A02 Dabrowski (type , size 1.09 MB)

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Classification
of Acute Pancreatitis
Andrzej Dąbrowski
Department of Gastroenterology
and Internal Medicine
Medical University of Bialystok, Poland
Why do we need good AP classification?
To improve clinical assessment of the AP
To facilitate communication between treating physicians
(uniformity)
For better reporting of clinical studies (common platform for
research)
Introduction – historical view
Nicholaes Tulp (1593-1674) of
Amsterdam is credited with the
first description (1652) of acute
pancreatitis.
Pannala R et al. Pancreas 2009, 38, 355
Introduction – historical view
Reginald Fitz in 1889 described
3 forms of acute pancreatitis
(hemorrhagic, suppurative, and
gangrenous) and proposed that
fat necrosis was a sequel of
severe pancreatitis
Pannala R et al. Pancreas 2009, 38, 355
Introduction – historical view
1942 – Lagerlof classified pancreatitis as acute and chronic
based on clinical, functional, and pathologic observations from
autopsy and operative findings.
Beginning in 1955, Joske, then Janowitz in 1957, Howard in
1960, and Dreiling in 1964 developed a comprehensive
classification system of pancreatitis based on etiologic factors.
Blumenthal and Probstein in 1959 provided a classification
system based on etiology in which they then categorized 163
patients from clinical and autopsy criteria.
1963 - Marseille Classification of pancreatitis
I.
II.
III.
IV.
Acute pancreatitis
Recurretnt acute pancreatitis
Recurrent chronic pancreatitis
Chronic pancreatitis
1983 – Cambridge classification
1984 – the second Marseille symposium
Frey CF, Pancreas 1986, 1, 62
Introduction – historical view
1983 – Cambridge classification
The Cambridge group defined the severity and complications of
acute pancreatitis.
An attack of acute pancreatitis was defined as “mild” if there was
no multisystem failure and “severe” if multisystem failure
occurred and/or there were early or late, local or systemic
complications.
The complications identified for definition were (a) phlegmon, an
inflammatory mass in and around the pancreas; (b) pseudocyst,
a localized collection of fluid containing high concentrations of
pancreatic enzymes within, adjacent to, or remote from the
pancreas: and (c) abscess, pus in or around the pancreas.
Frey CF, Pancreas 1986, 1, 62
Atlanta classification (1992)
Definition
Acute
pancreatitis
An acute inflammatory process of the pancreas with variable
involvement of other regional tissues or remote organ systems
(AP)
Associated with raised pancreatic enzyme levels in blood
and/or urine
Severity
Mild AP
Associated with minimal organ dysfunction and an uneventful
recovery; lacks the features of severe acute pancreatitis.
Usually normal enhancement of pancreatic parenchyma on
contrast-enhanced computed tomography
Severe AP
Associated with organ failure and/or local complications such
as necrosis, abscess or pseudocyst
Predicted
severity
Ranson score ≥3 or APACHE II score ≥8
Bradley EL III, Arch Surg 1993, 128, 586
Atlanta classification (1992)
Definition
Organ failure and
systemic
complications
Shock
Systolic blood pressure < 90 mmHg
Pulmonary
insufficiency
Pa O2≤60 mmHg
Renal failure
Creatinine ≥177 µmol/l or ≤2 mg/dl after rehydration
Gastrointestinal
bleeding
500 ml in 24 h
Disseminated
intravascular
coagulation
Platelets ≤100, 000/mm3, fibrinogen < 1·0 g/l and fibrinsplit products > 80 µg/l
Severe metabolic
disturbances
Calcium ≤1·87 mmol/l or ≤7·5 mg/dl
Bradley EL III, Arch Surg 1993, 128, 586
Atlanta classification (1992)
Definition
Local
complications
Acute fluid
collections
Occur early in the course of acute pancreatitis, are located in
or near the pancreas and always lack a wall of granulation of
fibrous tissue. In about half of patients, spontaneous
regression occurs. In the other half, an acute fluid collection
develops into a pancreatic abscess or pseudocyst
Pancreatic
necrosis
Diffuse or focal area(s) of non-viable pancreatic parenchyma,
typically associated with peripancreatic fat necrosis
Non-enhanced pancreatic parenchyma > 3 cm or involving
more than 30% of the area of the pancreas
Bradley EL III, Arch Surg 1993, 128, 586
Atlanta classification (1992)
Definition
Local
complications
Acute
pseudocyst
Collection of pancreatic juice enclosed by a wall of fibrous or
granulation tissue, which arises as a result of acute pancreatitis,
pancreatic trauma or chronic pancreatitis, occurring at least 4
weeks after onset of symptoms, is round or ovoid and most
often sterile; when pus is present, lesion is termed a pancreatic
abscess
Pancreatic
abscess
Circumscribed, intra-abdominal collection of pus, usually in
