Portal vein thrombosis

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Portal vein thrombosis
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Portal vein thrombosis seen with computed tomography.
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Portal vein thrombosis (PVT) is a vascular disease of the liver that occurs when a blood clot occurs in the hepatic portal vein, which can lead to increased pressure in the portal vein system and reduced blood supply to the liver. The mortality rate is approximately 1 in 10. [1]

Contents

An equivalent clot in the vasculature that exits the liver carrying deoxygenated blood to the right atrium via the inferior vena cava, is known as hepatic vein thrombosis or Budd-Chiari syndrome. [2]

Signs and symptoms

Portal vein thrombosis causes upper abdominal pain, possibly accompanied by nausea and an enlarged liver and/or spleen; the abdomen may be filled with fluid (ascites). [3] A persistent fever may result from the generalized inflammation. [1] While abdominal pain may come and go if the thrombus forms suddenly, long-standing clot build-up can also develop without causing symptoms, leading to portal hypertension before it is diagnosed. [4] [2]

Other symptoms can develop based on the cause. For example, if portal vein thrombosis develops due to liver cirrhosis, bleeding or other signs of liver disease may be present. If portal vein thrombosis develops due to pylephlebitis, signs of infection such as fever, chills, or night sweats may be present.[ citation needed ]

Causes

Slowed blood flow due to underlying cirrhosis or congestive heart failure is often implicated. The prevalence of PVT in patients with cirrhosis is unclear, with a wide variety of incidence claimed by various researchers (estimated to be 1 in 100 by some while others believe it affects nearly 1 in 4). [5]

Thrombophilia (including inherited conditions such as factor V Leiden deficiency, protein C or S deficiency, or antiphospholipid antibody syndrome) is another common cause. [3] Nearly one-third of patients have a myeloproliferative disorder (e.g. polycythemia vera [6] or primary thrombocytosis), most commonly due to a Janus kinase 2 (JAK2) gene mutation. [1] Oral contraceptive use or pregnancy are other non-inherited tendencies for thrombosis.[ citation needed ]

Alternatively, the portal vein may be injured as a result of pancreatitis, diverticulitis, cholangiocarcinoma, hepatocellular carcinoma (HCC), or abdominal surgery/trauma. [3] Red flags for cancerous growth as a cause are elevated alpha fetoprotein levels, portal vein diameter greater than 2.3 cm, pulsatility on Doppler ultrasound imaging, or hyperintense hepatic arterial phase (HAP) on CT scan with contrast. [1]

PVT is also a known complication of surgical removal of the spleen. [7] During the last several years, myeloproliferative neoplasms (MPNs) have emerged as a leading systemic cause of splanchnic vein thromboses (which include PVT).[ citation needed ]

Mechanism

The main portal vein is formed by the union of the splenic vein and superior mesenteric vein (SMV). It is responsible for approximately three-fourths of the liver’s blood flow, transported from much of the gastrointestinal system as well as the pancreas, gallbladder, and spleen. [3] Cirrhosis alters bleeding pathways thus patients are simultaneously at risk of uncontrolled bleeding and forming clots. [3] A long-standing hindrance in flow as in chronic PVT, also known as portal cavernoma, can cause an increase in the hepatic venous pressure gradient (portal hypertension) and increased blood flow through subsidiary veins. [1] This may lead to ascites or bleeding from varices. [6]

An infected thrombus may become septic, known as pylephlebitis; if blood cultures are positive for growth at this time, the most common organism is Bacteroides . [1]

Diagnosis

Portal vein thrombosis on computed tomography (left) and cavernous transformation of the portal vein after 1 year (right) Kavernoese Transformation nach Pfortaderthrombose 001.png
Portal vein thrombosis on computed tomography (left) and cavernous transformation of the portal vein after 1 year (right)

