Pancreatitis (Acute, Chronic) Causes and Symptoms
What is Pancreatitis?
Pancreatitis is the medical term for inflammation of the pancreas. It is one of the more common pancreas problems often associated with gallstones and alcohol misuse. The pancreas is an elongated gland lies in the upper abdomen and influences digestion, absorption, metabolism and storage of nutrients. It has both endocrine and exocrine functions which are discussed in detail under pancreas function.
Most of the pancreatic tissue is dedicated to its exocrine functions, which include the production and secretion of the pancreatic enzymes. These digestive enzymes are released in an inactive form and only activated once in the lumen of the duodenum where it acts on food.
Pancreatitis occurs when the outflow or dormant state of these digestive enzymes are hampered by any one of the causative factors. Activation of the enzymes while in the gland causes injury as the enzymes begin to digest pancreatic tissue. Therefore pancreatitis initially affects the exocrine parenchyma (pancreatic tissue) but as it progresses, it affects the endocrine parenchyma as well.
In acute pancreatitis the damage to the pancreatic tissue is usually reversible. Severe cases also affects surrounding tissues because the pancreas has a poorly developed capsule and therefore the activated pancreatic enzymes may cause inflammation of the duodenum, bile duct and sometimes even the transverse colon and splenic vein.
Acute interstitial pancreatitis is the milder form of pancreatitis and is marked by mild inflammation of the pancreatic parenchyma and fat necrosis.
Severe forms like acute necrotizing pancreatitis results in death of the parenchymal tissue (necrosis), particularly the acini and ductules, due to proteolytic digestion. There may also be mild hemorrhage into the pancreatic tissue due to injury of the blood vessels supplying the gland.
In the most severe form of acute pancreatitis known as hemorrhagic pancreatitis, there is widespread damage of the pancreatic tissue and extensive hemorrhaging into the gland.
In chronic pancreatitis, the damage to the pancreatic tissue is extensive usually affecting both the exocrine and endocrine parenchyma. Fibrosis of the pancreatic tissue is present due to the prolonged inflammation. The damage associated with chronic pancreatitis is usually irreversible.
Usually chronic pancreatitis is a consequence of repeated bouts of acute pancreatitis, although it may arise without a history of acute pancreatitis. Typical histological findings include extensive fibrotic scarring of the parenchyma, especially the exocrine parenchyma, with enlargement of the pancreatic duct and a atrophy of the acini. The islets of Langerhans which are responsible for the exocrine functions of the pancreas may be affected to varying degrees but in chronic pancreatitis, it is usually not unaffected. Hardening of the gland with focal areas of calcification may also be evident in chronic pancreatitis.
Hereditary pancreatitis is a type of recurrent pancreatic inflammation caused by genetic factors. In this case, mutations of the PRSS1 or SPINK1 genes affects the mechanisms that inhibit trypsinogen activation within the pancreas. Most cases of hereditary pancreatitis are characterized by repeated attacks of acute pancreatitis but a significant number of cases will progress to chronic pancreatitis.
Autoimmune pancreatitis (lymphoplasmacytic sclerosing pancreatitis) is a result of a high concentrations of immune cells (IgG4-producing plasma cells) within the pancreatic parenchyma. These cells are responsible for ongoing inflammation in the pancreas.
Signs and Symptoms of Pancreatitis
Acute Pancreatitis Symptoms
Constant upper abdominal pain is the most common symptom of acute pancreatitis. It may vary in intensity from mild to severe and radiates to the upper back and/or left shoulder. In severe cases the intensity of the pain causes a person to curl up and usually a patient will report some mild relief when leaning or stooping forward. The pain is worse upon standing up straight or lying flat.
Nausea and/or vomiting is usually present and the severity may be associated with the intensity of the pain. Most patients will report a lack of appetite and pain that exacerbates during and immediately after eating.
Abdominal examination will reveal diminished or absent bowel sounds and epigastric tenderness. In severe acute pancreatitis like hemorrhagic pancreatitis there may be discoloration of the skin noted on the flanks (Grey Turner’s sign) and around the umbilicus (Cullen’s sign).
Since gallstones are a common cause of pancreatitis, it is important to be familiar with the symptoms of gallstones. These features may be present simultaneously and contribute to the overall clinical presentation.
Other symptoms associated with acute pancreatitis includes :
- Jaundice (yellow skin and ‘whites’ of the eyes)
- Rapid heart rate (tachycardia)
Acute Pancreatitis Causes
Gallstones and alcohol misuse are two common causes of acute pancreatitis. The latter, alcohol misuse, is the reason that many acute pancreatitis cases are seen in the emergency room during the festive season where alcohol consumption is often excessive. It is also the reason for the prevalence of acute pancreatitis among alcoholics, which often progresses to chronic pancreatitis.
Another common cause seen these days is following an ERCP (endoscopic retrograde cholangiopancreatography), which is a widely used diagnostic procedure to investigate for gallbladder and bile duct diseases. Despite these known causative factors, many cases of acute pancreatitis arise for unknown reasons (idiopathic).
Other causes of acute pancreatitis includes :
- Post-operative injury
- Drugs like azathioprine, thiazide diuretics, sodium valproate
- Hereditary factors (mutations in PRSS1 and SPINK1 genes)
- Kidney failure
Chronic Pancreatitis Symptoms
Apart from these acute exacerbations marked by intense abdominal pain, patients with chronic pancreatitis may report persistent mild abdominal and back pain that gradually progresses in intensity over time. It is not uncommon, however, for chronic pancreatitis patients to report no pain.
Other signs and symptoms of chronic pancreatitis may include :
- Unintentional weight loss
- Steatorrhea (fatty stools)
- Signs of nutrient deficiencies due to malabsorption
- Symptoms of acute pancreatitis (discussed above)
Chronic Pancreatitis Causes
Chronic pancreatitis is characterized by repeated episodes of acute pancreatitis in most cases. Alcohol abuse is one of the common causes and eventually the damage to the pancreas is irreversible. Chronic pancreatitis is also associated with :
- Cigarette smoking
- Advancing age
- Hereditary factors (hereditary pancreatitis although not all cases will progress to chronic pancreatitis)
- Autoimmune causes (autoimmune pancreatitis or autoimmune diseases affecting multiple organs)
- Cystic fibrosis
- Congenital abnormalities discussed under pancreas problems
- Tropical pancreatitis (south Asia and west Africa)
- Persistent complications of acute pancreatitis like pseudocysts