Journal of Surgery| Lupine Publishers
Abstract
Introduction
Pancreatic pseudocysts often arise as a complication of acute or chronic pancreatitis with reported prevalence in chronic pancreatitis of 20-40%. Most common cause is alcoholic chronic pancreatitis (70-78%) then idiopathic chronic pancreatitis (6-16%), then biliary pancreatitis (6-8%). The aim of this study is to assess the demographic characteristic of patients diagnosed with pseudocysts, aetiology, characteristic features, and prognosis.
Methods
Prospective observational study to follow up patients diagnosed with pancreatic pseudocyst in 5 years (2006-2011). Data was collected in 2011 and patients followed up till June 2019. Radiology database searched for all cases that had a diagnosis confirmation by Computerised Tomography (CT). Total of 167 CT carried out for 119 patients. 35 patients were excluded due to absence of pancreatic pseudocyst after radiological re-evaluation.
Results
In 5 years, 84 patients diagnosed with pancreatic pseudocysts on CT. 127 CT scans done mainly for follow up. 51(60.7%) males and 33 (39.3%) females; mean age= 57.8 years (20-93). 41 cases (48.8%) were associated with acute pancreatitis (8 on background of chronic pancreatitis). 21 cases (25%) were associated with chronic pancreatitis, 4 were associated with pancreatic malignancy while 18 (21.4%) were reported as incidental finding. The underlying factor was alcoholic pancreatitis in 37 patients (44%), gall stones in 19 patients (22.6%), pancreatic malignancy in 4 (4.8%) patients, biliary strictures in 2 patients and trauma in 2 patients. Idiopathic pancreatic pseudocysts were seen in 20 patients (23.8%), 18 of them were incidentally found on CT scan. 8 cases (40%) of idiopathic pseudocysts, were associated with non-pancreatic malignancies. 50% mortality (42 patients). 17 had acute pancreatitis, 15 had chronic pancreatitis, 6 were from the incidental finding and 4 from acute on top of chronic group. As for aetiology, 25 patients of the 42 had alcoholic pancreatitis, 12 had gall stones pancreatitis, 3 were unknown aetiology and 2 had pancreatic cancer.
Conclusion
Our study showed that alcoholic pancreatitis remains the most frequent underlying aetiology for pancreatic pseudocysts although it is not as common as previously reported. Idiopathic pseudocysts constituted a substantial number of this study with a higher than expected incidental pseudocysts. The association of pancreatic pseudocysts with malignancy needs to be further evaluated.
Introduction
Pancreatic pseudo-cysts often arise as a complication of acute
or chronic pancreatitis. Previous reported prevalence of pancreatic
pseudo-cysts in chronic pancreatitis ranges from 20% to 40%.
Pancreatic pseudo-cysts most commonly arise in patients with
alcoholic chronic pancreatitis (70% to 78%) (1, 2). The second
most common cause is idiopathic chronic pancreatitis (6% to 16%),
followed by biliary pancreatitis (6% to 8%) (3). Various imaging
modalities are used in the diagnosis of pancreatic pseudo-cysts
with Computed Tomography (CT) being the gold standard with
82% to 100% sensitivity and 98% specificity (4). There is wide
variability in the range of spontaneous regression in the literature
from 8 to 70%., with almost 40% of cysts that are less than 6 weeks
old resolving without intervention compared to around 10% of the
cysts older than 6 weeks (5). The aim of this study is to assess the
demographic characteristic of diagnosed patients, aetiology of the
pseudo-cysts, their characteristic features, prognosis and mortality
rate
Methods
This is a prospective observational study to follow up all
consecutive patients diagnosed with pancreatic pseudo-cyst over
a period of five years (2006 – 2011) in a district general hospital.
Data collected retrospectively in 2011 to identify patients with
pseudopancreatic cysts. The search was conducted using the
radiology database of all cases had a diagnostic confirmation of
pseudo pancreatic cyst by Computerized Tomography (CT). A
total number of 167 CT scans were carried out for 119 patients.
Radiological re-evaluation was conducted by a designated
radiologist. 35 patients were excluded from the study due to
absence of pancreatic pseudo-cyst after radiological re-evaluation.
The remaining 84 patients were followed up till June 2019. The
following demographic data were collected (age, gender, aetiology
of pancreatitis, blood tests including amylase, liver function tests,
white cell count, serum calcium and oxygen saturation). Mode of
treatment and related complications. Radiological characteristics of
the pancreatic pseudo cyst included: site, size, duration, calcification
within the cyst. Other parameters observed prospectively were;
mortality/ morbidity, further episodes of pancreatitis and duration
between diagnosis and mortality/ morbidity. Subgroup analysis
was conducted to look at prevalence of different aetiologies in both
genders. Statistical analysis was conducted using Fisher Exact test,
Mann-Whitney U test and the multivariate analysis was carried out
using SPSS version 25 for Windows (SPSS Inc, Chicago, IL, USA). P
value ≤ .05 was considered significant.
