Acute pancreatitis is a sudden inflammation of the pancreas, a large gland that sits behind the stomach. It is a serious medical condition that requires prompt treatment. The main cause of acute pancreatitis is gallstones blocking the pancreatic duct. Alcohol abuse is another major cause. Less common causes include high blood calcium levels, high triglyceride levels, infections, trauma, certain medications, and genetics.
What is the pancreas?
The pancreas is an oblong organ located behind the stomach in the upper abdomen. It is about 6 inches long and sits across the back of the abdomen, behind the stomach. The pancreas has two main functional components:
- Exocrine glands – These produce enzymes that travel to the small intestine to help digest fats, proteins, and carbohydrates from food.
- Endocrine glands – These produce important hormones including insulin and glucagon to regulate blood sugar levels.
So the pancreas has a dual role in digestion and regulation of blood sugar.
What is acute pancreatitis?
Acute pancreatitis is sudden inflammation of the pancreas gland that comes on quickly and lasts for a short period of time. It causes abdominal pain that can sometimes be severe along with nausea, vomiting, fever, and an elevated heart rate. The inflammation causes digestive enzymes produced by the pancreas to become activated inside the pancreas, damaging pancreas tissue. This can lead to bleeding, tissue death, infection, cysts, and sometimes organ failure.
Mild cases of acute pancreatitis often resolve in a few days with treatment. Severe cases can cause serious complications and can be life-threatening. Acute pancreatitis requires hospitalization for treatment with IV fluids, pain control, and monitoring for complications.
What causes acute pancreatitis?
Gallstones
The most common cause of acute pancreatitis is gallstones. Gallstones are hard deposits that form in the gallbladder, a small organ that sits under the liver on the right side of the abdomen. Gallstones form when bile contains too much cholesterol or bilirubin.
Gallstones can block the pancreatic duct as it runs through the head of the pancreas. This blocks secreted digestive enzymes from draining out of the pancreas through the duct into the small intestine. The enzymes back up inside the pancreas, causing inflammation and damage.
Gallstones cause 35-40% of cases of acute pancreatitis. Risk factors for developing gallstones include being female, overweight, pregnancy, family history, and age over 40.
Alcohol Abuse
Heavy alcohol use is the second most common cause of acute pancreatitis, accounting for 30% of cases. Regularly drinking excessive amounts of alcohol can directly injure pancreas cells and cause inflammation. Alcohol also increases the likelihood that digestive enzymes will become activated inside the pancreas and cause self-digestion damage.
Binge drinking and chronic heavy alcohol use over many years are risk factors for alcoholic pancreatitis. Men are more frequently affected than women.
High Calcium Blood Levels
Hypercalcemia, or high calcium levels in the blood, is responsible for 7% of cases of acute pancreatitis. High blood calcium can activate digestive enzymes inside the pancreas. Causes of hypercalcemia include:
- Primary hyperparathyroidism – overactive parathyroid glands
- Cancer – especially of blood cells, breast, lung, kidney or ovary
- Granulomatous diseases like sarcoidosis
- Vitamin D toxicity
- Medications like thiazide diuretics or lithium
- Immobilization
- Inherited disorders like familial hypocalciuric hypercalcemia
High Triglycerides
Severely elevated blood triglyceride levels, a condition called hypertriglyceridemia, accounts for 1-4% of acute pancreatitis cases. Triglycerides are a type of fat found in the blood. High levels can cause pancreas inflammation.
Causes of severe hypertriglyceridemia include genetics, obesity, poorly controlled diabetes, hypothyroidism, and certain rare genetic disorders. Triglyceride levels above 1000 mg/dL increase pancreatitis risk.
Infections
Infections are the source of acute pancreatitis in approximately 5-10% of cases. Bacteria, viruses, and parasites can infect the pancreas directly and cause inflammation. Infected bile or gallstones can also block the pancreatic duct and cause pancreatitis.
Common causative infections include:
- Mumps
- Coxsackievirus
- Cytomegalovirus
- Hepatitis B
- Hepatitis C
- Mycoplasma
- Salmonella
- Toxoplasmosis
Medications
A variety of medications can cause drug-induced acute pancreatitis. The exact mechanisms are not fully understood, but may involve hypersensitivity reactions or cellular injury. The risk is higher when multiple medications are used, especially in older individuals or those with other medical conditions.
