What are the causes of encephalitis?
Herpes simplex is the classical cause but only accounts for a minority of cases. Many other viruses can also cause encephalitis. If there has been travel abroad there are a large number of other viral encephalitides and always remember malaria. An immunosuppressed patient can have other viral, bacterial or fungal causes. Encephalitis also occurs with bacterial infections, TB, listeria and atypical infections such as Legionnaire’s disease. It can be mimicked by neurosurgical emergencies such as cerebral abscess or subdural empyaema and other neurological diseases such as venous stroke and subclinical seizures. Encephalitis is rare and help needs to be sought promptly from the neurology and infectious diseases teams. The differential diagnosis of fever, seizures and altered awareness is very wide and includes metabolic and autoimmune diseases. What are the signs I should look for in encephalitis? The commonest is fever. Patients may be mildly disorientated with no other signs or may have