proximity to the pancreas, containing little or no pancreatic
necrosis, which arises as a consequence of acute pancreatitis or
pancreatic trauma
Often 4 weeks or more after onset
Pancreatic abscess and infected pancreatic necrosis differ in
clinical expression and extent of associated necrosis
Bradley EL III, Arch Surg 1993, 128, 586
Definitions for organ failure and predicted
severe AP in guidelines published after 1993
Guideline
Definitions for
organ failure
Definitions for severe AP
UK 2005
Refers to Atlanta
Classification
1992
At admission
Clinical assessment
BMI > 30 kg/m2
Pleural effusion
APACHE score > 8
At 24-48 h
Clinical assessment
Glasgow score ≥3
APACHE II score > 8
Persistent organ failure for 48 h (especially if
multiple and progressive)
CRP > 150 mg/l
Bollen TL et al., Br J Surg 2008, 95, 6
Note: Organ failure present within 1 week, which resolves
within 48 h, should not be considered an indicator of a
severe attack of acute pancreatitis
Definitions for organ failure and predicted
severe AP in guidelines published after 1993
Guideline
Definitions for
organ failure
Definitions for severe AP
ACG 2006
Refers to Atlanta
Classification
1992
At admission
Note: Criteria of
organ failure will
change in the
future:
gastrointestinal
bleeding will
undoubtedly be
deleted
Bollen TL et al., Br J Surg 2008, 95, 6
Age > 55 years
BMI > 30 kg/m2
Presence of organ failure
Pleural effusion/infiltrates
At 24-48 h
APACHE II score ≥ 8
Serum hematocrit ≥ 44%
Note: Ranson signs are no longer advocated, due to a
comprehensive evaluation of 110 studies that
concluded that Ranson signs provided very poor
predictive power of severity of acute pancreatitis
Definitions of severe AP local complications
need revision
Contrast-enhanced computed
tomography (CT) of a patient with
acute pancreatitis 30 days after onset
of symptoms. The fluid collection
seems to be homogeneous and
encapsulated (white arrows) and
could be interpreted as a pseudocyst
according to the Atlanta
Classification.
However, at operation the collection
was found to contain large amounts
of necrotic debris that CT had not
shown.
Acute
pseudocyst
(Atlanta 1992)
Collection of pancreatic juice enclosed by a wall of fibrous or granulation tissue,
which arises as a result of acute pancreatitis, pancreatic trauma or chronic
pancreatitis, occurring at least 4 weeks after onset of symptoms, is round or ovoid
and most often sterile; when pus is present, lesion is termed a pancreatic abscess
Bollen TL et al., Br J Surg 2008, 95, 6
CT findings in AP
The interobserver agreement of the Atlanta classification for categorizing
peripancreatic collections in acute pancreatitis on CT is poor. The Atlanta
classification should not be used to describe complications of acute
pancreatitis on CT.
Besselink MGH et al, Pancreas 2006, 33, 331
CT findings in AP
Besselink MGH et al, Pancreas 2006, 33, 331
The use of the Atlanta classification on CT in
necrotizing pancreatitis. A, Computed
tomography scan 12 days after onset of disease.
The definitions chosen for this collection were
"pseudocyst" (n = 1), "pancreatic abscess" (n =
1), "pancreatic necrosis" (n = 1), and "mixture" (n
= 2). B, Computed tomography scan 27 days
after onset of disease. The definitions chosen for
this collection were "pancreatic abscess" (n = 3)
and "mixture" (n = 2). C, Computed tomography
scan 31 days after onset of disease. The
definitions chosen were "pancreatic necrosis" (n
= 1), "pancreatic abscess" (n = 1), "pseudocyst"
(n = 1), and "mixture" (n = 2).
Although the Atlanta Classification has proved useful over the
following 16 years, many of the definitions proved confusing (used
inconsistently) and have not been accepted or utilized by the
pancreatic community (pancreatic gastroenterologists, surgeons, and
radiologists).
Need for the revision
Revision of the Atlanta classification of AP
DEFINITION OF ACUTE PANCREATITIS
The clinical definition of AP, whether in the presence or absence of
underlying chronic pancreatitis, requires two of the following three features:
1) abdominal pain suggestive strongly of AP,
2) serum amylase and/or lipase activity at least 3 times greater than the
upper limit of normal, and
3) characteristic findings of acute pancreatitis on transabdominal
ultrasonography or on CECT, which is considered to be the best, most
universally available imaging modality.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
CLINICAL CLASSIFICATION (1st week)
DEFINITION OF SEVERITY OF ACUTE PANCREATITIS
The definition of the severity of acute pancreatitis (during the first week) is
based on clinical rather than morphologic parameters (thereafter; over the
first week) .
