Chronic pancreatitis is a long-standing inflammation of the pancreas that progressively destroys the organ. It can lead to permanent damage to the pancreas and other complications. The most common cause of chronic pancreatitis is excessive alcohol consumption over many years.
What is Chronic Pancreatitis?
The pancreas is an organ located behind the stomach that produces enzymes and hormones essential for digestion. Pancreatitis refers to inflammation of the pancreas. In acute pancreatitis, inflammation develops quickly and may resolve in a few days with treatment. In chronic pancreatitis, pancreatic inflammation is persistent and recurrent, leading to irreversible structural damage. Chronic pancreatitis typically follows recurrent episodes of acute inflammation. As injury to the pancreas accumulates over time, normal pancreatic tissue is replaced with fibrous scar tissue, causing permanent impairment of exocrine and endocrine functions.
The main features of chronic pancreatitis include:
- Persistent or recurrent upper abdominal pain
- Exocrine pancreatic insufficiency – impaired production of digestive enzymes leads to malnutrition
- Endocrine pancreatic insufficiency – impaired insulin production leads to diabetes
- Pancreatic calcifications or cysts on imaging studies
- Dilated pancreatic duct evident on imaging
As the condition advances, complications can include pancreatic cancer, pseudocysts, bile duct or duodenal obstruction, vascular complications, and malnutrition.
Alcohol Consumption as Leading Cause
The most common cause of chronic pancreatitis is alcohol abuse. Heavy alcohol consumption over many years is attributed to 60-80% of chronic pancreatitis cases in the Western world. Less than 5% of individuals who drink heavily develop pancreatitis, indicating that other risk factors like genetic mutations may play a role. However, the risk of chronic pancreatitis increases substantially with higher levels of alcohol intake and longer duration of alcohol abuse. The threshold of alcohol consumption that can lead to pancreatitis is about 60-80 grams per day over 5-10 years. This level of intake corresponds to about 4-5 standard drinks per day. The risk rises sharply at consumption levels exceeding 100 grams per day.
Proposed mechanisms by which chronic heavy alcohol consumption induces chronic pancreatitis include:
- Toxic effects of alcohol metabolites on pancreatic acinar cells
- Pancreatic duct obstruction due to protein plugs
- Increased viscosity of pancreatic secretions
- Direct toxic effects of alcohol on pancreatic stellate cells leading to fibrosis
- Ischemia from alcohol-induced spasm of the splenic artery
Abstinence from alcohol and treatment of any nutritional deficiencies are key components of management. However, pancreatic injury may continue to progress even when alcohol consumption ceases.
Less common causes of chronic pancreatitis include:
- Genetic mutations – Hereditary mutations in genes associated with pancreatic secretion or repair mechanisms, such as PRSS1, CFTR, SPINK1, CTRC
- Autoimmune disease – The immune system attacks the pancreas, as in primary biliary cirrhosis, primary sclerosing cholangitis, Sjogren’s syndrome
- Metabolic conditions – Hypercalcemia, hyperlipidemia
- Anatomic abnormalities – Pancreas divisum, pancreatic duct strictures or stones
- Medications – Azathioprine, estrogens, tetracycline, valproic acid
- Infections – Mumps, coxsackievirus, HIV, parasitic infections
- Trauma – Blunt abdominal trauma, endoscopic retrograde cholangiopancreatography (ERCP)
- Obstructive tumors – Pancreatic or ampullary cancers
- Cystic fibrosis – Pancreatic duct plugging and scarring
- Hypercalcemia – From conditions like hyperparathyroidism
- Tropical pancreatitis – Seen in tropical developing countries, proposed association with cassava diets
- Smoking – Controversial and weak association
Even with extensive evaluation, no clear etiology is identified in up to 30% of chronic pancreatitis cases. These are classified as idiopathic chronic pancreatitis.
Chronic pancreatitis is often diagnosed clinically based on characteristic patterns of abdominal pain, along with progressive impairment of exocrine and endocrine functions. Diagnosis is supported by imaging studies showing pancreactic calcifications, dilation of the main pancreatic duct, parenchymal atrophy, and pancreatic pseudocysts. Imaging modalities used include:
- Abdominal ultrasound
- Contrast-enhanced CT scan
- Endoscopic ultrasound (EUS)
MRI and EUS are considered the most sensitive ways to detect early and mild chronic pancreatitis. Typical EUS features include hyperechoic foci, hyperechoic strands, lobularity, decreased vascularity, and ductal calcifications. Endoscopic retrograde cholangiopancreatography (ERCP) also allows visualization of the pancreatic duct but is used less commonly now.
Blood tests may show elevated amylase and lipase during attacks of acute pancreatitis. As chronic pancreatitis progresses, exocrine insufficiency leads to low serum concentrations of pancreatic enzymes like trypsin, chymotrypsin, and fecal elastase. Impaired endocrine function manifests as high blood glucose and hemoglobin A1C levels.
Treatment goals focus on relief of pain, management of exocrine and endocrine insufficiency, and correction of any nutritional deficiencies. Strategies include:
- Pain management – Narcotics, celiac plexus block, endoscopic or surgical drainage for obstructive complications
- Pancreatic enzyme replacement – Pancrelipase tablets with meals
- Management of diabetes – Insulin, oral hypoglycemics, dietary modification
- Nutritional support – Low fat diet, daily fat soluble vitamin supplements
- Treatment of any identified causes – Alcohol and smoking cessation, parathyroidectomy for hyperparathyroidism, stenting or surgery for pancreatic duct strictures
Refractory chronic pain due to an obstructing pancreatic duct stricture or pseudocyst may require endoscopic stenting or pancreatic resection surgery in some cases.
In summary, chronic pancreatitis refers to persistent inflammatory injury causing permanent structural damage and impairment of pancreatic function. The leading cause is heavy alcohol consumption over many years. Other causes include genetic mutations, autoimmune conditions, anatomical abnormalities, and metabolic disorders. Though advanced imaging is helpful, diagnosis is often based clinically on recurrent episodes of abdominal pain and progressive exocrine/endocrine insufficiency. Treatment centers around pain control, pancreatic enzyme replacement, insulin for diabetes, correcting nutritional deficiencies, and addressing any underlying etiology. Abstinence from alcohol and smoking is imperative to prevent further damage in susceptible individuals.