Autoimmune pancreatitis is difficult to diagnose, because its signs and symptoms are very similar to those of pancreatic cancer. However, an accurate diagnosis is extremely important. Undiagnosed cancer may result in delaying or not receiving necessary treatment.
People with AIP tend to have a general enlargement of the pancreas, but they may also have a mass in the pancreas. To pinpoint the diagnosis and determine which type of AIP you have, blood and imaging tests are necessary.
No single test or characteristic feature identifies autoimmune pancreatitis. Consensus guidelines for diagnosis use a combination of imaging, blood tests and biopsy results.
Specific tests may include:
- Imaging tests. Tests of your pancreas and other organs may include CT, MRI, endoscopic ultrasound (EUS) and endoscopic retrograde cholangiopancreatography (ERCP).
Blood tests. You will be tested for elevated levels of an immunoglobulin called IgG4, produced by your immune system. People with type 1 AIP, but usually not with type 2 AIP, will have highly elevated blood levels of IgG4.
However a positive test doesn't necessarily mean that you have the disease. A small number of people who don't have autoimmune pancreatitis, including some with pancreatic cancer, also have high blood levels of IgG4.
Endoscopic core biopsy. In this test, pathologists analyze a sample of pancreatic tissue in the laboratory. AIP has a distinctive appearance that can be easily recognized under a microscope by an expert pathologist. Doctors insert a small tube (endoscope) through the mouth into the stomach and, guided by ultrasound, remove some tissue from the pancreas using a special needle.
The challenge is obtaining a sample of tissue large enough to analyze, rather than just a few cells. This procedure is not widely available, and results may not be conclusive.
- Steroid trial. Autoimmune pancreatitis generally responds to steroids; doctors sometimes use a trial course of this drug to confirm a diagnosis. However, this strategy should ideally be under expert guidance, be used sparingly and only be done when there is strong evidence to support a diagnosis of autoimmune pancreatitis. Response to corticosteroids is measured by CT and improvement in serum IgG4 levels.
- Biliary stenting. Before starting medication, sometimes doctors will insert a tube to drain the biliary ducts (biliary stenting) in people with symptoms of obstructive jaundice. Often, though, jaundice improves with steroid treatment alone. Sometimes drainage is recommended if the diagnosis is uncertain. Tissue samples and cells from the bile duct may be obtained at the time of stent placement.
- Steroids. Symptoms of autoimmune pancreatitis often improve after a short course of prednisolone or prednisone. Many people respond quickly, even dramatically. Sometimes people get better without any treatment.
Immunosuppressants and immunomodulators. About 30% to 50% of the time in type 1 AIP and less than 10% of the time in type 2 AIP, the disease relapses, requiring additional treatment, sometimes long term.
To help reduce the serious side effects associated with extended steroid use, doctors often add drugs that suppress or modify the immune system, sometimes called steroid-sparing medications, to the treatment. You may be able to stop taking steroids altogether depending on your response to steroid-sparing medication.
Immunosuppressants and immunomodulators include mycophenolate (CellCept), mercaptopurine (Purinethol, Purixan), azathioprine (Imuran, Azasan) and rituximab (Rituxan). In general, they have been used in small sample groups and long-term benefits are still being studied.
- Monitoring of other organ involvement. Type 1 AIP often is associated with other organ involvement, including enlarged lymph nodes and salivary glands, scarring of the bile ducts, liver inflammation, and kidney disease. Although these signs may lessen or disappear completely with steroid therapy, your doctor will continue to monitor you.
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Preparing for your appointment
Start by seeing your primary care doctor if you have signs or symptoms that worry you. If your doctor suspects you may have autoimmune pancreatitis, you may be referred to a gastroenterologist or a pancreatologist.
What you can do
- Be aware of any pre-appointment restrictions. When you make your appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
- Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
- Write down key personal information, including any major stresses or recent life changes.
- Make a list of all medications and any vitamins or supplements that you're taking.
- Consider taking along a family member or friend. Sometimes it can be difficult to remember all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Write down questions to ask your doctor.
Your time with the doctor is limited. You may feel less rushed if you make a list of questions you want to ask at your appointment. Here are some possible questions about autoimmune pancreatitis:
- Can you explain my test results to me?
- How can you be sure that I do not have pancreatic cancer?
- Will I need more tests?
- How far has my disease progressed?
- Will it come back after initial treatment?
- Do I need lifelong treatment to prevent relapse?
- How should I be followed for relapse?
- How severe is the damage to my pancreas?
- What treatments can relieve my signs and symptoms?
- What are the potential side effects of each treatment?
- What signs and symptoms signal that my condition is worsening and I need to make another appointment?
- What signs and symptoms of complications should I watch for?
- I have other health conditions. How can I best manage them together?
- Are there any restrictions that I need to follow?
- Are there any brochures or other printed material that I can take with me? What websites do you recommend?
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions that come up during your appointment.
What to expect from your doctor
Your doctor is likely to ask you a number of questions. Being ready to answer them may allow more time later to cover points you want to address. Your doctor may ask:
- When did you begin experiencing symptoms?
- Do you have abdominal pain, dark urine, pale stools, itching or weight loss?
- Have your symptoms been continuous or occasional?
- How severe are your symptoms?
- What, if anything, seems to improve your symptoms?
- What, if anything, appears to worsen your symptoms?
- Have you had these symptoms before?
- Have you ever been diagnosed with pancreatitis?
- Did you start any new medications before your symptoms began?
Autoimmune pancreatitis care at Mayo Clinic
Jan. 22, 2021
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- Adam A, et al., eds. The pancreas. Grainger and Allison's Diagnostic Radiology. 7th ed. Elsevier Limited; 2021. https://www.clinicalkey.com. Accessed Dec. 1, 2020.
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- AskMayoExpert. Autoimmune pancreatitis (adult). Mayo Clinic; 2019.
- Brown AY. Allscripts EPSi. Mayo Clinic. Oct. 5, 2020.
- Majumder S (expert opinion). Mayo Clinic. Jan. 6, 2021.
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