Autoimmune pancreatitis (AIP) is an increasingly recognized type of chronic pancreatitis that can be difficult to distinguish from pancreatic carcinoma but which responds to treatment with corticosteroids, particularly prednisone. There are two categories of AIP: Type 1 and Type 2, each with distinct clinical profiles.

Type 1 AIP is now regarded as a manifestation of IgG4-related disease, and those affected have tended to be older and to have a high relapse rate. Type 1 is associated with pancreatitis, Sjogren syndrome, Primary sclerosing cholangitis and Inflammatory bowel disease. Patients with Type 2 AIP do not experience relapse, tend to be younger and not associated with systemic disease. AIP occurring in association with an autoimmune disorder has been referred to as "secondary" or "syndromic" AIP. AIP does not affect long-term survival.

AIP is relatively uncommon and is characterized by the following features:

1. Scleral Icterus (yellow eyes), jaundice (yellow skin) which is usually painless, usually without acute attacks of pancreatitis.

2. Relatively mild symptoms, such as minimal weight loss or nausea.

3. Increased serum levels of gamma globulins, immunoglobulin G (IgG) or IgG4.

4. The presence of serum autoantibodies such as anti-nuclear antibody (ANA), anti-lactoferrin antibody, anti-carbonic anhydrase II antibody, and rheumatoid factor (RF).

5. Contrast-enhanced CT demonstrates a diffusely enlarged (sausage-shaped) pancreas.

6. Diffuse irregular narrowing of the main pancreatic duct, and stenosis of the intrapancreatic bile duct on endoscopic retrograde cholangiopancreatography (ERCP).

7. Rare pancreatic calcification or cyst formation.

8. Marked responsiveness to treatment with corticosteroids.

Two-thirds of patients present with either obstructive painless jaundice or a "mass" in the head of the pancreas mimicking carcinoma. It is mandatory to rule out carcinoma prior to making a diagnosis of AIP.

Autoimmune hepatitis may present completely asymptomatic (12–35% of the cases), with signs of chronic liver disease, or acute or even fulminant hepatic failure.

People usually present with one or more nonspecific symptoms, sometimes of long lasting duration, as fatigue, general ill health, lethargy, weight loss, mild right upper quadrant pain, malaise, anorexia, nausea, jaundice or arthralgia affecting the small joints. Rarely, rash or unexplained fever may appear. In women, amenorrhoea is a frequent feature. Physical examination may be normal, but it may also reveal signs and symptoms of chronic liver disease. Many people have only laboratory abnormalities as their initial presentation, as unexplained increase in transaminases and are diagnosed during an evaluation for other reasons. Others have already developed cirrhosis at diagnosis.

Autoimmune hepatitis frequently appears associated with other autoimmune conditions, mainly celiac disease, vasculitis, and autoimmune thyroiditis.

An autoimmune disease is a condition arising from an abnormal immune response to a normal body part. There are at least 80 types of autoimmune diseases. Nearly any body part can be involved. Common symptoms include low grade fever and feeling tired. Often symptoms come and go.

The cause is generally unknown. Some autoimmune diseases such as lupus run in families, and certain cases may be triggered by infections or other environmental factors. Some common diseases that are generally considered autoimmune include celiac disease, diabetes mellitus type 1, Graves' disease, inflammatory bowel disease, multiple sclerosis, psoriasis, rheumatoid arthritis, and systemic lupus erythematosus. The diagnosis can be difficult to determine.

Treatment depends on the type and severity of the condition. Nonsteroidal anti-inflammatory drugs (NSAIDs) and immunosuppressants are often used. Intravenous Immunoglobulin may also occasionally be used. While treatment usually improves symptoms they do not typically cure the disease.

About 24 million (7%) people in the United States are affected by an autoimmune disease. Women are more commonly affected than men. Often they start during adulthood. The first autoimmune diseases were described in the early 1900s.

The clinical signs can vary from mild gastrointestinal upset to death, with most dogs presenting with common gastrointestinal signs of upset, such as vomiting, anorexia, painful abdomen, hunched posture, diarrhea, fever, dehydration, and lack of energy, with vomiting being the most common symptom. These signs are not specific just for pancreatitis and may be associated with other gastrointestinal diseases and conditions.

Acute pancreatitis can trigger a build-up of fluid, particularly in abdominal and thoracic (chest) areas, acute renal failure, and cause inflammation in arteries and veins. The inflammation triggers the body's clotting factors, possibly depleting them to the point of spontaneous bleeding. It is this form which can be fatal in animals and in humans.

Chronic pancreatitis can be present even though there are no clinical signs of the disease.

