Brain
Abscess
·
A
brain abscess is a collection of infectious material within the tissue of the
brain. It accounts for less than 2%
·
Brain
abscesses are rare in immunocompetent people; they are more frequently
diagnosed in people who are immunosuppressed as a result of an underlying
disease or use of immunosuppressive medications.
Pathophysiology
·
Predisposing
conditions (otitis media and rhino sinusitis, intracranial surgery, penetrating
head injury, or tongue piercing)
·
Organisms
causing brain abscess may reach the brain by hematologic spread from the
lungs, gums, tongue, or heart, or from a
wound or intra-abdominal infection
·
Bacteria
are the most common causative organisms.
·
Prevention:
To prevent brain abscess, otitis media, mastoiditis, rhino sinusitis, dental
infections, and systemic infections should be treated promptly.
Clinical Manifestations
·
The
clinical manifestations of a brain abscess result from alterations in
intracranial dynamics (edema, brain shift), infection, or the location of the
abscess.
·
Headache,
usually worse in the morning, is the most prevailing symptom.
·
Fever,
vomiting, and focal neurologic deficits occur as well.
·
Focal
deficits such as weakness and decreasing vision reflect the area of brain that
is involved.
·
As
the abscess expands, symptoms of increased ICP such as decreasing LOC and
seizures are observed.
Assessment and Diagnostic Findings
·
Neuroimaging
studies such as MRI or CT scanning identify the size and location of the
abscess.
·
The
MRI or CT scans reveal a ring around a hypodense area.
·
Aspiration
of the abscess, guided by CT or MRI, is the best method to culture and identify
the infectious organism.
·
Blood
cultures are obtained if the abscess is believed to arise from a distant
source. Chest x-ray is performed to rule out predisposing lung infections and
an electroencephalogram (EEG) may help localize the lesion.
Medical Management
·
Treatment
is aimed at controlling increased ICP, draining the abscess, and providing
antimicrobial therapy directed at the abscess and the primary source of
infection.
·
Large
IV doses of antibiotics are administered to penetrate the blood—brain barrier
and reach the abscess.
·
The
choice of the specific antibiotic medication is based on culture and
sensitivity testing and directed at the causative organism.
·
A
stereotactic CT-guided aspiration may be used to drain the abscess and identify
the causative organism.
·
Corticosteroids
may be prescribed to help reduce the inflammatory cerebral edema i the patient
shows evidence of an increasing neurologic deficit. Antiseizure medications
(phenytoin, Phenobarbital) may be prescribed to prevent or treat seizures.
Nursing Management
•
Nursing
care focuses on continuing to assess the neurologic status, administering medications,
assessing the response to treatment, and providing supportive care.
•
Ongoing
neurologic assessment alerts the nurse to changes in ICP, which may indicate a
need for more aggressive intervention.
•
The
nurse also assesses and documents the responses to medications. Blood
laboratory test results, specifically blood glucose and serum potassium levels,
need to be closely monitored when corticosteroids are prescribed.
•
Administration
of insulin or electrolyte replacement may be required to return these values to
normal or acceptable levels.
•
Patient
safety is another key nursing responsibility. Injury may result from decreased
LOC or falls related to motor weakness or seizures.
·
The
patient with a brain abscess is very ill, and neurologic deficits, such as hemi
paresis, seizures, visual deficits, and cranial nerve palsies, may remain after
treatment.
•
Seizures
are common sequel. The nurse must assess the family's ability to express
distress at the patient's condition, cope with the patient's illness and
deficits, and obtain support.
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