Find information on thousands of medical conditions and prescription drugs.

Aneurysm

An aneurysm (or aneurism) (from Greek ανευρυσμα, a dilatation) is a localized dilation or ballooning of a blood vessel by more than 50% of the diameter of the vessel. Aneurysms most commonly occur in the arteries at the base of the brain (the circle of Willis) and in the aorta (the main artery coming out of the heart) - this is an aortic aneurysm. more...

Home
Diseases
A
Aagenaes syndrome
Aarskog Ose Pande syndrome
Aarskog syndrome
Aase Smith syndrome
Aase syndrome
ABCD syndrome
Abdallat Davis Farrage...
Abdominal aortic aneurysm
Abdominal cystic...
Abdominal defects
Ablutophobia
Absence of Gluteal muscle
Acalvaria
Acanthocheilonemiasis
Acanthocytosis
Acarophobia
Acatalasemia
Accessory pancreas
Achalasia
Achard syndrome
Achard-Thiers syndrome
Acheiropodia
Achondrogenesis
Achondrogenesis type 1A
Achondrogenesis type 1B
Achondroplasia
Achondroplastic dwarfism
Achromatopsia
Acid maltase deficiency
Ackerman syndrome
Acne
Acne rosacea
Acoustic neuroma
Acquired ichthyosis
Acquired syphilis
Acrofacial dysostosis,...
Acromegaly
Acrophobia
Acrospiroma
Actinomycosis
Activated protein C...
Acute febrile...
Acute intermittent porphyria
Acute lymphoblastic leukemia
Acute lymphocytic leukemia
Acute mountain sickness
Acute myelocytic leukemia
Acute myelogenous leukemia
Acute necrotizing...
Acute promyelocytic leukemia
Acute renal failure
Acute respiratory...
Acute tubular necrosis
Adams Nance syndrome
Adams-Oliver syndrome
Addison's disease
Adducted thumb syndrome...
Adenoid cystic carcinoma
Adenoma
Adenomyosis
Adenosine deaminase...
Adenosine monophosphate...
Adie syndrome
Adrenal incidentaloma
Adrenal insufficiency
Adrenocortical carcinoma
Adrenogenital syndrome
Adrenoleukodystrophy
Aerophobia
Agoraphobia
Agrizoophobia
Agyrophobia
Aicardi syndrome
Aichmophobia
AIDS
AIDS Dementia Complex
Ainhum
Albinism
Albright's hereditary...
Albuminurophobia
Alcaptonuria
Alcohol fetopathy
Alcoholic hepatitis
Alcoholic liver cirrhosis
Alektorophobia
Alexander disease
Alien hand syndrome
Alkaptonuria
Alliumphobia
Alopecia
Alopecia areata
Alopecia totalis
Alopecia universalis
Alpers disease
Alpha 1-antitrypsin...
Alpha-mannosidosis
Alport syndrome
Alternating hemiplegia
Alzheimer's disease
Amaurosis
Amblyopia
Ambras syndrome
Amelogenesis imperfecta
Amenorrhea
American trypanosomiasis
Amoebiasis
Amyloidosis
Amyotrophic lateral...
Anaphylaxis
Androgen insensitivity...
Anemia
Anemia, Diamond-Blackfan
Anemia, Pernicious
Anemia, Sideroblastic
Anemophobia
Anencephaly
Aneurysm
Aneurysm
Aneurysm of sinus of...
Angelman syndrome
Anguillulosis
Aniridia
Anisakiasis
Ankylosing spondylitis
Ankylostomiasis
Annular pancreas
Anorchidism
Anorexia nervosa
Anosmia
Anotia
Anthophobia
Anthrax disease
Antiphospholipid syndrome
Antisocial personality...
Antithrombin deficiency,...
Anton's syndrome
Aortic aneurysm
Aortic coarctation
Aortic dissection
Aortic valve stenosis
Apert syndrome
Aphthous stomatitis
Apiphobia
Aplastic anemia
Appendicitis
Apraxia
Arachnoiditis
Argininosuccinate...
Argininosuccinic aciduria
Argyria
Arnold-Chiari malformation
Arrhythmogenic right...
Arteriovenous malformation
Arteritis
Arthritis
Arthritis, Juvenile
Arthrogryposis
Arthrogryposis multiplex...
Asbestosis
Ascariasis
Aseptic meningitis
Asherman's syndrome
Aspartylglycosaminuria
Aspergillosis
Asphyxia neonatorum
Asthenia
Asthenia
Asthenophobia
Asthma
Astrocytoma
Ataxia telangiectasia
Atelectasis
Atelosteogenesis, type II
Atherosclerosis
Athetosis
Atopic Dermatitis
Atrial septal defect
Atrioventricular septal...
Atrophy
Attention Deficit...
Autoimmune hepatitis
Autoimmune...
Automysophobia
Autonomic dysfunction
Familial Alzheimer disease
Senescence
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Medicines

