Pancreatic Pseudocysts - 101 to K.

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This will probably be more information than you ever want to know

about pseudocysts....lol! Since they are the sole contributors now

to any pain that I have, and I've had two pseudocysts inside my

pancreas for over 4 years, I've collected an extenisive amount of

information on them. One of my pseudocysts has finally resolved, the

one I have remaining is located near the head of my pancreas, measures

6.5 X 6.5 cm. and has remained relatively stable at that size for the

past 2 years. Following is information on pseudocysts from parts of

an article in emedicine.com:

Background: Pancreatic pseudocysts are the most common cystic lesions

of the pancreas, accounting for 75-80% of such masses. A pancreatic

pseudocyst is a collection of amylase-rich, lipase-rich, and

enterokinase-rich fluid. It is most frequently located in the lesser

peritoneal sac in proximity to the pancreas. Large pseudocysts can

extend into the paracolic gutters; pelvis; mediastinum; and, rarely,

to the neck or scrotum. Some pseudocysts in the pancreatic parenchyma

are loculated. The most common etiologies for pancreatic pseudocysts

include chronic pancreatitis, acute pancreatitis, and pancreatic

trauma. In addition, pseudocysts are associated with pancreatic ductal

obstruction and pancreatic neoplasms.

Pseudocystic fluid has electrolyte concentrations similar to those in

plasma. In contrast, pseudocystic fluid has a high concentration of

amylase, lipase, and enterokinases such as trypsin. These

concentrations reflecting the origin of the lesion from extravasated

pancreatic exocrine secretions resulting from pancreatic ductal

disruption. The pancreatic secretions incite an intense inflammatory

response, which eventually leads to the development of a thick fibrous

capsule surrounding the pancreatic fluid.

For the first 3-4 weeks, any fluid that is associated with an episode

of acute pancreatitis is called an acute fluid collection. Typically,

acute fluid collections do not have high amylase concentrations. They

do not possess a thick fibrous capsule, and they usually have an

irregular shape. They may or may not be associated with peripancreatic

fat necrosis. These features are in contrast with those of pancreatic

pseudocysts, which have high amylase concentrations, are surrounded

by a thick fibrous capsule, and are oval or round. The reason for

these differences is that acute fluid collections do not result from

pancreatic ductal disruption and the subsequent leakage of pancreatic

exocrine secretions.

Acute fluid collections represent an accumulation of transudative or

exudative fluids from surrounding tissues in reaction to the episode

of pancreatitis. An unusual form of pancreatitis called groove

pancreatitis may result in an acute fluid collection or the formation

of a pseudocyst between the pancreatic head and the duodenum.

Not until the fluid collection has been present for 4 or more weeks

is it called a pancreatic pseudocyst. By this time, the inflammatory

process leads to encapsulation of the fluid collection by a rim of

fibrous tissue that may contain some granulation tissue as well. The

capsule usually is densely adherent to surrounding viscera such as

the stomach or duodenum.

Note that the capsule of a pancreatic pseudocyst does not possess a

true epithelial lining. This is a critical point in the

differentiation of pancreatic pseudocysts from cystic neoplasms of

the pancreas.

Pathophysiology: Pseudocysts most commonly result from an acute or

chronic inflammatory process involving the pancreas. Pancreatic trauma

also can result in pseudocyst formation. In this process, the common

etiologic insult that causes leakage of pancreatic juice and

pseudocyst formation is pancreatic ductal disruption.

In acute pancreatitis, the ductal disruption is secondary to necrosis

of part of the pancreas and subsequent duct leakage. This finding led

to use of the term postnecrotic pseudocyst for pseudocysts that appear

in relation to an episode of acute pancreatitis.

Patients with chronic pancreatitis may have elevated pancreatic duct

pressures resulting from strictures, ductal calculi, or other causes.

This effect results in a small ductal disruption that frequently is

retained within the parenchyma of the gland. The types of pseudocysts

sometimes are called retention cysts.

