Congenital portosystemic shunt

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A portosystemic shunt or portasystemic shunt (medical subject heading term; PSS), also known as a liver shunt, is a bypass of the liver by the body's circulatory system. It can be either a congenital (present at birth) or acquired condition and occurs in humans as well as in other species of animals. Congenital PSS are extremely rare in humans [1] but are relatively common in dogs. [2] Improvements in imaging and awareness have contributed to an increase in cases [3] [4] .Thus a large part of medical and scientific literature on the subject is grounded in veterinary medicine.

Contents

Background

Blood leaving the digestive tract is rich in nutrients, as well as in toxins, which under normal conditions undergo processing and detoxification in the liver. The liver's position downstream to the intestines in the body's circulatory system - the hepatic portal vein conveys blood from the intestines to the liver - allows it to filter this nutrient rich blood before it passes to the rest of the body.[ citation needed ]

The presence of a shunt, a bypass of the liver, causes blood to flow directly to the heart. This blood is no longer filtered by the liver and reaches the systemic circulation, resulting in a number of symptoms and complications with effects on the cardiovascular, neurophysiological, gastro-intestinal, urinary and endocrinal systems. [5]

Congenital porto-systemic shunts are vascular malformations which occur during the development of an organism in the uterus and are present at birth. In contrast, acquired porto-systemic shunts occur after birth and typically develop secondary to portal hypertension. [6]

Physiopathology

There are no major and direct communications between the portal and hepatic veins within the liver, nor between the systemic veins and the portal, superieur mesenteric or splenic veins. [7] Two distinct systems provide the liver with blood. Oxygen rich blood is sent to the liver from the heart via the hepatic artery, while the portal vein brings nutrient rich (but depleted in oxygen) blood to the liver from the intestines. This blood passes by the network of capillaries before being evacuated by the hepatic veins into the inferior vena cava and subsequently the heart. The division between these two systems helps assure the liver's physiological roles.

A CPSS results in a direct communication between the portal circulation and the systemic circulation. This breaks down the separation between these two systems which is crucial in ensuring normal physiological function. A reduction in the proportion of blood flowing from the digestive system to the liver during the first pass results. [8] The coefficient of filtration is therefore reduced, less blood rich in nutrients and toxins is filtered, and an accumulation of toxins in the blood circulatory system occurs.

Epidemiology

CPSS are thought to affect 1 in 30,000–50,000 live births. While most patients present with a single shunt, complex shunts, which include multiple abnormal vessels, are also reported. [6] [7]

Clinical manifestation

The size of the liver in patients affected by PSS is typically 45% to 65% of the standard volume for a given age. [6] Neonatal cholestasis, liver tumours, hepatopulmonary syndrome, pulmonary hypertension and encephalopathy are common clinical manifestations of CPSS. [6] In adults, the discovery of a CPSS is often fortuitous but can also occur in response to the detection of one or several characteristic complications such as hepatic encephalopathy, hepatopulmonary syndrome and pulmonary hypertension. In children, CPSS may present as neonatal cholestasis. These complications are generally induced by long term portosystemic derivations and are more commonly observed in children than in adults. [9] Unexplained neurocognitive dysfunction and other behavioural issues linked to hepatic encephalopathy occur in 17% to 30% of cases. [7]

Gastrointestinal bleeding is another common complication of PSS and has been observed in 8.1% of patients with extrahepatic portosystemic shunts. [10] Other complications of CPSS are hyperandrogenism, pancreatitis, vaginal bleeding, and lower urinary tract symptoms like nephrolithiasis (kidney stones) and haematuria (presence of blood in the urine). [11] It is generally agreed amongst specialists that the majority of CPSSs should be closed by radiological or surgical intervention. [8]

Classification

Congenital porto-systemic shunts (CPSS) are classified occurring to the position of the anastomose. If the anastomosis occurs outside of the liver, the shunt is considered to be extrahepatic. On the other hand, if the anastomosis is located within the liver, it is considered to be intrahepatic. The clinical manifestations of intra- and extra- hepatic portal systemic shunts can be similar; however the pathophysiology and treatment of the two types are distinct. [9] [12] [13]

Treatment

Spontaneous closure of CPSS can occur in some anatomic forms during the first two year of life. [14] However, in instances where spontaneous closure does not occur, radiologic or surgical closure of the CPSS is recommended to prevent, resolve and/or stabilise complications.

Upon discovery of a CPSS in a child, it is important to rule out portal hypertension or hepatic hemangioma as the cause of the shunt, either of which would require a specific treatment. Once the congenital, and isolated, nature of the shunt has been ascertained, closure by surgical intervention is usually recommended. [6] Shunt closure prevents the development of complications in pre-symptomatic subjects and may reverse or stabilize signs and symptoms in patients.

