Pancreatic fistula

Introduction to pancreatic fistula Pancreatic fistula is one of the serious complications of acute, chronic pancreatitis, abdominal surgery, especially pancreatic surgery and trauma. Yeo and Cameron in Kline surgery are defined as: pancreatic duct rupture for various reasons, pancreatic juice is leaked from the pancreatic duct for more than 7 days. Pancreatic fistula is divided into pancreatic fistula and pancreatic fistula. Pancreatic juice through the abdominal drainage tube or incision outflow surface of the pancreatic fistula; pancreatic fistula including pancreatic pseudocyst, pancreatic pleural effusion and pancreatic duct and other organs between the fistula, such as pancreatic fistula. If the pancreatic juice flows into the abdominal cavity but is wrapped by the surrounding organ tissue, the pancreatic fistula is formed. It is customary to call the pancreatic fistula a pancreatic pseudocyst, but the essence is still pancreatic fistula. basic knowledge The proportion of the disease: the disease is rare, the incidence rate is about 0.0005%-0.0008% Susceptible people: no special people Mode of infection: non-infectious Complications: multiple organ dysfunction syndrome

Pancreatic causes

(1) Causes of the disease

Pancreas surgery

(1) Pancreatic trauma: the incidence of pancreatic fistula after pancreatic trauma is as high as 40%. Because of the normal pancreatic tissue during trauma, the texture is soft, so it is not satisfactory when embedding or anastomosis, prone to pancreatic fistula; Edema or stenosis in the ampulla of the ampulla causes the pancreatic juice to flow out and is more prone to pancreatic fistula.

(2) pancreatic cyst drainage: external drainage can cause pancreatic fistula, which has been replaced by internal drainage, which greatly reduces the incidence of pancreatic fistula. Internal drainage and pancreatic fistula are mainly related to the surgeon's surgical skills. It is related to the timing of the operation.

(3) pancreatectomy: including pancreaticoduodenectomy, pancreatic tumor resection, pancreatic body and tail resection, pancreatic body or head resection, which is an important cause of pancreatic fistula, the risk of pancreatic fistula The factors are:

1 age > 65 years old.

2 pancreatic duct inner diameter is small.

3 failed to insert the pancreatic duct stent.

4 The pancreas is soft or normal.

5 excessive blood loss during surgery.

6 preoperative jaundice.

7 operation time is too long.

In addition, the skill level of the surgeon also directly affects the incidence of pancreatic fistula after pancreatectomy. In addition, different treatment methods of pancreatic stump, preoperative chemotherapy, and application of somatostatin can affect the occurrence of pancreatic fistula.

2. Non-pancreatic surgery The pancreatic fistula caused by non-pancreatic surgery is actually a lesion that invades the pancreas or accidentally injures the pancreas. The most common is splenectomy and pancreatic fistula, partial gastrectomy and radical gastrectomy. Pancreatic fistula caused by accidental injury or pathological invasion of the pancreas.

3. Severe acute pancreatitis (SAP) Artz et al reported that 20% of survivors of SAP drainage have pancreatic fistula, and pancreatic tissue necrosis can occur at the beginning of SAP. The range of the pancreatic duct is eroded and the pancreatic juice leaks out for a long time. Drainage into the body, that is, the formation of pancreatic fistula; if accumulated in the pancreas, can form a pancreatic pseudocyst or abscess, pancreatic abscess can also erode the pancreatic duct, causing the pancreatic duct to rupture, leading to pancreatic fistula.

4. Secondary rupture of the pancreatic duct The injury of the pancreatic duct is the root cause of pancreatic fistula formation. The secondary rupture of the pancreatic duct is a more important factor in the occult disease. The secondary rupture of the pancreatic duct can be caused by progressive necrosis of the pancreas. It can also be caused by pancreatic infection and abscess. The two often cause each other. Pancreatic surgery, inflammation and trauma can cause continuous necrosis of the pancreas and formation of pancreatic abscess. Long-term erosion of the pancreatic duct can lead to pancreatic fistula. In addition, pancreatic fistula Infection affects the repair of damaged pancreatic ducts and is one of the causes of pancreatic fistula formation.