The diagnosis of portal vein thrombosis is usually made with imaging confirming a clot in the portal vein; ultrasound is the least invasive method and the addition of Doppler technique shows a filling defect in blood flow. PVT may be classified as either occlusive or nonocclusive based on evidence of blood flow around the clot. [5] An alternative characterization based on site can be made: Type 1 is limited to the main portal vein, Type 2 involves only a portal vein branch (2a, or 2b if both branches are affected), and Type 3 if clot is found throughout both areas. [8] Determination of condition severity may be derived via computed tomography (CT) with contrast, magnetic resonance imaging (MRI), or MR angiography (MRA). Those with chronic PVT may undergo upper endoscopy (esophagogastroduodenoscopy, EGD) to evaluate the presence of concurrent dilated veins (varices) in the stomach or esophagus. [3] Other than perhaps slightly elevated transaminases, laboratory tests to evaluate liver function are typically normal. [1] D-dimer levels in the blood may be elevated as a result of fibrin breakdown.[ citation needed ]

On duplex ultrasound, demonstration of echogenic material within the portal vein, complete or partial absence of colour flow in the portal vein, presence of collateral vessels around the portal vein or gall bladder that bypass the portal vein. [9]

Portal vein thrombosis grading after Yerdel et al Portal vein thrombosis grading after Yerdel et al.pdf
Portal vein thrombosis grading after Yerdel et al

Treatment

Treatment is aimed at opening the blocked veins to minimize complications; the duration of clot (acute versus chronic) affects treatment. Unless there are underlying reasons why it would be harmful, anticoagulation (low molecular weight heparin, followed by warfarin) is often initiated and maintained in patients who do not have cirrhosis. Anticoagulation for patients with cirrhosis who experience portal vein thrombosis is usually not advised unless they have chronic PVT 1) with thrombophilia, 2) with clot burden in the mesenteric veins, or 3) inadequate blood supply to the bowels. [3] In more severe instances, shunts or a liver transplant may be considered. If blood flow to the gastrointestinal tract has been compromised chronically, surgery may be required to remove dead intestine. [1]

Different considerations are made in the management of PVT in pediatric patients or those who have already received a liver transplant. [1]

See also

Related Research Articles

<span class="mw-page-title-main">Thrombosis</span> Formation of blood clots inside the blood vessels

Thrombosis is the formation of a blood clot inside a blood vessel, obstructing the flow of blood through the circulatory system. When a blood vessel is injured, the body uses platelets (thrombocytes) and fibrin to form a blood clot to prevent blood loss. Even when a blood vessel is not injured, blood clots may form in the body under certain conditions. A clot, or a piece of the clot, that breaks free and begins to travel around the body is known as an embolus.

<span class="mw-page-title-main">Ascites</span> Abnormal build-up of fluid in the abdomen

Ascites is the abnormal build-up of fluid in the abdomen. Technically, it is more than 25 ml of fluid in the peritoneal cavity, although volumes greater than one liter may occur. Symptoms may include increased abdominal size, increased weight, abdominal discomfort, and shortness of breath. Complications can include spontaneous bacterial peritonitis.

<span class="mw-page-title-main">Portal vein</span> Vein carrying blood from the GI tract, gallbladder, pancreas and spleen to the liver

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> Blockage of the hepatic veins that drain the liver

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">Esophageal varices</span> Dilated veins in the lower oesophagus

Esophageal varices are extremely dilated sub-mucosal veins in the lower third of the esophagus. They are most often a consequence of portal hypertension, commonly due to cirrhosis. People with esophageal varices have a strong tendency to develop severe bleeding which left untreated can be fatal. Esophageal varices are typically diagnosed through an esophagogastroduodenoscopy.

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

Portal hypertension is defined as increased portal venous pressure, with a hepatic venous pressure gradient greater than 5 mmHg. Normal portal pressure is 1–4 mmHg; clinically insignificant portal hypertension is present at portal pressures 5–9 mmHg; clinically significant portal hypertension is present at portal pressures greater than 10 mmHg. The portal vein and its branches supply most of the blood and nutrients from the intestine to the liver.

<span class="mw-page-title-main">Gastric varices</span> Dilated submucosal veins in the stomach lining

Gastric varices are dilated submucosal veins in the lining of the stomach, which can be a life-threatening cause of bleeding in the upper gastrointestinal tract. They are most commonly found in patients with portal hypertension, or elevated pressure in the portal vein system, which may be a complication of cirrhosis. Gastric varices may also be found in patients with thrombosis of the splenic vein, into which the short gastric veins that drain the fundus of the stomach flow. The latter may be a complication of acute pancreatitis, pancreatic cancer, or other abdominal tumours, as well as hepatitis C. Gastric varices and associated bleeding are a potential complication of schistosomiasis resulting from portal hypertension.

