ABDOMINAL TRAUMA:
As mentioned in earlier posts, trauma has two flavours: penetrating and blunt force. This applies to the abdomen just as it does any other anatomical region. If you have read the earlier information about the acute medical abdomen, you are well aware that this is an area with a number of organs, tissues, and blood vessels, all of which may be injured in a traumatic situation.
Blunt trauma injuries: Usually blunt trauma is the result of sudden deceleration, which causes the abdominal organs to continue moving forward within the abdominal cavity following an abrupt cessation of forward body motion. The resulting damage is the combination or isolated expression of one of three mechanisms. 1) Shearing: when abdominal organs or vessels are involved in sudden deceleration, they may tear away from points of attachment, 2) Crushing: Organs may be damaged when there is pressure against them that squeezes them between the abdominal wall and the spinal column, and 3) Compression: This can occur when force is applied against any organ, leading to tissue deformity, bleeding, and/or rupture. Typically blunt trauma produces closed-abdominal wounds that may be difficult to assess as they are not always immediately apparent.
Penetrating trauma injuries: The most common mechanisms are projectile injury (bullets, shrapnel, etc), and impaled foreign objects (stabbings, falls onto fences, etc). These injuries cause disruption of tissues, the capsules of organs, and the walls of blood vessels. They also produce open-abdominal wounds, which introduce the risk of infection and contamination.
In general, abdominal organs respond to trauma in 2 ways:
Solid organs bleed
Hollow organs rupture, spilling their contents into either the peritoneal, or retroperitoneal space.
Lets talk about trauma by specific organs affected:
Liver injuries: The liver is traversed by the Falciform Ligament, and in a rapid deceleration, it can tear laterally at this point of fixation. The result is severe hemorrhage. Additionally, direct trauma to the right flank and anterior abdomen can cause contusions that may lead to tissue death in the affected area. We want to suspect liver damage in any patient who presents with right sided abdominal pain, or where the mechanism suggests potential liver injury. Because of the potential for massive hemorrhage, these patients may rapidly show signs of shock. If the liver hemorrhages into the peritoneum, you may see rebound tenderness and other signs of peritonitis. Observe for peri-umbilical bruising (Cullen's Sign), or discolouration of the flank(s) (Grey-Turner's Sign).
Spleen injuries: The spleen is generally well protected with the majority of its mass housed behind the left lower rib cage. That being said, splenic injuries can result with relatively low velocity/low force trauma. Common mechanisms include sports related injuries, motorcycle crashes, and moderate-height falls. The spleen holds as much as 350cc of blood, which can spill into the peritoneal space, leading to peritonitis. However, splenic injuries may be insidious, and resent with non-specific pain in the left or diffuse abdomen. Mechanism is the best clue that the injury may be present.
Pancreatic injuries: The pancreas is housed in the retroperitoneal space, and is protected by the abdominal musculature. It takes significant blunt force trauma to cause injury. The more common mechanism is penetrating trauma. If the pancreas ruptures, digestive enzymes can cause significant internal damage, and may lead to retroperitoneal abscess formation.
Diaphragmatic injuries: Penetrating trauma or severe blunt force trauma can lead to perforation or rupture of the diaphragm. This alters the ability of the patient to participate in respiration. These patients will be struggling to breath, and notable diminished chest expansion in the absence of thoracic injuries is a big clue.
The small and large intestines: Hollow organs such as the intestines are generally able to handle blunt force trauma well, due to their ability to compress. Penetrating trauma is a more serious problem because it leads to spillage of fecal matter and digestive enzymes into the peritoneal space. This leads to peritonitis, abscess formation, and sepsis.
Stomach injuries: The stomach can be affected by blunt force and penetrating trauma, with the latter being more severe. Gastric juices, acids, and enzymes can spill into the peritoneal space and severely damage organs and blood vessels.
Vascular injuries: The descending aorta and its branches, and the inferior vena cava, pass through the abdomen. It takes significant force to cause shearing of these vessels, but it can happen. Penetrating trauma can definitely lead to laceration and severe internal hemorrhage.
While we cannot address internal bleeding directly outside of the surgical setting, it is our job to assess for it and triage our patients appropriately to a trauma centre. Common clues that the patient with a closed abdominal injury may have damage to organs or blood vessels include:
Abdominal distention
Rigidity
Tenderness
Asymmetry
Cullen's Sign
Grey-Turner's Sign
Signs of shock
Mechanism that suggests it
Eviscerations:
Evisceration is the term given to protrusion of abdominal contents through an opening in the abdominal wall. This most commonly involves the intestines, which may protrude in the event that the abdominal musculature is perforated by a penetrating injury. These wounds can be treated by irrigation, and covering them with a moist sterile dressing followed by an occlusive dressing.
Impaled objects: In the event of an impaled object in the abdominal cavity, attempt to stabilize the object in place to avoid further ijury.
The abdomen presents a significant challenge in both the medical and trauma arenas. In the prehospital field, we need to be suspicious of significant occult injury and carefully monitor for signs of shock. Though we ultimately cannot do a lot for these patients with overt treatments, we can ensure that the life threats are identified and the appropriate facility is chosen. We can address shock with fluid resuscitation, conservatively, to maintain a MAP of 65mmHg, or an SBP of 90mmHg, depending upon local protocols. We can address pain, prevent infection, and minimize further damage enroute to a trauma centre.
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