Autoimmune pancreatitis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

In 1995, Yoshida proposed the term “autoimmune pancreatitis” for the first time. Autoimmune pancreatitis is also known as primary inflammatory pancreatitis, lymphoplasmacytic sclerosing pancreatitis, pseudotumorous pancreatitis, chronic pancreatitis with irregular narrowing of the main pancreatic duct, idiopathic chronic pancreatitis, and nonalcoholic duct destructive chronic pancreatitis. Autoimmune pancreatitis (AIP) may be classified into two types; type 1 AIP and type 2 AIP or idiopathic duct-centric pancreatitis. Type 1 AIP meets the HISORt criteria, involves pancreas as one part of a systemic IgG4-positive disease. Type 2 consists of granulocytic lesions, does not involve IgG4-positive cells, has no systemic involvement, and is usually associated with inflammatory bowel disease. Th1-type CD4+ T cells are thought to play an important role in the pathogenesis of autoimmune pancreatitis (AIP) via autoimmune reaction against carbonic anhydrase type II or lactoferrin. Autoimmune pancreatitis may be associated with systemic autoimmune conditions such as IgG4-associated cholangitis, chronic sclerosing sialadenitis (Küttner’s tumor), Mikulicz’s disease (IgG4-related plasmacytic exocrinopathy), mediastinal fibrosis, adenopathy, chronic periaortitis, idiopathic retroperitoneal fibrosis, tubulointerstitial nephritis, IgG4-associated pseudolymphoma, ulcerative colitis and hypergammaglobulinemia. Diffuse pancreatic gland enlargement may be seen on gross examination. Microscopic findings suggestive of autoimmune pancreatitis may include Interlobular ducts surrounded by the infiltration of inflammatory cells and fibrosis. Immunohistochemistry stains may show CD4+ T cells (mainly), some CD8+ T cells, B cells and HLA-DR antigen expression on pancreatic duct or acinar cells. Autoimmune pancreatitis is idiopathic in origin and has no clear etiology. Autoimmune pancreatitis is thought to be due to some autoimmune reaction against pancreas and might be associated with other autoimmune diseases. Autoimmune pancreatitis needs to be differentiated from other diseases such as alcoholic chronic pancreatitis, pancreatic cancer, chronic pancreatitis, inflammatory bowel disease, dumping syndrome, celiac disease, Whipple’s disease, tropical sprue and colon carcinoma. In North America, 2.5% of pancreatoduodenectomies are done because of AIP being misdiagnosed as pancreatic cancer. The symptoms of autoimmune pancreatitis usually develop in the fifth decade of life, and start with symptoms such as painless jaundice, dark urine, and mild abdominal pain. During the later course of disease, patients may present with abdominal mass mimicking pancreatic cancer. If left untreated, patients with autoimmune pancreatitis may progress to develop pancreatic insufficiency, diabetes, and pancreatic calcifications or stones. The prognosis is usually good; about 2/3rd of patients show good response to glucocorticoids with complete recovery, 25% may require a second course of glucocorticoids, and a few patients with autoimmune pancreatitis may require continuous treatment. Autoimmune pancreatitis is diagnosed by revised HISORt criteria, proposed by Mayo clinic, that includes histology, pancreatic imaging, serology, other organ involvement, and response to steroid treatment. Patients with autoimmune pancreatitis may do not have a positive history of alcohol abuse. Common symptoms of autoimmune pancreatitis include mild abdominal pain, abdominal mass/pancreatic mass, painless jaundice, weight loss, and diabetes mellitus. Laboratory findings consistent with the diagnosis of autoimmune pancreatitis may include increased serum IgG4 levels and hypergammaglobulinemia (>2 times the upper limit of normal in most patients), antilactoferrin antibody, anticarbonic anhydrase II antibody, other autoantibodies (ANA), rheumatoid factor (RF), IgG4-positive plasma cells, elevated serum alkaline phosphatase levels (ALP), elevated serum aminotransferases, ESR, and CA19-9. CT scan findings suggestive of autoimmune pancreatitis may include diffusely enlarged pancreas with featureless borders, delayed enhancement with or without a capsule-like rim and rarely calcifications may be seen. ERCP or MRCP findings in autoimmune pancreatitis may include a narrowed main and dorsal pancreatic duct, diffuse and irregular narrowing of the pancreatic duct (beaded appearance), focal stricture of the pancreatic duct, proximal or distal common bile duct and irregular narrowing of the intrahepatic ducts. Glucocorticoids are found to play an important role in the management of autoimmune pancreatitis via several ways such as efficacy in alleviating symptoms, decreasing the size of the pancreas, reversing histopathologic features in patients with AIP, and mprovement of lab findings. Immunomodulatory drugs such as azathioprine are usually used when, AIP patients have no response to steroid management, relapse occurs and patients cannot be weaned off steroids. Surgery is usually considered when pain management fails with medical and endoscopic therapies. The goals of surgery include effective pain relief, and to preserve long-term pancreatic function. Surgery for chronic pancreatitis tends to be divided into two areas – resectional and drainage procedures. Dilated pancreatic duct may be managed with lateral pancreaticojejunostomy (LPJ) and lateralpancreaticojejunostomy with localized pancreatic head resection. Nondilated pancreatic duct is usually managed with pancreaticoduodenectomy, duodenal-preserving pancreatic head resection (DPPHR), distal pancreatectomy (DP) and total pancreatectomy (TP). Patients should be managed appropriately and timely with glucocorticoids and immunomodulatory drugs to prevent complications such as pancreatic insufficiency, diabetes, and pancreatic calcifications or stones.

