n. an abnormal collection of small blood vessels found in the mucosa of the gastrointestinal tract, which are thought to be due to degeneration of previously healthy blood vessels. Angiodysplasia may be isolated lesions or found in clusters; they are located predominately in the caecum or ascending colon and they may bleed or contribute to iron-deficiency anaemia. Angiodysplasia may be diagnosed at endoscopy or angiography. Treatment includes endoscopic coagulation with *diathermy, *argon plasma coagulation, *embolization at angiography, or surgical resection in cases not responding to other treatments.
(therapeutic embolization) n. the introduction of any material to reduce or completely obstruct blood flow. Conditions such as varicocele, fibroids, hepatoma, congenital arteriovenous malformations (see angioma), angiodysplasia, malignant tumours, or arterial rupture are commonly treated with embolization. Under X-ray screening control, a catheter is guided to the blood vessel (artery or vein) supplying the affected area and occluding material, such as microspheres, metallic coils, PVA (polyvinyl alcohol), or gel foam, is injected. The procedure may treat the underlying problem or simplify subsequent surgery. See also chemoembolization; coiling; uterine artery embolization.... embolization
n. the passage of fresh red blood through the rectum. Haematochesia occurs in patients with haemorrhoids, colorectal carcinoma, colitis, diverticulitis, angiodysplasia, and volvulus. Haematochesia also occurs as a result of severe haemorrhage in the upper gastrointestinal tract.... haematochesia
n. black tarry faeces discoloured by the presence of digested blood. Melaena usually reflects significant bleeding in the upper gastrointestinal tract, but may be due to disease in the small bowel or proximal large bowel (such as carcinoma or *angiodysplasia). It may be associated with vomiting blood (*haematemesis) or *coffee-ground vomit. See also haemorrhagic disease of the newborn.... melaena
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