What is Angiodysplasia?
Angiodysplasia is the term for enlarged blood vessels in the wall of the gut. It is most likely to occur in the cecum of the colon, the first part of the large intestine that leads from the small intestine. Angiodysplasia is an uncommon condition, occurring mainly in the elderly but is one of the more common causes of lower gastrointestinal bleeding in adults.
How does angiodyplasa occur?
The exact cause of angiodysplasia is unclear but it is almost always seen after the age of 60 years. This vascular malformation occurs in the mucosa and submucosa of the colon wall. It is believed that both mechanical and congenital factors may play a role in the development of angiodysplasia. Normal bowel contractions may increase tension on superficially lying submucosal veins causing an occlusion with subsequent bulging. This may weaken the wall of the blood vessels allowing it to become tortuous. It is more likely to occur in the cecum due to its large diameter and greater wall tension. The enlarged vessels are separated from the lumen of the colon only by a thin vessel wall and layer of epithelial cells. This means that it is prone to injury and bleeding.
Signs and Symptoms of Angiodysplasia
Angiodysplasia is a chronic condition characterized by persistent or repeated episodes of rectal bleeding. In acute cases, the bleeding may be massive giving rise to profuse bloody diarrhea. The bleeding usually resolves spontaneously but if massive bleeding persists then surgical intervention may be required, either thermal ablation of the site of the bleed or even resection of the bowel in severe cases with persistent bleeding.
Most patients will not notice any symptoms until there is a massive acute episode. Black, tarry stools (melena) and occasional episodes of bright red blood rectal bleeding (hematochezia) may be the only obvious signs of angiodysplasia. If there is vomiting of blood (hematemesis) then the angiodysplasia may be occurring in the upper gut, like the esophagus, stomach or upper parts of the small intestine.
In prolonged cases or following several bouts of massive bleeding, anemia may set in. Depending on the severity, it may give rise to symptoms such as dizziness, fatigue, shortness of breath and weakness. Tachycardia (rapid heart rate) and hypotension are signs of significant blood loss or long standing anemia and need to be assessed immediately. However, in most cases the symptoms goes by unnoticed either because it is so mild or the symptoms are attributed to other chronic conditions that are more frequently seen in the elderly.