Usually, the features of a brain abscess develop over 2-3 weeks; occasionally, they occur more slowly; in the immunosuppressed, onset is rapid.
The typical symptoms & signs of an inflammatory reaction (pyrexia, rigors, and dehydration) are uncommon during the time of presentation (1).
Characteristically:
- headache is usually the first symptom - it arises from raised intracranial pressure and may be accompanied by other typical features such as vomiting, drowsiness.
- toxicity effects, e.g. fever - but its absence does not exclude the diagnosis
- characteristics of the infective source - look for tenderness over the mastoid, sinuses; look for a discharging ear; other diagnostic signs - e.g. cardiac murmurs in SBE
- focal neurological signs:
- frontal abscess - impairment of memory and attention; rarely, hemiparesis +/- dysphasia and motor seizures;
- temporal lobe - nominal dysphasia, more usual when the abscess is on the left; visual field defect - usually, a homonymous upper quadrantanopia resulting from the involvement of lower fibres of optic radiation;
- cerebellar - headache, usually occipital; ataxia; cerebellar signs; neck stiffness
References: