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Severe
Headache May
Signal Clot in Brain Vein
A
severe headache can indicate a stroke, but it could signal a lot
of other things too. Research presented today at the American
Stroke Association’s 26th International Stroke Conference may
help doctors tell the difference between a headache or migraine
and a rare stroke called cerebral venous thrombosis (CVT). The
American Stroke Association is a division of the American Heart
Association.
Researchers
at the University of San Paulo, Brazil have pinpointed some characteristics
of headaches that indicate a CVT - the formation of a blood clot
in a vein of the brain. While most clots occur in arteries (which
carry blood from the heart to the rest of the body) blood clots
in a vein (which carries blood to the heart) is an infrequent
condition.
CVT is often
difficult to diagnose because individuals may experience a wide
range of symptoms including headaches, seizures or visual impairments.
Symptoms can occur suddenly or progress for weeks.
"It is particularly
important to recognize this condition early before the clot may
spread in the cerebral venous system leading to other neurological
complications such as - seizures, visual or motor deficits and
increase of intracranial pressure," says lead researcher Ãrica
C.S. de Camargo, M.D.
Headache
is frequently the first symptom reported by patients arriving
in emergency rooms. The Brazilian study aimed to identify the
specific characteristics of CVT-related headache to help differentiate
CVT from other conditions.
Thirty-nine
patients (69 percent female, average age 35 years) were evaluated
from March 1996 to June 2000. They were confirmed to have CVT
by magnetic resonance imaging and/or angiography. Pertinent headache
information such as location, severity and duration was recorded
on a standardized form.
Seventy-four
percent of patients with headaches also had weakness, sensory
deficits, visual impairments or nausea. Most of the headaches
were limited to one side of the head (63 percent) and pulsated
(49 percent). Pain worsened with head movement (31 percent), physical
activity (23 percent) and coughing or sneezing (20 percent).
Headache
onset occurred within 48 hours before seeking medical treatment
in 26 percent of patients, while 54 percent of patients reported
having chronic headaches for more than 30 days.
Headache
was the most common symptom (84.6 percent) given for seeking medical
care among those studied. But almost half those individuals had
experienced headaches before, which may have delayed a correct
diagnosis.
Another finding
was the presence of "thunderclap" headaches described as very
severe and sudden headaches in 11.4 percent of patients and higher
cerebrospinal fluid pressures in these patients as compared to
those with severe, but not thunderclap, headaches.
The researchers
found that in some CVT patients headaches may be sudden and severe
mimicking subarachnoid hemorrhage -- a type of stroke characterized
by a blood vessel bleeding into the small space between the membranes
surrounding the brain -- or chronic migraine.
In individuals
with prior headaches, changes in the characteristics of the headache
as well as the presence of neurological signs are important clues
to diagnosis, researchers say.
"An accurate
diagnosis means patients can receive optimal treatment, including
prompt anticoagulant therapy to manage the blood clot, which improves
outcomes," says Camargo.
Camargo acknowledges
that the small sample size of this study and lack of a control
group make the results less generalizable, but believes CVT is
underecognized and should be included in the diagnosis of headache
in the emergency room. A larger ongoing international study is
underway.
Reference
Source 101
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