Pancreatitis can result in exocrine pancreatic insufficiency, if the organ's acinar cells are permanently damaged; the pancreatic enzymes then need replacement with pancrelipase or similar products. The damage can also extend into the endocrine portion of the pancreas, resulting in diabetes mellitus. Whether the diabetes is transient (temporary) or permanent depends on the severity of the damage to the endocrine pancreas beta cells.

Autoimmune hepatitis, formerly called lupoid hepatitis, is a chronic, autoimmune disease of the liver that occurs when the body's immune system attacks liver cells causing the liver to be inflamed. Common initial symptoms include fatigue or muscle aches or signs of acute liver inflammation including fever, jaundice, and right upper quadrant abdominal pain. Individuals with autoimmune hepatitis often have no initial symptoms and the disease is detected by abnormal liver function tests.

Anomalous presentation of MHC class II receptors on the surface of liver cells, possibly due to genetic predisposition or acute liver infection, causes a cell-mediated immune response against the body's own liver, resulting in autoimmune hepatitis. This abnormal immune response results in inflammation of the liver, which can lead to further symptoms and complications such as fatigue and cirrhosis. The disease may occur in any ethnic group and at any age, but is most often diagnosed in patients between age 40 and 50.

For a disease to be regarded as an autoimmune disease it needs to answer to "Witebsky's postulates" (first formulated by Ernest Witebsky and colleagues in 1957 and modified in 1994):

- Direct evidence from transfer of disease-causing antibody or disease-causing T lymphocyte white blood cells

- Indirect evidence based on reproduction of the autoimmune disease in experimental animals

- Circumstantial evidence from clinical clues

- Genetic evidence suggesting "clustering" with other autoimmune diseases

Autoimmunity is the system of immune responses of an organism against its own healthy cells and tissues. Any disease that results from such an aberrant immune response is termed an "autoimmune disease". Prominent examples include celiac disease, diabetes mellitus type 1, sarcoidosis, systemic lupus erythematosus (SLE), Sjögren's syndrome, eosinophilic granulomatosis with polyangiitis, Hashimoto's thyroiditis, Graves' disease, idiopathic thrombocytopenic purpura, Addison's disease, rheumatoid arthritis (RA), ankylosing spondylitis, polymyositis (PM), dermatomyositis (DM) and multiple sclerosis (MS). Autoimmune diseases are very often treated with steroids.

Chronic pancreatitis is a long-standing inflammation of the pancreas that alters the organ's normal structure and functions. It can present as episodes of acute inflammation in a previously injured pancreas, or as chronic damage with persistent pain or malabsorption. It is a disease process characterized by irreversible damage to the pancreas as distinct from reversible changes in acute pancreatitis.

The most common symptoms of pancreatitis are severe upper abdominal or left upper quadrant burning pain radiating to the back, nausea, and vomiting that is worse with eating. The physical examination will vary depending on severity and presence of internal bleeding. Blood pressure may be elevated by pain or decreased by dehydration or bleeding. Heart and respiratory rates are often elevated. The abdomen is usually tender but to a lesser degree than the pain itself. As is common in abdominal disease, bowel sounds may be reduced from reflex bowel paralysis. Fever or jaundice may be present. Chronic pancreatitis can lead to diabetes or pancreatic cancer. Unexplained weight loss may occur from a lack of pancreatic enzymes hindering digestion.

Among the causes of chronic pancreatitis are the following:

The relationship between etiologic factors, genetic predisposition, and the pace of disease progression requires further clarification, though recent research indicates smoking may be a high-risk factor to develop chronic pancreatitis. In a small group of patients chronic pancreatitis has been shown to be hereditary. Almost all patients with cystic fibrosis have established chronic pancreatitis, usually from birth. Cystic fibrosis gene mutations have also been identified in patients with chronic pancreatitis but in whom there were no other manifestations of cystic fibrosis. Obstruction of the pancreatic duct because of either a benign or malignant process may result in chronic pancreatitis.

The pancreas is composed of two sections: the smaller endocrine portion, which is responsible for producing hormones such as insulin, somatostatin, and glucagon, and the larger, exocrine portion, which produces enzymes needed for the digestion of food. Acinar cells make up 82% of the total pancreas; these cells are responsible for the production of the digestive enzymes.

Early complications include shock, infection, systemic inflammatory response syndrome, low blood calcium, high blood glucose, and dehydration. Blood loss, dehydration, and fluid leaking into the abdominal cavity (ascites) can lead to kidney failure. Respiratory complications are often severe. Pleural effusion is usually present. Shallow breathing from pain can lead to lung collapse. Pancreatic enzymes may attack the lungs, causing inflammation. Severe inflammation can lead to intra-abdominal hypertension and abdominal compartment syndrome, further impairing renal and respiratory function and potentially requiring management with an open abdomen to relieve the pressure.

