Splenic vein thrombosis overview
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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]
Overview
Splenic vein thrombosis is 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. he incidence of Splenic vein thrombosis was estimated to be 141,00 cases per 100,000 individuals worldwide. Splenic vein thrombosis affects men and women equally. There is no racial predilection for splenic vein thrombosis. ost patients are asymptomatic SVT should be suspected in a * A patient with a history of pancreatitis and GI blood loss, * A patient with splenomegaly in the absence of portal hypertension, cirrhosis, and hematologic disease, in the setting of isolated gastric varices, * Splenomegaly with rare leukopenia, thrombocytopenia, splenic pain and abdominal pain. Ultrasound, CT and MRI scans are important diagnostic modalities. 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 out flow, decompresses surrounding varices.
Historical Perspective
Though thrombosis of the splenic vein is infrequently reported in the literature,1 , 2 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. This degree of involvement of the splenic vein, however, should be symptom less, but it is potentially important because of possible extension into the portal venous system and as a source of emboli to the liver.
Classification
There is no established system for the classification of splenic vein thrombosis
Pathophysiology
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.
Causes
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.
Differentiating Splenic vein thrombosis from Other Diseases
Splenic vein thrombosis must be differentiated from hepatic vein thrombosis, portal vein thrombosis, testicular cancer, hyperhomocystenemia and deep vein thrombosis
Epidemiology and Demographics
The incidence of Splenic vein thrombosis was estimated to be 141,00 cases per 100,000 individuals worldwide. Splenic vein thrombosis affects men and women equally. There is no racial predilection for splenic vein thrombosis.
Risk Factors
Common risk factors in the development of splenic vein thrombosis include: Abdominal cancer, liver cirrhosis, surgery, thrombophilias, hormonal treatments, myeloproliferative disorders, sickle cell anemia
Screening
There is insufficient evidence to recommend routine screening for splenic vein thrombosis. However, routine screening of PSVT after elective splenectomy is warranted because it allows to start anticoagulant therapy and avoid further life-threatening complications. The incidence of PSVT is particularly high among patients operated on for lymphoma or with splenomegaly
Natural History, Complications, and Prognosis
- If left untreated, patients with splenic vein thrombosis may progress to develop sinistral portal hypertension, gastric varices, ascites, splenomegaly, atraumatic splenic rupture
Diagnosis
Diagnostic study of choice
Venous phase angiography accurately visualises 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 nonvisualization of the splenic vein on delayed images.
History and Symptoms
Most patients are asymptomatic SVT should be suspected in a :
- A patient with a history of pancreatitis and GI blood loss
- A patient with splenomegaly in the absence of portal hypertension, cirrhosis, and hematologic disease
- In the setting of isolated gastric varices
Other signs /symptoms:
- Splenomegaly with rare leukopenia, thrombocytopenia, splenic pain
- Abdominal pain
Physical Examination
Physical examination of patients with splenic vein thrombosis is usually remarkable for abdominal pain or distention, splenomegaly and signs of upper GI bleed
Laboratory Findings
Some patients with splenic vein thrombosis may have reduced hgb/hct 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.
Electrocardiogram
There are no ECG findings associated with splenic vein thrombosis
X-ray
There are no X-ray findings associated with splenic vein thrombosis
Ultrasound
Ultrasound is the initial test for diagnosing splenic vein thrombosis, accuracy may be limited by 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.
- It should also be considered in cases of SVT occurring without a history of chronic pancreatitis to evaluate pancreatic carcinoma as a potential cause of SVT.
CT scan
CT scan is helpful in the diagnosis of Splenic vein thrombosis
Findings on CT scan in splenic vein thrombosis: The hyperattenuated material in splenic vein, non-enhanced intraluminal filling defect.
MRI
MRI of the splenic vein thrombosis shows:
- Severely attenuated and partially calcified retro pancreatic splenic vein resulting in formation of a prominent gastroepiploic collateral channel ( arrow heads) between the superior mesenteric vein and the remnant splenic vein at splenic hilum( solid arrow) along the greater curvature of stomach.
Other Imaging Findings
There are no other imaging findings associated with splenic vein thrombosis.
Other Diagnostic Studies
here are no other diagnostic studies associated with splenic vein thrombosis.
Treatment
Medical Therapy
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.
Surgery
Splenectomy is recommended for all patients with bleeding varices associated with isolated splenic vein thrombosis. Splenectomy eliminates venous collateral out flow, decompresses surrounding varices.
Primary Prevention
There is no established method for prevention of splenic vein thrombosis.
Secondary Prevention
There is no established method for prevention of splenic vein thrombosis.