<span class="mw-page-title-main">Thrombophilia</span> Abnormality of blood coagulation increasing the risk of blood clotting (thrombosis)

Thrombophilia is an abnormality of blood coagulation that increases the risk of thrombosis. Such abnormalities can be identified in 50% of people who have an episode of thrombosis that was not provoked by other causes. A significant proportion of the population has a detectable thrombophilic abnormality, but most of these develop thrombosis only in the presence of an additional risk factor.

<span class="mw-page-title-main">Splenic vein</span> Vein that drains blood from the spleen, stomach and pancreas

In human anatomy, the splenic vein is a blood vessel that drains blood from the spleen, the stomach fundus and part of the pancreas. It is part of the hepatic portal system.

<span class="mw-page-title-main">Transjugular intrahepatic portosystemic shunt</span> Artificial channel within the liver

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">Renal vein thrombosis</span> Medical condition

Renal vein thrombosis (RVT) is the formation of a clot in the vein that drains blood from the kidneys, ultimately leading to a reduction in the drainage of one or both kidneys and the possible migration of the clot to other parts of the body. First described by German pathologist Friedrich Daniel von Recklinghausen in 1861, RVT most commonly affects two subpopulations: newly born infants with blood clotting abnormalities or dehydration and adults with nephrotic syndrome.

<span class="mw-page-title-main">Banti's syndrome</span> Medical condition

Banti's syndrome, named for Guido Banti, is a chronic congestive enlargement of the spleen resulting in premature destruction of the red blood cells by the spleen.

<span class="mw-page-title-main">Hepatic portal system</span> System of veins comprising the hepatic portal vein and its tributaries

In human anatomy, the hepatic portal system or portal venous system is the system of veins comprising the portal vein and its tributaries. The other portal venous system in the body is the hypophyseal portal system.

<span class="mw-page-title-main">Splenic infarction</span> Medical condition

Splenic infarction is a condition in which blood flow supply to the spleen is compromised, leading to partial or complete infarction in the organ. Splenic infarction occurs when the splenic artery or one of its branches are occluded, for example by a blood clot.

<span class="mw-page-title-main">Vascular disease</span> Medical condition

Vascular disease is a class of diseases of the vessels of the circulatory system in the body, including blood vessels – the arteries and veins, and the lymphatic vessels. Vascular disease is a subgroup of cardiovascular disease. Disorders in this vast network of blood and lymph vessels can cause a range of health problems that can sometimes become severe, and fatal. Coronary heart disease for example, is the leading cause of death for men and women in the United States.

<span class="mw-page-title-main">Intestinal ischemia</span> Restriction of blood flow to the small intestine resulting in injury

Intestinal ischemia is a medical condition in which injury to the large or small intestine occurs due to not enough blood supply. It can come on suddenly, known as acute intestinal ischemia, or gradually, known as chronic intestinal ischemia. The acute form of the disease often presents with sudden severe abdominal pain and is associated with a high risk of death. The chronic form typically presents more gradually with abdominal pain after eating, unintentional weight loss, vomiting, and fear of eating.

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

Portal hypertensive gastropathy refers to changes in the mucosa of the stomach in patients with portal hypertension; by far the most common cause of this is cirrhosis of the liver. These changes in the mucosa include friability of the mucosa and the presence of ectatic blood vessels at the surface. Patients with portal hypertensive gastropathy may experience bleeding from the stomach, which may uncommonly manifest itself in vomiting blood or melena; however, portal hypertension may cause several other more common sources of upper gastrointestinal bleeding, such as esophageal varices and gastric varices. On endoscopic evaluation of the stomach, this condition shows a characteristic mosaic or "snake-skin" appearance to the mucosa of the stomach.