The concept of pancreas and pancreatic duct was first described by Johannes Wirsung of Padua in 1642. In 1761, Giovanni Morgagni described the clinical syndrome of severe upper abdominal pain, vomiting, and collapse. He is also credited with the earliest pathological recognition of cancer of the pancreas. In 1948, Eliason and Welty described distal pancreatectomy (DP). In 1980, Beger described duodenal-preserving pancreatic head resection (DPPHR) technique for chronic pancreatitis to decrease the morbidity of pancreatic head resection. In 1961, Sarles proposed autoimmunity as a pathogenetic mechanism of pancreatitis. In 1995, Yoshida proposed the term “autoimmune pancreatitis” for the first time. Autoimmune pancreatitis is also known as primary inflammatory pancreatitis, lymphoplasmacytic sclerosing pancreatitis, pseudotumorous pancreatitis, chronic pancreatitis with irregular narrowing of the main pancreatic duct, idiopathic chronic pancreatitis, and nonalcoholic duct destructive chronic pancreatitis. In 2009, the two types of autoimmune pancreatitis were first identified as type 1 (lymphoplasmacytic sclerosing pancreatitis) and type 2 (idiopathic duct-centric pancreatitis).

Autoimmune pancreatitis (AIP) may be classified into two types; type 1 AIP and type 2 AIP or idiopathic duct-centric pancreatitis. Type 1 AIP meets the HISORt criteria, involves pancreas as one part of a systemic IgG4-positive disease. Type 2 consists of granulocytic lesions, does not involve IgG4-positive cells, has no systemic involvement, and is usually associated with inflammatory bowel disease.

Th1-type CD4+ T cells are thought to play an important role in the pathogenesis of autoimmune pancreatitis (AIP) via autoimmune reaction against carbonic anhydrase type II or lactoferrin. Autoimmune pancreatitis may involve fibrosis of peripancreatic vessels leading to obliterative vasculitis and phlebitis similar to that occuring in pancreatic cancer. Autoimmune pancreatitis may be associated with systemic autoimmune conditions such as IgG4-associated cholangitis, chronic sclerosing sialadenitis (Küttner’s tumor), Mikulicz’s disease (IgG4-related plasmacytic exocrinopathy), mediastinal fibrosis, adenopathy, chronic periaortitis, idiopathic retroperitoneal fibrosis, tubulointerstitial nephritis, IgG4-associated pseudolymphoma, ulcerative colitis and hypergammaglobulinemia. Diffuse pancreatic gland enlargement may be seen on gross examination. Microscopic findings suggestive of autoimmune pancreatitis may include Interlobular ducts surrounded by the infiltration of inflammatory cells and fibrosis. Immunohistochemistry stains may show CD4+ T cells (mainly), some CD8+ T cells, B cells and HLA-DR antigen expression on pancreatic duct or acinar cells. 

Autoimmune pancreatitis is idiopathic in origin and has no clear etiology. Autoimmune pancreatitis is thought to be due to some autoimmune reaction against pancreas and might be associated with other autoimmune diseases.

Autoimmune pancreatitis needs to be differentiated from other diseases such as alcoholic chronic pancreatitis, pancreatic cancer, chronic pancreatitis, inflammatory bowel disease, dumping syndrome, celiac disease, Whipple’s disease, tropical sprue and colon carcinoma.

