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

Abstract

<b><i>Background:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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. <b><i>Conclusion:</i></b> 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.

Transient global amnesia with transient anosmia: a curious case suggestive of middle cerebral artery occlusion

“…TGA is a syndrome featuring acute anterograde amnesia as the most prominent clinical manifestation. 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 [2]. The most important differential diagnosis was cerebrovascular diseases.…”

Migraine Pharmacological Treatment and Cognitive Impairment: Risks and Benefits

“…From a clinical viewpoint, memory impairment is listed among the potential (infrequent) neurological side effects of rizatriptan [ 222 ]. Anecdotic reports suggest that acute or chronic exposure to triptan-driven vasoconstriction induces transient global amnesia-like symptoms, possibly due to reversible ischemia [ 223 , 224 ]. Preliminary results also suggest reversibility of 5-HT 1B/1D -driven memory impairment by administering 5-HT 1B/1D antagonists and ultimately restoring cholinergic-driven learning consolidation [ 221 , 225 , 226 ].…”

High point-like signal in the hippocampus

“…The differential includes migraine, complex partial seizures, alcoholic blackouts, minor head trauma; when symptoms are atypical or prolonged, other diagnoses, especially stroke, are found in about 10% of patients 1. The DWI-MRI finding of one or more punctate lesions of the hippocampus seen in TGA are often detected between 12 hours to 6 days after the onset,2 and 4 to 6 months later, these findings improve 3…”