Brain Abscess

Definition

A brain abscess is a collection of pus, immune cells, and other material in the brain, usually caused by a bacterial or fungal infection. It is a serious and potentially life-threatening condition that requires prompt medical treatment.

Aetiology

Brain abscesses can be caused by:

• Bacterial infections: Streptococci, Staphylococci, anaerobes
• Fungal infections: Aspergillus, Candida
• Parasitic infections: Toxoplasma gondii (rare)
• Direct extension from nearby infections: Sinusitis, otitis media, dental infections
• Haematogenous spread from distant infections: Endocarditis, lung abscess
• Trauma or neurosurgical procedures

Pathophysiology

The infection leads to a localised collection of pus in the brain parenchyma, causing inflammation, tissue necrosis, and oedema. This results in increased intracranial pressure and potential damage to brain tissue.

Risk Factors

• Immunocompromised state (e.g., HIV/AIDS, immunosuppressive therapy)
• Chronic sinusitis or otitis media
• Dental infections
• Congenital heart disease
• Recent head trauma or neurosurgery

Signs and Symptoms

• Headache
• Fever
• Neurological deficits (e.g., focal weakness, aphasia)
• Seizures
• Altered mental status
• Nausea and vomiting

Investigations

• Clinical history and physical examination
• Neuroimaging: MRI (preferred) or CT scan with contrast
• Blood tests: Full blood count, inflammatory markers (CRP, ESR), blood cultures
• Aspiration and culture of abscess material (if safe and feasible)

Management

Primary Care Management

• Immediate referral to hospital for suspected brain abscess
• Initial supportive care (e.g., pain management, fever control)

Specialist Management

• Empirical antibiotic therapy: Broad-spectrum antibiotics (e.g., ceftriaxone, metronidazole) adjusted based on culture results
• Antifungal therapy if a fungal infection is suspected or confirmed
• Neurosurgical intervention: Aspiration or excision of the abscess if indicated
• Management of complications: Anticonvulsants for seizures, steroids to reduce cerebral oedema
• Supportive care: Intravenous fluids, monitoring in an intensive care unit if necessary

Example Management for Brain Abscess

A patient presenting with a suspected brain abscess should be referred to hospital immediately. Initial empirical antibiotic therapy might include intravenous ceftriaxone and metronidazole. Surgical aspiration of the abscess may be performed for diagnostic and therapeutic purposes. The patient should be monitored closely in an intensive care setting if severe symptoms or complications are present.

References

1. NICE. (2024). Brain Abscess: Diagnosis and Management. Retrieved from NICE
2. NHS. (2023). Brain Abscess. Retrieved from NHS
3. Brook, I. (2017). Microbiology and Management of Brain Abscesses. Clinical Microbiology Reviews.
4. Connolly, E. S., & Rabinstein, A. A. (2020). Current Therapy in Neurological Surgery. Elsevier.
5. Solomon, T., Michael, B. D., Smith, P. E., & Sanderson, F. (2022). Infections of the Central Nervous System. Oxford University Press.