28th July 2023

Encephalitis

Encephalitis refers to the inflammation of the brain (i.e. cerebrum or cortex). It presents with a clinical syndrome of headache, fever, focal neurological deficits, and seizures, with the latter being more common than in meningitis.

It is most commonly viral in the UK, with herpes simplex virus (HSV) type 1 being the most common causative organism. The same pathogens which cause bacterial meningitis may also cause bacterial encephalitis.

Meningitis and encephalitis share symptoms, and there may be an overlap between the two; encephalitis is therefore managed in much the same way as meningitis. The key points are prompt diagnosis with CSF analysis and prompt initiation of treatment. As HSV is the most common cause in the UK, empirical treatment of encephalitis includes the antiviral drug aciclovir until the causative organism is identified.