Mesenteric vein thrombosis is a potentially life-threatening vascular disorder of the mesenteric venous system, which can arise due to numerous genetic, circulatory, neoplastic, infectious or iatrogenic conditions. Both acute and chronic forms have been described in the literature. Imaging studies, primarily contrast-enhanced computed tomography, are used to make the diagnosis.
A number of conditions can cause mesenteric vein thrombosis, a vascular abnormality that is responsible for about 5-15% of all cases of mesenteric ischemia  . Inherited coagulopathies and thrombophilias (antithrombin, protein C, protein S, or factor V Leiden deficiencies), local disorders (pancreatitis, diverticulitis, peritonitis, and other inflammatory diseases), obesity, neoplasias, hematological disturbances (particularly thrombocytopenia and polycythemia vera), soft tissue trauma, previous abdominal surgery, but also liver cirrhosis and stasis of the venous blood flow are some of the most important etiologies    . In a large number of cases (between 20-50%), however, the exact cause remains unclear, in which case the term idiopathic mesenteric vein thrombosis is used   Typical patients are aged between 40-60 years and are more commonly males . The clinical presentation of mesenteric vein thrombosis (MVT) is divided into acute and chronic forms. In the acute setting, a sudden onset of nonspecific abdominal pain is the principal manifestation, followed by nausea, vomiting, diarrhea and gastrointestinal bleeding (hematemesis, hematochezia, or melena)   . Mesenteric ischemia and bowel infarction are life-threatening complications of acute MVT, manifesting as dehydration, hypotension, fever, ascites, and shock . Unfortunately, several studies have confirmed that the majority of patients (about 75%) are symptomatic for days before being diagnosed, putting them at a life-threatening risk . A chronic course, on the other hand, may be completely asymptomatic, but persistent abdominal pain and edema are frequently reported  . Malnutrition is also a frequent manifestation, which is why many individuals require parenteral nutrition, whereas existing portal hypertension could lead to hemorrhage from esophageal varices   .
Because of the nonspecific clinical presentation of MVT, the diagnosis may be difficult to attain based on clinical criteria . Furthermore, the differential diagnosis of nonspecific abdominal pain and associated symptoms is quite broad. For this reason, a detailed and comprehensive approach is necessary in order to raise valid clinical suspicion, which is vital for making the diagnosis . Firstly, physicians should obtain a complete patient history, with an emphasis on the course and progression of symptoms, existence of comorbidities and underlying conditions in the patient or within the family that might be responsible for the presenting complaints, and a history of alcohol and medication use . A thorough physical examination, because of its role in excluding certain pathologies, is equally important, but imaging studies are crucial in confirming MVT. Plain radiography of the abdomen is a useful initial method that might detect dilated bowel loops, ileus and in most severe cases, free air within the abdomen and gas in the portal vein . Ultrasonography and magnetic resonance (MR) angiography have also been recommended for the evaluation of mesenteric veins, but contrast-enhanced computed tomography (CT) is the gold standard, with an accuracy of 90%    . The thrombus, seen as a focal translucency, is the hallmark of MVT on CT studies, whereas dilation of the veins is also an important finding   . Laboratory workup, although very important for the assessment of the overall status of the patient, is of limited diagnostic benefit in the case of MVT, as only leukocytosis, thrombocytosis, and mild elevations of hepatic and pancreatic enzymes can be observed  . Thus, the diagnosis of MVT rests on clinical findings and contrast-enhanced CT.