eMedicine Specialties > Radiology > Gastrointestinal

Liver, Trauma

Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR, Consultant Radiologist and Honorary Professor, North Manchester General Hospital Pennine Acute NHS Trust, UK
Coauthor(s): Hemant Vadeyar, MBBS, Consulting Hepatobiliary and Pancreatic Surgeon, North Manchester General Hospital; Sumaira MacDonald, MBChB, PhD, MRCP, FRCR, Lecturer, Sheffield University Medical School; Endovascular Fellow, Sheffield Vascular Institute; Muthusamy Chandramohan, MBBS, DMRD, FRCR, Consultant Radiologist, Bradford Teaching Hospitals, UK
Contributor Information and Disclosures

Updated: Aug 25, 2009

Introduction

Background

The liver is the largest solid abdominal organ with a relatively fixed position, which makes it prone to injury. The liver is the second most commonly injured organ in abdominal trauma, but damage to the liver is the most common cause of death after abdominal injury. The most common cause of liver injury is blunt abdominal trauma, which is secondary to motor vehicle accidents in most instances.

In the past, most of these injuries were treated surgically. However, surgical literature confirms that as many as 86% of liver injuries have stopped bleeding by the time surgical exploration is performed, and 67% of operations performed for blunt abdominal trauma are nontherapeutic.

Imaging techniques, particularly computed tomography (CT) scanning, have made a great impact on the treatment of patients with liver trauma, and use of these techniques has resulted in marked reduction in the number of patients requiring surgery and undergoing nontherapeutic operations. Almost 80% of adults and 97% of children are treated conservatively by using careful follow-up imaging studies.^1,2

Recent studies

Heuer et al found that severe liver injury is an independent predictor of severe hemorrhage and is associated with a significantly increased risk of sepsis, multiorgan failure, and trauma-related death. In addition, they found that a deleterious outcome was more frequently associated with severe liver trauma than with severe abdominal trauma. They noted that although conservative treatment of patients with liver trauma but without hemorrhage is effective, that is not the case in the presence of hemodynamic instability.³

Hussain et al studied 64 patients in Riyadh, Saudi Arabia, who underwent operative management for liver injuries between 1997 and 2006. Hepatorrhaphy (n=28) was the most common surgical technique to control bleeding, followed by perihepatic packing in unstable patients (n=12), simple hemostatic measures (n=9), and nonanatomic hepatic resection (n=8). Mortality was 11%. In 25% of patients, bleeding had either stopped from the injured liver or needed only simple hemostatic measures.⁴

Tinkoff et el used the National Trauma Data Bank (NTDB) to validate the American Association for the Surgery of Trauma (AAST) Organ Injury Scale (OIS) for spleen, liver, and kidney injuries. Injuries were stratified either as an isolated intra-abdominal organ injury or in combination with other abdominal injuries. The patients were analyzed for mortality, operative rate, hospital length of stay, ICU length of stay, and charges incurred. There were 54,148 NTDB entries with Abbreviated Injury Scale-coded injuries to the spleen, liver, or kidney, and 35,897 of these were isolated abdominal solid organ injuries.

For patients in the Tinkoff study in whom the solid organ was not the sole abdominal injury, a statistically significant increase in mortality, organ-specific operative rate, and hospital charges was associated with increasing OIS grade, except in the case of grade VI hepatic injuries; hospital and ICU lengths of stay did not substantially increase with increasing OIS grade. When isolated organ injuries were examined, there were statistically significant increases in all variables corresponding with increasing OIS grade.⁵

Pathophysiology

The liver is the largest intra-abdominal solid organ and is enclosed anteriorly and laterally by the rib cage. The large size of the liver, its friable parenchyma, its thin capsule, and its relatively fixed position in relation to the spine make the liver particularly prone to blunt injury. As a result of its larger size and proximity to the ribs, the right lobe is injured more commonly than the left.

Various biomechanical mechanisms have been proposed in the genesis of blunt hepatic injuries.

