Encephalitis is an inflammation of the brain due to a viral infection (infectious) or when the immune system mistakenly begins to attack brain tissue (autoimmune encephalitis) (Clinic, 2011). Encephalitis is sometimes considered an “acute” condition as the term means it happens abruptly, develops rapidly and requires urgent care (Clinic, 2011). This infection is not very common as statistics show that encephalitis occurs in approximately 0.5 in every 1 000 000 individuals, most of them children, elderly people and individuals with weakened immune system (Gondim, 2013). However, the National Health Service (NHS) states that they suspect incidence is higher than official figures because many causes go unreported when the symptoms are mild (Landis, 2013).
Encephalitis causes flu-like symptoms like fever and severe headaches (Gondim, 2013). This causes many cases of encephalitis to go unnoticed. However, confusion, drowsiness, loss of consciousness, seizures or problems with movement or senses becomes more prominent after some time (Gondim, 2013). Severe cases of encephalitis are rare but can be life-threatening as comas become more likely to occur. Sometimes, meningitis is confused with encephalitis but they are quite different. Meningitis is the inflammation of the protective layer of the brain that shields it (Gondim, 2013). With that said, sometimes patients have meningoencephalitis which is having both meningitis and encephalitis.
Causes and Pathology
Encephalitis can develop due to infections by viruses, bacterium, parasites or fungi or when the immune system responds to a previous infection and mistakenly attacks brain tissue (Gondim, 2013). These two types of encephalitis are called Primary Encephalitis and Secondary Encephalitis (post-infectious).
Primary Encephalitis occurs when a virus, bacterium or fungus infects an area in the brain; high concentrations of the infection in one area or widespread (Gondim, 2013). Many of these viruses cause minor infections elsewhere in the body, such as upset stomachs, skin rashes and cold sores. These infections rarely affect the brain; however that is why encephalitis is often described as a rare complication of common infections. Some common infections include: Herpes Simplex Virus (HSV), Enteroviruses, Mosquito-borne or Tick-borne viruses, Rabies virus or childhood infections (Simon, 2012). Herpes Simplex Virus is divide into two types– type 1 (HSV-1) and type 2 (HSV-2). HSV-1 causes cold sores, fever blisters around the mouth while HSC-2 causes genital herpes. HSV-1 is quite rare and has the potential to cause significant brain damage or even death; however it is frequently found within the British Isles. Other herpes viruses like chickenpox or shingles could cause Primary Encephalitis. Enteroviruses include poliovirus and coxsackievirs which cause flu-like symptoms, abdominal pain and eye inflammations (Gondim, 2013). Mosquito-borne viruses can cause infections like West Nile, La...