**9. Pancreatic pseudocysts complications**

Generally, peri-pancreatic fluid collections are sterile and most of the cases are resolved without any invasive intervention. Potentially, untreated pancreatic pseudocysts can cause life threatening complications including Infection, rupture, pancreatic fistulas and ascites, vascular complications (Pseudoaneurysm formation, Hemosuccus Pancreaticus, Splenic or Portal vein thrombosis), and splenic complications and local mass effect (Gastrointestinal, Urinary obstruction or biliary complications).

### **9.1 Infection**

As aforementioned, peri-pancreatic fluid collections are sterile. Infected pancreatic pseudocysts occur in up to 10% of cases, usually spontaneously or after iatrogenic intervention (diagnostic or therapeutic manipulation) [20]. The most common species of pathogens that are frequently found in PPCs originated from the enteric flora and include E. coli, Klebsiella pneumoniae, Enterococcus spp., and, Enterobacter spp., less frequent are Pseudomonas aeruginosa, Streptococcus spp., Staphylococcus spp., and Bacteroides [21]. The route of the bacteria leading to infection in pancreatic

pseudocyst is still unclear. Several mechanisms have been proposed, such as infection from the biliary tree or duodenum, translocation of bacteria from the gut, and hematogenous or lymphatic spread from other sites.

Since clinical manifestations may vary, infection should be suspected in any. patient with fever or suggestive signs or symptoms of sepsis. An infected pancreatic pseudocyst is accompanied by fever, shivering, and elevated white blood cell count. The presence of bubble gas sign on CT is a crucial finding for infection and the physician should be suspected. Nevertheless, US-guided aspiration (EUS-FNA) and sending the fluid for gram stains and cultures will provide the definitive diagnosis.

In addition, the results would provide information for the appropriate antibiotic treatment. If the acute infection is confirmed, then drainage should be performed by endoscopic, percutaneous, or surgical procedures.

### **9.2 Rupture**

Rupture of the pancreatic pseudocyst can lead to a favorable outcome or a potentially life-threatening situation. Rupture to the adjacent gastrointestinal tract will lead to vomiting, diarrhea, melena, hematemesis, or hematochezia. However, rupture into the peritoneal cavity can cause severe peritonitis or hemorrhagic shock and pancreatic ascites. Its clinical manifestation includes severe abdominal pain, fever, food intolerance, tachycardia, and hypotension. Intraperitoneal hemorrhage from ruptured pancreatic pseudocyst is associated with an extremely high mortality rate (35.3%) [22]. The exact mechanism of rupture remains unknown. Possibly, erosion or disruption due to either severe inflammation or the activated lytic enzymes in the pseudocyst, in a superficial vessel may have weakened the pseudocyst wall, subsequently resulting in the spontaneous rupture of the pseudocyst [23]. The content of the pseudocyst (amylase, lipase, and other proteolytic enzymes) can cause erosion of the nearby viscera, thrombosis of the adjacent vessels, or further complications [24].

Traditionally, the optimal therapeutic choice is the internal drainage either through cysteogastrostomy or Roux-en-Y cysteojejunostomy [25]. Extensive local inflammation or incapability of identifying the cyst walls can lead to the failure of creation of the anastomosis. In these cases, external drainage and lavage of the peritoneal cavity can be achieved with safety [9]. Recently, another option, which was reported, is the endoscopic ultrasound-guided drainage and endoscopic ultrasoundguided gastrocystostomy with a fully covered self-expandable metallic stent [26]. However, the authors highlighted that can be useful in local fluid collection due to the ruptured pseudocyst.

Regarding the ruptured pseudocysts in nearby viscera, the literature recommends conservative treatment unless there is active bleeding, or the patient is febrile. The most common site seems to be the stomach, but there is not enough data to support this. Beside the conservative treatment, the authors recommend endoscopic intervention (potential clipping of bleeding vessels, stenting) as first choice of treatment and surgical intervention when endoscopic management is impossible (gastrectomy) [23, 27–29].

### **9.3 Pancreatic fistula and ascites**

A big majority of patients with acute pancreatitis will develop pseudocysts, while only a small percentage of them will develop fistula or ascites as pseudocyst complications. There is no data regarding the mechanism for the creation of the fistula.

### *Pancreatic Pseudocyst DOI: http://dx.doi.org/10.5772/intechopen.107320*

Fistulas are divided into two categories: internal which include fistulas associated with the adjacent viscera to the pseudocyst; andnd external, mainly due to iatrogenic manipulations. Connection from the pseudocyst to the stomach, colon, small intestine, bronchi, biliary tract, and esophagus have been described. Early recognition of this rare entity is crucial. CT, MRI, and MRCP have a principal role. In addition, fistulography has been proven trustworthy for a definitive diagnosis [30]. Like the aforementioned complications, a stepwise approach is the key starting from conservative treatment to endoscopic or surgical interventions.

The external pancreatic pseudocyst fistulas can mostly occur as a complication of the percutaneous drainage. On suspicion, any aspired fluid must be checked for amylase levels ensuring the diagnosis. Also, another option is to inject a contrast media through the drain or fistula to assess for a pancreatogram, which confirms the diagnosis. Initial treatment is considered to be conservative as in the majority of the cases, fistulas are resolved without any intervention [31]. Although external fistulas are iatrogenic complications, there are a few cases that have been reported with spontaneous pancreatocutaneous fistula [32, 33]. In both cases, pseudocyst occurred retroperitoneally with swelling at the left lumbar and left flank region accordingly. In the first case, conservative treatment was chosen while the second one underwent surgical drainage. Both cases had favorable outcomes.

Ascites are another complication of the pancreatic pseudocyst. In most of the cases (about 80%), ascites appears due to leakage of the pseudocyst in patients with chronic pancreatitis [34, 35]. Patients with pancreatic ascites usually refer to mild abdominal pain, decreased appetite, sense of satiety, and weight loss. One very important leading point is the medical history of patient, which must include chronic pancreatitis or a recent episode of acute pancreatitis. The diagnosis is set by drainage and the ascitic fluid has high amylase concentration (over 1000IU/L) and protein concentration over 3 g/dl, which differentiates it from cirrhosis, tuberculosis, or malignancy [36]. Imaging modalities that could lead to diagnosis is the endoscopic retrograde cholangiopancreatography (ERCP) which is the "gold standard" to confirm the site of leakage; while in cases where ERCP is contraindicated, MRCP can define the anatomy of pancreatic duct and its abnormalities [37, 38]. Treatment of this entity concerns mainly the therapy of the pancreatic pseudocyst. Conservative treatment, drainage either internal (cystogastrostomy, cystojejunostomy, or cystoduodenostomy) or external and distal pancreatectomy when the leak is in the pancreatic tail are possible options [37].
