What is Pancreatic Fistula?
A fistula is essentially an abnormal or artificially created tunnel that links one lined surface inside the body to another. In the case of a pancreatic fistula, this abnormal link occurs between the lining of the pancreatic duct and another bodily surface. This connection can cause enzyme-rich pancreatic fluid to leak out.
There are three different ways to categorize pancreatic fistulas: by their structure, the disease that caused it, or the immediate reason it happened. Typically, they are classified by if they are internal or external fistulas.
An internal pancreatic fistula is when the pancreatic duct is broken, making it communicate with the spaces of the abdomen or around the lungs. An external pancreatic fistula, also known as a pancreaticocutaneous fistula, is when the pancreatic duct forms a direct connection to the skin and leaks pancreatic fluid.
External pancreatic fistulas can be further specified depending on whether they are related to surgical causes. According to the International Study Group for Pancreatic Fistula (ISGPF), a pancreatic fistula is defined as any measurable leakage from a drain three or more days after surgery with an amylase level (a digestive enzyme) more than three times above the normal limit for each specific institution. Importantly, this condition must have a significant impact on the patient’s health.
What Causes Pancreatic Fistula?
Pancreatic fistulas, which are abnormal connections between the pancreas and other organs or tissues, can be caused by both iatrogenic and non-iatrogenic factors. Iatrogenic means they’re caused by medical procedures or treatments.
These could include an injury during surgery or a biopsy of a pancreatic mass, removal of part of the pancreas, complications from endoscopic interventions (procedures using a tube-like instrument to examine inside the body), or as a result of draining fluid from a pancreatic collection like a pancreatic pseudocyst (a fluid-filled sac in the pancreas). Also, it’s worthy to note that most of the external pancreatic fistulas, those that drain outside of the body, occur because of such medical interventions.
On the other hand, non-iatrogenic causes include abdominal trauma (injury to the abdomen), acute pancreatitis (sudden inflammation of the pancreas), and chronic pancreatitis (long-term inflammation of the pancreas).
Risk Factors and Frequency for Pancreatic Fistula
Pancreatic fistula is a potential problem that might occur during pancreas surgery. How often this happens can range from 5% to almost 29%. These varying numbers are due to different definitions of what a fistula is. It’s a known issue that about 40% of individuals with sudden pancreas inflammation, also called acute pancreatitis, will experience abnormal fluid accumulation. Among these people, a small portion will eventually end up with a fistula.
Signs and Symptoms of Pancreatic Fistula
Recognizing a pancreatic fistula requires a thorough review of patient history and a physical examination. Depending on its location, size, and pathway, a pancreatic fistula may cause a wide range of signs and symptoms. These symptoms can range from no noticeable symptoms, to severe cases that result from fluid buildup.
For patients with internal pancreatic fistulas, possible signs and symptoms include:
- Abdominal pain
- Nausea
- Vomiting
- Swelling of the abdomen
- Lack of appetite
- Weight loss
- Problems with passing stool or gas
- Other digestion-related symptoms
With fluid buildup in the abdomen, patients can develop a condition known as ascites – which can be identified by an enlarged abdomen and dullness to percussion at the flanks.
If the fistula affects the chest area, leading to a pancreatic pleural effusion, patients may experience symptoms related to their lungs, such as:
- Shortness of breath
- Cough
- Wheezing
- Pain in the chest area
These symptoms are generally caused by a significant amount of fluid buildup in the chest.
In contrast, external pancreatic fistulas can create an outflow of mostly pancreatic fluid through an abdominal skin wound. This can cause symptoms such as dehydration and weight loss from malnourishment. Since the fistula is exposed to the external environment, there’s a risk of infection. Symptoms of which can include a warm, red wound site, skin damage, and potential infection leading to fever. Both internal and external pancreatic fistulas could eventually cause a high temperature due to infection, leading to a condition called sepsis.
Testing for Pancreatic Fistula
If you have a pancreatic fistula, it’s crucial that you are in a stable condition before any evaluations can be performed. Once your condition is stabilized, your doctor may use imaging techniques to help determine the cause of abdominal pain or shortness of breath. A speedy and useful first step could be a chest x-ray, which gives information about any issues involving the chest area and its structures.
A Computerized Tomography scan, often known as a CT scan, is another very helpful tool to evaluate what might be causing abdominal pain. It can detect problems such as bodily fluid build-ups or changes in the pancreas. However, a CT scan may not provide a clear enough picture to assess a pancreatic fistula.
Other techniques can be used to examine the fistula and the pancreatic duct more effectively. These include Magnetic Resonance Cholangiopancreatography (MRCP), Endoscopic Retrograde Cholangiopancreatography (ERCP), or Fistulography. MRCP provides a more detailed image of the pancreatic duct. ERCP gives a better view of the pancreatic duct structure and can locate any disruption sites. In some cases, ERCP can also be used for treatment procedures if needed. Fistulography allows doctors to see the fistula site and the surrounding anatomical structures.
In addition to imaging, lab tests should also be performed for a more precise evaluation. This could involve analyzing any fluid sample collected via a process known as thoracentesis (removal of fluid from the space between the lungs and the chest wall) or paracentesis (removal of fluid from the abdomen), or from the fistula itself.
Your doctor may also request a blood sample to be sent to the lab for testing. This could involve a complete blood count, complete metabolic panel, and levels of lipase and amylase enzymes (which are associated with pancreatic function). The complete metabolic panel includes several components, all of which are essential for understanding your body’s current state.
If you have a build-up of fluid in the space around the lungs (pleural effusion), thoracentesis may be necessary. The fluid sample will be tested for amylase levels and several other factors. If you have accumulated fluid in the abdomen (ascites), paracentesis will be performed, and the fluid will be sent to the lab for further tests. In both cases, if the amylase levels in the collected fluid are very high (usually more than 1000 U/dL), it could suggest a pancreatic issue.
