Brain abscess

Definition:

• A brain abscess is a localized collection of pus in the brain parenchyma, usually caused by a bacterial or fungal infection.

Epidemiology:

• Relatively rare but can be life-threatening.
• Can occur at any age, but more common in young and middle-aged adults.

Etiology:

• Commonly results from the spread of infection from nearby structures, such as the ears, sinuses, or teeth.
• Hematogenous spread from a distant site of infection (e.g., endocarditis).
• Direct infection following head trauma or neurosurgery.
• Immunocompromised states increase the risk.

Pathophysiology:

• The infection leads to an inflammatory response, collection of pus, and formation of a capsule.
• The abscess can cause increased intracranial pressure, brain tissue displacement, and can lead to herniation if untreated.

Clinical Features:

• Headache (most common symptom), fever, nausea, and vomiting.
• Focal neurological deficits depending on the abscess location.
• Altered mental status or seizures in severe cases.

Diagnosis:

• MRI with contrast is preferred for better delineation of the abscess.
• CT scan can also be used, especially in emergency settings.
• Blood cultures and cultures from primary sources of infection.
• Stereotactic aspiration may be necessary for both diagnosis and treatment.

Management:

• Antimicrobial therapy is the cornerstone of treatment. Empiric antibiotic therapy should be broad-spectrum and adjusted based on culture results.
• Surgical intervention (aspiration or excision) may be necessary, especially for larger abscesses or those not responding to antibiotics.
• Management of raised intracranial pressure is critical.

Prognosis:

• Depends on the size and number of abscesses, the organism responsible, the patient’s immune status, and how quickly treatment is initiated.
• Early diagnosis and treatment improve outcomes.