ERCP IN CHRONIC PANCREATITIS

PANCREATITIS

          Inflammation of pancreas is known as pancreatitis, commonly due to alcohol, gall stone, congenital abnormality, hereditary disorders and metabolic disease. The gall stone induced pancreatitis will be acute pancreatitis or recurrent pancreatitis. Patient with pancreatic divisum (Accessary pancreatic duct will be functioning) usually present with recurrent abdominal pain suggestive of pancreatitis (Recurrent pancreatitis) and then proceed to chronic pancreatitis. Normal anatomy of pancreas is that there will be one functioning pancreatic duct known as main pancreatic duct which opens over major duodenal papilla and another nonfunctioning smaller pancreatic duct which opens over minor duodenal papilla. In pancreatic divisum the nonfunctioning smaller pancreatic duct will be functioning due to congenital anomaly. Pancreatic divisum is noticed about 5% of population.

          Pancreatitis due to alcohol and hereditary disorders present with acute pancreatitis and proceed to chronic pancreatitis.

          Once the diagnosis of acute biliary pancreatitis is made then the treatment is to treat the bile duct stone first through ERCP technique followed by laparoscopic cholecystectomy.In case of recurring pancreatitis due to pancreatic divisum, the treatment is to place a stent in the pancreatic duct across minor duodenal papilla. But rarely, in patients with pancreatic divisum due to chronic pancreatitis, there will be dilated pancreatic duct may necessitate  pancreatico-jejunostomy. The treatment of pancreatitis due to metabolic disease is to treat the acute episode of pancreatitis with correction of metabolic abnormality. Chronic pancreatitis due to chronic alcohol intake and hereditary disorders behave differently. In case of chronic alcohol intake, stoppage of alcohol intake is the priority. Even after stopping alcohol if the pain persists then the treatment depends on the radiological findings of pancreas. But hereditary pancreatitis is an ongoing process and can treat the symptoms with endoscopic or surgical methods.

          The diagnosis of acute pancreatitis is made by the estimation of serum amylase and lipase which will be elevated. But this may be normal in some cases of chronic pancreatitis. The treatment for acute pancreatitis is to treat the cause. But the treatment for chronic pancreatitis depends on the cause of pancreatitis and current situation of pancreas which is assessed by the size of the pancreatic duct. In patients with chronic pancreatitis with normal pancreatic duct, the main treatment is to give analgesics with pancreatic enzyme supplements. In case of dilated pancreatic duct with single stricture at the head of the pancreas is ERP (ERCP) and pancreatic stenting. But having dilated pancreatic duct with multiple strictures will be benefited by surgical procedures like pancreatico-jejunostomy. 

CAUSES OF ACUTE PANCREATITIS

1. 1. ALCOHOL
2. 2. GALL STONES
3. 3. PANCREATIC DIVISUM
4. 4. HYPERCALCEMIA
5. 5. DYSLIPEDIMIA-HYPERTRIGLYCERIDEMIA
6. 6. HERIDITARY (AUTO-IMMUNE PANCREATITIS)
7. 7. VIRUSES LIKE MUMPS, MEASLES ETC.
8. 8. DRUGS
9. 9. POST PROCEDURE LIKE ERCP.

CAUSES OF RECURRENT PANCREATITIS

1. 1. GALL STONES
2. 2. PANCREATIC DIVISUM

CAUSES OF CHRONIC PANCREATITIS

1. 1. CHRONIC ALOCOHOL
2. 2. HERIDITARY
3. 3. PANCREATIC DIVISUM

EVALUATION OF PANCREATITIS

          BLOOD INVESTIGATIONS

1. 1. SERUM AMYLASE
2. 2. SERUM LIPASE
3. 3. LIVER FUNCTION TEST
4. 4. SERUM CALCIUM
5. 5. SERUM TRIGLYCERIDE LEVELS
6. 6. BLOOD HAEMOGLOBIN LEVELS
7. 7. BLOOD TOTAL LEUCOCYTE COUNT
8. 8. SERUM PROCALCITONIN LEVEL
9. 9. SERUM C REACTIVE PROTEIN
10. 10. BLOOD SUGAR
11. 11. HbA1C
12. 12. SECRETIN TEST

RADIOLOGICAL INVESTIGATIONS

1. 1. ULTRASONOGRAPHY OF ABDOMEN
2. 2. COMPUTERISED TOMOGRAPHY WITH IV CONTRAST
3. 3. MAGNETIC RESONENCE CHOLANGIOPANCREATOGRAPHY

