National Spinal Cord Injury Association Resource Center
Autonomic Dysreflexia (AD), also known as Hyperreflexia,
is a potentially dangerous complication of spinal cord
injury (SCI). In AD, an individual's blood pressure may
rise to dangerous levels and if not treated can lead to
stroke and possibly death. Individuals with SCI at the
T-6 level or above are at greater risk. AD usually occurs
because of a noxious (irritating) stimulus below the
level of the injury. Symptoms include headache, facial
flush, perspiration, and a stuffy nose.
What is Autonomic Dysreflexia?
AD occurs primarily because of an imbalance in the
body systems which control the blood pressure. The human
body is an incredibly complicated and beautifully
balanced machine. There are balances to each system of
the body, including the blood pressure. One of the major
ways the body controls blood pressure is by tightening or
relaxing little muscles around the blood vessels. When
the muscles contract, the blood vessels get smaller and
blood pressure increases. Imagine a garden hose with
water streaming through it; when you put your thumb over
the opening of the hose, reducing the opening for the
water to flow through, the water shoots out at a higher
pressure. Similarly, when the blood vessels are smaller,
the blood rushes around your body at higher pressure.
When a noxious stimulus occurs, a reflex is initiated
that causes the blood vessels to constrict and raises the
blood pressure. In an intact spinal cord, this same
stimulus also sets in motion another set of reflexes that
moderates the constriction of blood vessels. However, in
someone who has SCI at the T-6 level or above, the signal
which tells the blood vessels to relax cannot get through
the spinal cord because of the injury. Some of the nerves
at the T-6 level also control the blood flow to and from
the gut, which is a large reservoir of blood.
Uncontrolled activity of these nerves may cause the blood
from the gut to flow into the rest of the blood system.
The result is that blood pressure can increase to
dangerous levels and the increase in blood pressure must
be controlled by outside means.
Topics covered in this fact sheet include:
How do I recognize Autonomic Dysreflexia?
Common sources of Autonomic Dysreflexia
What to do...
For a complete text of this fact sheet, join NSCIA.
The Factsheet is provided as an
information service to you and is not intended to be
replace a physicians advice. We thank Dr. Greg Nemunaitis
of the Medical College of Ohio for assistance in creating
this factsheet. Information you may have to update this
Factsheet is greatly appreciated. The NSCIA Resource
Center (NSCIRC) provides information and referral on any
subject related to spinal cord injury. Contact the
resource center at 1-800-962-9629.
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