Angiodysplasia

In medicine(gastroenterology), angiodysplasia is a small vascularmalformation of the gut. It can be a source of gastrointestinal bleedingand anemia.

Signs, symptoms and diagnosis

Although some cases present with black, tarry stool (melena), the blood loss can be subtle, with the anemia symptoms predominating. Fecal occult bloodtesting is positive when bleeding is active. If bleeding is intermittent the test may be negative.

Diagnosis of angiodysplasia is often accomplished with endoscopy, either colonoscopyor esophagogastroduodenoscopy(EGD). Although the lesions can be notoriously hard to find, the patient usually is diagnosed by endoscopy. A new technique, pill enteroscopy, has been a major advance in diagnosis. With this technique a pill that contains a video camera and radio transmitter is swallowed, and pictures of the small intestine are sent to a receiver worn by the patient. In cases with negative endoscopic findings and high clinical suspicion, selective angiographyof the mesenteric arteriesis sometimes necessary.

Pathophysiology

Its predilection locus is the cecum, although it can develop at other places. Histologically, it resembles teleangiectasia. Development is related to age and strain on the bowel wall, which is thought to influence the caliber change and proliferation of the vascular tissue.

Although angiodysplasia is probably quite common, the risk of bleedingis increased in disorders of coagulation. A classic association is Heyde's syndrome(coincidence of aortic valve stenosisand bleeding from angiodysplasia). In this disorder, von Willebrand factor(vWF) is proteolysed due to high shear stressin the highly turbulent blood flow around the aortic valve. vWF is most active in vascular beds with high shear stress, including angiodysplasias, and deficiency of vWF increases the bleeding risk from such lesions.

Warkentin et al argue that apart from aortic valve stenosis, some other conditions that feature high shear stress might also increase the risk of bleeding from angiodysplasia.

Therapy

If the anemia is severe, blood transfusionis required before any other intervention is considered. Endoscopictreatment is an initial possibility, where cautery is applied through the endoscope. Resectionof the affected part of the bowel may be needed. However, the lesions may be widespread, making such treatment impractical. Embolisationthrough angiographyis occasionally contemplated with severely bleeding lesions that cannot be visualised on colonoscopy.

Estrogens can be used to stop bleeding from angiodysplasia. Estrogens cause mild hypercoaguability of the blood. Estrogen side effects can be dangerous and unpleasant in both sexes. Changes in voice and breast swellingis bothersome in men, but older women often report improvement of libidoand perimenopausalsymptoms. (The worries about hormone replacement therapy/HRT, however, apply here as well.)

References

• Warkentin TE, Moore JC, Anand SS, Lonn EM, Morgan DG. Gastrointestinal bleeding, angiodysplasia, cardiovascular disease, and acquired von Willebrand syndrome. Transfus Med Rev. 2003 Oct;17(4):272-86. PMID 14571395.

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It uses material from the http://en.wikipedia.org/wiki/Angiodysplasia Wikipedia article Angiodysplasia.