Most liver injuries (>85%) involve segments 6, 7, and 8 of the liver. This type of injury is believed to result from simple compression against the fixed ribs, spine, or posterior abdominal wall. Pressure through the right hemithorax may propagate through the diaphragm, causing a contusion of the dome of the right lobe of the liver. The liver's ligamentous attachment to the diaphragm and the posterior abdominal wall can act as sites of shear forces during deceleration injury.

Liver injury can also result from transmission of excessively high venous pressure to remote body sites occurring at the time of impact. Liver injury occurs more easily in children than in adults because the ribs are more flexible, allowing force to be transmitted to the liver. In addition, the liver is not fully developed in children, who have a weaker connective tissue framework than do adults. A steering-column injury may cause trauma to an entire lobe of the liver.⁶ Deceleration injuries produce shearing forces that may tear hepatic lobes from each other and often involve the inferior vena cava and hepatic veins. Increasing numbers of central liver hematomas caused by accidents involving mountain bikes are being encountered.⁷

Interventional radiology procedures, such as percutaneous biopsy, cholangiography or biliary drainage, transjugular intrahepatic portosystemic shunt (TIPS) procedures, and percutaneous alcohol injection, can cause capsular tears, hematoma, bile leaks, bilomas, arteriobiliary or venobiliary fistulas, and hemoperitoneum.

In the neonate, hepatic injury may be unsuspected. In neonatal fatalities, 9.6% of postmortem studies show evidence of liver trauma, especially subcapsular hematoma. Because the hepatic veins lie in rigid canals and contract poorly, the liver is incapable of achieving spontaneous hemostasis after injury. Blunt liver trauma is associated with splenic injury in 45% of patients. Rib fractures are associated with injury to the right superior aspect of the liver in 33% of patients, and duodenal and pancreatic injuries are more closely associated with hepatic left lobe trauma. Isolated liver injury occurs in less than 50% of patients.⁸

Liver trauma may result in the following:

• Subcapsular hematoma or intrahepatic hematoma
• Laceration
• Contusion
• Hepatic vascular disruption
• Bile duct injury

Most blunt liver trauma (80% in adults, 97% in children) is currently treated conservatively. Surgical literature confirms that more than 86% of hepatic injuries have stopped bleeding at the time of surgical exploration. Conservative treatment requires the ability to clinically monitor the physiologic signs adequately and to intervene surgically if conservative treatment fails.

A comparison of patients receiving operative and nonoperative treatment for liver injuries has revealed no difference in the length of hospital stay between the 2 groups, but in this study, blood transfusion requirements and intra-abdominal complications were significantly lower in the group of patients receiving conservative treatment.

The liver is the most common abdominal organ injured by penetrating trauma. Penetrating trauma of the liver may be caused by bullets, shrapnel, knives, and other sharp objects. In most centers, surgery for stab wounds is performed only in patients in whom internal injury is strongly suspected. Complications from liver trauma occur in approximately 20% of patients and include delayed rupture (very rare), hemobilia, arteriovenous fistula, pseudo-aneurysm, and biloma and abscess formation.

Mild hepatic injuries that involve less than 25% of 1 lobe resolve within 3 months. Most moderate injuries involving 25-50% of 1 lobe heal within 6 months, whereas severe injuries require 9-15 months to heal.

Gallbladder injuries are rare. Predisposing factors for gallbladder injuries include alcohol ingestion, which increases tone of the sphincter of Oddi, and a normal, distended gallbladder. Paradoxically, patients with chronic cholecystitis are less prone to experiencing gallbladder rupture. Gallbladder injuries are classified as contusions, lacerations or perforations, and avulsions; contusions are most common. Avulsion injuries are the second most common; the gallbladder is partially or completely torn from the gallbladder fossa. Healing takes 1-15 months, and the rate of healing correlates with the severity of trauma.

