Overview
Definition:
Portal vein injury shunting refers to the iatrogenic or traumatic creation of an abnormal vascular connection between the portal vein and systemic circulation
This can occur inadvertently during surgical procedures in the vicinity of the portal vein or as a result of direct trauma
Such shunting bypasses the liver, leading to altered hemodynamic and metabolic consequences.
Epidemiology:
The incidence of portal vein injury shunting is relatively low and often reported as a complication of complex abdominal surgeries, particularly liver resections, pancreaticoduodenectomies, and liver transplantations
Traumatic injuries, though less common in this context, can also lead to such fistulas.
Clinical Significance:
Portal vein injury shunting is clinically significant due to its potential to cause hepatic encephalopathy, portal hypertension, ascites, and altered drug metabolism
Prompt recognition and appropriate management are crucial to prevent severe morbidity and mortality, making it a vital topic for surgical trainees preparing for DNB and NEET SS examinations.
Clinical Presentation
Symptoms:
Development of ascites
Hepatic encephalopathy, manifesting as confusion, altered mental status, or coma
Gastrointestinal bleeding, particularly from esophageal varices
Jaundice may be present
Abdominal pain or discomfort in the operative region.
Signs:
Hepatomegaly or splenomegaly
Caput medusae
Ascites with shifting dullness and fluid thrill
Asterixis (flapping tremor) in cases of hepatic encephalopathy
Palpable abdominal masses or pulsatile masses in cases of traumatic arteriovenous fistulas.
Diagnostic Criteria:
Diagnosis is typically confirmed by imaging demonstrating the abnormal communication between the portal vein and a systemic vein or artery
Clinical suspicion in the context of recent abdominal surgery or trauma with suggestive signs and symptoms is paramount.
Diagnostic Approach
History Taking:
Detailed history of any recent abdominal surgery, trauma, or procedures involving the portal venous system
Review of surgical reports and operative findings
Assessment of neurological status for signs of hepatic encephalopathy
Inquiry about symptoms of portal hypertension.
Physical Examination:
Thorough abdominal examination to assess for ascites, organomegaly, and any palpable masses
Neurological assessment to identify signs of encephalopathy
Evaluation of peripheral stigmata of liver disease and portal hypertension.
Investigations:
Abdominal ultrasound with Doppler: To visualize the portal vein, identify flow abnormalities, and detect potential shunting
CT angiography (CTA): Gold standard for defining the anatomy of the shunt, its origin, and its drainage
MR angiography (MRA): An alternative to CTA, especially useful in patients with renal insufficiency
Upper GI endoscopy: To assess for esophageal varices and stigmata of bleeding
Liver function tests (LFTs): May show derangements but are often non-specific
Coagulation profile: Important for pre-operative assessment.
Differential Diagnosis:
Other causes of ascites (e.g., cirrhosis, malignancy)
Spontaneous portosystemic shunts
Budd-Chiari syndrome
Intra-abdominal abscess
Arteriovenous malformations not involving the portal system.
Management
Initial Management:
Hemodynamic stabilization if the patient is in shock
Management of hepatic encephalopathy with lactulose and antibiotics if indicated
Correction of coagulopathy
Control of gastrointestinal bleeding.
Medical Management:
Medical management is primarily supportive
Lactulose for hepatic encephalopathy
Beta-blockers or endoscopic variceal ligation for managing varices to prevent rebleeding
Diuretics for ascites control if not primarily due to the shunt.
Surgical Management:
Surgical management is indicated for symptomatic shunts
Options include: Transjugular intrahepatic portosystemic shunt (TIPS) revision or creation if indicated for portal hypertension complications
Ligation or resection of the shunt if clearly identifiable and amenable to surgical intervention
Embolization of the shunt by interventional radiology is often the preferred less invasive approach for focal injuries or fistulas
Management of underlying liver disease if present.
Supportive Care:
Close monitoring of neurological status, fluid balance, and vital signs
Nutritional support, including appropriate protein intake and vitamin supplementation
Management of electrolyte imbalances
Prophylaxis for gastrointestinal bleeding.
Complications
Early Complications:
Hemorrhage from the injury site or varices
Worsening hepatic encephalopathy
Sepsis
Acute kidney injury
Budd-Chiari syndrome if the outflow from the liver is compromised.
Late Complications:
Progressive liver dysfunction
Development or worsening of portal hypertension
Recurrence of varices or encephalopathy
Progressive liver fibrosis and cirrhosis
Development of hepatocellular carcinoma in the long term.
Prevention Strategies:
Meticulous surgical technique with careful dissection around the portal vein and its branches
Intraoperative ultrasound to identify the portal vein and its tributaries
Awareness of anatomical variations
Prompt identification and repair of any inadvertent injury to the portal vein or its tributaries during surgery.
Prognosis
Factors Affecting Prognosis:
The severity of the portal vein injury
The presence and degree of underlying liver disease
The promptness and success of treatment
The development of complications like hepatic encephalopathy or bleeding
The patency of the portal vein post-intervention.
Outcomes:
With timely and appropriate management, many patients can achieve good outcomes
However, patients with significant underlying liver disease or those who develop severe complications may have a poorer prognosis
Long-term follow-up is essential.
Follow Up:
Regular clinical assessment for symptoms of hepatic encephalopathy or portal hypertension
Periodic Doppler ultrasound or angiography to assess the patency of the portal vein and the absence of recurrent shunting
Endoscopic surveillance for varices
Monitoring of liver function tests.
Key Points
Exam Focus:
Understand the definition, common causes, and clinical manifestations of portal vein injury shunting
Be familiar with the diagnostic modalities, especially CTA and Doppler US
Know the management options, including interventional radiology and surgery, and their indications
Recognize the potential complications and their prevention.
Clinical Pearls:
Always consider portal vein injury in patients presenting with unexplained ascites, encephalopathy, or GI bleeding post-abdominal surgery or trauma
Early diagnosis with imaging is key
Interventional radiology offers a less invasive approach for many shunts.
Common Mistakes:
Delaying diagnosis by attributing symptoms solely to post-operative recovery
Inadequate imaging to define the shunt anatomy
Inappropriate management, such as attempting surgical repair without considering less invasive options or without addressing underlying liver disease.