Initially at presentation and over the first 48 hours, patients should be
classified temporarily as having severe acute pancreatitis based on the
presence of the persistent systemic inflammatory response syndrome (SIRS)
and/or developing organ failure.
Several potential risk factors of severity and measurements related to the
acute pancreatitis that may reflect severity should be recorded ideally and
evaluated prospectively, including age, BMI, hematocrit, APACHE II scores,
and serum levels of C-reactive protein.
It should be stressed that serum amylase and lipase activities, while
important in the diagnosis of “acute pancreatitis,” are not of any
clinical importance in defining the severity of acute pancreatitis.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
OVER THE FIRST WEEK
Over the first week, the distinction between non-severe old term: mild and
severe acute pancreatitis depends ultimately on the development of organ
failure.
Non-severe acute pancreatitis is defined as the absence of organ failure or
the presence of organ failure that does not exceed 48 hours in duration.
The definition of severe acute pancreatitis is the persistence of organ
failure that exceeds 48 hours duration (i.e., organ failure recorded at least
once during each of three consecutive days).
OF>48 hrs
Severe AP
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
DEFINITION OF ORGAN FAILURE
Three organ systems should be assessed to define organ failure:
respiratory, cardiovascular, and renal.
Organ failure is best and most easily defined in accordance with the
Marshall scoring system as a score ≥2 for at least one of these three organ
systems: respiratory (pO2/FIO2); renal (serum creatinine in μmol/l or mg/dl);
and cardiovascular (systolic blood pressure in mm Hg).
Multi-system organ failure is defined as two or more organs failing over the
same 2- to 3-day period.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
Marshall Scoring System
FIO2 = fraction of inspired oxygen
Acute Pancreatitis Classification Working Group. Revision of the
Atlanta classification of acute pancreatitis (3rd revision) . www.
pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
MORPHOLOGIC IMAGING-BASED CLASSIFICATION (used AFTER the first
week)
This new classification proposes the use of morphologic CECT criteria to
diagnose the specific type of acute pancreatitis:
•
Acute interstitial edematous pancreatitis (IEP)
•
Acute necrotizing pancreatitis.
A. Presence/absence and site(s) of necrosis, 3 subtypes:
•
normal pancreatic parenchyma enhancement with peripancreatic
fluid collections (fat necrosis)
•
one or more focal areas of nonenhancing pancreatic parenchyma
with peripancreatic fluid collections
•
without peripancreatic fluid collections
B. Evidence for the presence/absence of infection (FNA, gas within
nonenhancing retroperitoneal tissue)
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
NECROTIZING PANCREATITIS
Pancreatic Parenchyma:
About 80% of patients with necrotizing pancreatitis have a variable extent
of pancreatic parenchymal necrosis on CECT.
minimal
gland enlargement on CECT
diffuse
localized
The extent of necrosis is quantified in three categories: <30%, 30-50%,
and >50% of the total pancreatic parenchyma.
The presence of pancreatic parenchymal non-enhancement differentiates
necrotizing pancreatitis from IEP.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
NECROTIZING PANCREATITIS
Peripancreatic Tissues:
The presence or absence of necrosis in the peripancreatic tissues is more
difficult to evaluate by CECT, especially early in the course of the disease.
While the presence or absence of necrosis in the peripancreatic tissues is
not always possible to diagnose definitively with CECT, CECT may
suggest the presence of peripancreatic necrosis by the presence of
“thickening” of the paracolic gutters and of the base of the small bowel
mesentery, fat stranding and involvement of the anterior pararenal
spaces, or especially the presence of non-homogeneous fluid collections
containing solid components in one or more areas.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
solid
necrosis
liquefaction
<1 week
semi-solid
liquefaction liquefied necrosis
necrosis
(no resorption)
(WOPN)
(PNPFC)
>4 weeks
Characteristics of Necrosis:
The relative amount of liquid vs semi-solid components within areas of
necrosis varies with the time since onset of necrotizing pancreatitis.
As time evolves, the initially solid necrosis liquefies by a process of
liquefaction necrosis. Complete resolution of necrosis (weeks to months
later) may occur through liquefaction necrosis and eventual reabsorption
of the liquefaction. In some patients, complete reabsorption may never
occur.
