Clinical History:
62 year old woman with history of "burning" sensation in the epigastrium
Radiographic Findings:
There is a focal, septated, anechoic structure in the left hepatic lobe
superiorly (Fig.
1) demonstrating internal flow on color Doppler which completely fills
these anechoic spaces (Fig.
3). This structure is supplied by inflow from the left portal
vein (Fig.
2) and egress of flow can be noted, via a short conduit with turbulent
flow, into the left hepatic vein (Fig.
4).
Discussion:
Intrahepatic portosystemic shunts (IPVS) are rare venous vascular anomalies.
They are felt to result from either a congenital vascular anomaly or chronic
liver cirrhosis and portal hypertension (~40%). Shunts such as these
tend to occur more frequently in the right hepatic lobe, although they
may also be seen in left lobe or both hepatic lobes simultaneously.
Although IPVS may be seen in early childhood, patients tend to be middle
aged (average age 60-65) at the time of diagnosis and most often present
with hepatic encephalopathy (~60%). However, this may be noted as an incidental
finding. The late clinical emergence of systemic symptoms may be
related to a decreasing tolerance for toxic metabolites with increasing
age. In children, the presence of hepatic encephalopathy has been
shown to be directly related to the shunt ratio, such that encephalopathy
was apparent in patients with shunt ratios greater than 60% while encephalopathy
was not observed in patients with shunt ratios below 30%.
Four basic morphologic types of abnormal venous communication have been
described as follows:
- Single large conduit of near constant diameter connecting the right
portal vein to the inferior vena cava. Most patients with this type
of anomaly
have evidence of liver cirrhosis and portal hypertension.
- Localized peripheral shunt with single or multiple communications
between branches of the portal vein and hepatic vein in one
segment of the liver. These patients are less likely to present
with
hepatic encephalopathy (10-15%).
- The peripheral portion of the portal vein and hepatic vein are connected
via a focal venous aneurysm. Most likely congenital in origin.
- Multiple diffuse communications between peripheral portal veins and
hepatic
veins in both hepatic lobes. Most likely congenital in
origin.
Diagnosis:
Intrahepatic Portosystemic Venous Shunt (IPVS)
References:
- Park JH, Cha SH, Han JK, Han MC. Intrahepatic portosystemic
venous
shunt. Am J Roentgenol. 1990; 155:527-8.
- Mori H, Hayashi K, Fukuda T, Matsunaga N, Futagawa
S, Nagasake M, Mutsukura M. Intrahepatic
portosystemic venous shunt: occurrence in patients with and without
liver cirrhosis. Am J Roentgenol.1987;
149:711-4.
- Chagnon SF, Vallee CA, Barge J, Chevalier LJ, Le Gal
J, Blery MV. Aneurysmal
portahepatic venous fistula: report of two cases. Radiology.
1986; 159:693-5.
- Uchino T, Matsuda I, Endo F. The
long-term prognosis of congenital
portosystemic venous shunt. J Pediatr.
1999; 135:254-6.
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