Abernethy malformation
Updates to Article Attributes
Abernethy malformations are rare vascular anomalies of the splanchnic venous system. They compriseconsist of congenital portosystemic shunts and result from persistence of the embryonic vessels.
Epidemiology
Type I malformations are thought only to occur only in females with, while type II havinghave a male predilectionpredominance 1.
Pathology
Subtypes
There are two main types of Abernethy malformations that have been described (initially devised by G Morgan and R Superina 6):
- type I: end-to-end shunts
- type II: side-to-side shunts
In type I shunts (end-to-end), there is a congenital absence of the portal vein with a complete diversion of portal blood into systemic veins (inferior vena cava, renal veins, or iliac veins). These are further subdivided into those in which the splenic and superior mesenteric veins end up separately at the systemic veins, and those in which the splenic and superior mesenteric veins join to form a common trunk that ends up at the IVC, right atrium or iliac veins
-
type Ia: separate drainage of the superior mesenteric vein and splenic
veinsvein into systemic veins -
type Ib: superior mesenteric vein and splenic
veinsvein join to form a short extra-hepatic portal vein which drains into a systemic vein (inferior vena cava, right atrium or iliac veins)
In type II shunts (side-to-side), there is a hypoplastic portal vein with portal blood diversion into the inferior vena cava through a side-to-side, extrahepatic communication.
Associations
- hepatic encephalopathy: from portosystemic shunting
- hepatic mass lesions
-
focal nodular hyperplasia: thought to
begenerate due to the absence of the portal vein - hepatocellular carcinoma
- hepatoblastoma
-
focal nodular hyperplasia: thought to
- hepatopulmonary syndrome 2
-
pulmonary arteriovenous fistulae
- thought to
bearise due to hyperammonemia - may lead to systemic emboli
- thought to
- other congenital abnormalities
: particularly, particularly associated with type I 1 :
History and etymology
It was namedNamed after John Abernethy in 1793 who, who gave the first account of an absent portal vein and awith accompanying congenital mesentericocaval shunt 1,5in 1793.
See also
-<p><strong>Abernethy malformations</strong> are rare vascular anomalies of the splanchnic venous system. They comprise of congenital portosystemic shunts and result from persistence of the embryonic vessels. </p><h4>Epidemiology</h4><p>Type I malformations are thought only to occur in females with type II having a male predilection <sup>1</sup>.</p><h4>Pathology</h4><h5>Subtypes</h5><p>There are two main types of Abernethy malformations that have been described (initially devised by <strong>G Morgan </strong>and <strong>R Superina</strong> <sup>6</sup>):</p><ul>- +<p><strong>Abernethy malformations</strong> are rare vascular anomalies of the splanchnic venous system. They consist of congenital portosystemic shunts and result from persistence of the embryonic vessels. </p><h4>Epidemiology</h4><p>Type I malformations are thought to occur only in females, while type II have a male predominance <sup>1</sup>.</p><h4>Pathology</h4><h5>Subtypes</h5><p>There are two main types of Abernethy malformations that have been described (initially devised by <strong>G Morgan </strong>and <strong>R Superina</strong> <sup>6</sup>):</p><ul>
-</ul><p>In type I shunts (end-to-end), there is a congenital absence of the <a href="/articles/portal-vein">portal vein</a> with a complete diversion of portal blood into systemic veins (<a href="/articles/inferior-vena-cava-1">inferior vena cava</a>, <a href="/articles/renal-vein-1">renal veins</a> or <a href="/articles/iliac-veins">iliac veins</a>). These are further subdivided into those in which the <a href="/articles/splenic">splenic</a> and <a href="/articles/superior-mesenteric-vein">superior mesenteric veins</a> end up separately at the systemic veins, and those in which the splenic and superior mesenteric veins join to form a common trunk that ends up at the IVC, right atrium or iliac veins:</p><ul>- +</ul><p>In type I shunts (end-to-end), there is a congenital absence of the <a href="/articles/portal-vein">portal vein</a> with a complete diversion of portal blood into systemic veins (<a href="/articles/inferior-vena-cava-1">inferior vena cava</a>, <a href="/articles/renal-vein-1">renal veins</a>, or <a href="/articles/iliac-veins">iliac veins</a>). These are further subdivided into:</p><ul>
-<strong>type Ia:</strong> separate drainage of the superior mesenteric and splenic veins into systemic veins</li>- +<strong>type Ia:</strong> separate drainage of the superior mesenteric vein and splenic vein into systemic veins</li>
-<strong>type Ib:</strong> superior mesenteric and splenic veins join to form a short extra-hepatic portal vein which drains into a systemic vein</li>- +<strong>type Ib:</strong> superior mesenteric vein and splenic vein join to form a short extra-hepatic portal vein which drains into a systemic vein (inferior vena cava, right atrium or iliac veins)</li>
-<a href="/articles/focal-nodular-hyperplasia">focal nodular hyperplasia</a>: thought to be due to the absence of the portal vein</li>- +<a href="/articles/focal-nodular-hyperplasia">focal nodular hyperplasia</a>: thought to generate due to the absence of the portal vein</li>
-<li>thought to be due to hyperammonemia</li>- +<li>thought to arise due to hyperammonemia</li>
-<li>other congenital abnormalities: particularly type I <sup>1</sup><ul>- +<li>other congenital abnormalities, particularly associated with type I <sup>1</sup> :<ul>
-</ul><h4>History and etymology</h4><p>It was named after <strong>John Abernethy</strong> in 1793 who gave the first account of an absent portal vein and a congenital <a href="/articles/mesentericocaval-shunt">mesentericocaval shunt</a> <sup>1,5</sup>. </p><h4>See also</h4><ul><li><a href="/articles/portosystemic-shunts">portosystemic shunts</a></li></ul>- +</ul><h4>History and etymology</h4><p>Named after <strong>John Abernethy</strong>, who gave the first account of an absent portal vein with accompanying congenital <a href="/articles/mesentericocaval-shunt">mesentericocaval shunt</a> <sup>1,5 </sup>in 1793.</p><h4>See also</h4><ul><li><a href="/articles/portosystemic-shunts">portosystemic shunts</a></li></ul>
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