Viral encephalitis is a viral disease which attacks mostly children under one year and adults older than 55 years. Although relatively rare, encephalitis can cause life-threatening complications.
Article continues below
Encephalitis is an inflammation of the brain caused by bacteria, fungi or parasites, but the cause number one is virus. There are some other diseases, such as measles and rubella, which can cause the inflammation of the brain, but in those cases encephalitis is just a side-effect. In the most cases viral encephalitis is caused by enteroviruses, herpes simplex virus and arboviruses.
Enteroviruses live in the gut, they spread via faeces but most of these cases are mild with no lasting effects. Herpes simplex viruses are unfortunately responsible for the most serious cases. HSV type 2, also known as genital herpes, is in most cases passed from a mother to her child during delivery. HSV type 1 lives peacefully in most adults, but it can become active and travel to the brain. Arboviruses are viruses that spread by insects and they can be found mostly in the Midwest and eastern United States during summer and fall.
How the infection occurs? When the virus enters the blood it starts its travel to the brain. There it damages and ruptures the cells which simply means that they are dead. At the same time, the immune system starts to response to the invasion and as a result the brain starts to swell. That very combination of infection and body response creates symptoms of encephalitis.
Since brain is very fragile organ, the damage occurs fast and it can lead to death. When the brain is damaged, it causes low blood pressure, low oxygen levels in the blood, bleeding inside the brain, and death.
The symptoms of viral encephalitis, from mild to severe, are high temperature, headache, sensitivity to light, stiff neck, vomiting, personality changes, amnesia, seizures, paralysis, and coma. But, how can someone be infected in the first place? Unfortunately, viruses are highly infectious creatures and they can spread easily.
They spread when an infected person coughs or sneezes and viruses travel through the air and are inhaled by other person. Infected mosquitoes and ticks can transfer viruses directly into the blood when they bite. The virus can also live in contaminated food or drink, and there are cases when a virus is transmitted by touching an infected person.
Encephalitis caused by virus is diagnosed using a series of tests. In the first place there are physical examination and blood tests. If there is doubt, the doctor will then perform computed tomography, electroencephalography, examination of liquid that the brain is in, and magnetic resonance imaging.
Since viruses are difficult to treat, antiviral medications don't work on all viruses and we are limited in reducing symptoms. The very first measures are intravenous injection of solution that reduces brain swelling and antiviral drugs if we know that the virus is drug-sensitive.
The good news here is that herpes simplex virus which causes most troubles can be killed with drugs. Along with this, there is a usual infection treatment: the patient is given pain-killing drugs, anti-convulsive drugs, anti-fever drugs and fluids against dehydration.
What is the prognosis? Generally speaking, the acute phase of encephalitis lasts one or two weeks, and the symptoms then can disappear quickly, but they also can disappear very slowly. The good news: in most cases the patient will recover fully.
However, if help is given too late, the patient will have brain damage which can't be fixed and such person requires care and therapy for the lifetime. ■