INTRODUCTION
The portal vein is formed by the confluence of the splenic and superior mesenteric veins, which drain the spleen and small intestine, respectively (figure 1). Occlusion of the portal vein by thrombus (portal vein thrombosis [PVT]) typically occurs in patients with cirrhosis and/or prothrombotic disorders (table 1). Patients with acute PVT have the sudden onset of portal venous occlusion due to thrombus. The occlusion may be complete or partial. In addition to involving the portal vein, the clot may also involve the mesenteric veins or the splenic vein. Patients with acute PVT have not yet developed features of chronic PVT, such as collateral circulation (eg, cavernous portal transformation) or portal hypertension. If it is not known when the clot developed, but the patient does not have features of chronic PVT, the PVT can be referred to as being "recent" [1]. Patients with recent PVT are managed the same as those with acute PVT.This topic will review the clinical manifestations, diagnosis, and management of acute PVT. The epidemiology and pathogenesis of PVT, as well as the approach to patients with chronic PVT are discussed elsewhere. (See "Epidemiology and pathogenesis of portal vein thrombosis in adults" and "Chronic portal vein thrombosis in adults: Clinical manifestations, diagnosis, and management".)
The approach to patients with PVT has also been reviewed in society guidelines [2-4]. The discussion that follows is generally consistent with those guidelines.
CLINICAL MANIFESTATIONS
The clinical manifestations of acute portal vein thrombosis (PVT) depend on the extent of the obstruction and the speed of its development.Symptoms — Acute PVT may be clinically silent and diagnosed during a radiologic examination for other reasons (such as acute pancreatitis) (image 1). Other patients may have abdominal pain that develops suddenly or progresses over a few days [5]. Patients may also report fever and dyspeptic symptoms. Patients with cirrhosis may present with variceal bleeding. The presence of spiking fevers, chills, and a painful liver is suggestive of septic PVT (acute pylephlebitis). In addition to symptoms related to the PVT, patients may also have symptoms related to conditions that predispose to the development of PVT, such as acute pancreatitis. (See "Pylephlebitis", section on 'Clinical manifestations'.)