<span class="mw-page-title-main">Chronic venous insufficiency</span> Medical condition

Chronic venous insufficiency (CVI) is a medical condition in which blood pools in the veins, straining the walls of the vein. The most common cause of CVI is superficial venous reflux which is a treatable condition. As functional venous valves are required to provide for efficient blood return from the lower extremities, this condition typically affects the legs. If the impaired vein function causes significant symptoms, such as swelling and ulcer formation, it is referred to as chronic venous disease. It is sometimes called chronic peripheral venous insufficiency and should not be confused with post-thrombotic syndrome in which the deep veins have been damaged by previous deep vein thrombosis.

<span class="mw-page-title-main">Cirrhosis</span> Chronic disease of the liver, characterized by fibrosis

Cirrhosis, also known as liver cirrhosis or hepatic cirrhosis, and end-stage liver disease, is a condition of the liver in which the normal functioning tissue, or parenchyma, is replaced with scar tissue (fibrosis) and regenerative nodules as a result of chronic liver disease. Damage to the liver leads to repair of liver tissue and subsequent formation of scar tissue. Over time, scar tissue and nodules of regenerating hepatocytes can replace the parenchyma, causing increased resistance to blood flow in the liver's capillaries—the hepatic sinusoids—and consequently portal hypertension, as well as impairment in other aspects of liver function. The disease typically develops slowly over months or years.

Hepatic artery thrombosis occurs when a blood clot forms in the artery that provides blood flow to the liver. Hepatic artery thrombosis may occur as a complication after liver transplantation, and represents the most common complication of liver transplantation. Smoking tobacco increases the risk of hepatic artery thrombosis in people who have undergone liver transplantation.

References

  1. 1 2 3 4 5 6 7 8 9 DeLeve LD, Valla DC, Garcia-Tsao G (May 2009). "Vascular disorders of the liver". Hepatology. 49 (5): 1729–1764. doi:10.1002/hep.22772. PMC   6697263 . PMID   19399912.
  2. 1 2 O'Mara SR, Wiesner L. "Hepatic Disorders". In Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH (eds.). Tintinalli's Emergency Medicine: A Comprehensive Study Guide (9 ed.). New York, NY: McGraw-Hill.
  3. 1 2 3 4 5 6 7 Simonetto DA, Singal AK, Garcia-Tsao G, Caldwell SH, Ahn J, Kamath PS (January 2020). "ACG Clinical Guideline: Disorders of the Hepatic and Mesenteric Circulation". The American Journal of Gastroenterology. 115 (1): 18–40. doi: 10.14309/ajg.0000000000000486 . PMID   31895720.
  4. ↑ Hall TC, Garcea G, Metcalfe M, Bilku D, Dennison AR (November 2011). "Management of acute non-cirrhotic and non-malignant portal vein thrombosis: a systematic review". World Journal of Surgery. 35 (11): 2510–2520. doi:10.1007/s00268-011-1198-0. PMID   21882035. S2CID   7518468.
  5. 1 2 Nery F, Chevret S, Condat B, de Raucourt E, Boudaoud L, Rautou PE, et al. (February 2015). "Causes and consequences of portal vein thrombosis in 1,243 patients with cirrhosis: results of a longitudinal study". Hepatology. 61 (2): 660–667. doi: 10.1002/hep.27546 . PMID   25284616.
  6. 1 2 Bacon BR. "Cirrhosis and Its Complications". In Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J (eds.). Harrison's Principles of Internal Medicine (20 ed.). New York, NY: McGraw-Hill.
  7. ↑ Cadili A, de Gara C (May 2008). "Complications of splenectomy". The American Journal of Medicine. 121 (5): 371–5. doi:10.1016/j.amjmed.2008.02.014. PMID   18456028.
  8. ↑ Friedman LS (2020). "Noncirrhotic Portal Hypertension". In Papadakis MA, McPhee SJ, Rabow MW (eds.). Current Medical Diagnosis and Treatment 2020. McGraw-Hill.
  9. ↑ Sacerdoti D, Serianni G, Gaiani S, Bolognesi M, Bombonato G, Gatta A (March 2007). "Thrombosis of the portal venous system". Journal of Ultrasound. 10 (1): 12–21. doi:10.1016/j.jus.2007.02.007. PMC   3478708 . PMID   23396402.
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