Pancreatic Trauma

Published on 19/07/2015 by admin

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Last modified 19/07/2015

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 Secondary signs of pancreatic injury are usually present (peripancreatic fat stranding and fluid, thickening of pararenal fascia, peripancreatic hematoma)

– Peripancreatic signs of traumatic pancreatitis often subtle; more evident in 24-48 hours
image Pancreatic contusion: Ill-defined focal hypoattenuation at site of injury (not linear like laceration)
image Pancreatic laceration: Discrete linear hypodense cleft through pancreas
image Pancreatic fracture: Large laceration with clear separation of 2 ends of gland
image CT insensitive for pancreatic duct injury (usually inferred by laceration extending through duct)
• MR: MRCP (± secretin) is a useful tool in determining presence of pancreatic ductal disruption
• ERCP: Best modality for pancreatic ductal injury

image Transection of pancreatic duct: Abrupt duct termination or contrast extravasation

PATHOLOGY

• May result from either penetrating or blunt trauma

image Blunt traumatic injury usually results from anterior/posterior compression force to abdomen
• Pancreatic injuries almost never isolated and usually associated with polytrauma

CLINICAL ISSUES

• Blunt pancreatic injuries often clinically occult and unrecognized on initial evaluation
• Clinical presentation often due to traumatic pancreatitis: Upper abdominal pain, abdominal distention
• Serum amylase/lipase levels: Elevated in 90% of patients, but may be normal immediately after trauma
• Treatment: Penetrating trauma generally requires immediate laparotomy

image AAST grades I and II: Conservative management
image AAST grades III, IV, and V: Typically require surgery (including possible pancreatic resection)
image
(Left) Axial CECT shows subtle laceration of the pancreas image with fluid in the lesser sac image as well as retropancreatic fluid image.

image
(Right) Axial CECT in the same patient reveals fluid image tracking posterior to the pancreas along the splenic vein from extravasated pancreatic juice. Secondary signs of injury, such as peripancreatic fluid, hematoma, or fat stranding, are almost always present as a clue to the diagnosis.
image
(Left) Axial CECT in a patient with pancreatic fracture shows a fracture plane image through the neck of the pancreas. The pancreatic duct was disrupted, and the body and tail of the pancreas were resected at surgery.

image
(Right) Axial CECT 48 hours after trauma shows a pseudocyst image in the lesser sac in this pancreatic transection image.The fluid collection developed as a result of leakage of fluid from the site of the transected pancreatic duct.

TERMINOLOGY

Synonyms

• Traumatic pancreatic injury

Definitions

• Inflammatory disease of pancreas secondary to trauma

IMAGING

General Features

• Best diagnostic clue

image Enlarged, heterogeneous pancreas with peripancreatic fluid or hematoma in patient with history of trauma
• Location

image Most commonly involves pancreatic body > head > tail
• Morphology

image Spectrum of injury: Acute pancreatitis, contusions, deep lacerations, fractures with ductal disruption

Radiographic Findings

• ERCP

image Normal in cases of pancreatic contusion
image Best modality to identify pancreatic duct (PD) injury

– Transection of PD: Abrupt duct termination or contrast extravasation
– Communication of pseudocyst with PD
image May cause pancreatitis

CT Findings

• Secondary signs of pancreatic injury or post-traumatic pancreatitis usually present even in absence of discrete contusion/laceration

image Peripancreatic fat stranding and fluid with loss of normal peripancreatic fat planes almost always present

– Fluid separating pancreas from splenic vein is sensitive (60-90%) for pancreatic injury
– Fluid or hematoma is often seen in lesser sac, left anterior pararenal space, transverse mesocolon, adjacent to spleen, and mesenteric root
image Thickening of anterior pararenal fascia
image Peripancreatic or intrapancreatic hematoma: Intrapancreatic hematoma is more specific for pancreatic injury
image Peripancreatic signs of traumatic pancreatitis are often subtle: May be more evident in 24-48 hours
• Pancreatic contusion: Ill-defined focal hypoattenuation at site of injury 

image Appearance ranges from subtle contour deformity of pancreas to rounded mass-like enlargement of pancreas several cm in diameter
image Often associated with focal or diffuse pancreatic enlargement
• Pancreatic laceration: Discrete linear cleft of hypoattenuation running through pancreas (usually perpendicular to long-axis of gland)

image Much more likely to be associated with PD injuries than contusion
image Often associated with distortion or irregularity of contour of pancreas and hypoenhancement of gland upstream from laceration
image Lacerations may produce subtle parenchymal density changes and may be undetectable on CT in some cases 

– 20-40% of pancreatic injuries not visible on initial imaging
– May only be faintly visible on initial imaging, and become more conspicuous on follow-up imaging
image CT is not sensitive for detection of PD injury (∼ 40%):  Inferred by presence of laceration extending through duct (> 50% of pancreatic thickness)
• Pancreatic fracture: Linear low attenuation running through pancreatic parenchyma with clear separation of 2 ends of gland

image Most often through pancreatic neck
• Pancreatitis secondary to ERCP (± papillotomy, etc.) usually more severe in/around pancreatic head

MR Findings

• Variably decreased signal on T1WI at sites of contusion or laceration ± high T1 signal related to hematoma
• High signal on T2WI at sites of contusion or laceration
• Heterogeneous enhancement on T1WI C+ images with areas of nonenhancement related to fluid collections, pseudocysts, necrosis, laceration, or severe contusion
• MRCP useful tool to determine PD disruption

image Secretin stimulation may improve diagnostic sensitivity
image Ductal injury suggested by discontinuity in PD, along with direct communication to adjacent pseudocyst or fluid collection
image 

Ultrasonographic Findings

• Not sensitive for pancreatic injury or complications
• Findings similar to pancreatitis (enlarged, hypoechoic gland)

Imaging Recommendations

• Best imaging tool

image CECT for initial evaluation after trauma
image Emergency ERCP: Investigate pancreatic injuries when CT positive and status of PD uncertain
• Protocol advice
• Repeat CT at 24-48 hours may identify pancreatic injuries not appreciated on original examination

DIFFERENTIAL DIAGNOSIS

Shock Pancreas

• Part of hypoperfusion complex seen in severe traumatic injuries or in setting of severe hypotension
• Abnormally intense enhancement of pancreas, bowel wall, and kidneys, with decreased caliber of aorta and inferior vena cava, and diffuse dilatation of intestine with fluid

image Findings resolve spontaneously after fluid resuscitation
• Moderate to large peritoneal fluid collections
• Pancreas appears edematous, enlarged, and hyperenhancing with surrounding fluid and fat stranding, mimicking post-traumatic pancreatitis or injury
• Differentiate from direct traumatic injury by looking for other imaging features of hypoperfusion complex

Duodenal Injury Without Pancreatic Injury

• Duodenal injury (including rupture or hematoma) may simulate or coexist with pancreatic injury
• Duodenal hematoma appears as focal high-attenuation thickening of duodenal wall

image Picket-fence appearance on fluoroscopy from hemorrhage
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