Pancreatic Pseudoaneurysm - Causes, Symptoms, and Treatment

Introduction

The pancreas is an important organ in the human body that helps in food digestion and blood sugar regulation. Various pancreatic diseases may result from infection, inflammation, etc. The layer or lining of the pancreas tears off due to bile juice leakage, weak walls of the pancreas, leakage from anastomosis in the pancreas, or autodigestion in which the pancreatic enzyme damages the tissues. This results in the complete or partial formation of a cyst-like structure called pseudoaneurysm.

Pseudoaneurysm is the leakage and collection of blood from damaged or injured blood vessels. The wall of the pseudoaneurysm is made up of fibrous tissues. It is different from an aneurysm, which forms sac-like structures because of the weakening and bulging of blood vessels. The wall of the aneurysm is made up of arteries. In order to diagnose the condition, angiography is the most helpful option. This condition is best treated through a surgical approach called embolization or thrombin injections.

What Is Pancreatic Pseudoaneurysm?

It is a rare clinical condition as a result of pancreatic erosion (wearing off or breaking of the outermost skin layer) or peripancreatic artery pseudocyst (pancreatic artery running through the cyst).

What Are Aneurysms And Pseudoaneurysms?

An aneurysm is the formation of a sac-like structure because of the weakening and bulging of blood vessels. The wall of the aneurysm is made up of arteries, whereas pseudoaneurysm is the leakage and collection of blood from the damaged or injured blood vessels. The wall of the pseudoaneurysm is made up of fibrous tissues.

What Causes Pancreatic Pseudoaneurysm?

The common causes of pancreatic pseudoaneurysm are:

• Pancreatitis (inflammation of the pancreas).

• Pancreaticobiliary surgery (tumor or injury to the pancreas and bile duct).

• Trauma such as from accidents.

• Pancreas transplantation.

• Intraabdominal abscess.

• Leakage from anastomosis (surgical connection of two structures).

• Weakened walls of the blood vessels present near the pancreas.

What Is the Pathophysiology of Pancreatic Pseudoaneurysm?

The splenic artery is a major blood vessel that is involved or associated with this condition because it is located along the pancreas and innervates the spleen. The wall of the pseudoaneurysm is made of fibrous tissues that can rupture or grow large. This occurs as a result of bile juice leakage, weak walls of the pancreas, leakage from anastomosis in the pancreas, or autodigestion in which the tissues are damaged by the pancreatic enzyme. This results in the complete or partial formation of a cyst-like structure called pseudoaneurysm. In the later stages, when the pseudoaneurysm ruptures or grows large, it affects other organs, the bile duct, etc.

What Are the Pancreatic Pseudoaneurysm Symptoms?

Mostly this condition is asymptomatic. In general, the patient may develop these symptoms:

• Blood vomit (hematemesis).

• Recurrent pancreas inflammation.

• Blood in the stool or anus (hematochezia).

• Sudden onset of pain in the abdomen.

• Unstable count of red blood cells in the blood.

• Sentinel bleeding (it is called early warning bleed); minor blood loss or leakage from the pseudoaneurysm.

• Low blood pressure.

• Increased heart rate above 100 in a minute (tachycardia).

• The pale color of the skin.

How to Diagnose Pancreatic Pseudoaneurysm?

The most effective way to diagnose this condition is the imaging tests as mentioned below:

1. Angiography: It is the most helpful diagnostic tool. It identifies the exact location of the lesion, its type, etc. It is a type of radiograph or X-ray done to check the condition of the blood vessels because blood vessels do not appear in a normal X-ray. Therefore, a special contrast or dye is injected into the patient's blood, and an X-ray is taken in which the blood vessels show a contrast image.

2. Computed Tomography Angiography: It is another technique to visualize the blood vessels with the help of a computed tomography scan. Contrast is injected into the patient's blood, and images are taken to assess them.

The results of these imaging tests will help to identify:

• The origin of pseudoaneurysm by showing the blood vessel.

• Presence of blockage or obstruction in the gastrointestinal tract.

• Presence of pancreatic fluid accumulation in the pseudoaneurysm or blood leakage site.

How to Treat Pancreatic Pseudoaneurysm?

The main aim of treating the pancreatic pseudoaneurysm should be to control the bleeding. This can be achieved by various methods:

1. Endovascular Transarterial Catheter Embolization - In this technique, the blood supply from where the bleeding originates is blocked. To block the blood vessel:

• An incision is made at the affected site.

• A thin tube, called a catheter, is placed. This catheter is guided into the blood vessel near the affected site, such as the pancreas.

• Small gelatin particles or sponges are injected into the surgery site.

• These particles block the blood supply to the affected area or source of the bleeding.

2. Thrombin injection - If the neck of the pseudoaneurysm is narrow or there is a small pseudoaneurysm, thrombin injection is the treatment choice. More commonly, it is used to treat femoral artery-related pseudoaneurysms. Thrombin is a hemostatic agent that controls bleeding and minimizes it.

What Is the Differential Diagnosis for Pancreatic Pseudoaneurysm?

• Abscess formation in the pancreas.

• A rare cancer of salivary glands - cystic adenocarcinoma.

• Abdominal tumor - mesenteric cyst.

• Cysts in the liver and lungs - hydatid cysts.

• Ballooning or building of aorta - aortic aneurysm.

What Is the Success Rate of Pancreatic Pseudoaneurysm?

The success rate after embolization surgery is good, but the recurrence rate is also high. The mortality rate is as high as 90 % without surgery, and those after surgery have a 20 % higher risk of dying.

What Are the Complications of Pancreatic Pseudoaneurysm?

• Rupture of blood vessels, especially rupture of those that are crossing the cyst.

• Obstruction of the biliary duct.

• Arteriovenous fistula (AV): An uncommon connection between the artery and vein.

• Hemorrhage - excessive internal bleeding.

• Shock: A sudden drop in the blood flow.

• Failure of multiple organs.

• Death.

Which Artery Is the Most Common Location for Pancreatic Pseudoaneurysm?

The splenic artery acts as the most common location for the formation of pancreatic pseudoaneurysm.

Conclusion

Pancreatic pseudoaneurysm is an uncommon but life-threatening clinical event. It occurs because of the rupture of the pancreatic artery or, more commonly, the splenic artery, which results in the formation of a cyst-like structure called a pseudocyst. Inflammation of the pancreas is the most common cause of this condition. Angiography, more commonly known as computed tomography angiography, is a helpful diagnostic tool. Embolization is the recommended surgical treatment for most patients, but those who do not have stable blood flow in the body are recommended to undergo thrombin injection as an available treatment approach.