ENDOSCOPIC EVALUATION

1. 1. ENDOSCOPIC ULTRASOUND
2. 2. ENDOSCOPIC RETROGRADE CHOLANGIO PANCREATOGRAPHY

          The increased levels of serum amylase and serum lipase are the indicator of acute pancreatitis. Elevated liver enzymes with or without increased serum bilirubin levels indicates associated bile duct stones. Increased serum calcium level indicates that the hypercalcemia is the cause of pancreatitis. Decreased serum calcium level reflects the severity of the pancreatitis. Increased serum triglycerides level will be noticed in patients with acute pancreatitis due to hyper-triglyceridemia. High haemoglobin level will be noticed in patients with severe acute pancreatitis due to haemoconcentration. Increased leucocyte count is the indicator of pancreatitis with infection. The estimation of serum procalcitonin level and C reactive levels are the indicator of the magnitude of pancreatitis. Pancreatic function tests that measure pancreatic fluid volume, HCO₃^– and trypsin concentrations following secretin stimulation have been found to be sensitive and specific in diagnosing chronic pancreatitis but not done frequently.

          Ultrasonography of abdomen is the initial screening test for any acute abdominal pain due to gastrointestinal or non-gastrointestinal causes. In case of acute pancreatitis there may be oedematous pancreas with or without gall stone disease. The presence of severe pancreatitis leads to the gaseous distension of bowel and may obscure the pancreas. Presence of fluid collection around the pancreas is the indicator of pancreatitis.

          Computerised tomography is an important diagnostic test to confirm acute or chronic pancreatitis. When intravenous contrast is used, apart from confirmation of pancreatitis, also gives an idea about the severity of the pancreatitis.

          MRI of abdomen with MRCP is the investigation useful in the evaluation of bile duct in biliary pancreatitis, evaluation of pancreatic duct in chronic pancreatitis and assessing any fistulous communication with nearby organs.

          Endo-ultrasound will be a very important investigation in case of suspected bile duct stones, evaluation of pancreatic duct and also the evaluation of fluid collection like pseudocyst of pancreas. The undo-ultrasound also has a role in the endoscopic management of pseudocyst of pancreas.

          ERCP is a diagnostic as well therapeutic procedure in case of chronic pancreatitis. MRCP will make a diagnosis of chronic pancreatitis but involvement of side branches of pancreatic duct is better seen with ERCP. Normally, ERCP is not usually done for diagnostic purpose today. The role of ERCP in pancreatitis will be to retrieve stone from bile duct in case of acute biliary pancreatitis. ERCP with pancreatic stenting will drain the pancreatic duct in case of chronic pancreatitis. ERCP will also be useful in case of any pancreatic fistula in which placement of stent across the pancreatic duct enhance the healing of fistulas.

CHRONIC PANCREATITIS AND PANCREATIC STONES

          Chronic pancreatitis is an important cause for pancreatic stone formation. Stones may be in the main pancreatic duct, side branches of pancreatic duct and can be in the pancreatic parenchyma. Chronic pancreatitis due to chronic alcohol intake and hereditary pancreatitis are important reasons for pancreatic stone formation. When stones are present in the pancreatic duct then they are known as ductal stones and when it presents in the parenchyma it is known as parenchymal calcification.

COMPOSITION OF PANCREATIC DUCTAL STONES

          The maximum component of pancreatic ductal stone is calcium deposits. Other components are sulphur and chlorine.  

TREATMENT OF PANCREATITIS

          The treatment of pancreatitis depends on the severity of pancreatitis, cause of pancreatitis and duration of pancreatitis. In case of known causes of pancreatitis, the treatment is to stabilise the patient and then treat the cause to prevent the recurrence of pancreatitis. But in cases of chronic pancreatitis due to chronic alcoholism or hereditary chronic pancreatitis there will be constant pain with or without endocrine and exocrine insufficiency. So, the treatment will be directed towards the management of pain followed by management of endocrine and exocrine insufficiency. There can be complications of pancreatitis like pancreatic necrosis develops in acute phase of acute pancreatitis. The pseudocyst formation and pancreatic fistulas are late phase complications of acute pancreatitis or can develop in cases of chronic pancreatitis also.

          Endocrine insufficiency is usually managed with insulin. Exocrine insufficiency is managed with pancreatic enzyme supplements. But the management of pain will be difficult. In case of persistent pain after routine medications, the other options will be to do some interventions in the form of endoscopic management, surgical management radiological intervention like celiac plexus block.

