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Disease: Encephalitis Encephalitis
Category: Neurological diseases

Disease Definition:

Encephalitis is the brain inflammation that results from a viral infection. The severe and potentially life-threatening form of this disease is quite rare. The actual incidence of encephalitis is thought to be much higher; however, many cases go unrecognized because most people have mild signs or symptoms.


This disease has two forms, a primary form, which involves direct viral infection of the brain and spinal cord, and secondary form, which involves a viral infection that occurs elsewhere in the body and then travels to the brain.


The course of this disease is unpredictable, thus, it is important to see a doctor and receive timely treatment.

Work Group:

Symptoms, Causes


Usually, people that are infected with viral encephalitis have only mild flu-like symptoms; some people don’t even have any signs or symptoms. Usually, this illness doesn’t last long. Some of the possible signs and symptoms of this disease include:


  • Fever
  • Headache
  • Joint pain
  • Lethargy
  • Irritability


When the infection is more serious it could cause:


  • Tremors
  • Seizures
  • Rash
  • Double vision
  • Loss of consciousness
  • Personality changes
  • Muscle weakness
  • Confusion and hallucinations
  • Loss of sensation or paralysis in certain areas
  • Bulging in the soft spots called fontanels of the skull in infants.


Whenever a person or a child experiences signs and symptoms that suggest encephalitis, which is a serious and life-threatening disease, they should see a doctor as soon as possible. Some other potentially serious conditions can cause similar signs and symptoms, which also need to be considered.


There are some urgent signs and symptoms that occur in children and adults, such as:


  • Seizures
  • Mental disturbances
  • Muscle weakness or loss of feeling
  • Hallucinations or altered levels of consciousness


When these key signs and symptoms occur in infants, then immediate medical care is necessary, they are:


  • Vomiting
  • Body stiffness
  • Inconsolable crying
  • Bulging in the soft spots of the skull


Usually, a viral infection is the cause of encephalitis, such as:


  • Herpes viruses
  • Rabies transmitted through animal bites
  • Arboviruses transmitted by mosquitoes, ticks and other insects.


As mentioned before, encephalitis takes two forms, which are categorized by the two ways that viruses can infect the brain:



When a virus directly invades the brain and spinal cord, this form of encephalitis occurs. This could either be part of an outbreak (epidemic encephalitis), or it could happen to people at any time of the year (sporadic encephalitis).



Also known as postinfectious encephalitis, this form occurs when a virus infects another part of the body and then enters the brain.
Encephalitis could also be due to bacterial infections, such as Lyme disease, or parasitic infections, such as toxoplasmosis in people with weakened immune systems.


Some of the more common causes of encephalitis are:



Some herpes viruses that cause common infections may also cause encephalitis, such as:

Vaicella-zoster virus:

This virus, which causes shingles and chickenpox, could also cause encephalitis in adults and children; however, it tends to be mild.

Epstein-Barr virus:

This virus, which causes infectious mononucleosis (mono), could also cause encephalitis. Although it could be fatal in a small number of cases, but usually, it is mild.

Herpes simplex virus:

This virus has two types of infections. HSV type 1 (HSV-1), which usually causes cold sores or fever blisters around the mouth, and HSV type 2 (HSV-2), which usually causes genital herpes.



In some rare cases, after vaccine-preventable childhood viral infections, secondary encephalitis occurs. These viral infections include:


  • Mumps
  • Measles (rubeola)
  • German measles (rubella)


In these cases, encephalitis could be the result of hypersensitivity, which is an overreaction of the immune system to a foreign substance.



Well-publicized encephalitis epidemics have been caused lately by viruses that are transmitted by mosquitoes and ticks (arboviruses). Vectors are the organisms that transmit disease from one animal host to another; one example of vectors are mosquitoes, which transmit encephalitis from small creatures, such as birds and rodents, to humans. However, this type of encephalitis is quite uncommon.




In case the viral encephalitis is severe it could cause:


  • Seizures
  • Respiratory arrest
  • Coma
  • Death


Some problems that occur in people with severe encephalitis could last more than one year, such as:


  • Depression
  • Fatigue
  • Gait problems
  • Weakness
  • Personality changes
  • Memory difficulties


Hearing or vision defects, the inability to speak coherently, paralysis, lack of muscle coordination or memory loss are some of the complications that could be permanent.


Most mild cases require these treatments:


  • Rest
  • A healthy diet with lots of fluids.
  • In order to relieve headaches and fever, acetaminophen .


Because in more serious cases of encephalitis the viruses that cause the disease usually don’t respond to medications, they could be more difficult to treat. But some viruses respond to antiviral drugs, such as acyclovir , specially the varicella-zoster virus and the herpes simplex virus. Another antiviral that is used in some cases is ganciclovir. In case someone has one of these kinds of virus-induced encephalitis, they will probably be recommended acyclovir immediately.


Along with the antiviral medications, they may also be recommended:


  • Anticonvulsant medications in order to stop or prevent seizures
  • Anti-inflammatory drugs, such as corticosteroids, in order to help reduce pressure and swelling within the skull.


A person might also need speech and physical therapy after the illness.


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Consultants Corner

Dr. Talal Sabouni


Dr. Samer Al-Jneidy

Dr. Samer Al-Jneidy Pediatrician

Dr. Hani Najjar

Dr. Hani Najjar Pediatrics, Neurology

Yaser Habrawi , F.R.C.S.Ed

Yaser Habrawi , F.R.C.S.Ed Consultant Ophthalmologist

Dr. Tahsin Martini

Dr. Tahsin Martini Degree status: M.D. in Ophthalmology

Dr. Faisal Dibsi

Dr. Faisal Dibsi Specialist of Otolaryngology - Head and Neck Surgery

Dr . Dirar Abboud

Dr . Dirar Abboud Hepatologist – Gastroenterologist

Samir Moussa M.D.

Samir Moussa M.D. ENT Specialist

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