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Encephalitis: Causes, Symptoms, Treatment

Medically reviewed by Regina Victoria Boyles, MD · Pediatrics

Written by Nikita Bhalla · Updated May 06, 2022

    Encephalitis: Causes, Symptoms, Treatment

    Encephalitis is a brain inflammation due to infection. The most common type of encephalitis is viral encephalitis.

    Individuals with encephalitis may experience mild symptoms like headache or fever, or no symptoms at all. The condition is mostly seen in children, senior citizens, and those with a weak immune system. It is important to treat the condition in time. Leaving the condition untreated can be fatal or cause severe life-threatening complications.

    In some rare cases, viral encephalitis is also caused by bacterial infection.

    Types of Encephalitis

    There are different types of encephalitis and each has different causes. The two main causes of the condition include:

    Primary Encephalitis

    Primary encephalitis is caused when the virus (in rare cases, bacteria or fungus) directly inflames the brain.

    Secondary Encephalitis

    Secondary encephalitis is caused when an infection that begins in other parts of the body moves to the brain or when your immune system fights against infection and wrongly attacks the brain.

    In most cases, individuals with the condition may have mild to no symptoms at all. Some of the mild symptoms of the condition include:

    • Fever
    • Headache
    • Weakness
    • Lack of appetite

    viral encephalitis

    In severe cases, individuals with the condition may have the following symptoms:

    • Seizures
    • Hallucinations and changes in behavior
    • Coma
    • Severe headache
    • High fever
    • Difficulty in speaking or vision problems
    • Loss of memory

    It is difficult for children with the condition to describe the symptoms they experience. And so it is important to monitor unusual changes and symptoms in children. It is important to monitor your kid’s health closely. Consult your child’s doctor if your child has any of the below-mentioned symptoms:

    • Vomiting
    • Crying for no reason
    • Stiffness
    • Lack of appetite

    Causes of Encephalitis

    Primary encephalitis is caused by viruses that are majorly classified into three categories:

    1. Common Viruses

    The most common virus that causes the condition is the Herpes Simplex Virus (HSV). The two types of HSV include HSV type 1 that is related to cold sores and is considered severe and can be fatal or cause severe brain damage. While HSV type 2 that is related to genital herpes.

    Some of the common viruses that can cause the condition include HIV, cytomegalovirus, etc.

    2. Childhood Viruses

    Childhood viruses that can cause the condition include measles, rubella, mumps, etc.

    3. Arboviruses

    Insects usually spread this type of virus. Some arboviruses can cause conditions like West Nile, California Encephalitis, St. Louis Encephalitis, or Eastern Equine Encephalitis. Dengue Encephalitis is common in the Phillipines

    Risk Factors

    Common risk factors of  encephalitis include:

    • Young children and older adults are at a higher risk of developing encephalitis.
    • Individuals with a weak immune system or who have any condition that causes a weak immune system are at a greater risk of developing this condition.
    • Insects are common carriers of viruses. Mosquitoes and ticks can carry certain viruses that cause brain inflammation due to infection.

    Diagnosis of Encephalitis

    Your doctor will ask you about the symptoms you experience. If you have any signs and symptoms related to encephalitis, your doctor may ask you to undergo a few medical tests.

    Some of the medical tests to diagnose the condition include:

    Imaging tests – Tests like CT scans and MRI help to diagnose if there is any swelling or bleeding in the brain. The tests are helpful to understand the infected part of the brain and the type of virus present.

    Blood tests – Blood tests are helpful to check the presence of bacteria or virus in the blood.

    Lumbar puncture – The test is also called a spinal tap. In this test, your health care professional will collect cerebrospinal fluid from your lower back. The test helps to check the fluid sample for presence of infection.

    Brain biopsy – In this type of test, your doctor will collect samples of brain tissue and check for infection. Taking into consideration the risk involved in the test, your doctor will recommend the test only if absolutely required.

    Electroencephalogram (EEG) – The test helps to record brain activity. Though the test may not help to detect viruses, it is helpful to monitor the patterns to learn the extent of affected brain activity due to the infection. The test is also helpful to know which areas of the brain are infected.

    Treatment of Encephalitis

    Early diagnosis and timely treatment are important to treat the condition. The condition, if left untreated, may cause severe complications such as loss of memory, hearing and vision problems, difficulty in muscle coordination, changes in behavior, difficulty in breathing, coma, and even death.

    Upon diagnosis, your doctor may recommend a suitable treatment.

    The type of treatment your doctor may recommend is based on the symptoms you experience.

    • If you have only mild symptoms such as headache or fever, your doctor may prescribe paracetamol and ask you to follow a few healthy lifestyle changes.
    • Your doctor may prescribe antiviral medications to get rid of viral infections.
    • If you have secondary encephalitis, your doctor may prescribe corticosteroids to treat brain inflammation due to infection.
    • If you have a seizure or irritability, your doctor may prescribe anticonvulsants or sedatives.
    • In severe cases when individuals lose consciousness, breathing or feeding tube are required.

    Even after appropriate treatment, you may need certain follow-up therapies such as occupational therapy, speech therapy, and physical therapy.

    Encephalitis Prevention

    • You may prevent encephalitis by following good hygiene.
    • Make sure you are up-to-date when it comes to vaccinations including measles, mumps, etc. If you live in a locality where there are a lot of mosquitoes or other insects, ask your doctor if you need to take any vaccinations.
    • Avoid your exposure to mosquitoes and other insects as much as possible. Avoid stepping out of the home when mosquitoes and other insects are active.
    • Make sure there’s no accumulation of water in your locality that acts as a breeding ground for mosquitoes and other insects.
    Growing backyard plants that naturally repel insects can help too.
  • Avoid sharing utensils.
  • If you reside in a locality where you are more prone to insect bites, make sure you follow precautions to prevent yourself from insect bites. Use repellent creams and wear full clothes to prevent yourself from insect bites.
  • Make sure you stay hydrated and take adequate rest.
  • Learn more about Brain and Spine Disorders here.


    Hello Health Group does not provide medical advice, diagnosis or treatment.

    Medically reviewed by

    Regina Victoria Boyles, MD


    Written by Nikita Bhalla · Updated May 06, 2022

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