Autoimmune pancreatitis is a world wide entitiy but it’s incidence has been found to be recently increased in Japan. In North America, 2.5% of pancreatoduodenectomies are done because of AIP being misdiagnosed as pancreatic cancer. The mean age of patients with AIP is 59 yr (range, 45–75 yr). In autoimmune pancreatitis, the male-to-female ratio was found to be 15:2. Autoimmune pancreatitis usually involves elderly male population.

There are no established risk factors found to be associated with autoimmune pancreatitis. Patients with systemic autoimmune diseases such as Sjogren syndrome and Primary sclerosing cholangitis may be associated with an increased risk of autoimmune pancreatitis.

There is insufficient evidence to recommend routine screening for autoimmune pancreatitis.

The symptoms of autoimmune pancreatitis usually develop in the fifth decade of life, and start with symptoms such as painless jaundice, dark urine, and mild abdominal pain. During the later course of disease, patients may present with abdominal mass mimicking pancreatic cancer. If left untreated, patients with autoimmune pancreatitis may progress to develop pancreatic insufficiency, diabetes, and pancreatic calcifications or stones. The prognosis is usually good; about 2/3rd of patients show good response to glucocorticoids with complete recovery, 25% may require a second course of glucocorticoids, and a few patients with autoimmune pancreatitis may require continuous treatment.

Autoimmune pancreatitis is diagnosed by revised HISORt criteria, proposed by Mayo clinic, that includes histology, pancreatic imaging, serology, other organ involvement, and response to steroid treatment.

Patients with autoimmune pancreatitis may do not have a positive history of alcohol abuse. Common symptoms of autoimmune pancreatitis include mild abdominal pain, abdominal mass/pancreatic mass, painless jaundice, weight loss, and diabetes mellitus. Less common symptoms may include symptoms related to other autoimmune diseases such as Sjögren’s syndrome, primary sclerosing cholangitis (PSC), inflammatory bowel disease (IBD), and retroperitoneal fibrosis. Autoimmune pancreatitis may have extra-pancreatic involvement such as bile duct, salivary gland, retroperitoneum, kidneys, and orbit depending upon the various stages of autoimmune pancreatitis.

Patients with acute on chronic autoimmune pancreatitis may assume a characteristic position in an attempt to relieve their abdominal pain. Patients with steatorrhea or advanced disease may present with loss of subcutaneous fat, temporal wasting, sunken supraclavicular fossa, and other physical signs of malnutrition.

Laboratory findings consistent with the diagnosis of autoimmune pancreatitis may include increased serum IgG4 levels and hypergammaglobulinemia (>2 times the upper limit of normal in most patients), antilactoferrin antibody, anticarbonic anhydrase II antibody, other autoantibodies (ANA), rheumatoid factor (RF), IgG4-positive plasma cells, elevated serum alkaline phosphatase levels (ALP), elevated serum aminotransferases, ESR, and CA19-9.

There are no ECG findings associated with autoimmune pancreatitis.

There are no x-ray findings associated with autoimmune pancreatitis.

Endoscopic ultrasound guided fine needle aspiration (EUS-FNA) may be used to obtain histologic specimens from pancreas.

CT scan findings suggestive of autoimmune pancreatitis may include diffusely enlarged pancreas with featureless borders, delayed enhancement with or without a capsule-like rim and rarely calcifications may be seen.

MRI findings suggestive of autoimmune pancreatitis may include diffusely enlarged pancreas with featureless borders and delayed enhancement with or without a capsule-like rim.

ERCP or MRCP findings in autoimmune pancreatitis may include a narrowed main and dorsal pancreatic duct, diffuse and irregular narrowing of the pancreatic duct (beaded appearance), focal stricture of the pancreatic duct, proximal or distal common bile duct and irregular narrowing of the intrahepatic ducts.

Other diagnostic studies for autoimmune pancreatitis usually include pancreatic biopsy, which may demonstrate extensive fibrosis. Endoscopic ultrasound-guided trucut biopsy (EUS-TCB) is usually avoided due to increased risk of complications and limited diagnostic ability.