Pancreatic fistula can be divided into internal hemorrhoids and external hemorrhoids. In addition, according to the leakage of pancreatic juice, Sitges-Serra divides the pancreatic fistula into high-flow sputum (>200ml/d) and low-flow sputum (<200ml/d). In addition, the pancreatic fistula is divided into the lateral iliac crest and the lateral paralysis. The lateral paralysis refers to the continuity of the pancreatic duct and the gastrointestinal tract, also known as partial sputum; the sacral sac refers to the disappearance of the continuity of the pancreatic duct and the gastrointestinal tract. It is also known as complete paralysis. The self-healing rate of the contralateral lateral paralysis without infection is 86%, and the self-healing rate of the infected lateral paralysis can only reach 53% after 22 weeks of treatment. The more, the need for surgery, such as internal drainage of the pancreatic fistula or partial resection of the pancreas.

(two) pathogenesis

The pathological basis of pancreatic fistula formation is the rupture or rupture of the main pancreatic duct or the branch pancreatic duct. The partial pancreatic duct of the main pancreatic duct or branch pancreatic duct is called partial pancreatic fistula, and the amount of pancreatic juice is lost, and it can naturally heal; the main pancreatic duct Or the complete branch of the pancreatic duct is called complete pancreatic fistula. It loses the pancreatic juice and it is difficult to heal naturally. According to the flow rate of the pancreatic juice, the pancreatic fistula can be divided into high-flow pancreatic fistula (>200ml/d) and low-flow pancreatic fistula ( <200ml/d), according to the daily pancreatic juice flow rate, it is divided into large pancreatic fistula (>1000ml / d), medium pancreatic fistula (100 ~ 1000ml / d) and small pancreatic fistula (<100ml / d).

The pathophysiological changes brought by pancreatic fistula are mainly exocrine abnormalities. The composition of pancreatic juice is similar to that of tissue fluid. The concentrations of Na, K and Ca2 are basically the same as those of serum. Cl- is lower than serum value, and the concentration of HCO3- in pancreatic juice is higher, pH 8.0. ~ 8.6, alkaline, normal pancreas daily secretion of 800 ~ 1500ml, pancreatic fistula can lead to 1800ml pancreatic juice up to one day, due to pancreatic fistula caused by a large loss of pancreatic juice, can cause different degrees of water and electrolyte disorders and acid-base metabolic imbalance Severe cases can even cause hypoproteinemia. The skin around the pancreatic fistula may be congested, erosive, ulcerated or even bleeding. It may also form a pseudo-pancreatic cyst due to poor drainage, or a combined infection, which may result from secondary infection. Suppurative peritonitis and severe systemic infection and localized abscess formation. The pancreatic juice contains a large amount of digestive enzymes. When activated, it can corrode the tissues and organs of the pancreas, causing ulceration, necrosis, and even erosion of blood vessels to cause massive bleeding in the abdominal cavity; corrosive stomach, twelve The intestine or colon causes perforation of the digestive tract; the leaked pancreatic juice can also be wrapped by the surrounding fibrous tissue to form a pseudocyst; for example, pancreatic juice to the retroperitoneum Extension, digestive retroperitoneal adipose tissue causes extensive retroperitoneal infection, and upward development leads to pleural infection or mediastinal infection, causing toxemia, sepsis, multiple organ failure, and the consequences are extremely serious.

Pancreatic fistula prevention

Eliminate the cause of pancreatic fistula (such as trauma, mechanical reasons such as surgery, or acute pancreatitis caused by pancreatic duct rupture, etc.), to avoid pancreatic fistula.

The key to prevent the occurrence of pancreatic fistula is the good technique and method of pancreaticojejunostomy during operation. The correct treatment after operation is an important guarantee for reducing pancreatic fistula. Firstly, the improvement of pancreaticojejunostomy should be strengthened. Secondly, the treatment of pancreatic duct should be emphasized. Third, postoperative drainage must be kept open and effective; fourth, improve the patient's general condition and promote the healing of the anastomosis.

