Diagnostic Ultrasound - Abdomen and Pelvis

Acute Pancreatitis
Diagnoses: Pancreas
CT Severity Index
Grade CT Findings
A Normal pancreas
B Focal or diffuse enlargement of gland, contour irregularities & heterogeneous attenuation; no peripancreatic inflammation
C Intrinsic pancreatic abnormalities & associated inflammation in peripancreatic fat
D Small and usually single, small ill-defined fluid collection
E 2 or more large fluid collections, presence of gas in pancreas or retroperitoneum
○ Embryology-anatomy
– Annular pancreas: Failure of migration of ventral bud
to contact dorsal
– Pancreas divisum: Ventral & dorsal pancreatic buds fail
to fuse; relative obstruction at minor papilla
Gross Pathologic & Surgical Features
• Bulky pancreas, necrosis, fluid collection
Microscopic Features
• Interstitial edematous pancreatitis
○ Edema, congestion, leukocytic infiltrates
• Acute hemorrhagic pancreatitis
○ Tissue destruction, fat necrosis, and hemorrhage
CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Acute-onset epigastric pain, often radiating to back
○ Tenderness, fever, nausea, vomiting
• Clinical profile
○ Diagnosis based on presence of at least 2 out of 3 of the
following
– Abdominal pain consistent with pancreatitis
– Lipase or amylase level > 3x upper limit of normal
– CECT, MR, or US findings consistent with acute
pancreatitis
○ Other: Hyperglycemia, increased lactate dehydrogenase
(LDH), leukocytosis, hypocalcemia, fall in hematocrit, rise
in blood urea nitrogen (BUN)
Demographics
• Age
○ Usually young and middle-aged groups
• Gender
○ Males > females
Natural History & Prognosis
• Revised Atlanta Classification of Acute Pancreatitis:Early
phase < 1 week, late phase > 1 week
○ Early phase: Severity based entirely on clinical
parameters (APACHE II, Ranson, Marshall scoring system
for organ failure, presence of SIRS)
○ Late phase: Severity based on imaging/morphologic
criteria, in addition to clinical parameters
• Clinical: Presence of organ failure is main determinant of
severity; 3 grades
○ Mild: Absence of local or systemic complications,
absence of organ failure; usually resolves in early phase;
mortality very rare
○ Moderately severe: Transient organ failure (< 48 hours
duration); local or systemic complications; may resolve
spontaneously; fluid collections, necrosis may require
prolonged intervention
○ Severe: Persistent organ failure (> 48 hours duration)
• Imaging: CT severity index (CTSI): Point system based on 1
of 5 grades (A-E) and extent of necrosis
• Complications
○ APFCs develop into pseudocysts, ANCs develop into
walled-off necrosis (WON); either can become infected
○ GI:Hemorrhage, infarction, obstruction, ileus
○ Biliary: Obstructive jaundice
○ Vascular: Pseudoaneurysm, portosplenic vein
thrombosis, hemorrhage
○ Disseminated intravascular coagulation (DIC), shock,
renal failure
Treatment
• IEP: Conservative management; nothing by mouth (NPO);
gastric tube decompression; analgesics, antibiotics
• IEP with complications: Infected or obstructing fluid
collections require drainage (surgical, endoscopic, or
percutaneous routes)
• NP: Need for intervention based on CT severity index;
infected necrosis needs surgery/catheter drainage
DIAGNOSTIC CHECKLIST
Consider
• Rule out other pathologies that can cause "peripancreatic
infiltration"
Image Interpretation Pearls
• Bulky, irregularly enlarged pancreas with obliteration of
peripancreatic fat planes, peripancreatic collections,
abscess formation
SELECTED REFERENCES
1. Banks PA et al: Classification of acute pancreatitis--2012: revision of the
Atlanta classification and definitions by international consensus. Gut.
62(1):102-11, 2013
2. Thoeni RF: The revised atlanta classification of acute pancreatitis: its
importance for the radiologist and its effect on treatment. Radiology.
262(3):751-64, 2012
3. O'Connor OJ et al: Imaging of acute pancreatitis. AJR Am J Roentgenol.
197(2):W221-5, 2011
4. Balthazar EJ: Acute pancreatitis: assessment of severity with clinical and CT
evaluation. Radiology. 223(3):603-13, 2002
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