PORTAL VEIN THROMBOSIS

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					PORTAL VEIN THROMBOSIS



      Aswad H. Al.Obeidy
    FICMS, FICMS GE&Hep
    Kirkuk General Hospital
Portal Vein Thrombosis
   Portal vein obstruction results from thrombosis, constriction,
    or invasion of the portal vein
   The resulting portal hypertension leads to splenomegaly and
    formation of portosystemic collaterals and esophageal, gastric,
    duodenal, and jejunal varices
   Varices proliferate in the porta hepatis and involve the
    gallbladder and bile duct
   Upstream from the obstruction, the small intestine and colon
    become congested, and the stomach exhibits changes of portal
    hypertensive gastropathy. Mesenteric ischemia can occur if the
    thrombus extends into the mesenteric veins
   Downstream from the clot, the liver usually maintains normal
    function and appears unaffected
   Ascites may develop during the initial stages but usually
    recedes subsequently
   Clinically, portal vein thrombosis usually is asymptomatic until
    variceal bleeding occurs
ETIOLOGY
   Most cases of portal vein thrombosis have an
    identifiable cause related to hypercoagulability or to
    local factors such as inflammation, trauma, or
    malignancy
   Less than 20% of cases are considered idiopathic
   Better understanding of the multiple causes of
    hypercoagulability has led to the recognition that
    multiple coexisting risk factors are present in as
    many as 40% of affected patients
   Infection, most often umbilical vein sepsis, is the
    main cause of portal vein thrombosis in children.
    Portal vein thrombosis is well documented after
    neonatal umbilical vein catheterization but resolves
    in greater than 50% of cases
   In adults, cirrhosis or abdominal malignancies are
    responsible for more than one half of the cases of
    portal vein thrombosis
ETIOLOGY
   The disorder occurs in at least 10% of patients with
    cirrhosis, presumably as a result of sluggish portal vein
    blood flow, but acquired and inherited hypercoagulable
    states can be identified in many patients with cirrhosis and
    portal vein thrombosis
   Hepatocellular and pancreatic carcinomas are the most
    common malignant causes for portal vein thrombosis,
    usually because of a combination of hypercoaguability and
    invasion or constriction of the portal vein
   Local inflammatory reactions resulting from acute or
    chronic pancreatitis are a common cause of portal vein
    thrombosis
   Pylephlebitis, or septic portal vein thrombosis, can
    complicate intra-abdominal infections such as appendicitis,
    diverticulitis, and cholangitis
   In addition, splenic vein trauma during splenectomy results
    in portal vein thrombosis in 8% of cases; the risk increases
    to 40% if a myeloproliferative disorder is present
Causes of Portal Vein Thrombosis
   Hypercoagulable States
   Antiphospholipid syndrome
   Antithrombin deficiency
   Factor V Leiden mutation
   Methylenetetrahydrofolate reductase mutation TT677
   Myeloproliferative disorder
   Nephrotic syndrome
   Oral contraceptives
   Paroxysmal nocturnal hemoglobinuria
   Polycythemia rubra vera
   Pregnancy
   Prothrombin mutation G20210A
   Protein C deficiency
   Protein S deficiency
   Sickle cell disease
Causes of Portal Vein Thrombosis


   Inflammatory Diseases
   Behçet's syndrome
   Inflammatory bowel disease
   Pancreatitis
Causes of Portal Vein Thrombosis


   Infections
   Appendicitis
   Cholangitis
   Cholecystitis
   Diverticulitis
   Liver abscess
   Schistosomiasis
   Umbilical vein infection
Causes of Portal Vein Thrombosis
   Complications of Therapeutic Interventions
   Alcohol injection
   Colectomy
   Endoscopic sclerotherapy
   Fundoplication
   Gastric banding
   Hepatic chemoembolization
   Hepatobiliary surgery
   Islet cell injection
   Liver transplantation
   Peritoneal dialysis
   Radiofrequency ablation of hepatic tumor(s)
   Splenectomy
   TIPS procedure
   Umbilical vein catheterization
Causes of Portal Vein Thrombosis

   Impaired Portal Vein Flow
   Budd-Chiari syndrome
   Cirrhosis
   Cholangiocarcinoma
   Hepatocellular carcinoma
   Nodular regenerative hyperplasia
   Pancreatic carcinoma
   Sinusoidal obstruction syndrome
Causes of Portal Vein Thrombosis


