Concussion
Definition
A concussion is a significant blow to the head that may result
in unconsciousness (see also concussion - first
aid).
Causes
and risks
A concussion may result
from a fall in which the head strikes against
an object or a moving object strikes the head.
Significant jarring in any direction can produce
unconsciousness. It is thought that there may
be microscopic shearing of nerve fibers in the
brain from the sudden acceleration or decelaration
resulting from the injury to the head.
The length of unconsciousness
may relate to the severity of the concussion.
Often victims have no memory of events preceding
the injury or immediately after regaining consciousness
with worse injuries causing longer periods of
amnesia.
Often the maximal memory
loss occurs immediately after the injury with
regaining of some memory function as time passes.
Complete memory recovery for the event may not
occur.
Bleeding into or around
the brain can occur with any blow to the head,
whether or not unconsciousness occurs. If someone
has received a blow to the head, observe closely
for signs indicating possible brain damage.
Things to watch for
include repetitive vomiting, unequal pupils,
confused mental state or varying levels of consciousness,
seizure-like activity, weakness on one side
of the body or the inability to wake up (coma).
If any of these signs are present, contact your
health care provider promptly.
Prevention
Attention to safety, including
the use of appropriate athletic gear, such as
bike helmets and seat belts, reduces the risk
of head injury.
Symptoms
- Loss of consciousness
after a blow to the head
- Amnesia of events
surrounding the injury
Emergency signs:
- Persistent unconsciousness
(coma)
- Altered level of
consciousness (drowsy, hard to arouse, or
similar changes)
- Persistent confusion
- Convulsions
- Repeated vomiting
- Unequal pupils
- Unusual eye movements
- Muscle weakness on
one or both sides
- Gait or walking abnormalities
Signs
and tests
A neurological examination
may show abnormalities.
Tests that may be performed
include:
Treatment
An initial "baseline"
neurological evaluation by a health care worker
determines treatment for an uncomplicated concussion.
If a blow to the head during athletics leads
to unconsciousness, a trained person must determine
readiness for continued participation and timing
for return to play.
In this situation, if
a child or young adult has lost consciousness,
that person should not resume athletics for
a period of 3 months. Studies have shown that
there is an increased rate of brain injury and
occasionally death in people who have had a
previous concussion with unconsciousness.
Concussion complicated
by bleeding or brain damage must be treated
in a hospital.
Prognosis
Full recovery is expected
from an uncomplicated concussion, although prolonged
dizziness, irritability, headaches, and other
symptoms may occur.
