Chapter 23 OCCULT GASTROINTESTINAL BLEEDING AND IRON DEFICIENCY ANAEMIA
This chapter concentrates on unexplained or occult gastrointestinal bleeding from the upper gastrointestinal tract and small intestine.
AETIOLOGY
Arteriovenous malformations
Bleeding may be occult or severe. The most common presentation is with haematemesis or melaena. The diagnosis of gastric AVMs is made with upper endoscopy and in the small intestine using capsule endoscopy. The lesions are bright red and well circumscribed and they may be flat or raised. It is frequently difficult to determine whether a visualised AVM is the actual bleeding site. Generally, evidence for bleeding is required, as indicated by active bleeding from the lesion or an affixed clot.