CEREBRAL
ANEURYSM
What is Cerebral Aneurysm?
A cerebral or brain aneurysm is a
cerebrovascular disorder in which weakness in the wall of cerebral artery or
vein causes a localized dilation or ballooning
of the blood vessel .
Location
A common location of cerebral aneurysms is on the arteries at
the base of the brain, known as the
circle of willis , approximately 85% of cerebral aneurysms develop in the anterior part of the circle of
willis , and involve the internal carotid
arteries and their major branches
that supply the anterior and middle section of the brain . the most common
sites include the anterior cerebral artery and anterior communicating artery
(30-35%), the bifurcation , division of two branches, of the internal carotid
and posterior communicating artery (30-35%), the bifurcation
of the middle cerebral artery (20%), the bifurcation of the basilar
artery, and the remaining posterior circulation arteries (5%).
Classification
of aneurysm
According to size
1.
Fusiform
aneurysm: It is a diffuse dilation that involves the entire circumference of
the arterial segment i. e . whole artery.
2.
Saccular
aneurysm : It is a distention of a vessel projecting from one side. Saccular
aneurysm is a distinct , localized out pouching of the arterial wall.
3.
Dissecting
aneurysm : Hemorrhage or intramural hematoma , separating the layers of an
arterial wall. Dissecting aneurysm commonly involves arch of aorta.
According to Cause
1.True Aneury It is a result of the slow
weakening of the arterial wall caused by long term diseases such as
hypertension, atherosclerosis, etc
2. False Aneurysm Feudoaneurysm is caused by
traumatic break in the arterial wall.
Cause
and Risk Factors
An aneurysm occurs when the pressure of blood
passing through part of a weakened artery forces the vessel to bulge outward,
forming what you might think of as a blister.
·
Congenital
·
Trauma
·
Atherosclerosis
and Arteriosclerosis
·
Infection
·
Hypertension
·
Smoking
·
Chapter
14
·
Heavy
alcohol consumption Drug abuse, particularly the use of cocaine
·
Lower
estrogen levels after menopause Constant stress
·
Intracranial
arterio-venous malformation Family history of cerebral aneurysms
·
Certain
medical problems such as polycystic kidney disease and coarctation of the aorta
Clinical
Manifestations
Ruptured Cerebral Aneurysm Symptoms
Sometimes
patients describing <<the worst
headache in my life>> are actually experiencing one of the symptoms
of brain aneurysms related to having a rupture. Other ruptured cerebral
aneurysm
symptoms include:
·
Nausea
and vomiting
·
Stiff
neck or neck pain
·
Blurred
vision or double vision
·
Pain
above and behind the eye
·
Dilated
pupils
·
Sensitivity
to light
·
Loss
of sensation
Unruptured
Cerebral Aneurysm Symptoms
Before an aneurysm ruptures, patients often
experience no symptoms of brain aneurysms.
In
about 40 percent of cases, people with unruptured aneurysms will experience
some or all of the following cerebral aneurysm symptoms:
·
Peripheral
vision deficits Thinking or processing problems
·
Speech
complications
·
Perceptual
problems
·
Sudden
changes in behavior
·
Loss
of balance and coordination
·
Decreased
concentration
·
Short-term
memory difficulty
·
Fatigue
Because the symptoms of brain
aneurysms can also be associated with other medical conditions, diagnostic
neuroradiology is regularly used to identify both ruptured and unruptured brain
aneurysms.
Diagnostic
Evaluations:
·
History
and physical examination
·
Cerebral
angiogr
·
Cerebral
angiography or tomographic angiography
·
Computed
Tomographic Angiography (CTA)
·
Electroencephalogram
(EEG)
·
Computed
tomography (CT)
·
Magnetic
resonance imaging (MRI)
·
Cerebrospinal
fluid analysis
Medical
Management
Administer nitroprusside or alternative
IV antihypertensive agents and close monitoring of blood pressure Administer
calcium-channel blockers such as nimodopine to prevent vasospasm Prophylactic
antiepileptic drugs to prevent or control seizures such as phenytoin,
Phenobarbital are preferred medications.
Aneurysm
precautions include - complete bed rest with head elevated 30",
intravenous fluids, avoidance of Valsalva maneuver and neck flexion, decreasing
environmental stimul limitations of visitors and administration of analgesics
and sedatives.
Surgical
Management
There
are two common treatment options for a ruptured brain aneurysm
1.
Surgical Clipping: Surgical clipping is a procedure to close off an aneurysm.
The neuro surgeon removes a section of skull to access the aneurysm and locates
the blood vessel that feeds the aneurysm. Then he or she places a tiny metal
clip on the neck of the aneurysm to stop blood flow to it.
2
. Endovascular Coiling: Endovascular
coiling is a less invasive procedure than surgical clipping. The surgeon
inserts a hollow plastic tube (catheter) into an artery, usually in your groin,
and threads it through your body to the aneurysm. He or she then uses a guide
wire to push a soft platinum wire through the catheter and into the aneurysm.
The wire coils up inside the aneurysm, disrupts the blood flow and causes blood
to clot. This clotting essentially seals off the aneurysm from the artery.
3.
Ventricular or lumbar draining catheters and shunt surgery: Ventricular or
lumbar drain ing catheters and shunt surgery can lessen pressure on the brain
from excess cerebrospi nal fluid (hydrocephalus) associated with a ruptured
aneurysm. A catheter may be placed in the spaces filled with fluid inside of the
brain (ventricles) or surrounding brain and spinal cord to drain the excess
fluid into an external bag. Sometimes, it may then be necessary to introduce a
shunt system-which consists of a flexible silicone rubber tube (shunt) and a
valve-that creates a drainage channel starting in brain and ending in abdominal
cavity.
Nursing
Management
1.
Monitor
neurological status carefully every hour, and immediately notify the physician
of any changes in the patient's condition.
2.
Establish
and maintain a patent airway as needed. Administer supplemental oxygen as ordered.
3.
Position
the patient to promote pulmonary drainage and prevent upper airway obstruction.
Avoid placing the patient in the prone position as well as hyperextending his
neck.
4.
Suction
secretion from the airway as necessary to prevent hypoxia and vasodilation from
carbon dioxide accumulation.
5.
Monitor
pulse oximetry levels and arterial blood
gas level as ordered . use these levels
As a guide to determine appropriate
needs for supplemental oxygen.
6.
Prepare
the patient for emergency craniotomy, if indicated. If surgery can't be
performed immediately, institute aneurysm precautions to minimize the risk of
rebleeding and to avoid increasing the patient’s intracraninal pressure.
7.
Administer hydralazine or another
antihypertensive agent as ordered.
8.
Turn the patient often. Encourage deep
breathing and leg movement.
9.
Discourage
and control any measure that initiates Valsalva's maneuver, such as coughing,
straining at stool, pushing up in bed with the elbows, turning with the mouth
closed.
10.
Apply
elastic stockings or compression boots to the patient's legs to reduce the risk
of deep vein thrombosis.
11.
Assist
with hygienic care as necessary. If the patient has a facial weakness, assist
her or him during meals.
12.
Give
fluids as ordered and monitor IV. infusions to avoid overhydration, which may
increase ICP
13 . If the patient has facial weakness, assist
him during meals; assess his gag reflex and place the food in
the unaffected side of his mouth.
14. Implement a bowel elimination program based on previous habits. Raise the bed's side rails to protect the patient from injury.
15. Provide emotional support to the patient and his family. Encourage the patient to verbalise fears of dependency and of becoming a burden.
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