TAKE-HOME MESSAGE
-
The authors of this retrospective study reviewed the medical records and imaging data of 163 patients with 166 suspected episodes of transient global amnesia (TGA) over a 7-year period. Simple TGA was confirmed in 148 of 166 episodes (89.2%) following a comprehensive neurologic workup. In all, 18 patients (10.8%) were suspected of having an alternative diagnosis or a severe comorbidity (complicated TGA or mimic) that was causing the symptoms. Stroke was the most common diagnosis among patients with complicated TGA (11 patients; 6.6% of all TGA suspects). Transient epileptic amnesia (2 patients) and steroid-induced delirium (1 patient) were other mimics. Severe sleep apnea (2 patients), triptan overuse (1 patient), and amlodipine intoxication were less obvious comorbidities at the time of presentation. Generally,10% of patients admitted with TGA had an alternative diagnosis.
- Because ischemic stroke was the most common diagnosis, patient monitoring in a stroke unit and a complete neurologic workup are warranted in patients with TGA episodes.
abstract
This abstract is available on the publisher's site.
Access this abstract nowBACKGROUND
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.
Additional Info
Disclosure statements are available on the authors' profiles:
Prevalence of Mimics and Severe Comorbidity in Patients With Clinically Suspected Transient Global Amnesia
Cerebrovasc. Dis. 2021 May 01;50(2)171-177, R Werner, JC WoehrleFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Transient global amnesia (TGA) is a clinically diagnosed syndrome typically characterized by sudden onset anterograde amnesia, lasting up to 24 hours, without any other focal neurological deficits or epileptic features.1 The initial diagnostic criteria was proposed in 1985.2 Since then, the literature regarding the clinical description of TGA has grown and that has led to an increased recognition of this syndrome. Given the lack of confirmatory investigations, it remains important to carefully consider some of the potential diagnostic mimics, including transient epileptic amnesia, acute cerebrovascular accident, psychogenic amnesia, and metabolic disorders like hypoglycemia when evaluating a patient with suspected TGA.1 The actual prevalence of these diagnostic mimics among patients with suspected TGA is unknown and probably varies across different centers and nations.
In this study, Werner et al evaluated the frequency of TGA mimics among patients who presented to the emergency room of an academic hospital in Germany from 2008 to 2014 and met the clinical diagnostic criteria for TGA.3 The authors found that among 166 episodes of suspected TGA, 18 (10.8%) had an alternative diagnosis or underlying medical comorbidity that potentially influenced the amnestic episode. Of these 18 patients, 11 patients had an acute stroke (10 ischemic strokes and 1 hemorrhagic stroke), 2 patients had a new diagnosis of seizure and were likely suffering from transient epileptic amnesia, 2 patients had severe sleep apnea, 1 patient had steroid induced delirium, 1 patient had a possible side effect from daily use of triptans, and 1 patient had acute Amlodipine toxicity. So, nearly 10% of all patients initially suspected to have classic TGA were later discovered to have other significant diagnoses that require a different diagnostic and therapeutic approach. Therefore, the authors proposed an inpatient evaluation of all patients with suspected TGA to carefully rule out the concomitant diagnoses that might not be apparent at the initial encounter and without additional investigations like brain imaging and/or electroencephalogram. These results need to be validated in larger and ideally multi-center studies. Future studies are also needed to investigate any specific clinical signs that might support the diagnosis of a TGA mimic and to assess the yield of different diagnostic investigations for patients suspected to have TGA in order to help the clinicians chose appropriate tests in a cost-effective manner.
References