Brain
Aneurism and
Subarachnoid HemorrhageA brain
aneurism (=cerebral aneurysm) is a sac-like malformation of a blood vessel
of one of the main arteries underneath the brain. It is a rare condition. However,
as it usually ruptures in a younger age group of 40 to 65 years, it has an enormous
social impact. The natural course of a ruptured
aneurism has recently been described in a large study from Australia and
New Zealand (Ref. 4). After 1 year from the subarachnoid hemorrhage the
following was found: Only 56% of patients were alive after one year and 46% of
these had a neurologically incomplete recovery. The deficits ranged from memory
loss (50%) to mood disturbances (39%), speech problems ( 14%) and problems with
self-care(10%). Some of these findings overlap and that's why it adds up to more
than 100%. These authors concluded that there is a high incidence of deficits
in neuropsychological functioning, which justify a more aggressive stance when
non symptomatic aneurisms are found on CT or MRI scans for other reasons. Another
study from Japan (Ref.5) underscores this as well.These authors followed 62
asymptomatic aneurism patients for 6 months to 17 years and they calculated the
cumulative risk for bleeding at the 5 year and 10 year follow-up points. For large
aneurisms( more than 10 mm in diameter) they found the risks for bleeding to be
7.5% and 22%. For small aneurisms( less than 10 mm) that bleeding risk was 4.5%
and 13.9% at the 5 and 10 year point in the study. The authors concluded that
with a 3-fold increase of the risk of bleeding in just 5 years regardless of the
size of the aneurism and a higher risk for larger aneurisms, the neurosurgeon
is justified to intervene by treating the asymptomatic aneurism on a preventative
basis. Another interesting study from Turkey showed that one important,
but neglected factor in the development of aneurisms of brain arteries is when
high blood pressure is not controlled (Ref. 6). These authors found that the incidence
of uncontrolled high blood pressure prior to an subarachnoid hemorrhage was almost
double compared to normal controls. They suggested the following sequence of events
that lead to the development of aneurisms: The uncontrolled high blood pressure
leads to a closing off of the nutritional small blood vessels that supply the
arterial wall with nutrients. This leads to a loss of the normal collagen and
elastic material in the arterial wall in a focal area. Subsequently the continued
pressure inside the artery leads to the pouch of the aneurism, which in time grows
larger until it ruptures. This new insight makes it very important for patients
to measure their own blood pressure to help reduce the incidence of the complications
of intracerebral and subarachnoid hemorrhages. Aneurism brain symptoms: Up
to the point of rupture of the aneurysm the patient may be entirely asymptomatic.
However, sometimes small warning leaks occur weeks and months before. These usually
are associated with a new headache or, if the person is a headache sufferer, perhaps
a different type of headache. Because of what was said above, it is important
to take this serious and do a CT scan or MRI scan to rule out an aneurism. Sometimes
it is very confusing for the physician as well as the patient as tension type
headaches and migraine headaches, which are much more common than a new cerebral
aneurism, can interfere with the recognition of an aneurism. If the pouch of an
aneurism puts pressure on one of the cranial nerves, there might be symptoms such
as double vision, visual field loss or cross-eyedness. With the actual rupture
of a brain aneurism there is an acute onset of a severe headache. Associated with
this would be a change of consciousness, which is more severe, the larger the
hemorrhage is. As the pressure inside the skull builds up from the bleed (elevated
intracranial pressure), such symptoms as vomiting, changes in pulse rate and respiratory
rate occur. Other symptoms such as dizziness, confusion, and eventual loss of
consciousness develop in the next few hours. Time is of essence as with quick
action, a fast CT scan, and a fast referral to the neurosurgeon hopefully the
bleeder can be identified and either be stopped from bleeding through angiographic
means or else by neurosurgery. Diagnosis: The initial
test usually is a CT scan. However, as the blood vessels are affected with the
development of a structural change, angiography is used not infrequently. This
test involves the injection of a substance, which shows up on X rays ( radio-opaque).
This way all of the blood vessels of the brain can be detected as aneurisms occasionally
happen simultaneously in several cerebral arteries. Treatment:
Without intervention about 35% of patients with a ruptured aneurism die
with the first bleed. Another 15% die within a few weeks from another rupture.
Because of these unfavorable statistics it is important to be much more aggressive
in terms of preventative therapeutic intervention than was done in the past. A
study, which comes from Paris/France, ( Ref. 7) demonstrated on 395 consecutive
patients that with either endovascular
coiling(75% of patients) or conventional
surgical clipping (25% of patients) a total success rate of 98.8% can
be achieved. The authors followed these patients for 3 years in intervals and
only 6% of the patients had to be retreated. The mortality rate from the procedures
was only 4.8%. Considering the overall poor prognosis without intervention, these
figures are encouraging and support the authors conclusion that either a neurosurgical
clipping or an angiographic coiling procedure can improve the poor survival statistics.
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