Extrahepatic Portal Vein Obstruction and Cavernoma

Descriptive text is not available for this imageBASICS

DESCRIPTION

Portal vein (PV) obstruction

  • Interruption of forward hepatopetal portal blood flow within the extrahepatic PV
  • With or without involvement of intrahepatic PV branches, splenic vein, superior/inferior mesenteric vein
  • Cavernous transformation is used to describe the collection of collaterals vessels that develop around the obstructed extrahepatic PV.
  • Condition leads to prehepatic (noncirrhotic) portal hypertension.
  • In the pediatric population, obstruction is most typically due to PV thrombosis.
  • Main cause of noncirrhotic portal hypertension in children

EPIDEMIOLOGY

  • Typically present in childhood with complication of portal hypertension, including sometimes major gastrointestinal (GI) bleeding
  • GI bleeding is more typical in patients presenting <7 years of age.
  • Splenomegaly in the absence of symptoms is more typical for patients aged 5 to 15 years.

ETIOLOGY

50% of PV obstructions are idiopathic. Identified causes include the following:

  • Congenital vascular anomaly
    • PV malformation
    • Webs or diaphragms within the PV
  • Clot resulting from a hypercoagulable state
  • Clot from other causes:
    • Omphalitis
    • Umbilical vein catheterization
    • Portal pyelophlebitis
    • Intra-abdominal sepsis
    • Surgery near the porta hepatis
    • Sepsis
    • Cholangitis
    • Dehydration
    • Trauma
  • Other causes for PV obstruction in older children:
    • Ascending pyelophlebitis from perforated appendicitis
    • Primary peritonitis, cholangitis, and pancreatitis causing a splenic vein thrombosis
    • Inflammatory bowel disease

RISK FACTORS

Genetics

A genetic basis of this problem has not been identified, although hereditary hypercoagulable states are sometimes identified as risk factor.

PATHOPHYSIOLOGY

  • In most noncirrhotic etiologies, the thrombus usually starts at the site of origin along the PV.
  • Occasionally, thrombosis of the splenic vein propagates to the PV, most often resulting from an adjacent inflammatory process (e.g., severe pancreatitis).
  • Asymptomatic splenomegaly, hypersplenism, or upper GI hemorrhage results from extrahepatic portal hypertension.
  • Less commonly, ascites or failure to thrive can occur, as well as portopulmonary hypertension.

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