In the case of an external fistula, the discharge should be collected and analyzed for the presence of amylase.
Treatment Options for Pancreatic Fistula
Treating pancreatic fistulas, which are abnormal connections formed between the pancreas and other parts of the body, involves various measures. Regardless of how the condition shows up, it’s crucial to first make sure the patient is in the best possible health. This includes taking steps to control the fistula and ensure the person is well-nourished before any major treatment begins.
Three main supportive care measures help to stabilize and improve a patient’s condition. First, doctors will work to control the pancreatic exocrine secretion, or the digestive juices the pancreas produces. Patients may be advised not to eat or drink anything, while feeding through a tube placed after the stomach (postpyloric) or a temporary intravenous nutrition may also be started.
Further control of pancreatic secretion can be achieved medically by using drugs known as somatostatin analogs, such as octreotide. The second supportive care measure involves correction of fluids and electrolytes. Pancreatic fistula patients could lose pancreatic fluid that is rich in bicarbonate, leading to metabolic acidosis, a serious condition where your body produces too much acid. Lastly, skin care is important, particularly near an external pancreatic fistula, to prevent further damage.
Besides supportive care, some pancreatic fistulas might need more intervention involving endoscopic therapy or direct surgery. Endoscopic therapy is usually preferred for many pancreatic fistulas. During this process, doctors place a tube down your throat and into your digestive system via your mouth, also called an ERCP, performing sphincterotomy and/or placing a pancreatic stent to encourage the flow of pancreatic secretions along a chosen internal drainage route. As a result, the flow through the fistula tract reduces, helping with fistula closure. If the endoscopic approach doesn’t work or is not an option due to complexity, the next alternative is surgery.
Depending on the anatomy of the duct and location of the fistula, different surgical methods may be chosen. For patients with large duct disease, doctors may opt for a surgery called pancreaticojejunostomy. For patients whose only ductal injury is at the pancreatic tail, a caudal pancreatectomy might be recommended. And for pancreatic disruption in the body of the pancreas, a distal pancreatectomy might be performed. Surgery usually also includes draining the fluid. For pancreatic fistula cases that occur after a pancreatectomy, drains are placed to remove the fluids.
What else can Pancreatic Fistula be?
If a patient comes in with a pancreatic fistula, the doctor would first want to figure out what might be causing this. This is also known as a differential diagnosis and it usually considers various causes depending on the patient’s symptoms. This also takes into account where the fistula is located and its size.
For example, if the patient is feeling abdominal pain, the doctor would consider these conditions:
- Physical injury like trauma
- Bleeding in the area behind the abdomen (retroperitoneal bleeding)
- Type of cancer that is located in the abdomen (intra-abdominal malignancy)
- Inflammation of the pancreas (pancreatitis)
- Stones in the common bile duct (choledocholithiasis)
- Decreased blood supply to the small intestine (mesenteric ischemia)
- Blocking of the intestines (bowel obstruction)
- Rupture of an organ within the abdomen
- Inflammation of the thin layer of tissue that lines the inside of the abdomen (peritonitis)
If the patient has ascites (a buildup of fluid in the abdomen) or pleural effusions (extra fluid between the tissues that line the lungs and the chest), the doctor might consider these conditions:
- Kidney failure
- Liver disease (cirrhosis)
- Heart failure
- Various types of cancer (malignancy)
The key is for the doctor to think about all these possibilities to correctly identify the cause of the patient’s pancreatic fistula.
What to expect with Pancreatic Fistula
Pancreatic fistulas are a condition that can cause serious health problems if not properly treated. Essentially, they are abnormal passages or connections involving the pancreas. Less severe pancreatic fistulas usually improve with basic care and a conservative treatment approach, which is focused on improving the patient’s overall condition and stabilizing the fistula. In fact, it’s been reported that with this approach, about 80% of external and 50-65% of internal pancreatic fistulas usually heal in four to six weeks.
However, pancreatic fistulas that occur after surgery, like a distal pancreatectomy (surgery where part of the pancreas is removed), take a bit longer to get better – about 62 days with medical intervention. Surgical intervention has been successful in treating about 90-92% of pancreatic fistulas cases. But it’s worth noting that there’s a 6% to 9% mortality rate associated with it.
Possible Complications When Diagnosed with Pancreatic Fistula
Complications connected with pancreatic fistulas have a range which includes:
- Formation of necrosis, which is when tissue dies off within the pancreas
- Sepsis, a severe condition caused by the body’s response to an infection
- Pseudocyst formation, which are pockets of fluid that develop on or in the pancreas
- Pancreatic pleural effusion, a condition where fluid collects in the space covering the lungs (called the pleural space)
- Pancreatic ascites, referring to the accumulation of fluid in the abdominal cavity due to the pancreas
- Intra-abdominal hemorrhage, or internal bleeding in the abdomen area
- Increased duration of stay and cost associated with hospitalization
Preventing Pancreatic Fistula
Here’s what you need to remember:
- Stay in regular contact with a nutritionist or your usual doctor to manage or improve any nutrition problems.
- Keep up with caring for wounds and avoid causing any additional harm to the skin near any external fistulas. A fistula is an abnormal connection between two body parts, like an organ or blood vessel and the skin.
- Don’t miss any regular appointments with the specialist who is treating the pancreatic fistula. A pancreatic fistula is an abnormal connection that has developed from the pancreas to other parts of the body.
- Know how to identify the symptoms of pancreatic fistulas. These may include difficulty breathing, pain in the belly, a bloated belly, or a fever. If you notice any of these symptoms, you should seek medical help.