In severe acute pancreatitis, necrosis of part of the gland frequently

occurs. This leads to extravasation of enzyme-rich pancreatic

secretions and their loculation in potential spaces, including the

lesser peritoneal sac and anterior pararenal space. At this point,

this mass of pancreatic secretions and reactive exudate is termed an

acute fluid collection and is found in as many as 50% of patients

with acute pancreatitis, according to Luque-de Leon and Sarr. Acute

fluid collections may contain necrotic pancreatic tissue. These

collections should be considered sterile necrosis.

Most acute fluid collections associated with acute pancreatitis

resolve spontaneously. Some remain for longer than 4 weeks and become

encased in a fibrous capsule. Those that persist for longer than 6

weeks may be followed conservatively if they are smaller than 6 cm in

diameter. They still have an excellent chance of undergoing complete

spontaneous resolution with a low morbidity rate. Pseudocysts that

persist for more than 6 weeks and are 6 cm in diameter or larger have

a low likelihood of complete spontaneous resolution and are associated

with significant morbidity rates. These pseudocysts should be drained.

Chronic pancreatitis is the most common cause of pancreatic

pseudocysts. Pancreatic ductal disruption may be present in patients

with pseudocysts associated with chronic pancreatitis. The

presentation of a pancreatic pseudocyst resulting from chronic

pancreatitis is subtler than the presentation of acute pancreatitis.

Patients with chronic pancreatitis frequently complain of vague

abdominal pain or early satiety. Occasionally, nausea and vomiting

are prominent components of the clinical picture. Gastrointestinal

tract complaints can prompt the clinician to order abdominal

ultrasonographic (US) studies or abdominal CT scans. These studies

are highly sensitive for demonstration of pancreatic pseudocysts.

Research has determined the following:

* Acute fluid collections: An acute fluid collection occurs early in

the course of acute pancreatitis. It is located in proximity to the

gland or within it. An acute fluid collection has no epithelial lining

nor a capsule composed of fibrous or granulation tissue.

* Pancreatic pseudocysts: A pancreatic pseudocyst is a fluid

collection contained within a well-defined capsule of fibrous or

granulation tissue or a combination of both. A pseudocyst does NOT

possess an epithelial lining. Pseudocysts may develop in the setting

of acute pancreatitis or chronic pancreatitis.

* Pancreatic cysts: A pancreatic cyst is an epithelial wall or capsule

that contains a fluid collection. Included in this group are

congenital cysts and cystic neoplasms such as mucinous cystic tumors

or serous cystadenomas.

Frequency:

* In the US: Pseudocysts are the most common complication associated

with chronic pancreatitis. Morel and Rohner wrote that a pseudocyst is

found in 40-70% of patients undergoing surgical therapy for chronic

pancreatitis. The incidence of true pseudocyst formation after an

episode of acute pancreatitis is lower and approximately 10% according

to Bradley et al (Bradley, 1979). Overall, approximately 10,000

pancreatic pseudocysts are reported annually in the United States.

Mortality/Morbidity:

* Morbidity: Most pancreatic pseudocysts resolve spontaneously. Most

published reports describe spontaneous resolution rates of greater

than 50%. Beebe and associates reported that 85% of the pseudocysts

followed in their series resolved spontaneously.

* Mortality: Death directly attributable to a pancreatic pseudocyst is

rare. Death occurs most frequently when vessel erosion results in a

pseudoaneurysm that ruptures and bleeds freely into the peritoneal

cavity. Reported mortality rates in this situation are 40-80%.

Surgical mortality rates for patients undergoing surgical drainage are

0-6%.

Race: No well-described racial predilection exists for the formation

of pancreatic pseudocysts.

Sex: No data exist to prove a proclivity for pseudocyst formation on

the basis of sex.

Age: Pancreatic pseudocysts can occur anywhere in the pancreas in

persons of any age. Because the common etiologies for pseudocyst

formation include pancreatitis due to gallstones or alcohol, most

pseudocysts are detected in adults.

Anatomy: Thorough knowledge of the anatomy of the pancreas and

surrounding structures is essential for proper evaluation of patients

with pancreatic pseudocysts and for planning potential therapeutic

interventions. By convention, the pancreas is divided into 4 parts:

head, neck, body, and tail.

