Angiodysplasia
Encyclopedia
In medicine
(gastroenterology
), angiodysplasia is a small vascular
malformation of the gut
. It is a common cause of otherwise unexplained gastrointestinal bleeding and anemia
. Lesions are often multiple, and frequently involve the cecum
or ascending colon
, although they can occur at other places. Treatment may be with endoscopic interventions, medication, or occasionally surgery.
), the blood loss can be subtle, with the anemia symptoms predominating. Fecal occult blood
testing is positive when bleeding is active. If bleeding is intermittent the test may be negative at times.
, either colonoscopy
or 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, especially in the small bowel which is difficult to reach with traditional endoscopy. 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.
Angiodysplasiae in the small bowel can also be diagnosed and treated with double-balloon enteroscopy
, a technique involving a long endoscopic camera and overtube, both fitted with balloons, that allow the bowel to be accordioned over the camera.
In cases with negative endoscopic findings and high clinical suspicion, selective angiography of the mesenteric arteries is sometimes necessary, but this allows for interventions at time of the procedure. An alternative is scintigraphy
with red blood cell
s labeled with a radioactive marker; this shows the site of the bleeding on a gamma camera
but tends to be unhelpful unless the bleeding is continuous and significant.
. 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 bleeding
is increased in disorders of coagulation
. A classic association is Heyde's syndrome
(coincidence of aortic valve stenosis
and bleeding from angiodysplasia).
In this disorder, von Willebrand factor
(vWF) is proteolysed due to high shear stress
in 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.
is required before any other intervention is considered. Endoscopic
treatment is an initial possibility, where cautery or argon plasma coagulation
(APC) laser treatment is applied through the endoscope. Resection
of the affected part of the bowel may be needed. However, the lesions may be widespread, making such treatment impractical. Embolisation through angiography is occasionally contemplated with severely bleeding lesions that cannot be visualised on colonoscopy.
If the bleeding is from multiple or inaccessible sites, systemic therapy with medication
may be necessary. First-line options include the antifibrinolytic
s tranexamic acid
or aminocaproic acid
. 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 swelling
is bothersome in men, but older women often report improvement of libido
and perimenopausal
symptoms. (The worries about hormone replacement therapy
/HRT, however, apply here as well.)
In difficult cases, there have been positive reports about octreotide
and thalidomide.
In severe cases or cases not responsive to either endoscopic or medical treatment, surgery
may be necessary to arrest the bleeding.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
(gastroenterology
Gastroenterology
Gastroenterology is the branch of medicine whereby the digestive system and its disorders are studied. The name is a combination of three Ancient Greek words gaster , enteron , and logos...
), angiodysplasia is a small vascular
Blood vessel
The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...
malformation of the gut
Gut (zoology)
In zoology, the gut, also known as the alimentary canal or alimentary tract, is a tube by which bilaterian animals transfer food to the digestion organs. In large bilaterians the gut generally also has an exit, the anus, by which the animal disposes of solid wastes...
. It is a common cause of otherwise unexplained gastrointestinal bleeding and anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...
. Lesions are often multiple, and frequently involve the cecum
Cecum
The cecum or caecum is a pouch, connecting the ileum with the ascending colon of the large intestine. It is separated from the ileum by the ileocecal valve or Bauhin's valve, and is considered to be the beginning of the large intestine. It is also separated from the colon by the cecocolic...
or ascending colon
Ascending colon
The ascending colon is smaller in caliber than the cecum.It passes upward, from its commencement at the cecum, opposite the colic valve, to the under surface of the right lobe of the liver, on the right of the gall-bladder, where it is lodged in a shallow depression, the colic impression; here it...
, although they can occur at other places. Treatment may be with endoscopic interventions, medication, or occasionally surgery.
Signs and symptoms
Although some cases present with black, tarry stool (melenaMelena
In medicine, melena or melaena refers to the black, "tarry" feces that are associated with gastrointestinal hemorrhage. The black color is caused by oxidation of the iron in hemoglobin during its passage through the ileum and colon.-Melena vs...
), the blood loss can be subtle, with the anemia symptoms predominating. Fecal occult blood
Fecal occult blood
Fecal occult blood refers to blood in the feces that is not visibly apparent. A fecal occult blood test checks for hidden blood in the stool...
testing is positive when bleeding is active. If bleeding is intermittent the test may be negative at times.
Diagnosis
Diagnosis of angiodysplasia is often accomplished with endoscopyEndoscopy
Endoscopy means looking inside and typically refers to looking inside the body for medical reasons using an endoscope , an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ...
, either colonoscopy
Colonoscopy
Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
or esophagogastroduodenoscopy
Esophagogastroduodenoscopy
For other expansions of the initialism "OGD", see the disambiguation page.In medicine , esophagogastroduodenoscopy is a diagnostic endoscopic procedure that visualizes the upper part of the gastrointestinal tract up to the duodenum...
(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, especially in the small bowel which is difficult to reach with traditional endoscopy. 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.
Angiodysplasiae in the small bowel can also be diagnosed and treated with double-balloon enteroscopy
Double-balloon enteroscopy
Double-balloon enteroscopy, also known as push-and-pull enteroscopy is an endoscopic technique for visualization of the small bowel. It was developed by Hironori Yamamoto in 2001...
, a technique involving a long endoscopic camera and overtube, both fitted with balloons, that allow the bowel to be accordioned over the camera.
In cases with negative endoscopic findings and high clinical suspicion, selective angiography of the mesenteric arteries is sometimes necessary, but this allows for interventions at time of the procedure. An alternative is scintigraphy
Scintigraphy
Scintigraphy is a form of diagnostic test used in nuclear medicine, wherein radioisotopes are taken internally, and the emitted radiation is captured by external detectors to form two-dimensional images...
with red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...
s labeled with a radioactive marker; this shows the site of the bleeding on a gamma camera
Gamma camera
A gamma camera, also called a scintillation camera or Anger camera, is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy...
but tends to be unhelpful unless the bleeding is continuous and significant.
