aneurysm, or to rupture. An aneurysm that rup-
tures in the BRAINcauses hemorrhagic STROKE, with
mild to severe consequences depending on its
location and size. Fewer than 5 percent of strokes
are hemorrhagic.
Aneurysms sometimes accompany congenital
malformations of the blood vessels, called ARTERI-
OVENOUS MALFORMATIONS(AV Ms), in which the arter-
ies and veins in a particular location, usually in
the brain or brainstem, form an entangled mass.
Aneurysms are also common in MARFAN’S SYN-
DROME, a genetic disorder that affects the muscu-
loskeletal and cardiovascular systems. Most
aneurysms, however, result from atherosclerotic
deposits that damage and weaken the walls of the
arteries. HYPERTENSION(high BLOOD PRESSURE), when
present, exacerbates the situation by exerting fur-
ther pressure against the weakened area of the
artery.
A ruptured aneurysm is a life-threaten-
ing emergency that requires immediate
medical attention. Loss of blood can be
rapid and massive.Often an aneurysm shows no symptoms. The
doctor may detect an aneurysm during a ROUTINE
MEDICAL EXAMINATIONor during testing or treatment
for other medical conditions. Cerebral aneurysms
may cause seizures, HEADACHE, or symptoms simi-
lar to stroke such as weakness on one side of the
body and memory lapses or cognitive dysfunction.
An abdominal or thoracic aortic aneurysm may
cause PAIN (usually severe) in the area of the
aneurysm. These symptoms are usually transient
(come and go) though are crucial warning signs
that the aneurysm is unstable. Sometimes the doc-
tor can palpate an abdominal aneurysm, feeling its
pulsations through the abdominal wall. COMPUTED
TOMOGRAPHY(CT) SCANor MAGNETIC RESONANCE IMAG-
ING (MRI) can affirm the diagnosis. Surgery to
repair the aneurysm, in which the surgeon either
removes the weakened segment and sutures the
healthy ends of the artery together or applies a
synthetic patch over the area of weakness, is the
only curative treatment. When doctors detect and
repair aneurysms before they rupture, they sel-
dom cause further health problems and require no
special care after HEALING. It is important to treat
the condition that may have caused the
aneurysm, when possible, to prevent aneurysms
from developing in other locations.
See also ATHEROSCLEROSIS; COGNITIVE FUNCTION AND
DYSFUNCTION; CONGENITAL ANOMALY; CORONARY ARTERY
DISEASE(CAD); GENETIC DISORDERS; LIFESTYLE AND CAR-
DIOVASCULAR HEALTH; SEIZURE DISORDERS.angina pectoris Chest discomfort originating
from the HEART, usually resulting from restricted
BLOODflow due to CORONARY ARTERY DISEASE(CAD)
that occludes (blocks) one or more of the CORO-
NARY ARTERIES. Coronary ARTERYspasm, especially
that resulting from COCAINEuse, may also cause
angina. Some people experience a crushing pres-
sure that radiates into the left shoulder, arm, and
THROAT. Other people experience discomfort simi-
lar to DYSPEPSIA(indigestion or heartburn). Though
the nature and quality of discomfort varies among
individuals, for most people angina pectoris is a
chronic (long-standing) condition with predictable
symptoms that appear with exertion and subside
with rest.An angina pectoris attack lasts only a
few minutes, with rest bringing pro-
nounced relief. CHEST PAINthat persists
longer suggests HEART ATTACK and
requires immediate medical attention.Angina pectoris does not signalHEART ATTACK,
though it is a warning that atherosclerotic accu-
mulations in the coronary arteries have narrowed
the arterial lumen (channel or opening through
which blood flows) by 70 percent or more. When
exercise or other stress (such as stepping out into
a cold wind) increases the demand on the heart to
pump more blood, the stiffened and narrowed
coronary arteries, which in health could expand to
nearly double the volume of blood flowing
through them, cannot respond. The heart MUSCLE
(MYOCARDIUM) fails to receive the oxygen it needs
as well as to dispose of the metabolic wastes that
are accumulating within its cells.
Treatment for angina pectoris generally com-
bines relieving symptoms and mitigating the
underlying cause. Medications to treat angina pec-
toris cause smooth muscle tissue (such as makes
up the walls of the arteries) to relax. This allowsangina pectoris 11