          The decision to do endoscopic or surgical management in case of chronic pancreatitis depends on the nature of pancreatic duct. The nature of pancreatic duct is evaluated by MRCP. In case of dilated pancreatic duct with single stricture at the head of pancreas region are benefited by endoscopic management with ENDOSCOPIC RETROGRADE PANCREATOGRAPHY (ERP) AND PANCREATIC STENTING. But in case of dilated pancreatic duct with multiple strictures are benefited by surgery. The principle behind the surgery is to decompress the pancreatic ductal system and drain the pancreatic duct permanently with small intestine. The commonly done drainage procedure is lateral pancreatico-jejunostomy. In case of persisting pain due to chronic pancreatitis without ductal dilatation and if not able to manage with routine medications, then the option will be celiac plexus block by pain management physician.

DRAINAGE PROCEDURES IN CHRONIC PANCREATITIS

          There are various drainage procedures in chronic pancreatitis. The aim of the drainage procedure is to decompress the pancreatic duct. This can be done through endoscopic technique or through surgical procedures. The endoscopic procedure is Endoscopic Retrograde Pancreatography (ERP) and stone extraction.

          But in cases of ongoing pancreatitis due to alcohol induced pancreatitis or hereditary pancreatitis, the preferred technique will be to decompress the pancreatic duct and drain the pancreatic juice permanently in to the small intestine or stomach. The commonly done surgical procedures are:

1. 1. Longitudinal pancreaticojejunostomy (Puestow Procedure)
2. 2. Frey’s procedure
3. 3. Cystogastrostomy
4. 4. Cystojejunotomy
5. 5. External drainage.

1.LONGITIDUNAL PANCREATIOCO JEJUNOSTOMY

          This is done in case of chronic pancreatitis with dilated pancreatic duct due to any cause. The common causes are hereditary pancreatitis (Tropical pancreatitis), chronic pancreatitis due to pancreatic divisum and ethanol induced pancreatitis. The main indication is persistent pain abdomen due to chronic pancreatitis. The important criteria are that there should be pancreatic ductal dilatation. There can be multiple pancreatic ductal strictures or multiple pancreatic ductal calculi. The presence of pancreatic calcification alone is not a criterion to perform drainage procedures.

          In case of pancreatico-jejunostomy, under general anaesthesia with regional analgesia, abdomen is opened through bilateral subcostal incision. Pancreas will be exposed after opening the gastrocolic ligament with harmonic scalpel. Sometime, grossly dilated pancreatic duct can be felt with palpation of the surface of the pancreas. The dilated pancreatic duct is confirmed with needle aspiration of suspected dilated pancreatic duct. The presence of whitish fluid in the syringe confirms the pancreatic duct. In case of any doubt, intra-operative ultrasonography can be used to identify the pancreatic duct. Once duct is confirmed, then the duct will be opened on its longitudinal axis up to the head and tail of pancreas. Then all the contents from the pancreatic duct including all the stones will be removed.

          After removing stones from the pancreatic duct, an isolated loop of jejunum with a length of about 45 cm will be prepared to perform pancreatico-jejunostomy. To prepare this loop, jejunum will be divided about 15 cm from duodeno-jejunal junction with staplers (TLC 55). After getting a free loop of about 45 cm, jejuno-jejunal anastomosis will be done. Then, pancreatic duct will be anastomosed with jejunum in a side-to-side manner with absorbable sutures. The length of the anastomosis depends on the length of the dilated pancreatic duct. This procedure decompresses the pancreatic duct and also drain the pancreas permanently. The advantage of this procedure is that, it is one time procedure with pain relief of about 70 to 80% of the individuals.

2.FREY’S PROCEDURE

          This is a modified form of lateral pancreatico-jejunostomy. Local Resection of the pancreatic head with Lateral Pancreatico Jejunostomy is the procedure (LPJ). This procedure is designed to leave the duodenum and common bile duct intact, remove the diseased tissues within the head of the pancreas, and decompress the entire pancreatic ductal system. In this procedure initial steps are same. After opening the pancreatic duct, the diseased tissues present over the head of the pancreas will be removed and then the lateral pancreaticojejunostomy will be done. The advantage is that expected pain relief is better than routine lateral pancreaticojejunostomy.

3.CYSTOGASTROSTOMY

          This is done in case of acute or chronic pancreatitis with pseudocyst of pancreas. Pseudocyst of pancreas is formed within the pancreas or nearby pancreas. Pseudocyst of pancreas is confirmed with computerised tomography of abdomen with intravenous contrast. In case of symptomatic and large pseudocyst of pancreas needs drainage procedures. The commonly done procedures are laparoscopic or open cysto-gastrostomy, endoscopic cysto-gastrostomy, open cysto-jejunostomy and endoscopic cysto-gastrostomy.

