[Hepatopancreaticobiliary diseases in IgG4-associated autoimmune diseases]

[Autoimmune pancreatitis versus pancreatic cancer]

CLINICAL ISSUE

Autoimmune pancreatitis (AIP) is classified as a distinct form of pancreatitis according to the guidelines. It is characterized by imaging morphologic and histologic features and is associated with extrapancreatic manifestations in type 1 IgG 4-associated disease. Symptoms and findings almost always improve with administration of steroids. Differentiation from pancreatic ductal adenocarcinoma is required, particularly in the presence of AIP with focal parenchymal involvement.

STANDARD RADIOLOGIC PROCEDURES

If AIP is suspected, abdominal ultrasound and/or endosonography, computed tomography (CT), and preferably magnetic resonance imaging (MRI) are indicated. A distinction is made between parenchymal and ductal changes that specifically indicate the presence of AIP.

METHODOLOGICAL INNOVATIONS AND EVALUATION

The diagnosis of autoimmune pancreatitis should be made based on the International Consensus Criteria (ICDC), in which the five main features (imaging, serology, histology, other organ involvement, response to steroid medication) are assessed. In type 1 AIP, typical imaging changes are sufficient to establish the diagnosis even with negative histology, whereas for type 2 AIP, histologic evidence is required. Imaging changes help in the differential diagnosis from pancreatic cancer.

PRACTICAL RECOMMENDATIONS

The following article addresses and evaluates crucial imaging diagnostic CT and MRI criteria for correct classification of findings, description of results, and differentiation of autoimmune pancreatitis from pancreatic cancer.

[Guideline-based diagnosis of pancreatitis]

BACKGROUND

There is currently no S3 guideline that contains statements on the diagnosis and treatment of acute, chronic and autoimmune pancreatitis in a single guideline.

OBJECTIVES

This article presents the most relevant recommendations relating to radiological imaging from the new "S3 guideline for pancreatitis".

MATERIALS AND METHODS

The guideline was developed by the DGVS (German Society for Digestive and Metabolic Diseases). After an online-based Delphi survey, the statements were discussed by an interdisciplinary expert team at a 3-day consensus conference and then agreed upon. The level of evidence scheme (version 2) of the Oxford Centre for Evidence-based Medicine was used.

RESULTS

The new German "S3 guideline pancreatitis" comprises for the first time all entities of pancreatitis, acute, chronic and autoimmune pancreatitis and contains a large number of innovations with regard to diagnostic imaging and therapy. In addition to the evidence-based recommendations for diagnosis and therapy, a German-language glossary of the revised Atlanta classification on acute pancreatitis was adopted by consensus of the interdisciplinary guideline expert team. Furthermore, protocol recommendations for the performance of computed tomography (CT) are provided for the first time. In this article we introduce the key recommendations and innovations in the field of diagnostic radiologic imaging for acute, chronic and autoimmune pancreatitis.

CONCLUSIONS

In the future, every radiologist should have deep knowledge of the recommended time intervals for radiological imaging in acute pancreatitis and know the German terms for the description of acute pancreatitis; furthermore they should be able to classify the morphologies to the appropriate stages.

[Inflammatory and infectious abdominal peritoneal and mesenterial processes]

BACKGROUND

Mesenterial and peritoneal inflammation represents a major clinical challenge regarding differential diagnosis. In this review article, a systematic overview of the most common causes such as autoimmune reaction, infarction with consecutive necrosis and infection caused by protozoa or bacteria is provided.

RESULTS

The common clinical features of all inflammatory peritoneal and mesenterial diseases are the nonspecific abdominal symptoms. Even in radiological imaging an overlap of imaging features such as lymphadenopathy and nodular mesenteric structures is typical. Frequently the radiologist can narrow the differential diagnosis based on clinical information and anamnesis resulting in an optimized clinical outcome.

CONCLUSION

Having a huge spectrum of etiologies for inflammatory peritoneal and mesenterial conditions the radiologist has to consider autoimmune diseases (IgG4-associated disease), acute infarction with necrosis and bacterial or protozoan infection.