If resorption does not take place, the area of liquefaction necrosis may
persist as an area of walled-off pancreatic necrosis (WOPN; organized
necrosis, necroma, or pancreatic sequestration) without symptoms or
may cause pain or mechanical obstruction of the duodenum and/or bile
duct.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
NECROTIZING PANCREATITIS
Infection:
Depending on the stage of the necrosis (primarily solid, semi-solid, or
liquefaction) and the organism(s) involved, the infected necrosis will have
varying amounts of suppuration (pus).
In the later stages of infected necrosis, the content may be predominantly
pus (in addition to some solid components) as the process of liquefaction
necrosis matures.
“Pancreatic abscess” according to the Atlanta Classification in 1992 is a
“localized collection of purulent material without significant necrotic
material;” most agree that the latter Atlanta definition of “pancreatic
abscess” is an exceedingly uncommon finding in necrotizing pancreatitis.
The current imaging-based classification does not use the term
“pancreatic abscess” in order to avoid this confusion.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
Both acute IEP and necrotizing pancreatitis can be associated with
PANCREATIC AND PERIPANCREATIC FLUID COLLECTIONS
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
ACUTE PERIPANCREATIC FLUID COLLECTIONS (APFCs) (1st 4 weeks
after onset of IEP)
a. Sterile
Old term: acute fluid collections
b. Infected
These fluid collections arise in patients with IEP, have no solid
components, and result from parenchymal and/or peripancreatic
inflammation in the absence of necrosis. Resolve spontaneously within 6
weeks 40%, 80% if <6 cm; communication with pancreatic duct seen in
70%.
They exist predominantly adjacent to the pancreas, have no definable
wall, and are confined by the normal peripancreatic fascial planes,
primarily the anterior pararenal fascia.
APFCs arise presumably from rupture of the main duct or a small
peripheral pancreatic ductal side branch or they result from local edema
related to the pancreatic inflammation and have no connection with the
ductal system.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
POST-NECROTIC PANCREATIC/PERIPANCREATIC FLUID COLLECTIONS
a. Sterile
b. Infected
Old term: acute fluid collections
Fluid collections arising in patients with acute necrotizing pancreatitis are
termed PNPFCs to distinguish them from APFCs and pseudocysts.
PNPFCs contain both fluid and necrotic contents to varying
degrees.
In PNPFCs, a continuum exists from the initial solid necrosis to
liquefaction necrosis, depending on duration of the disease since onset.
PNPFC may or may not have a connection with the pancreatic ductal
system.
Necrosis
PNPFC
(necrosis+fluid)
WOPN (infected or sterile)
late stage
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
PANCREATIC PSEUDOCYST
Non-infected
Old term: pancreatic pseudocyst
Pseudocysts on CECT become defined >4 weeks after onset of
pancreatitis as a well-circumscribed (clearly evident wall; capsule),
usually round or oval, homogeneous fluid collection surrounded by a welldefined wall with no solid necrotic debris within the fluid collection.
Pseudocysts develop from an APFC that persists for >4 weeks after onset
of pancreatitis. Prior to 4 weeks, these collections are categorized as
APFC.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Revision of the Atlanta classification of AP
PANCREATIC PSEUDOCYST
Infected (suppurative)
Old term: pancreatic abscess
Determination of presence or absence of infection in a pancreatic
pseudocyst is also potentially important.
An infected pancreatic pseudocyst contains purulent liquid without an
associated solid component (necrosis).
This definition differentiates pseudocyst from infected PNPFC and
infected WOPN. As with all peripancreatic fluid collections, image-guided
FNA with Gram stain and culture or the presence of extraluminal gas are
necessary to confirm the pre-interventional diagnosis of infection.
Acute Pancreatitis Classification Working Group. Revision of the Atlanta classification of acute pancreatitis
(3rd revision) . www. pancreasclub.com/resources/AtlantaClassification.pdf
Acute pancreatitis has been described for the first time by:
A.Reginald Fitz
B.David Dreiling
C.Nicholaes Tulp
D.Hippokrates of Kos
What is the uncommon complication of acute pancreatitis:
A.Respiratory
B.Renal
C.Cardiovascular
D.Gastrointestinal bleeding
The true statement about acute peripancreatic fluid collections is:
A.Fluid collections arising in patients with acute necrotizing pancreatitis, but not in
patients with acute interstitial edematous pancreatitis.
B.Have no solid components, and result from parenchymal and/or peripancreatic
inflammation in the absence of necrosis.
C.Become defined >4 weeks after onset of pancreatitis as a well-circumscribed, usually
round or oval, homogeneous fluid collection surrounded by a well-defined wall with no
solid necrotic debris within the fluid collection.
D.Contain both fluid and necrotic contents to varying degrees.
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