[Acute primary ulcer of the small intestine. Present concepts (author's transl)].

Acute primary ulcer of the small intestine is an exceptional occurrence. Diagnosis is established only after a complication occurs. In most instances, this complication is perforation of the gut. Acute primary ulcer of the small intestine is accurately defined by specific histologic criteria. It can be unequivocally distinguished from the many other causes of spontaneous perforation of the small intestine. Experimental studies, although numerous, have not improved understanding of pathophysiology. Nosologic classification remains unclear. Many features are similar to those encountered in acute peptic ulcer but stress is usually absent. Other features resemble those of transient necrotizing enterocolitis ; acute primary ulcer of the small intestine may be a very localized form of this latter condition. Ischemia seems to be the most significant factor. However, for an ulcer and finally perforation to occur, ischemia must probably be associated with a number of other factors.