Glucocorticoids are found to play an important role in the management of autoimmune pancreatitis via several ways such as efficacy in alleviating symptoms, decreasing the size of the pancreas, reversing histopathologic features in patients with autoimmune pancreatitis (AIP), and mprovement of lab findings. About 2/3rd of patients show good response to glucocorticoids with complete recovery, 25% may require a second course of glucocorticoids, and a few patients with autoimmune pancreatitis may require continuous treatment. Immunomodulatory drugs such as azathioprine are usually used when, AIP patients have no response to steroid management, relapse occurs and patients cannot be weaned off steroids.

Surgery is usually considered when pain management fails with medical and endoscopic therapies. The goals of surgery include effective pain relief, and to preserve long-term pancreatic function. Surgery for chronic pancreatitis tends to be divided into two areas – resectional and drainage procedures. Dilated pancreatic duct may be managed with lateral pancreaticojejunostomy (LPJ) and lateralpancreaticojejunostomy with localized pancreatic head resection. Nondilated pancreatic duct is usually managed with pancreaticoduodenectomy, duodenal-preserving pancreatic head resection (DPPHR), distal pancreatectomy (DP) and total pancreatectomy (TP).

There are no established measures for the primary prevention of autoimmune pancreatitis.

Patients should be managed appropriately and timely with glucocorticoids and immunomodulatory drugs to prevent complications such as pancreatic insufficiency, diabetes, and pancreatic calcifications or stones.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]Feham Tariq, MD [3]

The concept of pancreas and pancreatic duct was first described by Johannes Wirsung of Padua in 1642. In 1761, Giovanni Morgagni described the clinical syndrome of severe upper abdominal pain, vomiting, and collapse. He is also credited with the earliest pathological recognition of cancer of the pancreas. In 1948, Eliason and Welty described distal pancreatectomy (DP). In 1980, Beger described duodenal-preserving pancreatic head resection (DPPHR) technique for chronic pancreatitis to decrease the morbidity of pancreatic head resection. In 1961, Sarles proposed autoimmunity as a pathogenetic mechanism of pancreatitis. In 1995, Yoshida proposed the term “autoimmune pancreatitis” for the first time. Autoimmune pancreatitis is also known as primary inflammatory pancreatitis, lymphoplasmacytic sclerosing pancreatitis, pseudotumorous pancreatitis, chronic pancreatitis with irregular narrowing of the main pancreatic duct, idiopathic chronic pancreatitis, and nonalcoholic duct destructive chronic pancreatitis. In 2009, the two types of autoimmune pancreatitis were first identified such as type 1 (lymphoplasmacytic sclerosing pancreatitis) and type 2 (idiopathic duct-centric pancreatitis).

The historical landmarks in the diagnostic evaluation and management of acute pancreatitis are as follows:^{[1] [2]}

• In 1642, Johannes Wirsung of Padua first described the pancreatic duct and the concept of the pancreas as a secretory organ.
• In 1737, Giovanni Santorini of Venice identified a second, accessory duct and was credited with primacy in the discovery of the ampulla of Vater.
• In 1887, Rugero Oddi published his observations of the structure and function of the choledochal sphincter in Archives Italiennes de Biologie that laid the basis for understanding its role in pancreatic and biliary disease.
• In the 16th century, Sylvius Franciscus de la Boe Sylvius found that the pancreas discharged a fluid that mixed with the partly digested food and bile in the intestine causing an effervescence (“effervescentia intestinalis”) which liquefied food.
• In the 16th century, Regnier de Graaf of Delft devised novel surgical techniques to create pancreatic fistulas (center) to collect this juice for analysis.
• In 1652, Nicholaes Tulp of Amsterdam is credited with the first description of acute pancreatitis.
• In 1761, Giovanni Morgagni described the clinical syndrome of severe upper abdominal pain, vomiting, and collapse (acute pancreatitis). He is also credited with the earliest pathological recognition of cancer of the pancreas.
• In 1652, Nicholaes Tulp was credited with the first description of acute pancreatitis.
• In 1842, Karl von Rokitansky, the premier pathologist of Vienna (Wiener Allgemeines Krankenhaus) was the first one to recognize acute hemorrhagic pancreatitis.
• In late 18th century, Reginald Fitz described 3 forms of acute pancreatitis (hemorrhagic, suppurative, and gangrenous) and proposed that fat necrosis was a sequel of severe pancreatitis.
• In late 18th century, Nicholas Senn of Chicago, not only addressed the mechanism of acute pancreatitis but also provided rational insight into the validity of surgical techniques for its treatment.
• In 1946, Whipple described classic pancreaticoduodenectomy for chronic pancreatitis.^[3]
• In 1961, Sarles proposed autoimmunity as a pathogenetic mechanism of pancreatitis.^[4]
• In 1995, Yoshida proposed the term “autoimmune pancreatitis” for the first time.^[5]
• Historically, autoimmune pancreatitis is also known as:^[6][7][8][9]
  • Primary inflammatory pancreatitis.
  • Lymphoplasmacytic sclerosing pancreatitis.
  • Pseudotumorous pancreatitis.
  • Chronic pancreatitis with irregular narrowing of the main pancreatic duct.
  • Idiopathic chronic pancreatitis.
  • Nonalcoholic duct destructive chronic pancreatitis.
• In 2009, the two types of autoimmune pancreatitis were first identified such as type 1 (lymphoplasmacytic sclerosing pancreatitis) and type 2 (idiopathic duct-centric pancreatitis).^[10][11]

