Although brain abscess is relatively rare, it is a complication en-countered increasingly in patients whose immune systems have been suppressed either through therapy or disease.
A brain abscess is a collection of infectious material within the tissue of the brain. It may occur by direct invasion of the brain from intracranial trauma or surgery; by spread of infection from nearby sites, such as the sinuses, ears, and teeth (paranasal sinus infections, otitis media, dental sepsis); or by spread of infection from other organs (lung abscess, infective endocarditis) (Hickey, 2003). To prevent brain abscess, otitis media, mastoiditis, sinusi-tis, dental infections, and systemic infections should be treated promptly.
The clinical manifestations of a brain abscess result from alter-ations in intracranial dynamics (edema, brain shift), infection, or the location of the abscess (Chart 64-2). Headache, usually worse in the morning, is the most prevailing symptom. Vomiting is also common. Focal neurologic signs (weakness of an extremity, de-creasing vision, seizures) may occur, depending on the site of the abscess. There may be a change in mental status, as reflected in lethargic, confused, irritable, or disoriented behavior. Fever may or may not be present.
Repeated neurologic examinations and continuing assessment of the patient are necessary to determine the location of the abscess. A computed tomography (CT) scan is invaluable in locating the site of the abscess, after the evolution and resolution of suppura-tive lesions, and in determining the optimal time for surgical inter vention. A magnetic resonance imaging (MRI) scan is useful to obtain images of the brain stem and posterior fossa if an abscess is suspected in these areas.
Brain abscess is treated with antimicrobial therapy and surgical incision or aspiration. If the abscess is encapsulated, CT-guided stereotactic needle aspiration under local anesthesia may be per-formed. Antimicrobial treatment is prescribed to eliminate the causative organism or reduce its virulence.
Penicillin G (20 million U) and chloramphenicol (Chloro-mycetin) (4 to 6 g/day given intravenously in divided doses) are usually prescribed because anaerobic streptococci and Bacterioides are the most common causative organisms (Hickey, 2003). Large IV doses are usually prescribed preoperatively to penetrate the blood–brain barrier and reach the abscess. The therapy is con-tinued postoperatively. Corticosteroids may be prescribed to help reduce the inflammatory cerebral edema if the patient shows evidence of an increasing neurologic deficit. Antiseizure medica-tions (phenytoin, phenobarbital) may be prescribed to prevent seizures. Multiple abscesses may be treated with appropriate anti-microbial therapy alone, with close monitoring by CT scans.
Nursing care focuses on ongoing assessment of the neurologic sta-tus, administering medications, assessing the response to treat-ment, 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 medica-tions. Blood laboratory test results, specifically blood glucose and serum potassium levels, need to be closely monitored when cor-ticosteroids are prescribed. Medical intervention may be required to return these values to normal or acceptable levels.
Patient safety is also a key nursing responsibility. Injury may result from decreased level of consciousness and falls related to motor weakness or seizures.
The patient with a brain abscess is extremely ill, and neuro-logic deficits may remain after treatment, such as hemiparesis, seizures, visual deficits, and cranial nerve palsies. Focal seizures are the most common sequelae, occurring in about 30% of pa-tients (Hickey, 2003). The nurse must assess the family’s ability to express their distress at the patient’s condition, cope with the patient’s illness and deficits, and obtain support.
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