Chapter 154 Abdominal Trauma
Rapid assessment and triage of a dog or cat following abdominal trauma is essential. A history and physical examination will assist in targeting appropriate diagnostic testing and prevent delays in stabilization. The traumatic event is often not witnessed and the full extent of injury to the animal may not be readily apparent. Injury may be confined to the skin and superficial tissues or may be life threatening and involve avulsion or rupture of abdominal organs. Conservative management and observation are indicated in some cases; however, others require immediate surgery and prolonged hospitalization. This chapter will discuss specific causes of abdominal trauma, the secondary effects of such trauma, and the diagnostic and treatment options.
Although motor vehicle accidents, high-rise falls, and intentional physical injuries are often encountered in a veterinary emergency setting, abdominal trauma does not commonly occur with these events in dogs and cats. When blunt trauma to the abdomen does occur, the severity of the abdominal injury is often not recognized immediately, while other life-threatening injuries are being addressed.
A retrospective study of 600 dogs1 that were struck with a motor vehicle noted that 5% experienced abdominal trauma (as diagnosed by surgery or necropsy). The liver was the abdominal organ most often damaged (31% of the abdominal organ injuries), with injuries ranging from fissures of the capsule/parenchyma to fragmentation of a hepatic lobe. Other organs that were injured frequently included the urinary bladder, diaphragm, and kidney. Of the 33 dogs that died from their injuries, 8 (24%) had abdominal injury alone and 13 (39%) had both abdominal and thoracic injury. It is important to remember that some dogs and cats may not experience internal abdominal trauma, but may still require aggressive surgical procedures for damage that occurs to the skin or abdominal muscles, especially when a vehicle drives over or drags the animal.
High-rise falls in dogs and cats result in abdominal injuries in 15% and 7% of cases, respectively.2,3 Dogs falling from a height of greater than three stories are more likely to experience abdominal injury than those falling less than or equal to three stories. Also, dogs that fall accidentally more often experience abdominal and hind limb injury than dogs that purposefully jump from a height.2 In most studies of dogs and cats, thoracic trauma is diagnosed more commonly than abdominal trauma, perhaps due to the readily apparent respiratory compromise in those patients.
Unfortunately, human abuse of companion animals is another cause of blunt abdominal trauma. In a study investigating nonaccidental injury4 to animals, internal injury to the abdomen was documented less frequently than superficial injuries or fractures. However, 13 of 217 (6%) dogs in this study experienced rupture of an organ, including spleen, liver, bladder, and kidney. Cats tended to experience abdominal muscle rupture. Kicking of the animal was the cause of the abdominal injury in most cases.
Penetrating trauma to the abdomen often results in both superficial and internal injuries. Skin wounds may not reveal the full extent of the injury in deeper tissues. The reported incidence of internal organ injury after penetrating trauma has been reported to be as high as 70%.5
Bite wounds can result in both blunt and penetrating trauma. Exploration of superficial wounds is often necessary to fully recognize the extent of any organ damage that has occurred.6 Wounds that do not penetrate the abdomen still require close surgical exploration, because bacteria from the biting animal’s mouth or environment will likely contaminate the wound and result in abscess formation.
When large animals attack smaller animals, the victims may be lifted and shaken. This can result in severe crushing and tearing injury as well as avulsion of internal organs or body wall/ diaphragmatic herniation. The organs most commonly injured from bite wounds included the liver, kidney, diaphragm, and stomach in one study.5
Gunshot wounds to the abdomen have been reviewed in several papers.5,7 Of 84 animals reported in one retrospective study,7 14 abdominal injuries were encountered. Animals with abdominal injury also tended to have more cardiovascular compromise on presentation than those without abdominal injury.
Other types of penetrating abdominal wounds include stab wounds and impalement injuries (from sticks or other devices) or following a high-rise fall.4,5,8 Some of these injuries are self-induced, and others are the result of mistreatment. Either way, early intervention is likely required to maximize the success of treatment.
Blood work may support a diagnosis of intraabdominal trauma; however, it rarely localizes the injury to a specific organ(s). A complete blood count may demonstrate the presence of anemia in a dog or cat that is experiencing a bleed from either a superficial wound or a deep injury (such as organ rupture), although this change is not typically present in the acute setting. The white blood cell count can increase secondary to stress, inflammation, or an infection that may be localized (in abscess form) or systemic (as with sepsis). The platelet count may be decreased from acute blood loss and subsequent consumption during clot formation. In severe cases of abdominal trauma, disseminated intravascular coagulation (DIC) may occur, leading to thrombocytopenia and prolongation of the prothrombin and activated partial thromboplastin times (see Chapter 117, Hypercoagulable States).
Liver enzyme elevations are often noted on the chemistry screen if hepatic trauma has occurred. If the biliary system is ruptured, progressive increases in total bilirubin will be observed. Azotemia and electrolyte disturbances (e.g., hyperkalemia) will occur secondary to urinary tract rupture. Animals with sterile or septic peritonitis or a persistently draining wound may develop hypoproteinemia.
Abdominal radiographs are useful in the diagnosis of abdominal pathology, but it is not always possible to identify a specific cause. The presence of intraabdominal gas suggests that abdominal wall penetration or organ perforation has occurred and requires immediate attention. The general loss of serosal detail in the abdomen is suggestive of fluid in the peritoneal space, retroperitoneal space, or both. Animals with traumatic pancreatitis or very young or thin animals may also have poor serosal detail on radiographs.
Fluid in the peritoneal space may originate from a bleeding organ or ruptured vessel, urine from a distal ureteral, bladder, or proximal urethral rupture, bile from a rupture in the biliary system, or a septic exudate due to septic peritonitis. Fluid in the retroperitoneal space is most commonly urine from damage to the kidney or proximal ureter or blood from a great vessel. Subcutaneous emphysema can be seen when gas accumulates in the subcutaneous spaces, with or without abdominal injury.
Diaphragmatic and body wall ruptures are commonly diagnosed with radiographs.9,10 Both thoracic and abdominal radiographs should be taken in cases of suspected diaphragmatic rupture. Characteristic changes seen on radiographs in animals with diaphragmatic rupture include loss of continuity of the diaphragm, loss of intrathoracic detail (specifically cardiac silhouette), and the presence of gas-filled bowel loops or a mass effect in the thorax. These changes are not always present, and further imaging may be necessary to confirm the diagnosis.