PORTAL VEIN THROMBOSIS

Epidemiology: Rare (0.05-0.5% in autopsy studies), but leading cause of portal HTN in non-cirrhotics in West. Often assx until variceal bleeding occurs. WIDE variety of etiologies.

Etiologies: Virchow’s Triad

1. Cirrhosis (24-32%): decreased portal flow, periportal lymphangitis

2. Neoplasm (21-24%): direct invasion, extrinsic compression

a. most common: pancreatic (11-12%), primary hepatocellular (5-6% in Western, much higher elsewhere)

b. others associated: lung, stomach, prostate, uterus, kidney, cholangioca, carcinoid, primary liver lymphoma

1. Infection (10-25%- most common cause in children): portal pyemia- often secondary to apendicitis, biliary tract infections, sepsis, amoebic colitis, diverticulitis

2. Inflammatory: pancreatitis (3-5%), appendicitis, cholecystitis, EtOH hepatitis, perforated DU.

3. Myeloproliferative disorders (3-12%): may be responsible for many “idiopathic” cases.

4. Hypercoagulable states

a. inherited: ProC, ProS, AT III

b. acquired: nephrotic syndrome, DIC, IBD, malignancy, estrogen use.

1. Other: non-cirrhotic portal fibrosis, trauma, post-surgical (esp. post-splenectomy).

Clinical features: Hematemesis/melena from ruptured varices is most common presentation.

1. SXS/SNS: increased abd girth, pain, N/V, anorexia, weight loss, diarrhea

2. EXAM: splenomegaly (75-100%), mild hepatomegaly, abd tenderness. Ascites less common, mild, transient.

LABS: may be mild elevations of transaminases, alk phos, bilis.

*may be differentiated from Budd-Chiari by hepatomegaly,

ascites, hepatocellular dysfunction seen in Budd-Chiari..

Imaging: Start with ultrasound, MR if available

1. Venogram: gold standard.

2. US: highly sensitive (>90%), but operator dependent.

3. CT: less sensitive (75%), highly specific.

4. MR: highly sensitive and specific.

Complications:

1. Variceal hemorrhage: average 5 episodes/pt.

2. Hepatic encephalopathy: uncommon unless coexisting cirrhosis or shunt surgery.

3. Small bowel infarction: extension of thrombus to SMV

Management:

1. Acute:

a. Control acute bleeding: correct coagulopathy, transfuse, SB balloon, vasopressin, endoscopic sclerotherapy, surgery.

b. Catheter directed thrombolysis: some anecdotal successes.

1. Chronic:

a. Treat underlying etiology.

b. Prophylactic sclerotherapy/banding of varices.

c. Surgical shunt: usually spenorenal, very effective for non-cirrhotics.

d. Anticoagulation: no clear benefit unless underlying hypercoagulable state.

Cohen, et al. Am J Med. Feb 1992, 92: 73-182.