Pancreatitis occurs when your pancreas becomes inflamed. It has several potential causes, including gallstones and heavy drinking, or an alcohol use disorder. But sometimes pancreatitis is due to autoimmune activity. This is called autoimmune pancreatitis.
Autoimmune pancreatitis is not common, although it may be underdiagnosed. It is estimated to be the cause of approximately 4.6 to 6% of cases of chronic (long-lasting) pancreatitis.
This article will take a closer look at autoimmune pancreatitis, its symptoms, and how it is diagnosed and treated.
The pancreas is an organ located in the upper part of your abdomen. It produces insulin, which helps your body regulate your glucose (sugar) levels. Your pancreas also makes digestive juices that help digest the food you eat.
When your pancreas becomes swollen and inflamed, it’s called pancreatitis. Autoimmune pancreatitis occurs when your immune system mistakenly attacks your pancreas.
The exact cause of autoimmune pancreatitis is unknown. It is possible that it is caused by a triggering event, such as a bacterial infection, in people genetically predisposed to autoimmune pancreatitis or other autoimmune diseases.
Types of autoimmune pancreatitis
There are 2 different types of autoimmune pancreatitis: type 1 and type 2.
Type 1 is the most common type. It is associated with high levels of IgG4, a type of antibody, and IgG4-producing immune cells. These antibodies can attack healthy tissue in your pancreas. Other organs, such as the bile ducts, kidneys and thyroid may also be involved.
Type 1 disease is more common in people designated male at birth and in people aged 60 and older. It also has a higher prevalence among people of Asian descent, according to research.
In type 2 disease, immune cells called neutrophils are found in the ducts (tubes) of the pancreas. The activity of these cells can damage the pancreas. IgG4 cannot be detected or is at very low levels. This type of autoimmune pancreatitis is also sometimes associated with inflammatory bowel disease (IBD).
Type 2 disease appears to affect men and women equally and occurs mainly in younger people, for example.
Symptoms of autoimmune pancreatitis can include:
Abdominal pain is usually more common in type 2 disease. When it occurs in type 1 disease, it is often mild and comes and goes.
Autoimmune pancreatitis can also cause enlargement of the pancreas as well as the appearance of non-cancerous growths. These findings, along with symptoms of autoimmune pancreatitis, can sometimes be confused with pancreatic cancer.
Several different methods can be used to diagnose autoimmune pancreatitis. Since autoimmune pancreatitis can present as pancreatic cancer, it is also important to carefully exclude the presence of cancer during diagnosis.
Your doctor will first perform a physical exam and ask for your medical history. They will ask you for details about:
- your symptoms
- any other medical condition you have
- if you have a personal or family history of pancreatitis
After that, the following methods can be used to diagnose autoimmune pancreatitis:
- Imaging. Imaging tests can provide a view of the pancreas and its ducts. This is usually done using computed tomography (CT) or magnetic resonance imaging (MRI). An ultrasound can also be used.
- Blood tests. Several types of blood tests can be used to help make a diagnosis. Examples include:
- a test to detect and determine IgG4 levels
- a metabolic panel, which includes tests that assess things like blood sugar, electrolytes, and liver and kidney function
- Biopsy. A biopsy may be performed to remove a sample of tissue from your pancreas. This tissue is then examined under a microscope to look for signs of autoimmune activity.
Another method that can be used to help diagnose this condition is called a steroid test, which is not actually a diagnostic test. It’s a therapeutic trial.
Most people with autoimmune pancreatitis respond well to treatment with corticosteroids. These drugs reduce inflammation by reducing the activity of the immune system. Examples of corticosteroids include prednisone and prednisolone.
Corticosteroids are available as pills or tablets. They are usually used for a short period of time, after which they are reduced. This is due to the risk of side effects with longer term use.
Symptoms that do not respond to corticosteroids can often suggest a misdiagnosis. Pancreatic cancer often presents in the same way as autoimmune pancreatitis.
If you have narrowing or blockage of the pancreatic or bile ducts due to autoimmune pancreatitis, your doctor may place a stent in the duct. It is a narrow tube that is placed in the affected duct, allowing fluids to pass more efficiently.
Autoimmune pancreatitis may relapse after treatment. Relapses are more common in type 1 disease, occurring in
In case of relapse, additional corticosteroid therapy may be necessary. It is also possible that another immunomodulatory or immunosuppressive drug will be used, such as azathioprine, methotrexate or rituximab.
Another potential complication is a narrowing or blockage of the bile ducts, which can lead to worsening symptoms such as jaundice, weight loss, and nausea or vomiting. A blockage can lead to its own complications, including bilirubin buildup and liver disease.
Other complications are associated with the side effects of corticosteroid therapy. These side effects may include:
Make an appointment with your doctor if you have symptoms such as:
- recurring or continuous pain in the upper abdomen
- dark urine
- pale or clay-like stools
- lose a noticeable amount of weight without trying
- frequent nausea or vomiting
Your doctor will assess your symptoms to diagnose the underlying cause, which will help them recommend a treatment plan for your condition.
Autoimmune pancreatitis is a rare type of pancreatitis in which your immune system attacks healthy tissue in your pancreas. This can lead to symptoms such as jaundice, fatigue, and pain in the upper abdomen.
Corticosteroids are generally very effective in treating autoimmune pancreatitis. However, it is still possible for relapses to occur after treatment, especially with autoimmune pancreatitis type 1.
If left untreated, autoimmune pancreatitis can lead to complications. In addition, pancreatic cancer has very similar symptoms. As such, it’s important to see your doctor if you experience symptoms such as jaundice, abdominal pain, or unexplained weight loss.