Splenic vein thrombosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

Splenic vein thrombosis is the formation of a thrombus in the splenic vein. When thrombosis of the splenic vein occurs, collateral vessels develop to shunt blood around the occluded splenic vein. The two most common collateral pathways use the short gastric vessels. In the distal esophagus, portosystemic collaterals connect the short gastric veins into the azygous system. There is no established system for classification of splenic vein thrombosis. Common causes of splenic vein thrombosis are pancreatitis, pancreatic pseudocyst, pancreatic carcinoma, lymphoma, adenopathy from metastatic cancer, iatrogenic causes, splenectomy, partial gastrectomy, distal spleno-renal shunt, factor V Leiden mutation, prothrombin G20210A mutation. The incidence of splenic vein thrombosis was estimated to be 14,100 cases per 100,000 individuals worldwide. Splenic vein thrombosis affects men and women equally. There is no racial predilection for splenic vein thrombosis. Most patients are asymptomatic, however, splenic vein thrombosis should be suspected in patients with a history of pancreatitis and gastrointestinal blood loss, splenomegaly in the absence of portal hypertension, cirrhosis, and hematologic disease, in the setting of isolated gastric varices, splenomegaly with rare leukopenia, thrombocytopenia, left upper quadrant and abdominal pain. Ultrasound, CT and MRI scans are important diagnostic modalities in the diagnosis of splenic vein thrombosis. Medical therapy for splenic vein thrombosis include anticoagulation to maintain INR between 2 to 3. The goal of anticoagulation is to prevent extension of the clot and to allow for recanalization. Splenectomy is recommended for all patients with bleeding varices associated with isolated splenic vein thrombosis. Splenectomy eliminates venous collateral outflow and decompresses surrounding varices.

Thrombosis of the splenic vein is infrequently reported in literature, it is common knowledge among surgeons that this condition may follow splenectomy. In fact, local thrombosis at the site of ligation of the splenic artery and vein with extension back to the first branching vessel is to be expected after splenectomy. This degree of involvement of the splenic vein, however, should be asymptomatic, but it is potentially important because of possible extension into the portal venous system and as a source of emboli to the liver.

There is no established system for the classification of splenic vein thrombosis.

When thrombosis of the splenic vein occurs, collateral vessels develop to shunt blood around the occluded splenic vein. The two most common collateral pathways use the short gastric vessels. In the distal esophagus, portosystemic collaterals connect the short gastric veins into the azygous system. Splenoportal collaterals decompress the short gastric veins through both the coronary vein into the portal vein and via the gastroepiploic arcade into the superior mesenteric vein. In either case, the hypertensive short gastric veins cause increased pressure within the submucosal veins of the gastric fundus, resulting in varices.

Common causes of splenic vein thrombosis are ancreatitis, pancreatic pseudocyst, pancreatic carcinoma, lymphoma, adenopathy from metastatic cancer. Some iatrogenic causes are splenectomy, partial gastrectomy, distal spleno renal shunt, Factor V Leiden mutation, prothrombin G20210A mutation.

Splenic vein thrombosis must be differentiated from hepatic vein thrombosis, portal vein thrombosis, testicular cancer, hyperhomocystenemia and deep vein thrombosis.

The incidence of splenic vein thrombosis was estimated to be 14,100 cases per 100,000 individuals worldwide. Splenic vein thrombosis affects men and women equally. There is no racial predilection for splenic vein thrombosis.

Common risk factors in the development of splenic vein thrombosis include abdominal cancer, liver cirrhosis, surgery, thrombophilias, hormonal treatments, myeloproliferative disorders, sickle cell anemia.

There is insufficient evidence to recommend routine screening for splenic vein thrombosis. However, routine screening of splenic vein thrombosis after elective splenectomy is warranted because it allows the initiation of anticoagulant therapy to avoid further life-threatening complications. The incidence of splenic vein thrombosis is particularly high among patients operated on for lymphoma or with splenomegaly.

If left untreated, patients with splenic vein thrombosis may progress to develop sinistral portal hypertension, gastric varices, ascites, splenomegaly, atraumatic splenic rupture.

Venous phase angiography accurately visualizes both the location of splenic vein obstruction and the routes of collateralization. The diagnosis of splenic vein thrombosis is confirmed on angiography when selective injection of the splenic artery shows non visualization of the splenic vein on delayed images.

