Why Intracystic Hemorrhage Occurs in Hepatic Cysts
Intracystic hemorrhage results from injury to fragile blood vessels within the cyst wall lining, making it the most frequent complication of hepatic cysts. 1
Pathophysiologic Mechanism
The fundamental cause is rupture or injury of delicate blood vessels that line the inner wall of the cyst. 1 These vessels are inherently fragile and prone to bleeding when subjected to mechanical stress or spontaneous rupture. 1
Risk Factors and Triggers
Cyst Size
- Larger cysts (arbitrarily defined as >8 cm) have significantly higher hemorrhage risk due to increased wall tension and vessel fragility. 1
- The risk of hemorrhage increases proportionally with cyst size. 1
Mechanisms of Injury
Spontaneous hemorrhage occurs without identifiable precipitating factors in many cases, likely from progressive wall weakening and vessel fragility. 1
Iatrogenic causes include:
- Percutaneous aspiration sclerotherapy, which directly traumatizes cyst wall vessels 1
- EUS-guided FNA procedures, which cause acute intracystic hemorrhage in approximately 6% of pancreatic cyst aspirations 2
Cyst rupture can trigger hemorrhage as the structural integrity of the wall fails. 1
Anticoagulation and Antiplatelet Therapy
While not explicitly stated as causative in the guidelines, patients on aspirin or other antiplatelet/anticoagulant therapy are at theoretical increased risk, as evidenced by specific management recommendations for these medications after hemorrhage occurs. 1, 3
Clinical Presentation
Sudden, severe abdominal pain occurs in 80% of patients with intracystic hemorrhage, though hemodynamic instability is rare. 1, 4
Key clinical features include:
- Pain resolves spontaneously within days to weeks 1, 4
- Hemoglobin drops are exceptional but may occur 1
- CA19-9 levels may transiently increase 1
Important Clinical Caveat
The hemorrhage is confined within the cyst (intracystic) and does not typically cause intraperitoneal or systemic bleeding, which explains the absence of hemodynamic instability despite severe pain. 1 This is a self-limited process where blood accumulates within the cyst cavity rather than causing life-threatening hemorrhage.