The head of the pancreas forms the right side of the gland. It is

cradled within the C-loop created by the course of the second through

fourth portions of the duodenum. Anteriorly, the head of the pancreas

is covered partially along its superior surface by the first portion

of the duodenum. The gastroduodenal artery courses along the anterior

surface of the pancreas, in a cephalic-to-caudal direction, creating

a groove or indentation in the anterior surface of the gland that

describes the boundary between the head and neck of the pancreas.

Other anterior relations of the pancreatic head include the omental

bursa, the greater omentum, the transverse colon, and the transverse

mesocolon.

Posteriorly, the head of the pancreas rests against the right crus of

the diaphragm, and it overlies the inferior vena cava. The termini of

the renal veins are also posteriorly related to the pancreatic head,

as is the aorta. The uncinate process is a projection of the left

caudal area of the head of the pancreas, which is insinuated between

the aorta and the superior mesenteric vessels. The intrapancreatic

portion of the common bile duct courses along the posterior surface

of the pancreas, or it may be partially embedded in the gland.

Anteriorly, the neck of the pancreas is in contact with the pylorus

and the lesser peritoneal sac or omental bursa. Anterior to the

omental bursa is the posterior surface of the stomach. The posterior

relations of the neck of the pancreas include the termini of the

splenic and superior mesenteric veins and their confluence to form

the portal vein. The aorta and, more deeply, the spinal column are

also important posterior relations of the pancreatic neck.

The predominant anterior relation of the body of the pancreas is the

lesser peritoneal sac or omental bursa. The superior edge of the

transverse mesocolon is in continuity with the peritonealized surface

of the body of the pancreas. The splenic vein courses along the

posterior surface of the pancreatic body and the inferior mesenteric

vein may course cephalad posterior to the body to join the splenic

vein. The body of the pancreas rests against the aorta and the takeoff

of the superior mesenteric artery. Other posterior relations include

the left kidney, left renal vessels, left adrenal gland, and the left

crus of the diaphragm. The ligament of Treitz, the first several

centimeters of the jejunum, and the splenic flexure of the colon are

inferiorly related to the body of the pancreas.

The tail of the pancreas is at the left end of the gland and extends

in the lienorenal ligament to contact the spleen at the splenic hilum.

Anteriorly, the omental bursa and the splenic flexure of the colon

are related to the pancreatic tail. Posteriorly, the left kidney is

found.

The normal pancreatic ductal system consists of the major pancreatic

duct of Wirsung and the minor pancreatic duct of Santorini. The duct

of Wirsung drains exocrine secretions from the tail, body, neck, and

most of the head of the pancreas. It approached to the common bile

duct and may join it, but it more commonly drains through a separate

orifice at the ampulla of Vater. The duct of Santorini is responsible

for draining part of the pancreatic head. Its orifice is found in the

duodenum just proximal to the ampulla of Vater.

The arterial blood supply to the pancreas is derived from 4 major

sources. The anterior superior and posterior superior

pancreaticoduodenal arteries are branches of the gastroduodenal

artery. The anterior inferior and posterior inferior

pancreaticoduodenal arteries are derived from the superior mesenteric

artery. The splenic artery provides numerous branches to the pancreas

during its course along the dorsal superior aspect of the gland. The

gastroduodenal artery provides additional arterial blood to the

pancreas via its retroduodenal branch.

Pancreatic veins drain into the superior mesenteric and splenic veins,

and the lymphatic drainage from the pancreas goes to the

pancreaticoduodenal, pancreaticolienal, portal, and celiac lymph nodes.

The major relevance of these anatomic relations is that a pancreatic

pseudocyst can adhere to one or more hollow viscera after forming in

a potential space, most commonly the lesser peritoneal sac.

Therapeutic options are dictated by the anatomy and can include

cystgastrostomy, cystoduodenostomy, cystojejunostomy, or combinations

of the three.

With the abundance of major vessels in the region, imagining how

vascular complications related to pseudocysts can occur is not

difficult. Complications include thrombosis; pseudoaneurysm formation;

or rupture of vessels, most commonly the splenic artery or vein.