Most patients are asymptomatic, splenic vein thrombosis should be suspected in patients with a history of pancreatitis and gastrointestinal blood loss, splenomegaly in the absence of portal hypertension, cirrhosis, and hematologic disease and in the setting of isolated gastric varices. Other signs and symptoms are splenomegaly with rare leukopenia, thrombocytopenia, left upper quadrant pain and generalized abdominal pain.

Physical examination of patients with splenic vein thrombosis is usually remarkable for abdominal pain or distension, splenomegaly and signs of upper gastrointestinal bleed.

Some patients with splenic vein thrombosis may have reduced hemoglobin / hematocrit which is usually suggestive of gastrointestinal bleeding. Splenic vein thrombosis secondary to pancreatitis might have elevated levels of amylase and lipase. Some patients may have elevated liver function tests if the underlying cause is liver disease.

There are no ECG findings associated with splenic vein thrombosis.

There are no X-ray findings associated with splenic vein thrombosis.

Ultrasound is the best initial test for diagnosing splenic vein thrombosis. Accuracy may be limited by body size or location of veins. Endoscopic ultrasound appears to be a more accurate test than trans abdominal ultrasound for assessing patency of the splenic vein. Because EUS is a sensitive imaging tool for assessing small pancreatic cancers and determining vascular invasion, it should be considered when other tests have failed to confirm SVT as a cause of bleeding gastric or gastroesophageal varices.

CT scan is helpful in the diagnosis of Splenic vein thrombosis. Findings on CT scan in splenic vein thrombosis include an hyperattenuated material in the splenic vein, non-enhanced intraluminal filling defect.

MRI in splenic vein thrombosis shows severely attenuated and partially calcified retro pancreatic splenic vein resulting in formation of a prominent gastroepiploic collateral channel between the superior mesenteric vein and the remnant splenic vein at splenic hilum along the greater curvature of stomach.

There are no other imaging findings associated with splenic vein thrombosis.

There are no other diagnostic studies associated with splenic vein thrombosis.

Medical therapy for splenic vein thrombosis include anticoagulation to maintain INR between 2 to 3. The goal of anticoagulation is to prevent extension of the clot and to allow for recanalization. The mainstay of therapy in splenic vein thrombosis with gastric varices is sclerotherapy and gastric banding.

Splenectomy is recommended for all patients with bleeding varices associated with isolated splenic vein thrombosis. Splenectomy eliminates venous collateral out flow and decompresses surrounding varices.

There is no established method for prevention of splenic vein thrombosis.

There is no established method for prevention of splenic vein thrombosis.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]Sunny Kumar MD [3]

Thrombosis of the splenic vein is infrequently reported in literature, it is common knowledge among surgeons that this condition may follow splenectomy. In fact, local thrombosis at the site of ligation of the splenic artery and vein with extension back to the first branching vessel is to be expected after splenectomy. This degree of involvement of the splenic vein, however, should be asymptomatic, but it is potentially important because of possible extension into the portal venous system and as a source of emboli to the liver.

Thrombosis of the splenic vein is infrequently reported in literature, articles were published in the New England journal of medicine in the late 1940’s. Benjamin et al described cases of splenic vein thrombosis following trans thoracic gastrectomy and incidental splenectomy.

• In the year 1952, percutaneous splenoportography was first described by Dreyer and Bandtz which helped to increase the discovery rate of causes of splenic vein thrombosis.
• In the year 1956, three cases of splenic vein thrombosis were diagnosed by percutaneous splenoportography among 36 splenectomies done at Ohio State University hospitals for hematologic cases.
• In the year 1951 a german article cited cases of portal embolism following thrombosis of splenic vein and causing infarct like cyanotic atrophy(‘Zahn’s infarcts’) of the liver, as a complication of splenectomy in the course of total gastrectomy.
• In 2016, atypical cases of splenic vein thrombosis were reported in patients with epigastric pain whose initial diagnosis was presumed to be gastritis but later were diagnosed as having biopsy-proven pancreatic cancer.^[1]
• Spleno-portal thrombosis accompanying complications of Banti’s disease has been reported in 1960’s.
• In 1970s, cases of splenic vein thrombosis secondary to pancreatic disease have been reported.
• In 1990s, Weber Christian disease producing splenic vein occlusion and bleeding gastric varices and it’s successful treatment with sclerotherapy was described in British Medical Journal.^[2]
• In early 2000s splenic vein thrombosis has been reported in pediatric sickle cell disease and splenic vein thrombosis secondary to mutation of prothrombin gene has been reported.^[3]
• In late 2000s, cases of splenic vein thrombosis associated with antiphospholipid antibodies in a patient with wegener’s granulomatosis has been reported.^[4]

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

There is no established system for the classification of splenic vein thrombosis.