Pancreatic fistula is the most common complication after pancreaticoduodenectomy. The treatment of pancreatic stump is the key to prevent pancreatic fistula after pancreaticoduodenectomy. The pancreatic stump should be cut into a fish mouth, and Stitching the residual margin, the pancreatic stump should avoid the tear damage of the pancreas when it is anastomosed with the jejunum. At the same time, the pancreatic duct should be kept unobstructed. The support tube is placed in the pancreatic duct to effectively introduce the pancreatic juice into the intestine or lead out of the body to reduce the pancreatic juice. Stimulation of the mouth, while avoiding accidental injury to the pancreatic duct during surgery, it is necessary to ensure that the intestine segment is of sufficient length, blood supply is good, and the pancreatic jejunum does not match any kind of anastomosis. It is necessary to ensure that the anastomosis is tight and reliable, no tension, and the intestinal tract should be ensured after the anastomosis is completed. There is no obstruction factor, and the placement of the pancreatic duct support tube should be noted: select the support tube that fits the diameter of the pancreatic duct to avoid over- or over-fine; avoid distortion and blockage, and prevent pancreatic juice from penetrating to the anastomosis outside the tube wall without Conducive to anastomotic healing; support tube outside the pancreas must have a certain length, there should be no side holes in the wall; pancreatic duct support tube is properly fixed to avoid early tube removal, support tube drainage after surgery 3 Removed after ~4 weeks.

The way of pancreaticojejunostomy is also very important for the occurrence of pancreatic fistula. Theoretically, mucosal end-to-mud anastomosis can better drain pancreatic juice into the intestine, reducing the stimulation of pancreatic juice to the anastomosis, but because the end-to-side anastomosis and the in-line anastomosis are Under different conditions, it is not clinically possible to explain which method is more conducive to the prevention of pancreatic fistula. In general, when the pancreatic duct diameter is larger than 0.5cm, the end-to-side anastomosis is better, while the diameter is less than 0.5 cm. The end-to-side anastomosis should be forcibly performed, and the in-line anastomosis is better in the case of the support tube embedded in the pancreatic duct.

During distal pancreatectomy, fibrin glue can be used to seal the pancreatic stump to prevent postoperative pancreatic fistula formation. After transection of the pancreas, the main pancreatic duct is ligated with an atraumatic line, and the pancreatic stump is sutured continuously and finally at the suture. Apply 2ml of fibrin glue, also use alcohol-soluble glutenin gel to segment the pancreatic duct to prevent the formation of pancreatic fistula after distal pancreatectomy. The pancreas is bluntly transected, the cut surface is concave fish mouth, and the main pancreatic duct remains. The cut surface was 5mm, and the pancreas was clamped with non-invasive forceps at the proximal end of the margin. The main pancreatic duct was filled with 0.2 ml of procoagulant gluten, and then ligated and sutured. After the gel was hardened, the pancreas was sutured. Both were good and no toxicity was observed.

Pancreatic fistula complications Complications, multiple organ dysfunction syndrome

Abnormal drainage of pancreatic juice can cause necrosis of surrounding tissues and facilitate secondary infection. The process of pancreatic enzyme activation is accelerated after infection, which enhances the digestion and corrosion of pancreatic juice. Corrosion of the gastrointestinal tract can cause bleeding in the stomach, small intestine, colon, etc. And internal hemorrhoids, such as erosive blood vessels can cause fatal bleeding, patients with low body weakness and low resistance can be followed by multiple abscesses that are difficult to control in the abdominal cavity and retroperitoneum, and soon there are multiple organ dysfunction and even death.

Pancreatic fistula symptoms common symptoms irritability metabolic acidosis abdominal pain peritonitis shortness of breath cyst hypocalcemia abscess

According to the daily drainage of pancreatic juice, pancreatic fistula can be divided into high-flow and low-flow pancreatic fistula, which can also be divided into mild pancreatic fistula (<100ml/d), moderate pancreatic fistula (100-500ml/d), severe pancreatic fistula. (>500ml / d), mild pancreatic fistula can be expressed only as an increase in drainage fluid amylase, and no other symptoms, severe pancreatic fistula often manifests as obvious abdominal tenderness, tachycardia, shortness of breath, or mild patient Irritable and uneasy, there is peritonitis in the infection, and the amylase in the drainage fluid is often significantly increased, but this is not an indispensable feature. Losing a lot of pancreatic juice containing water, electrolytes and protein, the supplement is not timely, can cause dehydration and electrolyte balance disorder. As well as nutrient digestion and malabsorption, manifested as weight loss and malnutrition, loss of excessive alkaline pancreatic juice can cause metabolic acidosis, skin edema around the mouthwash, ulceration and even bleeding, but also due to poor drainage caused by fistula The skin heals before the pancreas and forms a pseudo-pancreatic cyst.

