Abdominal Trauma/ Injury
Abdomen : The abdomen (colloquially called the stomach, belly, tummy or midriff) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the trunk.
Hence Trauma means the abdominal injury and it can be injured in many types; injury may be confined to the abdomen or be accompanied by severe, multisystem trauma. The nature and severity of abdominal injuries vary widely depending on the mechanism and forces involved, thus generalizations about mortality and need for operative repair tend to be misleading.
Injuries are often categorized by type of structure that is damaged:
• Abdominal wall
• Solid organ (liver, spleen, pancreas, kidneys)
• Hollow viscus (stomach, small intestine, colon, ureters, bladder)
Abdominal trauma is typically also categorized by mechanism of injury:
• Penetrating (Sharp)
· Blunt trauma may involve a direct blow (eg, kick), impact with an object (eg, fall on bicycle handlebars), or sudden deceleration (eg, fall from a height, vehicle crash). The spleen is the organ damaged most commonly, followed by the liver and a hollow viscus (typically the small intestine).
· Penetrating injuries may or may not penetrate the peritoneum and if they do, may not cause organ injury. Stab wounds are less likely than gunshot wounds to damage intra-abdominal structures; in both, any structure can be affected. Penetrating wounds to the lower chest may cross the diaphragm and damage abdominal structures.
CLASSIFICATION (INJURY SCALE)
· Injury scales have been devised that classify organ injury severity from grade 1 (minimal) to grades 5 or 6 (massive); mortality and need for operative repair increase as grade increases. Scales exist for the liver, spleen, and kidneys
· Blunt or penetrating injury that affects intra-abdominal structures may also damage the spine, ribs, and/or pelvis. Patients who experience significant deceleration often have injuries to other parts of the body, including the thoracic aorta.
· Blunt or penetrating trauma may lacerate or rupture intra-abdominal structures. Blunt injury may alternatively cause only a hematoma in a solid organ or the wall of a hollow viscus lacerations hemorrhage immediately.
· Hemorrhage due to low-grade solid organ injury, minor vascular laceration, or hollow viscus laceration is often low-volume, with minimal physiologic consequences.
· More serious injuries may cause massive hemorrhage with shock, acidosis, and coagulopathy; intervention is required.
· Hemorrhage is internal (except for relatively small amounts of external hemorrhage due to body wall lacerations resulting from penetrating trauma).
· Internal hemorrhage may be intraperitoneal or retroperitoneal.
· Laceration or rupture of a hollow viscus allows gastric, intestinal, or bladder contents to enter the peritoneal cavity, causing peritonitis.
Delayed consequences of abdominal injury include
• Hematoma rupture
• Intra-abdominal abscess
• Bowel obstruction or ileus
• Biliary leakage and/or biloma
• Abdominal compartment syndrome
Abscess, bowel obstruction, abdominal compartment syndrome, and delayed incisional hernia also can be complications of treatment.
Hematomas typically resolve spontaneously over several days to months, depending on the size and location.
Splenic hematomas and, less often, hepatic hematomas may rupture, typically in the first few days after injury (although sometimes up to months later), sometimes causing significant delayed hemorrhage.
Intestinal wall hematomas sometimes perforate, typically within 48 to 72 hours after injury, releasing intestinal contents and causing peritonitis, but without causing significant hemorrhage.
Intra-abdominal abscess typically is the result of undetected hollow viscus perforation but may be a complication of laparotomy.
Rate of abscess formation ranges from 0% after nontherapeutic laparotomies to about 10% after therapeutic laparotomies, although the rate may be as high as 50% after surgery to repair severe liver lacerations.
Bowel obstruction rarely develops in weeks to years after injury due to intestinal wall hematoma or adhesions caused by intestinal serosal or mesenteric tears.
More commonly bowel obstruction is a complication of exploratory laparotomy. Even nontherapeutic laparotomies occasionally cause adhesions, which develop in 0 to 2% of such cases.
BILIARY LEAKAGE AND/OR BILOMA
Biliary leakage and/or biloma is a rare complication of liver injury and, even less commonly, of bile duct injury. Bile can be excreted from the raw surface of a liver injury or from an injured bile duct. It may be disseminated throughout the peritoneal cavity or become walled off into a distinct fluid collection, or biloma. Biliary leakage can result in pain, a systemic inflammatory response, and/or hyperbilirubinemia.
ABDOMINAL COMPARTMENT SYNDROME
Abdominal compartment syndrome is analogous to extremity compartment syndrome after orthopedic injury.