The layer of the artery that is in direct contact with the flow of blood is the tunica intima, commonly called the intima. This layer is made up of mainly endothelial cells. Adjacent to this layer is the tunica media, known as the media. This "middle layer" is made up of smooth muscle cells and elastic tissue. The outermost layer (farthest from the flow of blood) is known as the tunica adventitia or the adventitia. This layer is composed of connective tissue.

Types

Aneurysms are also described according to their shape: Saccular or fusiform. Aneurysms can be broken down into two groups: true aneurysms and false aneurysms. A true aneurysm involves an outpouching of all three layers of a blood vessel: the intima, the media, and the adventitia. True aneurysms can be due to congenital malformations, infections, or hypertension. A false aneurysm, also known as a pseudoaneurysm, involves an outpouching of only the adventitia. Pseudoaneurysms can be due to trauma involving the intima of the blood vessel, and are a known complication of percutaneous arterial procedures.

Locations

Aneurysms can occur anywhere where there is a blood vessel, although they are most common in arteries. Most non-intracranial aneurysms (95%) arise distal to the origin of the renal arteries at the infrarenal abdominal aorta, a condition mostly caused by atherosclerosis. The thoracic aorta can also be involved. One common form of thoracic aortic aneurysm involves widening of the proximal aorta and the aortic root, which leads to aortic insufficiency. Aneurysms occur in the legs also, particularly in the deep vessels (e.g., the popliteal vessels in the knee). Arterial aneurysms are much more common, but venous aneurysms do happen (for example, the popliteal venous aneurysm).

  • While most aneurysms occur in an isolated form, the occurrence of berry aneurysms of the anterior communicating artery of the circle of Willis is associated with autosomal dominant polycystic kidney disease (ADPKD).
  • The third stage of syphilis also manifests as aneurysm of the aorta, which is due to loss of the vasa vasorum in the tunica adventitia.

Risks

Rupture and blood clotting are the risks involved with aneurysms. Rupture leads to drop in blood pressure, rapid heart rate, and lightheadedness. The risk of death is high except for rupture in the extremities. Blood clots from popliteal arterial aneurysms can travel downstream and suffocate tissue. Only if the resulting pain and/or numbness are ignored over a significant period of time will such extreme results as amputation be needed. Clotting in popliteal venous aneurysms are much more serious as the clot can embolise and travel to the heart, or through the heart to the lungs (a pulmonary embolism).

Read more at Wikipedia.org


[List your site here Free!]


Aortic aneurysm
From Gale Encyclopedia of Medicine, 4/6/01 by Dominic De Bellis

Definition

An aneurysm is an abnormal bulging or swelling of a portion of a blood vessel. The aorta, which can develop these abnormal bulges, is the large blood vessel that carries oxygen-rich blood away from the heart to the rest of the body.

Description

The aorta carries oxygen-rich blood to the body, and is therefore called an artery. Because the aorta is an artery, its walls are made of up three layers; a thin inner layer, a muscular middle layer (that gives the vessel its flexibility under pressure from the filling blood), and a fiber-like outer layer that gives the vessel strength to not burst when the heart pumps blood to the body.

Aortic aneurysms occur when a weakness develops in part of the wall of the aorta; three basic types are usually found. If all three layers of the vessel are affected and weakness develops along an extended area of the vessel, the weakened area will appear as a large, bulging region of blood vessel; this is called a fusiform aneurysm. If weakness develops between the inner and outer layers of the aortic wall, a bulge results as blood from the interior of the vessel is pushed around the damaged region in the wall and collects between these layers. This is called a dissecting aneurysm because one layer is "dissected" or separated from another. If damage occurs to only the middle (muscular) layer of the vessel, a sack-like bulge can form; therefore, this is a saccular aneurysm.