Pancreatic fistula

After the pancreas and the duodenum or the high jejunum form internal hemorrhoids, the leaked pancreatic juice directly enters the intestine, which can alleviate the symptoms and signs brought by the original pseudo-pancreatic cyst or infected peripancreatic abscess, and even heal itself. That is, there is no obvious clinical manifestation, no complications such as hemorrhage and infection after the formation of internal hemorrhoids, and the patient has no special performance. When the colonic fistula is formed, the pancreatic juice is lost, which may cause different degrees of low sodium, low potassium and low calcium. Symptoms, as well as indigestion, metabolic acidosis, malnutrition, etc.

2. Pancreatic fistula

Most of them occur after surgery. It is generally believed that 1 to 2 weeks after surgery is a good period of pancreatic fistula. Low flow of pancreatic fistula or small pancreatic fistula can cause skin changes around the external fistula. Generally, there is no other clinical manifestation. High-flow pancreatic fistula or medium-sized pancreatic fistula may have clinical manifestations similar to those in the colonic sputum. There is no communication with the digestive tract. The leakage of pure pancreatic external hemorrhoids is a clear, colorless and transparent liquid with a pancreatic amylase content of >20,000. U/L (Soxhlet unit, the same below); when mixed with lymphatic leakage, the amylase content is 1000-5000U/L; the leakage liquid is turbid, with bile color, green or dark brown, indicating that pancreatic juice has been mixed with intestinal juice The pancreatic enzyme is activated, its corrosiveness may cause tissue destruction, complications such as major bleeding, if there is blood, infection or intestinal fistula, there is a corresponding clinical manifestation. When the pancreatic fistula is not well drained, the patient may have abdominal pain and fever. , muscle tension, leukocytosis and other symptoms.

Pancreatic examination

1. More than 7 days after surgery, the drainage fluid contains pancreatic juice, amylase content>1000U/L, after pancreaticoduodenectomy, the amylase of drainage fluid is increased, even more than 3 times higher than normal serum amylase, for diagnosis Pancreatic fistula is a very valuable criterion.

2. Puncture and drainage of ascites, its amylase content> 5000U / L, and even > 10,000 U / L.

3.CT: First of all, it should be judged by CT examination whether it is pancreatic fistula or pancreatic pseudocyst. Observe the presence of abscess formation and necrotic tissue around the pancreatic fistula. It is generally known whether the wall of the pseudocyst is thickened. CT is very good at judging the timing of surgery. Important, and can reveal rare pancreatic fistula, external hemorrhoids, such as pancreatic bronchospasm and pancreatic pleural fistula, can also further understand the pancreatic lesions and pancreatic ducts through the thin-slice CT scan of the pancreas and contrast enhancement.

4.ERCP: For the external pancreatic fistula, it is necessary to understand the relationship between the fistula and the pancreatic duct and the surrounding organs. Whether the fistula is bifurcated, whether the pancreatic fistula drainage is smooth and distinguishes between the iliac crest and the lateral iliac crest, it is feasible to observe the angiography, for the fistula Patients with unsatisfactory angiography and pancreatic pseudocysts require ERCP.

At the same time of ERCP examination, the proximal pancreatic duct is narrow and can be treated with internal stent. This method can promote the self-healing of pancreatic fistula. When performing ERCP or fistula angiography, care should be taken to avoid pancreatitis. It is reported that prostaglandin and its analogs are used to prevent and treat pancreatitis before and after the examination.

Diagnosis and differentiation of pancreatic fistula

Abdominal trauma, history of pancreatic or pancreatic organ surgery or acute hemorrhagic necrotizing pancreatitis, amylase in the peritoneal drainage fluid is significantly increased, and the drainage volume exceeds 50ml per day, can be diagnosed as pancreatic fistula, Sano et al believe that postoperative Close monitoring of changes in the amylase content of the ascites can promptly determine the occurrence of pancreatic fistula and its return trend.

Common diagnostic methods for pancreatic fistula include CT, endoscopic retrograde cholangiopancreatography (ERCP) and fistula angiography.

Pancreatic ascites and pancreatic pleural effusion should be differentiated from cirrhosis ascites or reactive pleural effusion, liver function abnormalities in patients with cirrhosis, obvious cirrhosis in imaging examination, splenomegaly and hypersplenism, portal system dilatation, In particular, esophageal varices, ascites amylase is not high, reactive pleural effusion is less, puncture and pleural effusion is better, tuberculous pleural effusion and reactive pleural effusion amylase are not high, cancer Cancer cells can be found in the chest and ascites.

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