CC BY 4.0 · TH Open 2023; 07(02): e94-e96
DOI: 10.1055/s-0043-57225
Case Report

Prolonged Fasting as a Cause of Deep Vein Thrombosis: A Case Report

1   Centre d'Excellence des Maladies Vasculaires, Centre Hospitalier Universitaire de Québec, Université Laval, Hôpital Saint-François d'Assise, Québec, Canada
Carine Samson
2   MaClinique Médicale Lebourgneuf, Québec, Canada
3   Department of Medicine, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada
Anthony Calabrino
1   Centre d'Excellence des Maladies Vasculaires, Centre Hospitalier Universitaire de Québec, Université Laval, Hôpital Saint-François d'Assise, Québec, Canada
› Author Affiliations


Background Intermittent fasting is becoming more popular as health benefits are described in recent literature. Various forms of fasting exist, one of them involving a zero-calorie diet and drinking only water. However, the safety of water-only fasting is still not well established. We report a case of a man who developed a lower limb deep vein thrombosis at the end of a 2-week water-only fasting and characterized by an initial period of 5 days of no food and no water intake. We reviewed literature regarding potential links between fasting and venous thromboembolism (VTE).

Clinical Approach We believe that fasting can induce important dehydration, leading to hypercoagulability and then contribute to the development of a venous thrombosis. The patient was treated with apixaban for 3 months as is recommended in patients with a provoked event caused by a transient risk factor. No thrombotic recurrence was observed during the 6-month follow-up.

Conclusion The public needs to be aware of the potential life-threatening complications associated with important dehydration in the setting of medically unsupervised fasting, and these might include VTE. Whether a VTE with dehydration as the only identified risk factor should be approached as a low recurrence risk situation or not still needs to be clarified.

Publication History

Received: 31 January 2023

Accepted: 21 March 2023

Article published online:
20 April 2023

© 2023. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (

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