Several systems have been devised to classify liver injuries; however, the lack of consistency of scoring severity in organ injury is a problem. To rectify the problem, the American Association for the Surgery of Trauma (AAST) developed a system based on the amount of anatomic disruption of an individual organ. The scoring system is used routinely in the United States and includes grades 1-6. A CT scan classification of liver injuries based on the AAST liver injury criteria has been devised by Mirvis and colleagues.⁹ This classification has been found to be valuable in predicting prognosis and treatment needs in adult patients with liver trauma (see CT Scan).

Frequency

United States

Liver trauma accounts for 15-20% of blunt abdominal injuries.

International

Exact worldwide incidence of liver trauma is not known.

Mortality/Morbidity

Although blunt liver trauma accounts for 15-20% of abdominal injuries, it is responsible for more than 50% of deaths resulting from blunt abdominal trauma. The mortality rate is higher with blunt abdominal trauma than with penetrating injuries. Previously, as a result of this high mortality rate, emergency surgery was frequently indicated in patients with hepatic injury. However, with better monitoring facilities and imaging techniques, most patients with blunt abdominal trauma are now treated conservatively.

Sex

Blunt and penetrating liver injuries are more common in males.

Age

Most liver trauma occurs in adults who drive motor vehicles or engage in fighting.

Anatomy

Functional (physiologic or surgical) anatomy based on hepatic vasculature is the basis of modern hepatic surgery. The nomenclature of functional anatomy is an invaluable asset for radiologists and surgeons, allowing other clinicians to define the location of liver lacerations, rupture, hematomas, and vascular complications of trauma, as well as the relationships with major vascular structures.

Classic anatomic descriptions of the liver are based on hepatic vasculature. Cantlie first described the main anatomic divisions along a main plane (Cantlie line) extending from the gallbladder fossa to the inferior vena cava. This line reaches the superior surface of the liver to the right of the falciform ligament and roughly divides the liver into equal halves.

Couinaud further refined the functional anatomy and demonstrated that the liver is divided into 4 sectors and 8 segments. The liver is divided by vertical and oblique planes, or scissurae, defined by the 3 main hepatic veins and a transverse plane, or transverse scissura, following a line drawn through the right and left portal branches.

Hepatic veins lie between segments. The left hepatic vein divides the left side of the liver into medial and lateral segments. The middle hepatic vein divides the liver into left and right lobes. The right hepatic vein divides the right side of the liver into anterior and posterior segments. A further imaginary line (horizontal), drawn through the left and right main portal vein branches, may be used to divide the hepatic lobes into superior and inferior segments. Determining the anatomy of the liver segments allows accurate localization of hepatic masses relative to the hepatic vasculature. This localization is important because advances in liver surgery allow hemihepatectomy, as well as segmental and subsegmental resections. The 8 liver segments (namely 1, 2, 3, 4a, 4b, 5, 6, 7, 8) are numbered clockwise on the frontal view.

Presentation

A patient history of blunt or penetrating abdominal trauma may be forthcoming.

• Signs and symptoms of hepatic injury are related to loss of blood, peritoneal irritation, right upper quadrant tenderness, and guarding.
• Rebound abdominal tenderness is common but nonspecific.
• Occasionally, patients with blunt abdominal trauma, after initially doing well, develop a liver abscess, presumably due to unrecognized liver damage. These patients present with signs and symptoms of deep-seated infection.
• Patients may present with severe peritonism due to bile peritonitis resulting from bile leaks.
• Signs of blood loss, such as shock, hypotension, and a falling hematocrit level, may dominate the picture.
• Elevation of serum liver enzyme levels in a patient with blunt abdominal trauma suggests that the liver has been injured, although a pre-existing cause, such as a fatty liver, may be responsible for abnormal results in liver function test results.
• Clinical signs and symptoms of biliary peritonitis include abdominal pain, nausea, and vomiting. These signs may evolve gradually, making diagnosis difficult and leading to increased morbidity and mortality rates. CT scanning or ultrasonography-guided aspiration of peritoneal fluid can help to confirm the diagnosis.
• Diagnostic peritoneal lavage has been shown to be useful in evaluating patients with blunt abdominal trauma, with reported sensitivities of as high as 95%. Although peritoneal lavage has advantages in the diagnosis of abdominal injuries that cause intraperitoneal hemorrhage, it has no role in examining patients with injuries to the retroperitoneal organs. In addition, peritoneal lavage is an invasive procedure that must be performed in the absence of patient movement and is inappropriate for stable, alert patients. A complication rate of 1-2% has been linked to the procedure.