          In laparoscopic cysto-gastrostomy, the procedure is done under general anaesthesia. Usually, five ports are used on either side of the upper abdomen. After entry, cyst position is confirmed and other trocars are placed as per need. Anterior wall of stomach is opened in between stay sutures. Then the cyst position is confirmed with needle aspiration of the cyst. Once cyst is confirmed then posterior wall of stomach is opened with diathermy or harmonic scalpel. Then the cyst contents will be sucked out. The necrotic materials if present will also be removed (Necrosectomy). Thorough wash will be given. Laparoscopic examination of cyst will be done which will give better idea about the completeness of removal of pancreatic necrosis. After this, posterior wall of stomach and cyst wall will be sutured with absorbable sutures (Cysto-gastrostomy). Finally, anterior wall of stomach will be sutured. Usually, a drainage tube will be placed and ports will be closed.

          This is a technically demanding procedure. Open cystogastrostomy will be done in case of inadequate facilities or the cyst is in the difficult or inaccessible areas. Any comorbid conditions like severe lung disease are also an indication for open cystogastrostomy. Except for opening the abdomen, other steps are same.

4.OPEN CYSTOJEJUNOSTOMY

          Open cysto-jejunostomy is an alternate procedure to drain the pseudocyst of pancreas. The main indication is the presence of cyst in the abnormal position or away from the pancreas. Abdomen will be opened through midline laparotomy. Cyst will be assessed. Cyst will be drained depending on the site of the cyst. Then an isolated loop of jejunum will be harvested and cysto-jejunostomy will be done. (Roux-en-Y Cysto-jejunostomy)

 5.EXTERNAL DRAINAGE OF CYST OF PANCREAS

          External drainage is done in case of infected cyst where the internal drainage is technically not possible. This can be done through a CT or Ultrasound guidance, laparoscopic technique and rarely through open technique. The advantage is to tide over the situation of ongoing infection. But there is a possibility of recurrence of the same cyst and may require permanent surgical procedure later. 

ENDOSCOPIC PROCEDURES IN CHRONIC PANCREATITIS

          The commonly done endoscopic procedures in chronic pancreatitis are endoscopic cysto-gastrostomy and Endoscopic Retrograde Cholangio Pancreatography (ERCP). Endoscopic cysto-gastrostomy is done in case of pseudocyst present behind the stomach. The procedure is done with the help of endoscopic ultrasonography. Usually, a communication will be made between stomach and cyst and a stent will be place across the communication.

ERCP IN CHRONIC PANCREATITIS (EIGHTEEN)

          ERCP is indicated in chronic pancreatitis for two reasons. First is to treat the biliary stricture due to chronic pancreatitis. Here, usually a biliary stent will be placed across the ampulla into the bile duct. The presence of pancreatitis can lead to narrowing of lower bile duct which ends up with jaundice. MRCP is the investigation of choice to confirm the biliary stricture. ERCP along with biliary sphincterotomy and placement of biliary stent commonly solve the problem.

          The second reason to perform ERP (ERCP) in chronic pancreatitis is to drain the pancreatic duct in case of stricture of pancreatic duct at the head of pancreas associated pancreatic ductal dilatation. In case of chronic pancreatitis, there can be normal pancreatic duct, dilated pancreatic duct with single stricture at the head of the pancreas, dilated pancreatic duct with multiple strictures and with single or multiple stones in the dilated pancreatic duct. Endoscopic management will be more useful in case of dilated pancreatic duct with single stricture in the region of head of pancreas.  

          ERP (ERCP) will be done under total intravenous anaesthesia using a side viewing endoscope (Duodenoscope). Pancreatic duct will be cannulated selectively and pancreatic sphincterotomy will be done. Small stones present in the pancreatic duct can be removed by flushing the pancreatic duct with distilled water. Bigger stones can be retrieved by balloon sweeping. But in case of big stones that can be extracted with combination of ESWL (Extracorporeal Shock Wave Lithotripsy) therapy just before or after the ERP and pancreatic stenting. ESWL makes the big stones into a smaller piece. This will help to retrieve the pancreatic ductal stones better way. After endoscopic retrograde pancreatic sphincterotomy and stone extraction, single pigtail pancreatic stent will be placed across the pancreatic duct. The pancreatic stent has multiple side holes to drain the pancreatic juice coming from the pancreatic ductal side branches. 

          The presence of multiple strictures in the pancreatic duct is less effectively drained by endoscopic technique. The presence of chain of lakes appearance (Multiple strictures of pancreatic duct) of pancreatic duct is an indication to perform lateral pancreatico-jejunostomy.