   Miscellaneous
   Bladder cancer
   Choledochal cyst
   Living at high altitude
CLINICAL FEATURES AND COURSE
   Portal vein thrombosis is found with equal
    frequency in adults (mean age, 40 years) and
    children (mean age, 6 years)
   The presenting manifestation is almost always
    hematemesis from variceal bleeding
   Abdominal pain is unusual unless the
    thrombosis involves the mesenteric veins and
    causes intestinal ischemia
   Splenomegaly usually is present
   Ascites is uncommon, except in acute portal
    vein thrombosis or when the thrombosis
    complicates cirrhosis
CLINICAL FEATURES AND COURSE
   Liver biochemical test results usually are
    normal
   Occasionally, common bile duct varices
    can cause biliary obstruction
   Even mimic cholangiocarcinoma on
    endoscopic retrograde
    cholangiopancreatography
   Other unusual locations for ectopic
    varices in portal vein thrombosis include
    the gallbladder, duodenum, and rectum
CLINICAL FEATURES AND COURSE
   Doppler ultrasonography is highly sensitive for
    detection of this disorder and reveals an
    echogenic thrombus in the portal vein ,
    extensive collateral vessels in the porta hepatis,
    an enlarged spleen, and occasionally
    nonvisualization of the portal vein
   When the diagnosis of portal vein thrombosis is
    still uncertain, magnetic resonance angiography
    is better than CT in demonstrating the typical
    changes of portal vein thrombosis
   Portal venography usually is unnecessary
    unless a surgical shunt is being considered
   Evaluation of the patient for precipitating
    hypercoagulable risk factors may require a
    consultation with a hematologist
    Natural history of portal vein
    thrombosis
   Is related primarily to the underlying disorder
   In the absence of cirrhosis, cancer, and mesenteric vein
    thrombosis, the 10-year survival rate for patients with
    portal vein thrombosis is greater than 80%
   Only 2% experience fatal variceal hemorrhage
   Variceal bleeding caused by portal vein thrombosis has
    a much better outcome than that observed with variceal
    bleeding caused by cirrhosis
   Because of preserved hepatic function and lack of
    coagulopathy in patients with thrombosis alone
   In addition, development of spontaneous portosystemic
    collaterals can lead to a reduced frequency of recurrent
    variceal bleeding in patients with portal vein thrombosis
TREATMENT
   Endoscopic band ligation or sclerotherapy is first-
    line therapy for variceal bleeding in patients with
    portal vein thrombosis
   Sessions should be repeated until the varices are
    obliterated
   Therapy with beta blockers is beneficial in
    preventing initial and, in combination with
    endoscopic therapy, recurrent variceal bleeding
   Recurrent or refractory variceal bleeding or bleeding
    from varices distal to the esophagus is an indication
    for placement of a portosystemic shunt
   TIPS is an option if the technical challenge of
    gaining access to the portal vein can be overcome
TREATMENT
   Focal malignant portal vein obstruction can be stented
    percutaneously, with successful control of refractory
    variceal bleeding and ascites
   Elective mesocaval and splenorenal shunts and the
    extended Sugiura procedure (esophagogastric
    devascularization and transection)[81] also have been
    performed successfully in patients with portal vein
    thrombosis, with low mortality and long survival
   Anticoagulation is recommended in patients with acute
    portal vein thrombosis, to prevent cavernous transformation
    and complications of portal hypertension
   Spontaneous recanalization with acute thrombosis is rare
   Therapeutic recanalization can be achieved in greater than
    80% of the cases with anticoagulants (intravenous heparin
    or subcutaneous LMWH, followed by warfarin to achieve an
    INR of 2.0 to 2.5 for at least 6 months)
TREATMENT
   Prompt use of broad-spectrum antibiotics in cases of septic
    pylephlebitis also leads to resolution of the thrombosis
   Systemic and selective venous infusions of thrombolytic
    agents have been used successfully in acute portal vein
    thrombosis and are beneficial when the thrombosis is
    associated with mesenteric vein thrombosis and intestinal
    ischemia
   Chronic anticoagulation should be considered in patients
    with portal vein thrombosis and a recognized
    hypercoagulable state, surgical shunt, or concomitant
    mesenteric vein thrombosis
   anticoagulants are not recommended for chronic portal vein
    thrombosis, especially when associated with cavernous
    transformation
    liver transplantation for liver failure complicated by portal
    vein thrombosis is now possible

				
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posted:5/23/2012
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