On-going research

An International Registry of Porto-Systemic Shunts (IRCPSS) has been elaborated in order to better understand the underlying causes, as well as the signs and symptoms of CPSS. The primary aim of the registry is to "better identify patients who are at risk of developing complications and to offer them standardized care." [5]

See also

Related Research Articles

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<span class="mw-page-title-main">Shunt (medical)</span> Hole or passage within the human body that allows fluids to move throughout it

In medicine, a shunt is a hole or a small passage that moves, or allows movement of, fluid from one part of the body to another. The term may describe either congenital or acquired shunts; acquired shunts may be either biological or mechanical.

<span class="mw-page-title-main">Portal vein</span> Short thick vein formed by the union of the superior mesenteric vein and the splenic vein

The portal vein or hepatic portal vein (HPV) is a blood vessel that carries blood from the gastrointestinal tract, gallbladder, pancreas and spleen to the liver. This blood contains nutrients and toxins extracted from digested contents. Approximately 75% of total liver blood flow is through the portal vein, with the remainder coming from the hepatic artery proper. The blood leaves the liver to the heart in the hepatic veins.

<span class="mw-page-title-main">Budd–Chiari syndrome</span> Medical condition

Budd–Chiari syndrome is a very rare condition, affecting one in a million adults. The condition is caused by occlusion of the hepatic veins that drain the liver. The symptoms are non-specific and vary widely, but it may present with the classical triad of abdominal pain, ascites, and liver enlargement. It is usually seen in younger adults, with the median age at diagnosis between the ages of 35 and 40, and it has a similar incidence in males and females. The syndrome can be fulminant, acute, chronic, or asymptomatic. Subacute presentation is the most common form.

<span class="mw-page-title-main">Portal hypertension</span> Abnormally increased portal venous pressure

Portal hypertension is abnormally increased portal venous pressure – blood pressure in the portal vein and its branches, that drain from most of the intestine to the liver. Portal hypertension is defined as a hepatic venous pressure gradient greater than 5 mmHg. Cirrhosis is the most common cause of portal hypertension; other, less frequent causes are therefore grouped as non-cirrhotic portal hypertension. When it becomes severe enough to cause symptoms or complications, treatment may be given to decrease portal hypertension itself or to manage its complications.

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<span class="mw-page-title-main">Ductus venosus</span>

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Transjugular intrahepatic portosystemic shunt is an artificial channel within the liver that establishes communication between the inflow portal vein and the outflow hepatic vein. It is used to treat portal hypertension which frequently leads to intestinal bleeding, life-threatening esophageal bleeding and the buildup of fluid within the abdomen (ascites).

<span class="mw-page-title-main">Portal vein thrombosis</span> Disease of the liver

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<span class="mw-page-title-main">Distal splenorenal shunt procedure</span>

In medicine, a distal splenorenal shunt procedure (DSRS), also splenorenal shunt procedure and Warren shunt, is a surgical procedure in which the distal splenic vein is attached to the left renal vein. It is used to treat portal hypertension and its main complication. It was developed by W. Dean Warren.

In the course of the round ligament of the liver, small paraumbilical veins are found which establish an anastomosis between the veins of the anterior abdominal wall and the portal vein, hypogastric, and iliac veins. These veins include Burrow's veins, and the veins of Sappey – superior veins of Sappey and the inferior veins of Sappey.

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A portacaval shunt, portocaval shunt, or portal-caval shunt is a treatment for portal hypertension. A connection is made between the portal vein, which supplies 75% of the liver's blood, and the inferior vena cava, the vein that drains blood from the lower two-thirds of the body. The most common causes of liver disease resulting in portal hypertension are Budd–Chiari syndrome or cirrhosis. Budd–Chiari syndrome should not be mistaken for cirrhosis.

<span class="mw-page-title-main">Portal hypertensive gastropathy</span> Changes in the mucosa of the stomach in patients with portal hypertension

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<span class="mw-page-title-main">Hepatic hydrothorax</span> Medical condition

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Congenital portosystemic shunts (PSS) is a hereditary condition in dogs and cats, its frequency varying depending on the breed. The shunts found mainly in small dog breeds such as Shih Tzus, Tibetan Spaniels, Miniature Schnauzers and Yorkshire Terriers, and in cats such as Persians, British Shorthairs, Himalayans, and mixed breeds are usually extrahepatic, while the shunts found in large dog breeds such as Irish Wolfhounds and Labrador Retrievers tend to be intrahepatic.

