Acute encephalitis describes a rapidly developing inflammation of the brain and, as you can imagine, is a neurological emergency. Not only is it a life-threatening disease with a mortality rate of up to 15%, it also presents a unique diagnostic challenge for doctors. Patients presenting to the emergency room with common symptoms of encephalitis such as fever, confusion or seizures, could have any number of other conditions which mimic these symptoms. With roughly 6,000 cases per year, encephalitis is relatively rare compared to, say, drug or alcohol misuse which can present in a similar way. As a result, Even once encephalitis is diagnosed there is a further complication. Inflammation can be caused by an external factor, in the case of encephalitis this is usually a virus, but it can also be caused by autoimmune disease in which the body develops an immune reaction against its own proteins. In cases of autoimmune disease, the aim of treatment would be to suppress the immune system and prevent it from causing further damage.

But if a virus is causing the encephalitis such a treatment would remove the body’s own defense mechanisms and worsen the patient’s condition. Therein lies the dilema for a doctor treating a case of encephalitis, they are presented with a condition of two possible causes with opposite treatments. This dilema would be easily resolved with a realiable diagnostic test that could differentiate between viral and autoimmune encephalitis. However, the cause of 37 to 62% of encephalitis cases is not identified, even after a thorough diagnostic investigation. With us today to talk about encephalitis and his work on diagnostic tests for encephalitis is Dr Mark Ellul. Mark is a Specialist Registrar in Neurology and Clinical Research Fellow funded by the Association of British Neurologists at IGH. He recently published a paper in Clinical Medicine “Acute encephalitis – diagnosis and management”, available at: http://www.clinmed.rcpjournal.org/content/18/2/155.abstract.