Makindo Medical Notes

Related Subjects: |Brain tumour s |Astrocytomas |Brain Metastases

Brain abscess - Biopsy is often needed to differentiate from a tumour.

About

• Brain Abscess: Can be challenging to differentiate from a tumour due to similar imaging features.
• Common causative organisms are Staphylococcus and Streptococcus species.

The incidence of fungal brain abscesses has also risen due to the increased use of broad-spectrum antibiotics and immunosuppressive agents like steroids.

Risks

• Alcoholism and immunodeficiency
• Skull fractures
• Associated mastoiditis or other localized infections
• Dental abscess, bronchiectasis, tuberculosis (TB)
• AIDS and endocarditis

Clinical Features

• Headache (69%-70%) - the most common presenting symptom
• Mental status changes indicating possible cerebral edema
• Fever, focal to generalized seizures
• General malaise, drowsiness, toxic appearance, signs of a space-occupying lesion
• Headache with focal seizure and neurological signs
• Poor dentition or evidence of neglect/alcoholism
• Rupture of abscess - presents as a sudden worsening headache followed by signs of meningism
• Differential diagnosis includes distinguishing from a tumour

Investigations

• Blood Tests: Elevated CRP, WCC; blood cultures; HIV serology
• Echocardiogram and CXR: Useful for identifying bronchiectasis or excluding a lung tumour
• CT Brain with Contrast: Early cerebritis appears as an irregular low-density area that does not enhance or may show patchy enhancement. As it progresses, a rim-enhancing lesion typically forms.
• MRI Brain with Gadolinium: Preferred imaging for brain abscess, especially early cerebritis or satellite lesions. Offers better contrast and detail of cerebral oedema and inflammation spread.
• Lumbar Puncture: Generally avoided due to risk of brain herniation and coning; only performed following CT/MRI clearance to rule out increased intracranial pressure.
• Brain Biopsy: Needle aspiration or surgical drainage is recommended to identify the etiologic agent and establish the diagnosis.

Management

• Stereotactic Biopsy and Culture: To confirm diagnosis and identify the causative organism.
• Antibiotics: Targeted therapy based on culture and sensitivity results.
• Anticonvulsants: To manage seizure activity if present.
• Neurorehabilitation: May be necessary due to the destructive nature of lesions; CSF pressure management may be required for headaches.