Arteriovenous Malformation (cont.)
What other types of vascular lesions affect the central nervous system?
Besides AVMs, three other main types of vascular lesion can arise in the
brain or spinal cord: cavernous malformations, capillary
telangiectases, and venous malformations. These lesions may form
virtually anywhere within the central nervous system, but unlike AVMs, they are
not caused by high-velocity blood flow from arteries into veins. In contrast,
cavernous malformations, telangiectases, and venous malformations are all
low-flow lesions. Instead of a combination of arteries
and veins, each one involves only one type of blood vessel. These lesions are
less unstable than AVMs and do not pose the same relatively high risk of
significant hemorrhage. In general, low-flow lesions tend to cause fewer
troubling neurological symptoms and require less aggressive treatment than do AVMs.
- Cavernous malformations.
These lesions are formed from groups of tightly packed, abnormally
thin-walled, small blood vessels that displace normal neurological tissue in
the brain or spinal cord. The vessels are filled with slow-moving or stagnant
blood that is usually clotted or in a state of decomposition. Like AVMs,
cavernous malformations can range in size from a few fractions of an inch to
several inches in diameter, depending on the number of blood vessels involved.
Some people develop multiple lesions. Although cavernous malformations usually
do not hemorrhage as severely as AVMs do, they sometimes leak blood into
surrounding neurological tissues because the walls of the involved blood
vessels are extremely fragile. Although they are often not as symptomatic as
AVMs, cavernous malformations can cause seizures in some people. After AVMs,
cavernous malformations are the type of vascular lesion most likely to require
treatment.
- Capillary telangiectases. These lesions consist of groups of
abnormally swollen capillaries and usually measure less than an inch in
diameter. Capillaries are the smallest of all blood vessels, with diameters
smaller than that of a human hair; they have the capacity to transport only
small quantities of blood, and blood flows through these vessels very
slowly. Because of these factors, telangiectases rarely cause extensive
damage to surrounding brain or spinal cord tissues. Any isolated hemorrhages
that occur are microscopic in size. Thus, the lesions are usually benign. However, in
some inherited disorders in which people develop large numbers of these
lesions (see below), telangiectases can contribute to the development of
nonspecific neurological symptoms such as headaches or seizures.
- Venous malformations. These lesions consist of abnormally
enlarged veins. The structural defect usually does not interfere with the
function of the blood vessels, which is to drain oxygen-depleted blood away
from the body's tissues and return it to the lungs and heart. Venous
malformations rarely hemorrhage. As with telangiectases, most venous
malformations do not produce symptoms, remain undetected, and follow a
benign course.
Next: What causes vascular lesions? »
- CT Scan (Computerized Axial Tomography) - CT Scan (Computerized Axial Tomography, CAT scan) is a procedure that assists in diagnosing tumors, fractures, bony structures, and infections in the organs and tissues of the body.
- Headache - Learn about the different types of headaches, migraine, tension, cluster, menstrual, and spinal headaches; and their causes, symptoms, diagnosis and treatment.
- MRI (Magnetic Resonance Imaging Scan) - Medical information on magnetic resonance imaging (MRI) used in detecting structural abnormalities of the body. Learn uses, risks, and how to prepare for an MRI scan
Latest Medical News
|
|
 |
From WebMD
Healthy Resources
Featured Centers
Health Solutions From Our Sponsors
|
Neurology RSS