Late complications include recurrent pancreatitis and the development of pancreatic pseudocysts—collections of pancreatic secretions that have been walled off by scar tissue. These may cause pain, become infected, rupture and bleed, block the bile duct and cause jaundice, or migrate around the abdomen. Acute necrotizing pancreatitis can lead to a pancreatic abscess, a collection of pus caused by necrosis, liquefaction, and infection. This happens in approximately 3% of cases, or almost 60% of cases involving more than two pseudocysts and gas in the pancreas.

Autoimmune diseases can be broadly divided into systemic and organ-specific or localised autoimmune disorders, depending on the principal clinico-pathologic features of each disease.

- Systemic autoimmune diseases include SLE, Sjögren's syndrome, sarcoidosis, scleroderma, rheumatoid arthritis, cryoglobulinemic vasculitis, and dermatomyositis. These conditions tend to be associated with autoantibodies to antigens which are not tissue specific. Thus although polymyositis is more or less tissue specific in presentation, it may be included in this group because the autoantigens are often ubiquitous t-RNA synthetases.

- Local syndromes which affect a specific organ or tissue:

- Endocrinologic: Diabetes mellitus type 1, Hashimoto's thyroiditis, Addison's disease

- Gastrointestinal: Coeliac disease, Crohn's disease, Pernicious anaemia

- Dermatologic: Pemphigus vulgaris, Vitiligo

- Haematologic: Autoimmune haemolytic anaemia, Idiopathic thrombocytopenic purpura

- Neurological: Multiple sclerosis, Myasthenia gravis, Encephalitis

Using the traditional “organ specific” and “non-organ specific” classification scheme, many diseases have been lumped together under the autoimmune disease umbrella. However, many chronic inflammatory human disorders lack the telltale associations of B and T cell driven immunopathology. In the last decade it has been firmly established that tissue "inflammation against self" does not necessarily rely on abnormal T and B cell responses.

This has led to the recent proposal that the spectrum of autoimmunity should be viewed along an “immunological disease continuum,” with classical autoimmune diseases at one extreme and diseases driven by the innate immune system at the other extreme. Within this scheme, the full spectrum of autoimmunity can be included. Many common human autoimmune diseases can be seen to have a substantial innate immune mediated immunopathology using this new scheme. This new classification scheme has implications for understanding disease mechanisms and for therapy development.

The pancreas is central in the pathophysiology of both major types of diabetes mellitus. In type 1 diabetes mellitus, there is direct damage to the endocrine pancreas that results in insufficient insulin synthesis and secretion. Type 2 diabetes mellitus, which begins with insulin resistance, is characterized by the ultimate failure of pancreatic β cells to match insulin production with insulin demand.

Primary biliary cirrhosis. CD is prevalent in primary biliary cirrhosis (PBC). In PBC anti-mitochondrial antibodies are directed toward 3 mitochondrial autoantigens (pyruvate dehydrogenase, oxoglutarate dehydrogenase, branched-chain alpha-keto acid dehydrogenase), 2 or more nuclear proteins (nucleoporin 210kDa, nucleoporin 62kDa, centromere protein, and sp100), and 57% of acute liver failure patients have anti-transglutaminase antibodies.

Cholangitis. CD also found at higher than expected frequencies in autoimmune cholangitis and primary sclerosing cholangitis. CD is frequently linked to pancreatitis but also to papillary stenosis and, in India, tropical calcific pancreatitis appears also to be associated with CD.

Ten (of 75) young patients had neurologic findings such as febrile seizures, single generalized seizures, mild ataxia, and muscular hypotonia with retarded motor development, but magnetic resonance imaging detected unilateral and bilateral T2-hyperintensive white-matter lesions in 15 patients (20%)

The second stage is characterized by an abnormally high level of eosinophils (a type of white blood cell) in the blood and tissues. The symptoms of hypereosinophilia depend on which part of the body is affected, but most often it affects the lungs and digestive tract. The signs and symptoms of hypereosinophilia may include weight loss, night sweats, asthma, cough, abdominal pain, and gastrointestinal bleeding. Fever and malaise are often present.

The eosinophilic stage can last months or years, and its symptoms can disappear, only to return later. Patients may experience the third stage simultaneously.

Pancreatitis is inflammation of the pancreas. There are two forms of pancreatitis, which are different in causes and symptoms, and require different treatment:

- Acute pancreatitis is a rapid-onset inflammation of the pancreas, most frequently caused by alcoholism or gallstones.

- Chronic pancreatitis is a long-standing inflammation of the pancreas.