There is no established system for the classification of splenic vein thrombosis.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

Splenic vein thrombosis in acute or chronic pancreatitis results from peri-venous inflammation caused by the anatomic location of the splenic vein along the entire posterior aspect of the pancreatic tail, where it lies in direct contact with the peri-pancreatic inflammatory tissue. The exact mechanism of thrombosis is likely multi factorial, including both intrinsic endothelial damage from inflammatory or neoplastic processes and extrinsic damage secondary to venous compression from fibrosis, adjacent pseudocysts or edema.

Following are important facts regarding vasculature of splenic venous system:

• 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.
• It follows a course superior to the pancreas, alongside the splenic artery.
• It collects branches from the stomach and pancreas, and most notably from the large intestine (also drained by the superior mesenteric vein) via the inferior mesenteric vein, which drains in the splenic vein shortly before the origin of the hepatic portal vein.
• The portal vein is formed when the splenic vein joins the superior mesenteric vein.

It is thought that splenic vein thrombosis is caused by Virchow’s triad which includes:^[1]

• Reduced portal blood flow
• Hypercoagulable state
• Vascular endothelial injury

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Shown below is a table depicting the elements of Virchow’s triad and their modern counterparts.

Virchow’s[2]	Modern	Notes
Phenomena of interrupted blood-flow	“Stasis” or “venous stasis“[3]	The first category includes alterations in normal blood flow in several situations. These include turbulence, stasis, mitral stenosis, and varicose veins. The equivalence of Virchow’s version and the modern version has been disputed.[4]
Phenomena associated with irritation of the vessel and its vicinity	“Endothelial injury” or “vessel wall injury”	The second category includes injuries and/or trauma to endothelium, damage to the veins arising from shear stress or hypertension.
Phenomena of blood–coagulation	“Hypercoagulability”	The last category includes alterations in the constitution of blood,[5] has numerous possible risk factors such as hyperviscosity, deficiency of antithrombin III, nephrotic syndrome, changes after severe trauma or burn, disseminated cancer, late pregnancy, and delivery, race, age, whether the patient is a smoker or obese. All of these risk factors lead to hypercoagulability.

Mechanism of development of splenic vein thrombosis:

• Splenic vein thrombosis in acute or chronic pancreatitis results from acute inflammation.
• The pathophysiology of thrombosis is likely multi factorial.
• Endothelial damage from inflammatory or neoplastic process is also one of the mechanism reported.
• Another mechanism known to cause thrombosis is extrinsic damage secondary to venous compression from fibrosis, adjacent pseudocysts, or edema.
• Obstruction of the splenic vein caused by enlarged retroperitoneal lymph nodes or by pancreatic or peri-splenic nodes which are located near the splenic artery,above the splenic vein.

• These nodes lie adjacent to the pancreas and splenic vein and compress the splenic vein when involved in an inflammatory or neoplastic process.

• When thrombosis of the splenic vein occurs, collateral vessels develop to shunt blood around the occluded splenic vein. The two most common collateral pathways use the short gastric vessels.

• In the distal esophagus, portosystemic collaterals connect the short gastric veins into the azygous system. Spleno-portal collaterals decompress the short gastric veins through both the coronary vein into the portal vein and via the gastroepiploic arcade into the superior mesenteric vein. In either case, the hypertensive short gastric veins cause increased pressure within the submucosal veins of the gastric fundus, resulting in varices.

• At times, an enlarged gastroepiploic vein found at laparotomy may be the only indicator of occult splenic vein thrombosis. Isolated esophageal varices, although uncommon in SVT, can occur in cases in which the coronary vein joins the splenic vein proximal to the obstruction. This anatomic variant has been reported to occur in 17 % of the cases.

• Less common collateral pathways may also develop to decompress the splenic vein. The left gastroepiploic vein can collateralize to the left colic and inferior mesenteric veins. Although rare, this development has been reported to result in colonic variceal hemorrhage. Other collateral venous channels may develop via the diaphragmatic and intercostal veins to the inferior vena cava .The splenic vein may also collateralize to the renal vein via the adrenal vein.