Medications linked to drug-induced acute pancreatitis include:
- Azathioprine
- 6-mercaptopurine
- 5-aminosalicylates
- Sulfonamides
- Tetracycline
- Valproic acid
- Pentamidine
- Didanosine
- Estrogens
- Corticosteroids
- Furosemide
- Thiazide diuretics
Trauma
Direct abdominal trauma, like a car accident, can damage the pancreas and cause inflammation and acute pancreatitis.
Surgery
Surgeries in the abdomen sometimes inadvertently cause injury to the pancreas. This accounts for 2-3% of cases. Types of surgery linked to postoperative pancreatitis include:
- Cardiac surgery – Especially where a heart-lung machine is used
- Abdominal surgeries – Such as bariatric or bowel surgery
- ERCP – Endoscopic retrograde cholangiopancreatography
Structural Abnormalities
Sometimes abnormalities in the structure of the pancreas itself can obstruct pancreatic enzymes from draining normally through the ducts. These rare congenital conditions include:
- Pancreas divisum – failure of the two parts of the pancreas to fuse properly during development
- Annular pancreas – a ring of pancreatic tissue encircles the duodenum
This causes pancreatitis episodes early in life.
Genetic Mutations
There are inherited genetic disorders that cause recurrent acute pancreatitis. These include autosomal dominant mutations in the PRSS1, CFTR, SPINK1 and CTRC genes. These mutations cause trypsin or enzyme regulatory problems that lead to pancreas damage. The PRSS1 mutation is one cause of hereditary pancreatitis where recurrent episodes often begin in childhood.
Autoimmune Pancreatitis
This rare form of chronic pancreatitis appears to have an autoimmune mechanism. The body’s immune system attack cells in the pancreas. About 5% of these cases are acute pancreatitis episodes rather than chronic.
Unknown Causes
Even after extensive testing, no cause can be identified in approximately 10% of acute pancreatitis cases. These are categorized as idiopathic. Some theories for idiopathic pancreatitis include undiscovered genetic mutations, microlithiasis, and microscopic ductal abnormalities.
Risk Factors
Factors that increase the risk of developing acute pancreatitis include:
- Gallstones
- Alcoholism
- High triglycerides – above 1000 mg/dL
- Family history of pancreatitis
- Cystic fibrosis gene mutations
- Being male
- Age over 30
- Obesity
- Smoking
Diagnosis
Acute pancreatitis is diagnosed based on symptoms, physical examination, blood tests, and imaging studies.
Symptoms
The most common symptoms of acute pancreatitis include:
- Abdominal pain – Generally in the upper abdomen and severe. Pain can last for several days.
- Nausea and vomiting
- Fever
- Rapid heart rate
- Tenderness of the abdomen – When the doctor presses on the abdomen
- Swelling of the abdomen
Blood Tests
Blood tests assess inflammation and pancreatic damage. Tests usually include:
- Complete blood count
- Comprehensive metabolic panel
- Lipase – An enzyme produced by the pancreas. Levels will be elevated.
- Amylase – Another pancreatic enzyme. Levels may be elevated.
- CRP – c-reactive protein levels are elevated with inflammation.
- Albumin – Levels often decrease as fluid leaks into tissues with pancreatitis.
- Liver enzymes like AST and ALT may be elevated if there is also liver inflammation.
- Triglycerides – Levels over 1000 mg/dL point to pancreatitis cause.
- Calcium – High levels can indicate hypercalcemia as the cause.
Imaging
Imaging of the pancreas and abdomen assists in diagnosis and identifying complications. Imaging tests include:
- Abdominal ultrasound – Helps identify gallstones and fluid collections.
- Abdominal CT scan – Good for detailed views of inflammation, infection, and tissue damage.
- MRCP – Magnetic resonance cholangiopancreatography uses MRI for detailed pancreas images.
- ERCP – Endoscopic cholangiopancreatography examines ducts with an endoscope and x-rays.
Treatment
The treatment of acute pancreatitis focuses on providing supportive care while the body heals itself in mild cases. Severe cases require closely monitored hospital intensive care and treatment of complications. Treatment components include:
Pain Management
Controlling severe abdominal pain is an initial priority. This requires intravenous administration of narcotic pain medications like morphine, hydromorphone, or fentanyl. Patients are monitored closely for oversedation and respiratory depression.
