The M-ANNHEIM classification of chronic pancreatitis: introduction of a unifying classification system based on a review of previous classifications of the disease

Abstract

Background: Several classification systems of chronic pancreatitis have been proposed to provide a basis for treatment and research. All of these previous classifications were designed at the height of pancreatic research of their respective times; thus, each represented the most current knowledge available to pancreatologists at the time. However, none of these classifications provide simultaneously a simple standardized system for the clinical classification of chronic pancreatitis according to etiology, clinical stage, and severity of the disease, nor are they consistently useful for directing clinical practice and comparing interinstitutional data. Thus, we aimed to develop a new classification system of chronic pancreatitis to provide a framework for studying the interaction of various risk factors on the course of the disease.

Methods: We reviewed the literature on the clinical course of all different forms of chronic pancreatitis, and we reviewed all previous classification systems of the disease. This approach provided a basis for the development of a new and unifying classification of chronic pancreatitis.

Results: We established the M-ANNHEIM multiple risk factor classification system based on the current knowledge of acute and chronic pancreatitis. This classification allows patients to be categorized according to the etiology, clinical stage, and severity of their disease. The severity of pancreatic inflammation was assessed using a scoring system that takes into account the clinical symptoms and treatment options of chronic pancreatitis. Finally, four hypothetical patients were categorized according to the M-ANNHEIM classification system to provide examples of its applicability in clinical practice.

Conclusions: The M-ANNHEIM multiple risk factor classification system is simple, objective, accurate, and relatively noninvasive, and it incorporates etiology, different stages of the disease, and various degrees of clinical severity. This new classification system will be helpful for investigating the impact and interaction of various risk factors on the course of the disease and will facilitate the comparison and combination of interinstitutional data.