Antithrombin deficiency with portal vein and superior mesenteric vein thrombosis—a case report

Introduction: A deficiency in antithrombin (AT) can be hereditary or acquired. It is characterized by an AT activity level that is less than 80% of normal or the lower limit of the reference range on a regular basis. In some cases, AT deficiency has been linked to an increased risk of thromboembolism. Case presentation: We present the case of a 56-year-old Malay man with long-segment thrombosis of the portal vein and superior mesenteric vein with small bowel ischemia. He was diagnosed with AT deficiency following an extensive hematological and thrombophilia workup supported by a strong familial history of venous thromboembolism (VTE) affecting his brothers and sister. Conclusion: Inherited AT deficiency must be considered when spontaneous VTE occurs in young patients with unusual localizations, such as mesenteric veins and portal veins.