Preferred Examination

• Plain radiographic findings are nonspecific, but they may be useful in showing the extent of associated skeletal trauma.
• Contrast-enhanced CT scanning remains the examination of choice in patients with blunt abdominal trauma.^10,11
• Radionuclide study with technetium-99m (^99m Tc) iminodiacetic acid (IDA) is the examination of choice in patients in whom bile leaks are suspected.
• Magnetic resonance imaging (MRI) has yet to find a role but can be used to monitor liver injury. Magnetic resonance cholangiopancreatography (MRCP) may be used for the diagnosis and follow-up observation of bile duct injuries.¹²
• Angiography is useful in localizing the site of hemorrhage and in providing an opportunity for the interventional radiologist to proceed to transcatheter embolization of bleeding sites.

Limitations of Techniques

• Plain radiographs cannot depict liver trauma directly, and radiographic findings may be completely normal.
• In penetrating abdominal trauma, overall sensitivity of focused ultrasonography is 46%, and specificity is 94%.¹³ Emergency ultrasonographic findings based on the demonstration of free fluid and/or parenchymal injury demonstrate the overall sensitivity of ultrasonography for detection of blunt abdominal trauma to be 72%. However, the sensitivity is higher (98%) for injuries of grade 3 or higher. However, negative ultrasonographic findings do not exclude hepatic injury.
• Angiographic images can fail to depict active bleeding, and false-negative or false-positive diagnoses can occur with liver trauma.

Differential Diagnoses

Kidney, Trauma
Spleen, Trauma

Other Problems to Be Considered

Delayed liver rupture (rare)
Liver rupture secondary to cyst or neoplasm
Liver rupture in hemolysis, elevated liver enzymes, and low-platelet-count (HELLP) syndrome
Intrahepatic bleed from ruptured intrahepatic aneurysm (eg, vasculitides)
Liver infarct from portal venous thrombosis

Blunt and penetrating abdominal injuries may involve other organs, such as the spleen, kidneys, or duodenum, or the mesentery; therefore, examining other intra-abdominal organs is mandatory.

• Search for CME/CE on This Topic »

• Abdominal Trauma, Blunt (Trauma)
• Abdominal Trauma (Pediatrics: Surgery)
• Birth Trauma (Pediatrics: Cardiac Disease and Critical Care Medicine)
• Bile Duct Strictures (Gastroenterology)

• Liver, Gallbladder, and Pancreas Center
• Abdominal Pain in Adults Causes
• Esophagus, Stomach, and Intestine Center
• Abdominal Pain in Adults Overview
• Abdominal Pain in Adults Symptoms
• Abdominal Pain in Adults Treatment

• FDA Safety Changes: Strattera, Aptivus, CellCept
• Changing Mortality Trends in HIV-Infected US Women: Report
• Dietary Nutrient Composition Associated With Cirrhosis, Liver Cancer

• Analysis of Urobilinogen and Urine Bilirubin for Intra-Abdominal Injury in Blunt Trauma Patients
• Effects of Simvastatin 40 mg Daily on Muscle and Liver Adverse Effects in a 5-Year Randomized Placebo-Controlled Trial in 20,536 High-Risk People
• Emergency Department Ultrasound Is Not a Sensitive Detector of Solid Organ Injury

• Liver &Intestine Transplant Resource Center
• Trauma Resource Center
• Gallbladder and Biliary Disease Resource Center