Acute complicated portal vein thrombosis: the forgotten diagnosis

A 50-year-old woman presented to the emergency department with intense diffuse abdominal pain with two days of evolution. She had no relevant past medical history. Blood samples showed leukocytosis, elevated C-reactive protein and moderately elevated lactate dehydrogenase. Ultrasound revealed small ascites and wall-thickened small bowel loops. CT was subsequently performed.

Ultrasound was firstly performed, revealing ascites and wall-thickened small bowel loops.

CT showed extensive partial portal vein thrombosis (PVT), extending to the right branch and, caudally, to the superior mesenteric vein (Fig. 1). The liver had smooth surface contours, without signs of cirrhosis, presenting heterogeneous parenchyma enhancement on the hepatic arterial phase, becoming homogenously enhanced on the portal venous phase. There were some biliary cysts in the liver parenchyma. There was small ascites but no signs of collateral circulation or splenomegaly.

Additionally, the cecum and ascending colon walls were markedly thickened and hypoenhanced after contrast administration, suggesting bowel ischemia (Fig. 1 and 2). There was spontaneously hyperdense fluid inside the cecum lumen, suggesting recent haemorrhage. With the exception of the most proximal jejunal loops, the small bowel loops had thickened and hypoenhancing walls. These imaging findings suggested acute PVT, extending to the superior mesenteric vein, and complicated with bowel ischemia.

Acute PVT is defined as a recent formation of a thrombus within the portal vein or its branches, which can be complete or partial [1]. It is a common complication of liver cirrhosis, but it is rare in the general population without known liver disease. Intra-abdominal inflammatory foci, such as pancreatitis or diverticulitis, neoplasms and myeloproliferative diseases are recognized risk factors for PVT [2]. Additionally, more than 60% of cases of noncirrhotic, nonmalignant PVT are associated with congenital or acquired thrombophilic disorders [3].

Abdominal pain is present in 90% of acute PVT cases, being accompanied by systemic inflammatory response in 85% of cases [1]. Additional clinical manifestations include diarrhoea, vomiting, rectal bleeding, fever and lactacidosis. However, the clinical presentation is usually unspecific, and the diagnosis is frequently overlooked.  

Doppler ultrasound is usually the first imaging modality and it can demonstrate the absence of flow within the portal vein [3]. CT provides additional information, allowing to evaluate the thrombus extent, to look for secondary causes, such as liver cirrhosis, inflammatory or neoplastic intra-abdominal diseases, and to exclude complications. Particularly, CT allows the diagnosis of intestinal ischemia, the most dreaded complication of PVT. Because acute PVT was shown to respond better to anti-coagulation than chronic PVT [4], it is important to ascertain chronicity. Mural calcification is pathognomonic of chronic PVT [3]. Splenomegaly and extensive collaterals suggest chronic thrombosis but are unspecific findings. Moreover, the presence of ascites and splenic vein thrombosis are independently related to anticoagulation treatment failure [4]. Venous ischemia usually presents with thickened, hypodense and hypoenhanced bowel wall due to oedema [5].

This patient had no liver cirrhosis nor signs of inflammatory, infectious or neoplastic abdominal disease. The liver showed transitional perfusion abnormalities related with the PVT. There were no signs of PVT chronicity. The poor enhancement of dilated small bowel loops suggested bowel ischemia. The patient underwent emergent abdominal surgery, which confirmed the extensive thrombosis of the portal vein and superior mesenteric vein, complicated with small bowel ischemia. The cecum was still viable. Extensive enterectomy was performed and anticoagulation therapy was started. The patient is still alive, and under investigation for pro-thrombotic diseases.

Teaching points:

Acute PVT should not be forgotten as a cause of acute abdominal pain. In the emergency setting, it is important to look for intra-abdominal causes of acute PVT and it is crucial to exclude intestinal infarction, a potentially fatal complication.