Results
In five years, period (2006 – 2011), 84 patients were diagnosed
with pancreatic pseudo-cysts on CT scan. These patients had a total
of 127 CT scans mainly for follow up. There were 51 male patients
(60.7%) and 33 female patients (39.3%) with mean age of 57.8 years
(20 – 93). In 41 cases (48.8%) the pseudo-cysts were associated
with acute pancreatitis (8 on background of chronic pancreatitis).
21 cases (25%) were associated with chronic pancreatitis, 4 were
associated with pancreatic malignancy while in 18 cases (21.4%)
there was no obvious history of pancreatitis and the diagnosis was
reported as incidental finding.
The underlying factor was alcoholic pancreatitis in 37 patients
(44%), gall stones in 19 patients (22.6%), pancreatic malignancy
in 4 (4.8%) patients, biliary strictures in 2 patients and trauma
in 2 patients. Idiopathic pancreatic pseudo-cysts were seen in
20 patients (23.8%), 18 of them were incidentally found on the
CT scan. Of note, in 8 cases (40%) of the idiopathic pseudo-cysts,
were associated with non-pancreatic malignancies. In a subgroup
analysis, alcohol was the commonest aetiology in male patients
29/51 (57%) while in female patients, incidental pseudo-cysts
constituted 11/33 (33.3%), P= 0.23. Gall stones were the 2nd most
common aetiology in females 10/33 (30.3%). Nine patients had
more than one pseudo-cyst. The size of the pseudo-cysts varied
significantly in reporting from small to huge pseudo-cysts withextension into the left thigh in one case. The body of the pancreas
was the most common site (33 pseudo-cysts) followed by the head
of the pancreas with 28, tail 27, uncinate 4, neck 2, not specified
7, 1 junction between body and tail, 2 junction between head and
body (Table 1). The majority were managed conservatively with
two drained percutaneously and two drained endoscopically. The
84 patients were followed up till June 2019 (mean follow up of 10
years). This showed that 42 patients (50%) died (male: female,
21:21), mean age of 61.8 (27- 93). 9 patients (21% of the mortality)
died from complications related to the pancreatitis or due to
complications from the pseudo-cyst like infection or bleeding into
the cyst, with one patient dying from respiratory failure following
laparoscopic cholecystectomy for gall stones pancreatitis (Table
2). The 9 patients represent 10.7% cause-related mortality. 17 of
those 42 patients (40%) were from the acute pancreatitis group, 15
patients (36%) from the chronic pancreatitis group, 6 patients (14%)
from the incidental finding group and 4 patients (10%) from the
acute on chronic group. As regards the aetiology, 25 patients of the
42 (59.5%) were from the alcoholic pancreatitis group, 12 patients
(28.5%) from the gall stones pancreatitis group, 3 patients (7%)
from the unknown aetiology group and 2 patients (5%) from the
pancreatic cancer group, Table 2. Multivariate analysis (MANOVA)
yielded a highly significant association between the aetiology of
pancreatitis and death, p = 0.007; however, there was no significant
association between the mode of pancreatitis (acute or chronic)
and death, p = 0.338, Table 3. Using death or alive dichotomy, chi
square test confirmed the highly significant relationship between
the aetiology of pancreatitis and death, p = .000. A two-way analysis
of variance yielded a significant relationship between the aetiology
of pancreatitis and its mode of onset (acute or chronic), p = 0.000
(Table 3). The duration of time form diagnosis of pancreatitis/
pancreatic pseudo-cyst to death was quite variable ranging from 8
to 3809 days (median 1018 days) for the whole cohort of mortality
patients. The range for the cause specific cohort was 10 to 1424
days (median 112 days), p-value is .04006. 12 patients (14%) had
further episodes of pancreatitis requiring admission to hospital.
The outcome from the follow up of the pancreatic pseudo-cysts
over the study period is shown in Table 4.
Table 1: Sites of the pseudo-cysts within the pancreas
*1 in junction between body and tail, 2 in junction between head
and body.
Discussion
Pancreatic pseudocysts are the commonest pancreatic cystic
lesions and represent 75%-80% [1]. They are localized fluid
collections rich in amylase and other pancreatic enzymes that
gets surround by fibrous tissue wall not lined by epithelium
[2]. Pseudocysts are a common clinical problem and arise as a
complication of chronic pancreatitis in up to 40% of cases [3].
Alcoholic pancreatitis is the most common cause and account for
over 75% of cases in some series [4]. The incidence of pancreatic
pseudocysts is low and ranges between 1.6%-4.5% irrespective of
the aetiology [5,6]. The pathogenesis of pancreatic pseudocysts is
the disruption to the pancreatic duct as a result of pancreatitis or
trauma which results in extravasation of pancreatic secretions. Two
thirds of patients with pseudocysts have demonstrable connections
between the cyst and the pancreatic duct. In the other third, an
inflammatory reaction most likely sealed the connection so that
it is not demonstrable [7]. In acute pancreatitis, fluid collections
persisting for more than 4-6 weeks that are lined by a well-defined
wall of fibrous or granulation tissue, would be regarded as acute
pseudocysts [2,4]. In chronic pancreatitis the mechanism is less
clear, but it could be as a consequence of an acute exacerbation of
the underlying disease and/or blockage of a major branch of the
pancreatic duct by a protein plug, calculus or localized fibrosis [8].
