What are the causes and management of hepatic infarction?

Causes and Management of Hepatic Infarction

Hepatic infarction is a rare but potentially fatal condition caused primarily by interruption of the liver's blood supply through vascular occlusion, with management focused on treating the underlying cause and providing supportive care.

Causes of Hepatic Infarction

Vascular Occlusive Disorders

• Budd-Chiari Syndrome (BCS): Thrombosis or obstruction of hepatic veins leading to hepatic congestion and potential infarction 1
• Portal Vein Thrombosis (PVT): Occlusion of the portal vein that can compromise liver perfusion, especially when combined with other vascular issues 1, 2
• Hepatic Artery Thrombosis: Critical cause of infarction, especially post-liver transplantation 1
• Arteriovenous Malformations: Abnormal vascular connections that can compromise normal blood flow 1

Hemodynamic Causes

• Shock Liver (Ischemic Hepatitis): Resulting from systemic hypotension, hypoxia, or cardiac failure causing hepatic hypoperfusion 1
• Cardiac Arrest: Severe hypoperfusion during cardiac arrest can lead to hepatic infarction 1, 3
• Severe Congestive Heart Failure: Chronic passive congestion leading to compromised hepatic perfusion 1, 3

Pregnancy-Related Causes

• HELLP Syndrome: Hemolysis, Elevated Liver enzymes, and Low Platelets syndrome can cause hepatic infarction through microthrombi formation 4, 5
• Acute Fatty Liver of Pregnancy: Can progress to liver failure with potential infarction 1

Other Causes

• Malignant Infiltration: Cancers like breast, lung, lymphoma can infiltrate liver vasculature 1
• Infectious Emboli: Can obstruct hepatic vessels 6
• Polyarteritis Nodosa: Vasculitis affecting hepatic vessels 6
• Trauma: Severe liver trauma can disrupt blood supply 1
• Iatrogenic: Complications from procedures like endoscopic variceal ligation 2
• Venomous Stings: Rare cause through systemic effects and microthrombi formation 5
• Acute Pancreatitis: Can cause vascular complications affecting the liver 5

Diagnostic Approach

Laboratory Findings

• Markedly elevated transaminases (often 50-150 times normal values) 5
• Conjugated hyperbilirubinemia 5
• Elevated alkaline phosphatase 1
• Coagulation abnormalities in many cases 1

Imaging

• Ultrasound with Doppler: First-line imaging to assess vascular patency and liver parenchyma 1
• CT with IV contrast: Shows non-enhancing wedge-shaped areas of hepatic parenchyma 1
• MRI with IV contrast: Demonstrates increased T2 signal, decreased T1 signal, and non-enhancing areas 1
• Angiography: May be needed for definitive vascular assessment in complex cases 1

Management Approach

Immediate Stabilization

• Hemodynamic Support: Maintain mean arterial pressure >65 mmHg while avoiding fluid overload 1
• Blood Product Replacement: Target hemoglobin >7 g/dL, platelets >50,000, and fibrinogen >120 mg/dL 1
• Correction of Coagulopathy: Essential before any invasive procedures 1

Treatment Based on Etiology

For Budd-Chiari Syndrome:

1. Anticoagulation: Start immediately and continue indefinitely unless contraindicated 1

   • LMWH initially for 5-7 days, followed by vitamin K antagonists (target INR 2-3) 1

2. Stepwise Approach:

   • Angioplasty/Stenting: First-line for short hepatic vein or IVC stenosis 1
   • TIPS (Transjugular Intrahepatic Portosystemic Shunt): For patients not responding to medical treatment or angioplasty 1
   • Liver Transplantation: For patients with progressive liver failure despite other interventions 1

For Portal Vein Thrombosis:

• Anticoagulation: When diagnosed early (<6 months), recanalization rates of 55-75% 1
• TIPS with Portal Vein Recanalization: For cases with extensive thrombosis 1
• Treatment of Portal Hypertension Complications: As needed (variceal bleeding, ascites) 1

For Ischemic/Shock Liver:

• Cardiovascular Support: Primary focus on improving cardiac output and systemic perfusion 1
• Treating Underlying Cardiac Condition: Heart failure management, arrhythmia control 1, 3
• Avoid Hepatotoxic Medications: To prevent further liver injury 1

For HELLP Syndrome:

• Expeditious Delivery: In pregnancy-related cases 1, 4
• Multidisciplinary Management: Including hepatology, obstetrics, and critical care 4
• Consider Liver Transplantation: In cases progressing to fulminant liver failure 4

Advanced Interventions

• Angioembolization: For persistent arterial bleeding 1
• Surgical Intervention: Rarely needed except in trauma cases with hemodynamic instability 1
• Liver Transplantation: Ultimate rescue therapy for fulminant liver failure from massive hepatic infarction 4

Supportive Care

• Intensive Care Monitoring: Close observation of hemodynamic parameters and liver function 1
• Nutritional Support: To maintain hepatic recovery potential 1
• Prevention and Treatment of Complications: Including infection, renal failure, and encephalopathy 1, 4

Special Considerations

• Hepatic infarction is rare due to the liver's dual blood supply, but can occur when multiple vascular pathways are compromised simultaneously 6
• The presence of microthrombi in hepatic vessels can cause infarction even without macroscopic vascular thrombosis 5
• Mortality is high in cases of massive hepatic infarction progressing to fulminant liver failure 4