Clinical Details:

Physical findings

Results of physical examination vary. Patients can have tenderness to

palpation in the epigastrium. Thorough physical examination elicits

the presence of a palpable upper abdominal mass in approximately 50%

of patients with pancreatic pseudocysts. Ongoing free intraperitoneal

hemorrhage can be associated with abdominal pain and also with signs

of shock.

Acute fluid collections are common in patients with acute pancreatitis

or exacerbations of chronic pancreatitis. Acute fluid collections are

easily diagnosed by using abdominal CT, which has become a routine

study in the evaluation of patients with pancreatitis. The vast

majority of acute fluid collections resolve.

Clinical suspicion for the presence of a pancreatic pseudocyst usually

is aroused first by the persistence of abdominal pain following

resolution of pancreatitis. Abdominal pain that persists for longer

than 3 weeks after recovery from pancreatitis is a presenting symptom

in 80-90% of patients with pancreatic pseudocysts, according to Cohen

and Prinz. The authors also described abdominal fullness, nausea and

vomiting, and weight loss as occurring in 40-50% of patients with

pseudocysts. If the cyst compresses or obstructs the common bile duct

or the second portion of the duodenum, jaundice and pruritus may

become part of the clinical constellation.

Involvement of the stomach can cause early satiety, nausea and,

occasionally, vomiting. Pseudocysts that compress the duodenum can

cause nausea, vomiting, and varying degrees of biliary obstruction.

Vague epigastric or upper quadrant abdominal pain is a frequent

complaint in all of these scenarios.

Prolonged studies on the natural history of pseudocysts are a rarity.

Vitas and Sarr published a series in which 68 patients with pancreatic

pseudocysts were followed. After 51 months, 63% of the patients were

asymptomatic. Only 9% of the patients developed any of the

complications described above.

Complications

Among the important complications associated with pancreatic

pseudocysts are infection, obstruction, perforation, hemorrhage, and

thrombosis. The most common acute complication of pancreatic

pseudocysts is infection, which is heralded clinically by the presence

of fever; worsening abdominal pain; and, occasionally, systemic signs

of sepsis such as tachycardia, tachypnea, and hypotension. Laboratory

analysis frequently demonstrates leukocytosis.

Obstruction of the hollow viscera of the gastrointestinal tract is

not uncommon with pseudocysts that have been present for a long time.

The presentation is usually less dramatic and complete obstruction is

uncommon. The presentation depends on the location of the pseudocyst

and the particular viscus it is compressing, although true

differentiation based on the symptoms alone may be difficult because

of protean manifestations.

Pseudocysts may erode one of several named vessels, leading to

pseudoaneurysm formation. The vessel most commonly affected is the

splenic artery. The gastroduodenal artery, pancreaticoduodenal

arteries, gastroepiploic and gastric arteries, and others have been

involved as well. Acute episodes of hemorrhage associated with rupture

of a pseudoaneurysm may be limited and present with sudden severe

abdominal pain.

Pseudocysts may compress vascular structures as well, most commonly

veins, which can lead to thrombosis. The most frequently affected

vessel is the splenic vein.

Preferred Examination: Abdominal CT is performed in virtually every

patient presenting with clinically significant pancreatitis or

abdominal trauma severe enough to result in pancreatic ductal

disruption. Therefore, abdominal CT is commonly the initial radiologic

examination used to identify an acute fluid collection related to

pancreatic ductal disruption.

Once the diagnosis is made, screening patients for resolution of the

fluid collection is acceptable by using abdominal US. However, if a

mature pseudocyst forms and does not resolve, repeat CT scanning is

advised prior to planned percutaneous, endoscopic, or surgical

interventions.

Limitations of Techniques: Currently available CT scanners enable the

identification of virtually all clinically significant pancreatic

pseudocysts. The major limitation is the inability to differentiate

pseudocysts from cystic neoplasms by using CT.

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I hope this information helps you, or anyone intested in pseudocysts.

With love, hope and prayers,

Heidi

Heidi H. Griffeth

SC State & SE Regional Rep

PAI

Note: All comments or advice is based on personal experience or

opinion, and should not be substituted for consultation with your

medical professional.