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

Autoimmune pancreatitis may be classified into two types; type 1 AIP and type 2 AIP or idiopathic duct-centric pancreatitis. Type 1 AIP meets the HISORt criteria, involves pancreas as one part of a systemic IgG4-positive disease. Type 2 consists of granulocytic lesions, does not involve IgG4-positive cells, has no systemic involvement, and is usually associated with inflammatory bowel disease.

• Autoimmune pancreatitis can be:^{[1][2][3][4][5][6][7][8][9]}
  • Primary (when main pathology is in pancreas) or,
  • Secondary (when associated with other systemic autoimmune diseases such as IgG4-associated cholangitis, chronic sclerosing sialadenitis, tubulointerstitial nephritis, and ulcerative colitis).
• Autoimmune pancreatitis may be classified into two types:
  • Type 1 AIP.
  • Type 2 AIP or idiopathic duct-centric pancreatitis.

• Type 1 AIP meets the HISORt criteria.^[10][11]
• Type 1 AIP involves pancreas as one part of a systemic IgG4-positive disease.
• Type 1 AIP is more prevalent in males compared to females.
• Type 1 patients have high relapse rates when compared to type 2 patients.^[12]
• Type 1 patients are usually older on presentation.
• Type 1 patients have higher prevalence of increased IgG4 levels.
• Type 1 patients have greater extrapancreatic organ involvement compared to Type 2 AIP patients.

Criteria	Definition
(H)	Histology suggestive of autoimmine pancreatitis
(I)	Pancreatic imaging suggestive of autoimmine pstricturess
(S)	Serology (IgG4 ≥2 times the upper limit of normal)
(O)	Other organ involvement Biliary strictures Parotid/lacrimal gland involvement Mediastinal lymphadenopathy Retroperitoneal fibrosis
(Rt)	Response to steroid treatment

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

Th1-type CD4+ T cells are thought to play an important role in the pathogenesis of autoimmune pancreatitis (AIP) via autoimmune reaction against carbonic anhydrase type II or lactoferrin. Autoimmune pancreatitis may involve fibrosis of peripancreatic vessels leading to obliterative vasculitis and phlebitis similar to that occuring in pancreatic cancer. Autoimmune pancreatitis may be associated with systemic autoimmune conditions such as IgG4-associated cholangitis, chronic sclerosing sialadenitis (Küttner’s tumor), Mikulicz’s disease (IgG4-related plasmacytic exocrinopathy), mediastinal fibrosis, adenopathy, chronic periaortitis, idiopathic retroperitoneal fibrosis, tubulointerstitial nephritis, IgG4-associated pseudolymphoma, ulcerative colitis and hypergammaglobulinemia. Diffuse pancreatic gland enlargement may be seen on gross examination. Microscopic findings suggestive of autoimmune pancreatitis may include Interlobular ducts surrounded by the infiltration of inflammatory cells and fibrosis. Immunohistochemistry stains may show CD4+ T cells (mainly), some CD8+ T cells, B cells and HLA-DR antigen expression on pancreatic duct or acinar cells. 