The exact genetics of splenic vein thrombosis is not fully understood.

The conditions associated with splenic vein thrombosis include:

• Pancreatitis
• Genetic disorders such as Factor V Leiden mutations
• Thrombophilias
• Abdominal trauma

• There is no finding on gross pathology of Splenic vein thrombosis.

• There is no finding on microscopic histopathological analysis.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

Common causes of splenic vein thrombosis are pancreatitis, pancreatic pseudocyst, pancreatic carcinoma, lymphoma, adenopathy from metastatic cancer. Some iatrogenic causes include splenectomy, partial gastrectomy, distal spleno-renal shunt, Factor V Leiden mutation, prothrombin G20210A mutation.

Common causes of splenic vein thrombosis are: ^[1][2][3]

• Pancreatitis
• Pancreatic pseudocyst
• Neoplasm
• Trauma
• Prothrombin G20210A mutation

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

Splenic vein thrombosis must be differentiated from hepatic vein thrombosis, portal vein thrombosis, testicular cancer, hyperhomocystenemia, and deep vein thrombosis.

Splenic vein thrombosis (SVT) must be differentiated from hepatic vein thrombosis (HVT), portal vein thrombosis (PVT), testicular cancer, hyperhomocystenemia, and deep vein thrombosis.^[1][2][3]

Disease	Abdominal pain	Leg swelling	Portal HTN	Rectal bleeding	CT abdomen	Doppler US of deep viens	Urine chemistry
SVT	Present	Absent	Present	Present	Thrombosis in SV	Normal	Normal
HVT	Present	Absent	Present	Present	Thrombosis in HV	Normal	Normal
Hyperhomocystenemia	Present	Absent	Present if PVT	Present if PVT	No specific finding	May have thrombosis if deep veins involved	Elevated homocysteine
DVT	Present	Present	Absent	Absent	No specific	Thrombosis in deep veins	Normal
PVT	Present	Absent	Present	Present	Thrombosis in PV	Normal	Normal

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

The incidence of splenic vein thrombosis was estimated to be 14,100 cases per 100,000 individuals worldwide. Splenic vein thrombosis affects men and women equally. There is no racial predilection for splenic vein thrombosis.

The incidence of splenic vein thrombosis was estimated to be 14,100 cases per 100,000 individuals worldwide.^[1][2]

Splenic vein thrombosis affects men and women equally

There is no racial predilection for splenic vein thrombosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

Common risk factors in the development of splenic vein thrombosis include abdominal cancer, liver cirrhosis, surgery, thrombophilias, hormonal treatments, myeloproliferative disorders, sickle cell anemia

Common risk factors in the development of splenic vein thrombosis include:^[1]

• Abdominal cancer
• Liver cirrhosis
• Surgery
• Thrombophilias ^[2]
• Hormonal treatments
• Myeloproliferative disorders
• Sickle cell anemia ^[3]

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

There is insufficient evidence to recommend routine screening for splenic vein thrombosis. However, routine screening of portal and splenic vein thrombosis after elective splenectomy is warranted because it allows the initiation of anticoagulant therapy and avoid further life-threatening complications. The incidence of portal and splenic vein thrombosis is particularly high among patients operated on for lymphoma or with splenomegaly.

There is insufficient evidence to recommend routine screening for splenic vein thrombosis. However, routine screening of portal and splenic vein thrombosis after elective splenectomy is warranted because it allows to start anticoagulant therapy and avoid further life-threatening complications. The incidence of portal and splenic vein thrombosis is particularly high among patients operated on for lymphoma or with splenomegaly.^[1][2][3]

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-in-Chief: Vindhya BellamKonda, M.B.B.S [2]

If left untreated, 6% of patients with splenic vein thrombosis may progress to develop sinistral portal hypertension, gastric varices, ascites, splenomegaly, and atraumatic splenic rupture.

If left untreated, patients with splenic vein thrombosis may progress to develop sinistral portal hypertension, gastric varices, ascites, splenomegaly, atraumatic splenic rupture.

Common complications of splenic vein thrombosis include:^[1][2][3]

• Gastric varices
• Atraumatic splenic rupture
• Splenomegaly
• Ascites