Pathophysiology
Histologically, it resembles telangiectasiaTelangiectasia
Telangiectasias /tɛ.læn.dʒiː'ɛk.teɪ.ʃi:ə/ are small dilated blood vessels near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. They can develop anywhere on the body but are commonly seen on the face around the nose, cheeks, and chin...
. 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 bleeding
Bleeding
Bleeding, technically known as hemorrhaging or haemorrhaging is the loss of blood or blood escape from the circulatory system...
is increased in disorders of coagulation
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
. A classic association is Heyde's syndrome
Heyde's syndrome
Heyde's syndrome is a syndrome of aortic valve stenosis associated with gastrointestinal bleeding from colonic angiodysplasia. It is named after Dr. Edward C. Heyde, who first described the association in 1958...
(coincidence of aortic valve stenosis
Aortic valve stenosis
Aortic valve stenosis is a disease of the heart valves in which the opening of the aortic valve is narrowed. The aortic valve is the valve between the left ventricle of the heart and the aorta, which is the largest artery in the body and carries the entire output of blood.-Pathophysiology:The...
and bleeding from angiodysplasia).
In this disorder, von Willebrand factor
Von Willebrand factor
von Willebrand factor is a blood glycoprotein involved in hemostasis. It is deficient or defective in von Willebrand disease and is involved in a large number of other diseases, including thrombotic thrombocytopenic purpura, Heyde's syndrome, and possibly hemolytic-uremic syndrome...
(vWF) is proteolysed due to high shear stress
Shear stress
A shear stress, denoted \tau\, , is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section...
in 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
Aortic valve stenosis
Aortic valve stenosis is a disease of the heart valves in which the opening of the aortic valve is narrowed. The aortic valve is the valve between the left ventricle of the heart and the aorta, which is the largest artery in the body and carries the entire output of blood.-Pathophysiology:The...
, some other conditions that feature high shear stress might also increase the risk of bleeding from angiodysplasia.
Therapy
If the anemia is severe, blood transfusionBlood transfusion
Blood transfusion is the process of receiving blood products into one's circulation intravenously. Transfusions are used in a variety of medical conditions to replace lost components of the blood...
is required before any other intervention is considered. Endoscopic
Endoscopy
Endoscopy means looking inside and typically refers to looking inside the body for medical reasons using an endoscope , an instrument used to examine the interior of a hollow organ or cavity of the body. Unlike most other medical imaging devices, endoscopes are inserted directly into the organ...
treatment is an initial possibility, where cautery or argon plasma coagulation
Argon plasma coagulation
Argon plasma coagulation or APC is a medical endoscopic procedure used primarily to control bleeding from certain lesions in the gastrointestinal tract, and also sometimes to debulk tumours in the case of patients for whom surgery is not recommended...
(APC) laser treatment is applied through the endoscope. Resection
Segmental resection
Segmental resection is a surgical procedure to remove part of an organ or gland. It may also be used to remove a tumor and normal tissue around it. In lung cancer surgery, segmental resection refers to removing a section of a lobe of the lung.- External links :* entry in the public domain NCI...
of the affected part of the bowel may be needed. However, the lesions may be widespread, making such treatment impractical. Embolisation through angiography is occasionally contemplated with severely bleeding lesions that cannot be visualised on colonoscopy.
If the bleeding is from multiple or inaccessible sites, systemic therapy with medication
Medication
A pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
may be necessary. First-line options include the antifibrinolytic
Antifibrinolytic
Antifibrinolytics, such as aminocaproic acid and tranexamic acid are used as inhibitors of fibrinolysis. These lysine-like drugs interfere with the formation of the fibrinolytic enzyme plasmin from its precursor plasminogen by plasminogen activators which takes place mainly in lysine rich areas...
s tranexamic acid
Tranexamic acid
Tranexamic acid is a drug used to treat or prevent excessive blood loss during surgery and in certain other conditions...
or aminocaproic acid
Aminocaproic acid
Aminocaproic acid is a derivative and analogue of the amino acid lysine, which makes it an effective inhibitor for enzymes that bind that particular residue. Such enzymes include proteolytic enzymes like plasmin, the enzyme responsible for fibrinolysis...
. 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 swelling
Gynecomastia
Gynecomastia or Gynaecomastia, , is the abnormal development of large mammary glands in males resulting in breast enlargement. The term comes from the Greek γυνή gyné meaning "woman" and μαστός mastós meaning "breast"...
is bothersome in men, but older women often report improvement of libido
Libido
Libido refers to a person's sex drive or desire for sexual activity. The desire for sex is an aspect of a person's sexuality, but varies enormously from one person to another, and it also varies depending on circumstances at a particular time. A person who has extremely frequent or a suddenly...
and perimenopausal
Menopause
Menopause is a term used to describe the permanent cessation of the primary functions of the human ovaries: the ripening and release of ova and the release of hormones that cause both the creation of the uterine lining and the subsequent shedding of the uterine lining...
symptoms. (The worries about hormone replacement therapy
Hormone replacement therapy (menopause)
Hormone replacement therapy is a system of medical treatment for surgically menopausal, perimenopausal and to a lesser extent postmenopausal women...
/HRT, however, apply here as well.)
In difficult cases, there have been positive reports about octreotide
Octreotide
Octreotide is an octapeptide that mimics natural somatostatin pharmacologically, though it is a more potent inhibitor of growth hormone, glucagon, and insulin than the natural hormone...
and thalidomide.
In severe cases or cases not responsive to either endoscopic or medical treatment, surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
may be necessary to arrest the bleeding.