• In the normal pancreatic gland, carbonic anhydrase type II and lactoferrin are located in the ductal cells and pancreatic acini respectively.
• Th1-type CD4+ T cells are thought to play an important role in the pathogenesis of autoimmune pancreatitis (AIP) via autoimmune reaction against carbonic anhydrase type II or lactoferrin.^[1][2][3]

• Autoimmune exocrinopathy is usually defined as an autoimmune disease affecting more than one exocrine organs.^[4]
• It can be explained based on the fact that carbonic anhydrase type II and lactoferrin (that act as target antigens) are found not only in pancreatic gland but also in others such as salivary gland, lacrimal gland, and bile duct.^[4]
• Autoimmune pancreatitis may also be found coexisting with other autoimmune conditions such as Primary sclerosing cholangitis (PSC) and Sjögren’s syndrome.^[5]

• Autoimmune pancreatitis may involve fibrosis of peripancreatic vessels leading to obliterative vasculitis and phlebitis similar to that occurs in pancreatic cancer.^[6][7][8][9]
• Follicular hyperplasia may also be seen due to peripancreatic lymph nodes enlargement.

• Autoimmune pancreatitis may be associated with polymorphisms in antigen gene 4 of cytotoxic T lymphocytes (CTLA-4, CD152).^[10]

• Autoimmune pancreatitis may be associated with systemic autoimmune conditions such as:^{[11][12][13][14][15][16][17][18][19]}
  • IgG4-associated cholangitis
  • Chronic sclerosing sialadenitis (Küttner’s tumor)
  • Mikulicz’s disease (IgG4-related plasmacytic exocrinopathy)
  • Mediastinal fibrosis, adenopathy
  • Chronic periaortitis
  • Idiopathic retroperitoneal fibrosis
  • Tubulointerstitial nephritis
  • IgG4-associated pseudolymphoma
  • Ulcerative colitis
  • Hypergammaglobulinemia

• On gross pathology, findings suggestive of autoimmune pancreatitis may include
  • Diffuse pancreatic gland enlargement
  • Autoimmune pancreatitis mostly involves the head of pancreas manifesting as mass-forming pancreatitis^[9][7]

• Microscopic findings suggestive of autoimmune pancreatitis may include:^[20]
  • Interlobular ducts surrounded by the infiltration of inflammatory cells 
    • Lymphocytes
    • Plasma cells
    • Eosinophils and neutrophils (occasionally)^[7][21]
  • Fibrosis^[8][7]
  • Patchy inflammatory infiltrates

• Immunohistochemistry stains may show:^[7][22]
  • CD4+ T cells (mainly)
  • Some CD8+ T cells and B cells
  • HLA-DR antigen expression on pancreatic duct or acinar cells 

• A lymphoplasmacytic sclerosing pancreatitis
• >10 IgG4-positive cells with at least two of the following
  • Periductal lymphoplasmacytic infiltrate
  • Obliterative phlebitis
  • Acinar fibrosis

• Pancreatic duct: Granulocytic epithelial lesion
• Pancreatic parenchyma: Minimal IgG4-positive cells

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

Autoimmune pancreatitis is idiopathic in origin and has no clear etiology. Autoimmune pancreatitis is thought to be due to some autoimmune reaction against pancreas and might be associated with other autoimmune diseases.

• Autoimmune pancreatitis is idiopathic in origin and has no clear etiology.
• Autoimmune pancreatitis is thought to be due to some autoimmune reaction against pancreas and might be associated with other autoimmune diseases.^[1][2]

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

Autoimmune pancreatitis needs to be differentiated from other diseases such as alcoholic chronic pancreatitis, pancreatic cancer, chronic pancreatitis, inflammatory bowel disease, dumping syndrome, celiac disease, Whipple’s disease, tropical sprue and colon carcinoma.

Autoimmune pancreatitis needs to be differentiated from other diseases such as alcoholic chronic pancreatitis, pancreatic cancer, chronic pancreatitis, inflammatory bowel disease, dumping syndrome, celiac disease, Whipple’s disease, tropical sprue and colon carcinoma.^[1][2]

Abbreviations: RUQ= Right upper quadrant of the abdomen, LUQ= Left upper quadrant, LLQ= Left lower quadrant, RLQ= Right lower quadrant, LFT= Liver function test, SIRS= Systemic inflammatory response syndrome, ERCP= Endoscopic retrograde cholangiopancreatography, IV= Intravenous, N= Normal, AMA= Anti mitochondrial antibodies, LDH= Lactate dehydrogenase, GI= Gastrointestinal, CXR= Chest X ray, IgA= Immunoglobulin A, IgG= Immunoglobulin G, IgM= Immunoglobulin M, CT= Computed tomography, PMN= Polymorphonuclear cells, ESR= Erythrocyte sedimentation rate, CRP= C-reactive protein, TS= Transferrin saturation, SF= Serum Ferritin, SMA= Superior mesenteric artery, SMV= Superior mesenteric vein, ECG= Electrocardiogram

