Causes and Management of Inferior Mesenteric Vein Varix

Primary Underlying Mechanisms

Noncirrhotic causes of portal/mesenteric vein thrombosis include hypercoagulable states, myeloproliferative disorders (JAK2V617F mutation in 20-40% of splanchnic vein thrombosis), inherited thrombophilia, and paroxysmal nocturnal hemoglobinuria, according to the National Comprehensive Cancer Network 1
Abdominal inflammatory conditions, recent surgery (especially splenectomy), and malignancy are additional risk factors for portal/mesenteric vein thrombosis, as reported in the Journal of Hepatology 2 and the Journal of the National Comprehensive Cancer Network : JNCCN 1

The American College of Radiology recommends CT portal venous phase to assess patency of portal vein, splenic vein, superior/inferior mesenteric veins; identify filling defects, cavernous transformation, or collateral vessels, as stated in the Journal of Hepatology 2 and the Journal of the American College of Radiology 3
Doppler ultrasound is used to evaluate flow direction (hepatofugal vs hepatopetal), velocity, and presence of collaterals, according to the Journal of Hepatology 2
Endoscopic ultrasound with color Doppler is a second-line diagnostic tool for deep rectal varices when diagnosis is uncertain, as reported in the World Journal of Emergency Surgery 4

A complete thrombophilia workup is recommended if thrombosis is identified, including JAK2V617F mutation, antithrombin deficiency, protein C/S deficiency, Factor V Leiden, and prothrombin gene mutation, as stated in the Journal of the National Comprehensive Cancer Network : JNCCN 1 and the Journal of the National Comprehensive Cancer Network : JNCCN 5
Liver function tests and coagulation parameters are used to assess severity of underlying liver disease, according to the World Journal of Emergency Surgery 4

The European Association for the Study of the Liver recommends immediate anticoagulation with low-molecular-weight heparin for acute portal/mesenteric vein thrombosis, unless major contraindications, as reported in the Journal of Hepatology 2 and the Journal of Hepatology 6
Non-selective beta-blockers are recommended for primary prophylaxis in patients with portal hypertension from cirrhosis, as stated in Clinical and Molecular Hepatology 7

The American College of Radiology suggests that splenic vein thrombosis from pancreatitis or pancreatic pathology causes isolated left-sided portal hypertension, forcing blood through inferior mesenteric collaterals 8, 9
Patients with liver cirrhosis and bleeding rectal varices from inferior mesenteric collaterals have an 80% mortality within 2 months, primarily from hepatic failure rather than hemorrhage itself, as stated by the World Journal of Emergency Surgery 10

The Journal of the American College of Radiology indicates that portal vein occlusion forces development of extensive portosystemic collaterals, including inferior mesenteric varices as alternative drainage pathways 11, 8
Noncirrhotic portal vein thrombosis can occur from hypercoagulable states, myeloproliferative disorders, or inherited thrombophilia, according to Praxis Medical Insights 12

The World Journal of Emergency Surgery recommends that patients with hepatofugal flow in the inferior mesenteric vein require stepwise management starting with octreotide, followed by endoscopic procedures, then BRTO or direct percutaneous embolization via the inferior mesenteric vein 10, 9

The American College of Radiology advises that inferior mesenteric varices should not be assumed to indicate only cirrhosis—always obtain cross-sectional imaging with portal venous phase CT or MRI to distinguish between portal hypertension with patent portal vein, splenic vein occlusion, or portal vein thrombosis, as each requires fundamentally different treatment approaches 9, 12