Hepatic Subcapsular Hematoma: Definition and Clinical Entity
A hepatic subcapsular hematoma is a collection of blood that accumulates between the liver parenchyma and Glisson's capsule (the liver's outer fibrous covering), not under the scapula as the anatomical term might suggest. 1
Anatomical Classification
Subcapsular hematomas are classified by the percentage of liver surface area involved: 1
- Grade I: <10% surface area
- Grade II: 10-50% surface area
- Grade III: >50% surface area or expanding/ruptured hematoma
The hematoma displaces hepatic parenchyma inward while remaining contained beneath the liver capsule, creating a characteristic crescent-shaped fluid collection on imaging. 2
Common Etiologies
Traumatic causes:
- Blunt abdominal trauma is the most common cause, with subcapsular hematomas occurring in 12-14% of high-grade liver injuries. 3
- Penetrating trauma can also result in subcapsular blood collection. 3
Non-traumatic causes:
- Severe preeclampsia and HELLP syndrome (hemolysis, elevated liver enzymes, low platelets) in pregnancy are important obstetric causes. 4, 5
- Iatrogenic injury from procedures such as colonoscopy has been reported. 6
- Chronic expanding hematomas can develop from persistent low-grade bleeding over months. 2
Clinical Presentation
Patients typically present with:
- Right upper quadrant or epigastric pain that may be severe, shooting, or pleuritic in nature 4
- Pain radiating to the right shoulder (Kehr's sign) 4, 6
- Nausea and vomiting 4, 5
- Hemodynamic instability if rupture occurs or bleeding is ongoing 1
Diagnostic Approach
Initial assessment must focus on hemodynamic status, as this determines management strategy. 1
- Extended FAST (E-FAST) ultrasound rapidly detects intra-abdominal free fluid and can identify the subcapsular collection as a hyperechoic mass. 6
- CT scan with intravenous contrast is the gold standard for hemodynamically stable patients, showing the characteristic subcapsular location and extent of the hematoma. 1, 4
- Serial hemoglobin measurements and liver enzyme monitoring detect ongoing bleeding or hepatic parenchymal ischemia. 3, 1
Potential Complications
Large subcapsular hematomas carry significant risk even when initially stable: 3
- Delayed rupture can occur days after initial presentation, requiring continued vigilance. 1
- Secondary infection leading to abscess formation occurs in 0.6-7% of cases. 3
- Hepatic artery pseudoaneurysm formation (1% prevalence) carries high rupture risk. 3
- Biliary complications including bile leak, biloma, and biliary peritonitis may develop. 3
- Infected pleural effusions requiring surgical drainage have been reported. 4