Transcript Severe acute pancreatitis

Role of CT in acute
pancreatitis
Dr. Ahmed Refaey
Consultant radiologist
Riyadh Military Hospital
Normal CT anatomy of the upper
abdomen
Anterior pararenal space
Normal Anatomy by CT
• Pancreas is located in the
anterior pararenal space
• Head adjacent to
duodenum
• Tail extending toward
spleen
• Splenic vein posterior to
body and tail
Normal Morphology by CT
• No capsule
• AP dimensions
 Head 2-2.5 cm
 Body and tail 1-2 cm
• Pancreatic duct
 Maximal diameter 3 mm in adults (5 mm in elderly)
Evaluation of Acute Pancreatitis
• Contrast-enhanced CT is imaging modality of
choice
• Oral and IV contrast differentiate pancreatic
tissue from adjacent blood vessels and
duodenum
• There is no additional value of an early CT
(within 72 hours) in patients with acute
pancreatitis.
• The diagnosis is usually made on clinical and
laboratory findings.
• An early CT may be misleading concerning the
severity of the pancreatitis, since it can
underestimate the presence and amount of
necrosis.
Etiology
Pathophysiology
• Activated pancreatic enzymes escaping the
ductal system and auto digesting the pancreas
and adjacent structures ( mainly amylase,
lipase & trypsin ).
• Lack of capsule facilitates spread
Acute pancreatitis
• Mild acute pancreatitis ----- 80 %
* edematous ( interstitial )
* exudative
• Severe acute pancreatitis ----20 %
• Mild acute pancreatitis
- run a mild course without development of
multiple organ failure
- improvement within 3 days following
conservative therapy with gradual decrease of
elevated enzymes.
- has a mortality rate of < 1%
• Severe acute pancreatitis “ necrotizing “
- run a serious clinical course with pancreatic
necrosis and the development of multiple
organ failure
- of these, 60% of pancreatic necrosis remain
sterile , while 40% becomes infected
- this last category ( infected necrosis ) , has the
highest mortality rate ( 25-70%)
Clinical outcome
CT Imaging of acute pancreatitis
Mild acute pancreatitis
• Acute edematous “interstitial” pancreatitis
• Acute exudative pancreatitis
Acute edematous “interstitial”
pancreatitis
• Edematous pancreas with/without peripancreatic
fat stranding.
• No collections or necrosis
Acute exudative pancreatitis
• an intermediate form of pancreatitis without
pancreatic necrosis with an intermediate
clinical course.
• This is called extrapancreatic necrosis (EXPN)
• Avoid early drainage of collections and avoid
introducing infection!
• 50% of these collections show spontaneous
regression
The other 50% either remain stable (
pseudocyt ) or develop infection ( abscess ) .
Peripancreatic fluid
50% spontaneous regression
sterile ( pseudocyst)
50% stable
infection ( asbscess )
Spontaneous regression of peripancreatic
collection
Severe pancreatitis
“ necrotizing pancreatitis”
occurs in 20% of patients.
* partial necrotizing pancreatitis
* total necrotizing pancreatitis
Partial necrotizing
• Delayed or no response
to conservative therapy
• Delayed or no
normalization of
enzymes
• Mortality : 30 – 75 %
Total necrotizing
• Deterioration under
conservative therapy
• Mortality : 100 %
- 40% by 2nd day
- 75% by 5th day
- 100% by 10th day
Central gland necrosis
Central gland necrosis
• Subtype of necrotizing pancreatitis.
• Necrosis between the pancreatic head and tail
and is nearly always associated with disruption of
the pancreatic duct.
• This leads to persistent collections as the viable
pancreatic tail continues to secrete pancreatic
juices.
• These collections react poorly to endoscopic or
percutaneous drainage.
• Definitive treatment often requires distal
pancreatectomy.
• An early CT may be misleading concerning the
severity of the pancreatitis, since it can
underestimate the presence and amount of
necrosis.
Mortality
• Early mortality in acute pancreatitis is the
result of the systemic inflammatory response
with multiple organ failure.
Late mortality is the result of infection of
pancreatic necrosis and peripancreatic fluid
collections which results in sepsis and is seen
in more than 50% of deaths.
• CT Severity Index
• It is critical to identify patients who are at high
risk for severe disease, since they require
close monitoring and possible intervention
• Balthazar et al constructed a CT severity
index (CTSI) for acute pancreatitis that
combines the grade of pancreatitis (A-E) with
the extent of pancreatic necrosis.
CT Severity Index
• 1- 3 …………….. Mild
• 4-6 …………….. Moderate
• 7-10 ……………. Severe
Complications of pancreatits
Complications
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Pancreatic Pseudocysts
Abscess
Hemorrhagic Pancreatitis
Splenic Artery Pseudoaneurysm
Pancreatic Pseudocyst
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Fluid collection surrounded by fibrous capsule
Time of onset : > 4 weeks from the onset
Amylase rich-fluid
Prognosis : spontaneous resolution in 44%
Abscess
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Well demarcated fluid collection of pus
Suspected clinically with fever and septicemia
Pathognomonic finding → presence of gas
Time of onset : 2- 4 weeks after onset
Hemorrhagic pancreatitis
• Type of severe pancreatitis
• Peripancreatic fat necrosis and hemorrhage
due to erosion of small vessels
• Falling hematocrit
• Cullen sign and Grey-Turner sign
–
• (Grey-Turner sign): flank ecchymosis
• (Cullen sign)
: periumbilical ecchymosis
• associated with a 37% mortality rate
• Grey Turner sign
• Cullen’s sign
Splenic Artery Pseudoaneurysm
• Presents similarly to hemorrhagic pancreatitis
with a ↓ in hematocrit
Take home messages
• Severity of acute pancreatitis and pancreatic
necrosis can only be reliably assessed by
imaging after 72 hours.
• CT can not reliably differentiate between
collections that consist of fluid and those that
contain solid debris.
In these cases MRI can be of additional value.
• Central gland necrosis is a subtype of
necrotizing pancreatitis with important
implications.
• Avoid early drainage of collections and avoid
introducing infection!
Thank you