Transient Global Amnesia Triggered by Cold Water Swimming: A Series of 9 Cases Presenting to a Hospital on the Coast of Ireland Within 5 Years.

Abstract

Background: Transient global amnesia is a clinical syndrome characterized by sudden onset of anterograde amnesia, often accompanied by repetitive questioning, lasting up to 24 hours with complete resolution and no other neurological deficits. This case series presents 9 patients who experienced transient global amnesia following sea swimming between 2019 and 2024 at Bantry General Hospital, a hospital located in a coastal town on the south of Ireland.

Case presentations: Patients who presented with "amnesia" or "transient global amnesia" were identified through searching the hospital database. Patients whose symptoms were directly related to sea swimming were included in this report. All 9 patients were women, with ages ranging from 55 to 82 years. Symptoms typically developed during or immediately after swimming, with durations ranging from 1 to 7 hours. Common symptoms included confusion, short-term memory loss, repetitive questioning and disorientation to time and/or place. Water temperatures ranged from 9.2°C to 18°C. Neuroimaging, including computed tomography scans of the brain for all patients and magnetic resonance imaging for 3 patients, showed no acute changes. All patients experienced full symptom resolution within 24 hours.

Conclusions: This case series highlights the link between cold water immersion during sea swimming and transient global amnesia. The consistent association with sea swimming aligns with previous reports identifying cold water immersion as a trigger for transient global amnesia. These findings warrant further investigation into the relationship between sea swimming and transient global amnesia. Clinicians should be aware of this potential trigger when evaluating patients with acute onset amnesia, especially in coastal areas.

Learning points: This case series highlights the link between sea swimming and the occurrence of transient global amnesia.With the increasing popularity of sea swimming around Europe, clinicians should be aware of this phenomenon.Further research is necessary to understand the underlying mechanism behind this phenomenon.