investigations
Last reviewed 01/2018
In patients with impaired consciousness, signs of raised intracranial pressure or focal signs then a CT of the head should be done before lumbar puncture.
In herpes simplex encephalitis there may be long attentuation lesions in one or both temporal lobes. There may be diffuse brain oedema. An MRI scan is more sensitive at detecting early encephalitic changes.
The CSF is characterised by:
- moderately increased cell count, mostly lymphocytes
- raised protein
- normal glucose
- viral antigens or nucleic acids may be detected