Pancreatic Trauma

Diagnosis

Patients with torso trauma who manifest early indications of intraabdominal bleeding or peritonitis require immediate operative intervention, at which time direct evaluation of the pancreas should be carried out. For patients who are hemodynamically stable, a thorough diagnostic evaluation is warranted. The stable patient with blunt abdominal trauma is the person in whom timely diagnosis of pancreatic injury is most challenging.

Physical examination and evaluation of hemodynamic status remain the key factors in the diagnostic algorithm of abdominal trauma. A hypotensive patient with abdominal trauma should proceed to the operating room without delay. For the clinically stable patient, selective management can be successful as long as careful attention is given to clinical progress or deterioration. Even patients with abdominal gunshot wounds, once uniformly accepted as a clear indication for exploratory laparotomy, are now managed selectively at some large trauma centers under the appropriate circumstances. The initial clinical examination (vital signs, physical examination of the abdomen) becomes the main determinant of whether the patient is triaged immediately to the operating room, to other diagnostic testing, or to an observation site where physical examinations and monitoring can be undertaken. Important prerequisites for considering selective management of abdominal gunshot wounds rather than mandatory exploration include (1) experienced in-house surgeons who are available to take the patient to the operating room in the event of change of the initial benign clinical examination; (2) a predetermined site in the hospital that facilitates observation and serial examination (i.e., monitoring the vital signs, urine output, hematocrit, and repeated abdominal examinations); and (3) priority status that allows patients with deteriorating clinical examinations to be triaged immediately to the operating room. Serial physical examination is more universally accepted as a mainstay in the selective management of stab wounds to the anterior abdomen.

A full laboratory panel should be collected including serum amylase and lipase levels. Serum amylase is elevated in 80% of patients with blunt pancreatic injury. This figure is much lower for penetrating wounds, but in either case an elevated amylase level mandates a directed evaluation of the pancreas. Studies show that amylase levels upon admission are not very sensitive. The diagnostic yield of amylase is time sensitive, and a value obtained 3 to 6 hours after presentation has a much higher accuracy in predicting pancreatic trauma. An elevated amylase level can be a result of bowel perforation, salivary gland trauma, or nondisruptive pancreatic injury because it is not a very specific test. Serum lipase may be used if there is confusion because it is not elevated when hyperamylasemia is of salivary origin. Pancreatic isoenzyme fractionation can identify salivary amylase but is often not available. It is often useful to repeat the serum amylase in patients being observed for abdominal trauma because first blood specimens may be drawn so close to the time of wounding that a misleading normal value may result.

Additional diagnostic studies are indicated if there is suspicion of pancreatic injury. An example should be patients with amylase elevation and upper abdominal tenderness and distention. Plain or contrast radiographs offer little assistance. The focused abdominal sonogram for trauma (FAST) rapidly identifies fluid in the hepatorenal recess of Morrison. As a modality that provides prompt assessment of patients with blunt trauma in the emergency department, it has essentially supplanted the diagnostic peritoneal lavage. Following the initial physical examination, the hemodynamically stable patient should undergo a CT scan of the abdomen and pelvis (with intravenous contrast) to elucidate the presence of any visceral injuries. A pancreatic injury can be challenging to assess, given that some injuries may not be obvious without significant inflammatory changes. Such findings may not be apparent in the initial 24 hours post injury. In 2009 the American Association for the Surgery of Trauma (AAST) published a multicenter study examining the use of CT scan in the evaluation of pancreatic injuries. They enrolled 206 patients with confirmed pancreatic injuries on operative exploration and determined the following radiographic characteristics were “hard signs” of a pancreatic injury:

• Active bleeding

• Pancreatic hematoma or laceration

• Diffuse enlargement or edema of pancreas

• Low pancreatic attenuation

The study also suggested that lacerations greater than 50% of the gland thickness on CT scan should raise concern for a pancreatic ductal injury.

In cases in which the clinical findings leading to the CT scan are persistent and the CT scan is equivocal or even negative, ERCP will delineate the pancreatic ductal anatomy ( Fig. 102.1 ). Magnetic resonance cholangiopancreatography (MRCP) has not been evaluated specifically in large numbers of trauma patients, but its use has been extrapolated from its use in nontraumatic scenarios. Its potential benefits include its noninvasive nature, and the fact it can be performed even after anatomy-altering surgery has made ERCP impossible (i.e., pyloric exclusion or gastric bypass procedures). However, it does have a potential drawback, specifically the need to send an acutely injured patient to a remote location. Although the situation occurs infrequently, ERCP can identify major ductal disruption well before clinical signs lead to laparotomy. Early identification and treatment of pancreatic injury can reduce morbidity.

Nonoperative Management

As stressed previously, to attempt nonoperative management for abdominal trauma, the patient must be hemodynamically stable in a facility where there is an experienced in-house surgeon and facilities available for intensive monitoring, serial examinations, and the option to be in the operating room at a moment's notice in the event that the patient's condition deteriorates. Nonoperative management of pancreatic trauma diagnosed on CT scanning is generally reserved for grade I and II injuries. Velmahos et al. conducted a multiinstitutional review of blunt abdominal trauma and studied 230 patients with blunt pancreatoduodenal injury. Ninety-seven (42%) of these were selected for nonoperative management and with a success rate of 90%. A study from the Nationwide Inpatient Sample shows that over a 10-year period from 1998 to 2009 the number of pancreatoduodenal injuries increased by 8.3%; however, the proportion of patients receiving operative intervention declined from 21.7% to 19.8% without affecting morbidity. ERCP can be a very useful adjunct in the diagnosis and management of low-grade pancreatic injuries.