Disease Clinical manifestations Diagnosis Comments Symptoms Signs Abdominal Pain Fever Rigors and chills Nausea or vomiting Jaundice Constipation Diarrhea Weight loss GI bleeding Hypo- tension Guarding Rebound Tenderness Bowel sounds Lab Findings Imaging Chronic pancreatitis Epigastric − − ± ± − + + − − − − N Increased amylase / lipase Increased stool fat content Pancreatic function test CT scan Calcification Pseudocyst Dilation of main pancreatic duct Predisposes to pancreatic cancer Pancreatic carcinoma Epigastric − − + + − + + − − − − N ↑ Alkaline phosphatase ↑ serum bilirubin ↑ gamma-glutamyl transpeptidase ↑ CA 19-9  MDCT with  PET/CT MRI Skin manifestations may include: Bullous pemphigoid Cicatricial pemphigoid Migratory superficial thrombophlebitis (classic Trousseau’s syndrome) Pancreatic panniculitis Dumping syndrome Lower and then diffuse − − + − − + + − + − − Hyperactive Glucose challenge test Hydrogen breath test Upper GI series Gastric emptying study Postgastrectomy Inflammatory bowel disease Diffuse ± − − ± − + + + − − − Normal or hyperactive Anti-neutrophil cytoplasmic antibody (P-ANCA) in Ulcerative colitis Anti saccharomyces cerevisiae antibodies (ASCA) in Crohn’s disease String sign on abdominal x-ray in Crohn’s disease Extra intestinal findings: Uveitis Arthritis Irritable bowel syndrome Diffuse − − − − ± ± + − − − − N Normal Normal Symptomatic treatment High dietary fiber Osmotic laxatives Antispasmodic drugs Whipple’s disease Diffuse ± − − ± − + + − ± − − N Thrombocytopenia Hypoalbuminemia Small intestinal biopsy for Tropheryma whipplei Endoscopy is used to confirm diagnosis. Images used to find complications Chest and joint x-ray CT MRI Echocardiography Extra intestinal findings: Uveitis Endocarditis Encephalitis Dementia Hepatosplenomegaly Arthritis Ascites Disease Abdominal Pain Fever Rigors and chills Nausea or vomiting Jaundice Constipation Diarrhea Weight loss GI bleeding Hypo- tension Guarding Rebound Tenderness Bowel sounds Lab Findings Imaging Comments Tropical sprue Diffuse + − − − − + + − − − − N Fat soluble vitamin deficiency Hypoalbuminemia Fecal stool test Barium studies: Dilation and edema of mucosal folds Steatorrhea– 10-40 g/day (Normal=5 g/day) Celiac disease Diffuse − − − − − + + − − − − Hyperactive IgA endomysial antibody IgA tissue transglutaminase antibody Anti-gliadin antibody Small bowel biopsy US: Bull’s eye or target pattern Pseudokidney sign Gluten allergy Colon carcinoma Diffuse/localized − − − − ± ± + + ± − − Normal or hyperactive if obstruction present CBC Carcinoembryonic antigen (CEA) Colonoscopy Flexible sigmoidoscopy Barium enema CT colonography  PILLCAM 2: A colon capsule for CRC screening may be used in patients with an incomplete colonoscopy who lacks obstruction Viral hepatitis RUQ + − + + − Positive in Hep A and E + − Positive in fulminant hepatitis Positive in acute + N Abnormal LFTs Viral serology US Hep A and E have fecal-oral route of transmission Hep B and C transmits via blood transfusion and sexual contact. Liver abscess RUQ + + + + − ± + − + + ± Normal or hypoactive CBC Blood cultures Abnormal liver function tests US CT Mesenteric ischemia Periumbilical Positive if bowel becomes gangrenous − + − − + + + Positive if bowel becomes gangrenous Positive if bowel becomes gangrenous − Hyperactive to absent Leukocytosis and lactic acidosis Amylase levels D-dimer CT angiography SMA or SMV thrombosis Also known as abdominal angina that worsens with eating Acute ischemic colitis Diffuse + ± + − − + + + + + + Hyperactive then absent Leukocytosis Abdominal x-ray Distension and pneumatosis CT scan Double halo appearance, thumbprinting Thickening of bowel May lead to shock

To review the differential diagnosis of Abdominal pain, click here.

