Autoimmune Pancreatitis
Autoimmune Pancreatitis (AIP) is a unique form of chronic pancreatitis where the body’s immune system mistakenly targets and attacks its own healthy pancreatic tissue.
The two subtypes:
AIP is generally categorized into two main types, which differ in their presentation and extent of organ involvement:
Type 1 AIP:
- This is the more common subtype.
- It typically occurs in older individuals and is observed more frequently in men.
- It is considered a multi-organ condition, often affecting organs beyond the pancreas, such as the liver and gallbladder.
Type 2 AIP:
- This subtype affects males and females equally and may present in a younger age group.
- The inflammation is generally confined only to the pancreas.
- It has a strong association with Inflammatory Bowel Diseases (IBD), such as ulcerative colitis or Crohn's disease.
Symptoms:
The symptoms of AIP can be varied and include signs related to pancreatic dysfunction and bile duct blockage:
- Jaundice: Yellowing of the skin and eyes.
- Abdominal pain.
- Weight loss.
- Fatigue/Extreme tiredness/Weakness.
- Dark-colored urine.
- Loss of appetite.
Cause:
The specific trigger for AIP is unknown. However, it is fundamentally caused by the body’s immune system attacking its own healthy body tissue, which is the hallmark of an autoimmune disorder.
Diagnosis:
A definitive diagnosis of AIP relies on a combination of laboratory and imaging tests, often used to differentiate it from pancreatic cancer:
- Liver Function Tests: Blood work showing elevated levels of bilirubin and serum alkaline phosphatase, which suggest bile duct obstruction.
- Blood Test: Checking the levels of the IgG4 antibody, particularly relevant for Type 1 AIP.
- Imaging Tests: Including Ultrasonography (USG) and CT scan to visualize the pancreas.
- Biopsy (via Endoscopic Ultrasound - EUS): A procedure using endoscopic ultrasound is performed to evaluate the pancreas and safely obtain a biopsy (tissue sample) to confirm the diagnosis and, crucially, rule out pancreatic cancer.
Treatment:
The primary goals of treatment are to relieve symptoms caused by blockages and reduce the pancreatic inflammation:
- Relief of Jaundice: If jaundice is present due to bile duct obstruction, an endoscopic stent is placed in the bile duct to restore flow.
- Reducing Pancreatic Swelling: Medications (typically corticosteroids) are given to suppress the immune system and reduce the inflammation of the pancreas. This may require either short-term or prolonged therapy depending on the patient's response and disease subtype.