In abdominal compartment syndrome, mesenteric and intestinal capillary leakage (eg, due to shock, prolonged abdominal surgical procedures, systemic ischemia-reperfusion injury, and the systemic inflammatory response syndrome [SIRS]) causes tissue oedema within the abdomen.
Although there is more room for expansion in the peritoneal cavity than in an extremity, unchecked oedema, and occasionally ascites, ultimately elevates intra-abdominal pressure (defined as > 20 mm Hg), causing pain and organ ischemia and dysfunction. Intestinal ischemia further worsens vascular leakage, causing a vicious cycle.
Other affected organs include the
• Kidneys (causing renal insufficiency)
• Lungs (elevated abdominal pressure can interfere with respiration, causing hypoxemia and hypercarbia)
• Cardiovascular system (elevated abdominal pressure decreases venous return from the lower extremities, causing hypotension)
• Central nervous system (intracranial pressure increases, possibly due to rise in central venous pressure preventing adequate venous drainage from brain, decreasing cerebral perfusion, which can worsen intracranial injuries)
SYMPTOMS AND SIGNS
• Abdominal pain typically is present; however, pain is often mild and thus easily obscured by other, more painful injuries (eg, fractures) and by altered sensorium (eg, due to head injury, substance abuse, shock).
• Pain from splenic injury sometimes radiates to the left shoulder.
• Pain from a small intestinal perforation typically is minimal initially but steadily worsens over the first few hours.
• Patients with renal injury may notice hematuria.
• On examination, vital signs may show evidence of hypovolemia (tachycardia) or shock (eg, dusky color, diaphoresis, altered sensorium, hypotension).
• Penetrating injuries by definition cause a break in the skin, but clinicians must be sure to inspect the back, buttocks, flank, and lower chest in addition to the abdomen, particularly when firearms or explosive devices are involved.
• Cutaneous lesions are often small, with minimal bleeding, although occasionally wounds are large, sometimes accompanied by evisceration.
• Abdominal tenderness is often present.
• This sign is very unreliable because abdominal wall contusions can be tender and many patients with intra-abdominal injury have equivocal examinations if they are distracted by other injuries or have altered sensorium or if their injuries are mainly retroperitoneal.
• Although not very sensitive, when detected, peritoneal signs (eg, guarding, rebound) strongly suggest the presence of intraperitoneal blood and/or intestinal contents.
• Rectal examination may show gross blood due to a penetrating colonic lesion, and there may be blood at the urethral meatus or perineal hematoma due to genitourinary tract injury. Although these findings are quite specific, they are not very sensitive.
• Clinical evaluation
• Often CT or ultrasonography
· Sometimes laparotomy for hemorrhage control, organ repair, or both
· Rarely arterial embolization
· Patients are given intravenous fluid resuscitation as needed, typically with crystalloid fluids, either 0.9% saline or lactated Ringer solution.
· Observation (beginning in an intensive care unit [ICU]) is often appropriate for hemodynamically stable patients with solid organ injury, many of which heal spontaneously.
· Ongoing hemorrhage is suggested by
· Worsening hemodynamic status
· Significant ongoing transfusion needs (eg, more than 2 to 4 units over a 12-hour period)
· A significant decrease in hematocrit (Hct; eg, by > 10 to 12%)
· Peritonitis requires further investigation by diagnostic peritoneal lavage (DPL), CT, or in some cases, exploratory laparotomy.
· Patients who remain stable are typically transferred to a regular floor after 12 to 48 hours, depending on the severity of their abdominal and other injuries.
· Their activity and diet are advanced as tolerated. Typically, patients may be discharged home after 2 to 3 days.
· They are instructed to restrict activity for a minimum of 6 to 8 weeks.
· Laparotomy is elected either because of the initial nature of the injury and clinical status (eg, hemodynamic instability) or because of subsequent clinical decompensation. Most patients can have a single procedure during which hemorrhage is controlled and injuries repaired.
· However, patients with extensive intra-abdominal injuries who undergo a prolonged initial surgical procedure tend to fare poorly, particularly when they have other serious injuries, have been in shock for a prolonged period, or both.
· Ongoing bleeding can sometimes be stopped without surgery by embolizing the bleeding vessel using a percutaneous angiographic procedure (angiographic embolization).
· Hemostasis is obtained by injecting a thrombogenic substance (eg, powdered gelatin) or metallic coils into the bleeding vessel.