References

  1. ↑ DiPaola F, Trout AT, Walther AE, Gupta A, Sheridan R, Campbell KM, et al. (April 2020). "Congenital Portosystemic Shunts in Children: Associations, Complications, and Outcomes". Digestive Diseases and Sciences. 65 (4): 1239–1251. doi:10.1007/s10620-019-05834-w. PMC   8180198 . PMID   31549332.
  2. ↑ Alonso-Gamarra E, Parrón M, Pérez A, Prieto C, Hierro L, López-Santamaría M (2011-05-01). "Clinical and radiologic manifestations of congenital extrahepatic portosystemic shunts: a comprehensive review". Radiographics. 31 (3): 707–722. doi:10.1148/rg.313105070. PMID   21571652.
  3. ↑ DiPaola F, Trout AT, Walther AE, Gupta A, Sheridan R, Campbell KM, et al. (April 2020). "Congenital Portosystemic Shunts in Children: Associations, Complications, and Outcomes". Digestive Diseases and Sciences. 65 (4): 1239–1251. doi:10.1007/s10620-019-05834-w. PMC   8180198 . PMID   31549332.
  4. ↑ Bernard O, Franchi-Abella S, Branchereau S, Pariente D, Gauthier F, Jacquemin E (November 2012). "Congenital portosystemic shunts in children: recognition, evaluation, and management". Seminars in Liver Disease. 32 (4): 273–287. doi: 10.1055/s-0032-1329896 . PMID   23397528. S2CID   6584627.
  5. 1 2 "International Registry of Congenital Portosystemic Shunts (IRCPSS)" . Retrieved 2021-07-28.
  6. 1 2 3 4 5 Bernard O, Franchi-Abella S, Branchereau S, Pariente D, Gauthier F, Jacquemin E (November 2012). "Congenital portosystemic shunts in children: recognition, evaluation, and management". Seminars in Liver Disease. 32 (4): 273–287. doi: 10.1055/s-0032-1329896 . PMID   23397528.
  7. 1 2 3 Stringer MD (March 2008). "The clinical anatomy of congenital portosystemic venous shunts". Clinical Anatomy. 21 (2): 147–157. doi:10.1002/ca.20574. PMID   18161055. S2CID   42632424.
  8. 1 2 "Interview d'Amaria Remil, Cheffe de projet du Centre de Référence AVB-CG, et du Pr Stéphanie Franchi-Abella, Responsable du secteur de radiologie interventionnelle pédiatrique (Université Paris-Saclay)" [Interview with Amaria Remil, Project Manager of the AVB-CG Reference Center, and Prof. Stéphanie Franchi-Abella, Head of the pediatric interventional radiology sector (Paris-Saclay University)]. Filfoie: tout savoir sur les maladies rares du foie, recherche, enseignement[Filfoie: all about rare liver diseases, research, teaching] (in French). 2020-12-17. Retrieved 2021-07-28.
  9. 1 2 Papamichail M, Pizanias M, Heaton N (March 2018). "Congenital portosystemic venous shunt". European Journal of Pediatrics. 177 (3): 285–294. doi:10.1007/s00431-017-3058-x. PMC   5816775 . PMID   29243189.
  10. ↑ Gong Y, Zhu H, Chen J, Chen Q, Ji M, Pa M, et al. (December 2015). "Congenital portosystemic shunts with and without gastrointestinal bleeding - case series". Pediatric Radiology. 45 (13): 1964–1971. doi:10.1007/s00247-015-3417-6. PMID   26209117. S2CID   19515262.
  11. ↑ Bahadori A, Kuhlmann B, Debray D, Franchi-Abella S, Wacker J, Beghetti M, et al. (February 2022). "Presentation of Congenital Portosystemic Shunts in Children". Children. 9 (2): 243. doi: 10.3390/children9020243 . PMC   8870378 . PMID   35204963.
  12. ↑ McLin V, Franchi-Abella S, Debray D, Korff S, Casotti V, Colledan M, et al. (April 2019). "FRI-436-Congenital porto-systemic shunts in children: Preliminary results from the IRCPSS". Journal of Hepatology. 70 (1): e586. doi:10.1016/s0618-8278(19)31173-9. ISSN   0168-8278. S2CID   145951554.
  13. ↑ McLin VA, Franchi Abella S, Debray D, Guérin F, Beghetti M, Savale L, et al. (May 2019). "Congenital Portosystemic Shunts: Current Diagnosis and Management". Journal of Pediatric Gastroenterology and Nutrition. 68 (5): 615–622. doi: 10.1097/MPG.0000000000002263 . PMID   30628988. S2CID   58578546.
  14. ↑ Franchi-Abella S, Gonzales E, Ackermann O, Branchereau S, Pariente D, Guérin F (August 2018). "Congenital portosystemic shunts: diagnosis and treatment". Abdominal Radiology. 43 (8): 2023–2036. doi:10.1007/s00261-018-1619-8. PMID   29730740. S2CID   19116849.
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