The clinical presentation is quite variable and while some patients
could be asymptomatic, others might present with abdominal
catastrophe as a result of; bleeding, infection or rupture of the cyst
[9,10]. In our study, 2 patients had acute hemorrhage into the cyst
from erosion into the splenic artery while 1 patient had infection
of the cyst and all 3 patients died. Various imaging modalities are
used in the diagnosis of pancreatic pseudo-cysts with Computed
Tomography (CT) being the gold standard with 82% to 100%
sensitivity and 98% specificity [11]. Endoscopic Ultrasound (EUS)
has the highest sensitivity (93% to 100%) and specificity (92%
to 98%) in differentiating acute fluid collections from pancreatic
abscess and other pancreatic pseudocysts [12]. In our study 41
patients (48.8%) of the pancreatic pseudocysts were associated
with acute pancreatitis and 21 cases (25%) were associated with
chronic pancreatitis. However, it is worth mentioning that 8 cases of
the 41 in the acute pancreatitis group had a background of chronic
pancreatitis. 4 patients (19%) were associated with pancreatic
malignancy while 18 patients (21.4%) were incidental finding on CT
scans done for other reasons. These results are different from other
studies showing the prevalence of pancreatic pseudocysts in acute
pancreatitis to range from 6% to 18.5% [13,14]. The prevalence of
pancreatic pseudocysts in chronic pancreatitis is 20%- 40% [15].
In our study, the most common underlying factor was alcoholic
pancreatitis in 37 patients (44%), gall stones in 19 patients (22.6%),
pancreatic malignancy in 4 patients (4.8%), biliary strictures in 2
patients and trauma in 2 patients. Idiopathic pancreatic pseudocysts were seen in 20 patients (23.8%), 18 of them were incidentally
found on the CT scan. Of note, in 8 cases (40%) of the idiopathic
pseudo-cysts, were associated with non-pancreatic malignancies.
Results from other series showed that pancreatic pseudocysts are
most common in patients with chronic alcoholic pancreatitis (up to
78%) [16], followed by idiopathic chronic pancreatitis (6% to 16%)
and biliary pancreatitis (6% to 8%) [17]. The range of spontaneous
regression of pancreatic pseudocysts ranges from 8% to 70% and
the two major factors affecting this are; the size of the pseudocyst
and the time since diagnosis [17]. In our study, 40 patients (47.6%)
had spontaneous resolution of their pseudocysts and only 4
patients had drainage procedure for their cysts (2 percutaneously
and 2 endoscopically) in the initial period of the study and 1 further
patient having endoscopic drainage in the follow up period of the study. The body of the pancreas was the most common site with
33 pseudo-cysts, followed by the head of the pancreas with 28, tail
27, uncinate process 4, neck 2, not specified 7, 1 in the junction
between body and tail, and 2 in the junction between head and
body. 9 patients in our study had multiple pseudocysts. The results
in the literature about the site of pseudocysts within the pancreas
is variable, as some studies showed that most pseudocysts would
be in or near the tail of the pancreas [18]. In another study, most
extra pancreatic pseudocysts were located in the body and tail
region, whereas most intrapancreatic pseudocysts were in the
head of the pancreas [19]. The overall mortality in our study was
50% (42 patients), however the cause specific mortality was only
9 patients (10.7%). 59.5% of the whole mortality cohort had
alcoholic pancreatitis while 28.5% had gall stones pancreatitis. The
9 cause specific mortality patients; 7 were alcoholic pancreatitis
and 2 were gall stones pancreatitis. On multivariate analysis there
was a statistically significant association between the aetiology of
pancreatitis and death which was also confirmed on Chi-square
testing. There was no statistically significant association between
the mode of pancreatitis (acute or chronic) and death. The duration
of time form diagnosis of pancreatitis/ pancreatic pseudo-cyst to
death was quite variable ranging from 8 to 3809 days (median 1018
days) in the whole mortality cohort. In the cause specific mortality
group, the range was 10 to 1424 days (median 112 days), this was
statistically significant
Conclusion
Our study showed that alcoholic pancreatitis remains the most
frequent underlying aetiology for pancreatic pseudocysts although
it is not as common as in other studies. The incidence of incidental
pseudocysts with no history of pancreatitis is higher than that in
the literature. Around 50% of pseudo pancreatic cysts in our study
resolved spontaneously; therefore, conservative treatment has
a big role in management of pancreatic pseudocysts. Bleeding or
infection of a pseudo pancreatic cyst is an emergency associated
with high mortality and should be managed promptly with
laparoscopic and endoscopic approaches now gaining popularity
over the surgical approach which is only used if the previously
mentioned approaches fail.
To know more about our Journal of Surgery Articles : https://surgery-casestudies-lupine-publishers.blogspot.com/
To Know More about Lupine Publishers blogger Articles: https://lupinepublishers.blogspot.com
To Know More about Lupine Publishers blogger Articles: https://lupinepublishers.blogspot.com
No comments:
Post a Comment