The most common symptoms and signs include:

- severe epigastric pain (upper abdominal pain) radiating to the back in 50% of cases

- nausea

- vomiting

- loss of appetite

- fever

- chills (shivering)

- hemodynamic instability, including shock

- tachycardia (rapid heartbeat)

- respiratory distress

- peritonitis

- hiccup

Although these are common symptoms, they are not always present. Simple abdominal pain may be the sole symptom.

Signs that are less common, and indicate severe disease, include:

- Grey-Turner's sign (hemorrhagic discoloration of the flanks)

- Cullen's sign (hemorrhagic discoloration of the umbilicus)

- Pleural effusions (fluid in the bases of the pleural cavity)

- Grünwald sign (appearance of ecchymosis, large bruise, around the umbilicus due to local toxic lesion of the vessels)

- Körte's sign (pain or resistance in the zone where the head of pancreas is located (in epigastrium, 6–7 cm above the umbilicus))

- Kamenchik's sign (pain with pressure under the xiphoid process)

- Mayo-Robson's sign (pain while pressing at the top of the angle lateral to the Erector spinae muscles and below the left 12th rib (left costovertebral angle (CVA))

- Mayo-Robson's point – a point on border of inner 2/3 with the external 1/3 of the line that represents the bisection of the left upper abdominal quadrant, where tenderness on pressure exists in disease of the pancreas. At this point the tail of pancreas is projected on the abdominal wall.

- Pandiaraja's sign- ecchymosis of right axilla

The diagnosis of SSC requires the exclusion of secondary causes of sclerosing cholangitis and recognition of associated conditions that may potentially imitate its classic cholangiographic features. It is morphologically similar to primary sclerosing cholangitis (PSC) but originates from a known pathological process. Its clinical and cholangiographic features may mimic PSC, yet its natural history may be more favorable if recognition is prompt and appropriate therapy is introduced. Sclerosing cholangitis in critically ill patients, however, is associated with rapid disease progression and poor outcome. Serologic testing, radiological imaging and histological analysis can help diagnose SSC.

HP is characterised by attacks of epigastric pain, which are often associated with nausea and vomiting. Symptoms may start shortly after birth but onset varies periodically, with some patients not exhibiting symptoms until adulthood. There is usually progression to chronic pancreatitis with endocrine and exocrine failure and a mortally increased risk of pancreatic cancer. Lifetime risk of cancer has been variously calculated as 35–54% to the age of 75 years and screening for early pancreatic cancer is being offered to HP sufferers on a scientific basis. Some patients may choose to have their pancreas surgically removed to prevent pancreatic cancer from developing in the future.

The epidemiology of HP follows a similar pattern to alcohol-associated chronic pancreatitis, but there are important differences. For example, HP typically has an earlier age of pancreatitis onset; although malabsorption and diabetes mellitus occur at a later stage in the disease progression.

The prodromal stage is characterized by allergy. Almost all patients experience asthma and/or allergic rhinitis, with more than 90% having a history of asthma that is either a new development, or the worsening of pre-existing asthma, which may require systemic corticosteroid treatment. On average, asthma develops from three to nine years before the other signs and symptoms.

The allergic rhinitis may produce symptoms such as rhinorrhea and nasal obstruction, and the formation of nasal polyps that require surgical removal, often more than once. Sinusitis may also be present.

Autoimmune polyendocrine syndromes (APS) occur when more than one autoimmune disease occurs in endocrine glands. These syndromes are also called Polyendocrine Autoimmune Disorders. In Type 3, autoimmune thyroiditis and another endocrine autoimmune disease are present, but the adrenal cortex is not involved.

Systemic complications include ARDS, multiple organ dysfunction syndrome, DIC, hypocalcemia (from fat saponification), hyperglycemia and insulin dependent diabetes mellitus (from pancreatic insulin-producing beta cell damage), malabsorption due to exocrine failure

- Metabolic

- Respiratory

- Renal

- Renal artery or vein thrombosis

- Renal failure

- Circulatory

- Arrhythmias

- Hypovolemia and shock

- myocardial infarct

- Pericardial effusion

- vascular thrombosis

- Gastrointestinal

- Gastrointestinal hemorrhage from stress ulceration;

- gastric varices (secondary to splenic vein thrombosis)

- Gastrointestinal obstruction

- Hepatobiliary

- Jaundice

- Portal vein thrombosis

- Neurologic

- Psychosis or encephalopathy (confusion, delusion and coma)

- Cerebral Embolism

- Blindness (angiopathic retinopathy with hemorrhage)

- Hematologic

- Anemia

- DIC

- Leucocytosis

- Dermatologic

- Painful subcutaneous fat necrosis

- Miscellaneous

- Subcutaneous fat necrosis

- Arthalgia