Causes & symptoms

Aortic aneurysms occur in different portions of the aorta, which begins in the chest (at the heart) and travels downward through the abdomen. Aneurysms found in the region of the aorta within the chest are called thoracic aortic aneurysms. Aneurysms that occur in the part of the aorta within the abdomen are called abdominal aortic aneurysms.

Thoracic aortic aneurysms do not usually produce any noticeable symptoms. However, as the aneurysm becomes larger, chest, shoulder, neck, lower back, or abdominal pain can result. Abdominal aortic aneurysms occur more often in men, and these aneurysms can cause pain in the lower back, hips, and abdomen. A painful abdominal aortic aneurysm usually means that the aneurysm could burst very soon.

Most abdominal aortic aneurysms are caused by atherosclerosis, a condition caused when fat (mostly cholesterol) carried in the blood builds up in the inner wall of the aorta. As more and more fat attaches to the aortic wall, the wall itself becomes abnormally weak and often results in an aneurysm or bulge.

Aortic aneurysms are also caused by a breakdown of the muscular middle layer of the artery wall, by high blood pressure, by direct injury to the chest, and although rare, by bacteria that can infect the aorta.

Diagnosis

Silent, stable aneurysms are often detected when a person has an x ray as part of a routine examination or for other medical reasons. Otherwise, when chest, abdominal, or back pain is severe, aortic aneurysm is suspected and x-ray (radiographic) studies can confirm or rule out that condition.

Treatment

Aortic aneurysms are potentially life-threatening conditions. Small aneurysms should be monitored for their rate of growth and large aneurysms require consideration for a surgical repair. The most common method of surgical repair is to cut out the bulging section of artery wall and sew a Dacron fiber material into its place in the vessel wall.

Prognosis

Only 1-2% of people die from having surgical repair of an aortic aneurysm. However, if the aneurysm is untreated and eventually ruptures, less than half of the people with ruptured aneurysms will survive. The challenge for the physician is to decide when or if to do the preventive surgery.

Prevention

Aneuryms can develop in people with atherosclerosis. High blood pressure can also lead to this condition. Although no definite prevention exists, lifestyle and dietary changes that help lower blood pressure and the amount of fat in the blood stream may slow the development of aneurysms.

Key Terms

Atherosclerosis
The accumulation of fat on the inner wall of an artery. This fat is largely made up of cholesterol being carried in the blood.
Dacron
A synthetic polyester fiber used to surgically repair damaged sections of blood vessel walls.

Further Reading

For Your Information

    Books

  • "Aneurysms and Other Vascular Disorders." In Cardiovascular Diseases and Disorders Sourcebook, edited by Karen Bellenir and Peter D. Dresser. Detroit: Omnigraphics, Inc., 1995, 99-101.
  • Dzau, Victor J. and Mark A.Creager. "Diseases of the Aorta." In Harrison's Principles of Internal Medicine, edited by Anthony S. Fauci, et al. New York: McGraw Hill, 1998, 1394-1395.
  • Lindsay, Joseph L., Michael E. DeBakey, and Arthur C. Beall. "Diagnosis and Treatment of Diseases of the Aorta." In Hurst's The Heart, edited by Robert C. Schlant, et al. New York: McGraw Hill, 1994, 2166-2170.

    Periodicals

  • van der Vleit, J. Adam and Albert P.M. Boll. "Abdominal Aortic Aneurysm." The Lancet 349 (March 22, 1997): 863.

    Organizations

  • The American Heart Association. 7272 Greenville Ave., Dallas, TX 75231-4596. (800)787-8984. http://www.americanheart.org/.
  • National Heart, Lung, and Blood Institute. P.O. Box 30105 Bethesda, MD 20892-2486. (301) 251-1222. http://www.nhlbi.nih.gov/nhlbi/nhlbi.htm.

Gale Encyclopedia of Medicine. Gale Research, 1999.

Return to Aneurysm
Home Contact Resources Exchange Links ebay