References

1. ↑ Chari ST, Takahashi N, Levy MJ, Smyrk TC, Clain JE, Pearson RK, Petersen BT, Topazian MA, Vege SS (2009). “A diagnostic strategy to distinguish autoimmune pancreatitis from pancreatic cancer”. Clin. Gastroenterol. Hepatol. 7 (10): 1097–103. doi:10.1016/j.cgh.2009.04.020. PMID 19410017.
2. ↑ Kamisawa T, Egawa N, Nakajima H, Tsuruta K, Okamoto A, Kamata N (2003). “Clinical difficulties in the differentiation of autoimmune pancreatitis and pancreatic carcinoma”. Am. J. Gastroenterol. 98 (12): 2694–9. doi:10.1111/j.1572-0241.2003.08775.x. PMID 14687819.

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

Autoimmune pancreatitis is a world wide entitiy but it’s incidence has been found to be recently increased in Japan. In North America, 2.5% of pancreatoduodenectomies are done because of AIP being misdiagnosed as pancreatic cancer. The mean age of patients with AIP is 59 yr (range, 45–75 yr). In autoimmune pancreatitis, the male-to-female ratio was found to be 15:2. Autoimmune pancreatitis usually involves elderly male population.

• Autoimmune pancreatitis is a world wide entitiy but it’s incidence has been found to be recently increased in Japan.^[1][2][3]

• In Japan, the prevalence of autoimmune pancreatitis is estimated to be 0.82 per 100 000 inhabitants.
• In North America, 2.5% of pancreatoduodenectomies are done because of AIP being misdiagnosed as pancreatic cancer.

• The mean age of patients with AIP is 59 yr (range, 45–75 yr).

• In autoimmune pancreatitis, the male-to-female ratio was found to be 15:2.
• Autoimmune pancreatitis usually involves elderly male population.^[4][5][6]

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

There are no established risk factors found to be associated with autoimmune pancreatitis.Patients with systemic autoimmune diseases such as Sjogren syndrome and Primary sclerosing cholangitis may be associated with an increased risk of autoimmune pancreatitis.

• There are no established risk factors found to be associated with autoimmune pancreatitis.
• Patients with systemic autoimmune diseases such as Sjogren syndrome and Primary sclerosing cholangitis may be associated with an increased risk of autoimmune pancreatitis.^[1][2]

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

There is insufficient evidence to recommend routine screening for autoimmune pancreatitis.

There is insufficient evidence to recommend routine screening for autoimmune pancreatitis.

Template:WH Template:WS

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Iqra Qamar M.D.[2]

The symptoms of autoimmune pancreatitis usually develop in the fifth decade of life, and start with symptoms such as painless jaundice, dark urine, and mild abdominal pain. During the later course of disease, patients may present with abdominal mass mimicking pancreatic cancer. If left untreated, patients with autoimmune pancreatitis may progress to develop pancreatic insufficiency, diabetes, and pancreatic calcifications or stones. The prognosis is usually good; about 2/3rd of patients show good response to glucocorticoids with complete recovery, 25% may require a second course of glucocorticoids, and a few patients with autoimmune pancreatitis may require continuous treatment.

• The symptoms of autoimmune pancreatitis usually develop in the fifth decade of life, and start with symptoms such as painless jaundice, dark urine, and mild abdominal pain. During the later course of disease, patients may present with abdominal mass mimicking pancreatic cancer.
• If left untreated, patients with autoimmune pancreatitis may progress to develop pancreatic insufficiency, diabetes, and pancreatic calcifications or stones.

• Common complications of autoimmune pancreatitis include:
  • Pancreatic insufficiency
  • Diabetes
  • Pancreatic calcifications or stones

• The prognosis is usually good and following responses have been observed in response to corticosteroid therapy:
  • About 2/3rd of patients show good response to glucocorticoids with complete recovery.^[1][2][3]
  • Approximately 25% may require a second course of glucocorticoids.
  • A few patients with autoimmune pancreatitis may require continuous treatment.
• Patients with biliary strictures have a variable response to glucocorticoids such as:^{[1][3][4][5][6]}
  • Patients with biliary strictures may respond to glucocorticoids.
  • Patients with biliary strictures may not respond to glucocorticoids.
  • Patients with biliary strictures may have an incomplete response to glucocorticoids.
  • Patients with biliary strictures may require maintenance therapy with glucocorticoids to prevent relapse.
  • Patients with biliary strictures may require maintenance therapy with glucocorticoids and/or immunomodulatory drugs  to prevent relapse.

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