IV Fluids
Fluid resuscitation with intravenous isotonic fluids helps maintain adequate blood volume and prevent dehydration. Fluids are given at 1.5 to 2 times maintenance rates.
Bowel Rest
Keeping the pancreas at rest by holding oral foods and fluids avoids stimulation of the pancreas to produce enzymes. Pain can also prevent oral intake. Nutrition is provided through total parenteral nutrition (TPN) intravenous feeding.
Monitoring
Hospitalized patients require cardiac monitoring and regular assessment of fluid status, pain, abdominal signs, electrolytes, and kidney function to detect any complications.
Treatment of Complications
Severe acute pancreatitis involves aggressive treatment of complications:
- Infection – Antibiotic therapy, drainage procedures
- Bleeding – Fluid and blood transfusions, endoscopic treatment, surgery
- Cysts or abscesses – Drainage procedures
- Respiratory failure – Ventilator support
- Low blood pressure – Aggressive IV fluids, vasopressor medications
- Kidney failure – Dialysis
- Gastrointestinal perforation – Surgery to close holes or drainages in GI tract
Treatment of Underlying Causes
Once the acute episode resolves, any underlying cause of pancreatitis is treated to help prevent recurrence. This can include:
- Gallbladder removal surgery for gallstone pancreatitis
- Medication or dietary changes to lower very high triglycerides
- Stopping any medication linked to the pancreatitis
- Treating infections
- Correcting high calcium blood levels
- Alcohol abstinence treatment program
Low Fat Diet
A low fat diet may be recommended after recovery from acute pancreatitis to help prevent recurrence. Fatty foods stimulate the pancreas to produce enzymes, so limiting fats allows the pancreas to rest and heal.
Prognosis and Complications
The prognosis for acute pancreatitis depends on whether it is a mild or severe case.
Mild Acute Pancreatitis
In mild cases without complications, acute pancreatitis usually resolves in 3-5 days with conservative treatment. Full recovery and return to normal eating takes about one week.
The overall mortality rate is below 1% for mild acute pancreatitis. The pancreas is able to heal itself without permanent damage or impairment of function. However, mild cases can sometimes progress to the severe form.
Severe Acute Pancreatitis
Severe cases involve extensive inflammation and frequently develop dangerous complications like:
- Necrosis – cell death in large regions of pancreas tissue
- Infection – bacteria invade damaged or dead pancreas tissue
- Abscesses – pockets of infected fluid and debris
- Pseudocysts – fluid-filled sacs of pancreatic juices that develop in the abdomen
- Pleural effusions – fluid buildup in the chest cavity that causes breathing problems
- Acute respiratory distress syndrome – severe respiratory failure
- Low blood pressure
- Kidney failure
- Gastrointestinal bleeding
- Diabetes mellitus – Loss of insulin-producing beta cells in the pancreas
Severe acute pancreatitis has a mortality rate of 10-30%. Death can result from organ failure, necrotic infected tissue, or complications from prolonged intensive care.
Patients surviving the initial severe episode take about 2-3 weeks to recover. However, they may suffer long-term sequelae like chronic pancreatitis, diabetes, pancreatic insufficiency, and pancreatic cancer risk.
Prevention
Preventive measures to help avoid acute pancreatitis episodes include:
- Avoiding heavy alcohol consumption and alcohol abuse
- Maintaining normal triglyceride levels through diet, exercise, medications
- Not smoking
- Achieving an ideal body weight
- Having gallstones treated to prevent migration to the pancreas – This may involve gallbladder removal surgery
- Taking steps to prevent infections
- Using alternative medications where possible if drugs are triggering pancreatitis episodes
Conclusion
In summary, the main cause of acute pancreatitis is gallstones migrating and obstructing the pancreatic duct, accounting for 35-40% of cases. The second most common cause is excessive alcohol consumption. Hypertriglyceridemia, hypercalcemia, medications, infections, trauma, structural abnormalities, genetics, and autoimmune disease are less frequent causes.
With mild acute pancreatitis, the pancreas usually recovers well with conservative treatment. But severe cases can involve life-threatening complications like organ failure, sepsis, and hemorrhage. Preventing modifiable risk factors can help avoid acute pancreatitis episodes.