OverviewKey FactsSymptomsCausesRisk factorsDiagnosisPreventionSpecialist to visitTreatmentHome-careComplicationsLiving withFAQsReferences
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Also known as Acute encephalitis syndrome (AES), Chamki bukhar and Chamki fever


Encephalitis, known as “chamki bukhar” in Hindi, is a disease that causes inflammation of the brain. According to the World Health Organization (WHO), acute encephalitis is defined as the acute onset of fever and a change in the mental status of a person of any age and at any time of the year. The changes in mental status include the signs and symptoms of confusion, disorientation, delirium, or coma. It may also cause an onset of seizures for the first time, especially in children, after they are infected.

Also known as acute encephalitis syndrome (AES), it mostly affects children below 15 years of age. The most common cause of encephalitis are viruses, however, in rare cases, bacteria, as well as fungi or autoimmunity can cause the illness. Japanese encephalitis (JE), a viral infection spread by mosquitoes, has been considered to be the leading cause of AES in Asia.

Encephalitis is a medical emergency and requires attention right away. The treatment of encephalitis depends on its cause. Antivirals, antibiotics, immunotherapy and supportive treatment are the main stays in management of encephalitis.

Recovery depends on the severity of symptoms experienced during the illness. Both the acute stage of the disease and its after effects can be overwhelming for patients and their families. However, various rehabilitation therapies can go a long way in helping the patients to make the best possible recovery.

Key Facts

Usually seen in
  • Children below 15 years of age

Gender affected
  • Both men and women
Body part(s) involved
  • Brain
  • Worldwide: 68,000 (2019)
  • India: 10,485 (2018)
Mimicking Conditions
  • Brain abscess
  • Bacterial meningitis
  • Sepsis
  • Tuberculosis
  • Fungal infection
  • Parasitic infection 
  • Syphilis 
  • Leptospirosis
  • Malignancy
  • Autoimmune or paraneoplastic diseases
  • Drug-induced delirium
Necessary health tests/imaging
Specialists to consult
  • Neurologist
  • Internal medicine specialist
  • Infectious disease specialist
  • Pediatrician

Symptoms Of Encephalitis

Acute encephalitis causes fever and a change in the mental status of a person. It may also cause an onset of seizures for the first time, especially in children, once infected. Most people suffering from the condition don’t have any symptoms. However, some might experience symptoms such as:

  • Headache

  • Vomiting

  • Neck stiffness

  • Weakness

  • Increase in irritability

  • Confusion

  • Disorientation

  • Coma

  • Hallucinations

  • Inability to talk or speak (Aphasia)

  • Loss of balance (Ataxia)

  • Involuntary movements

  • Personality change 

The infection turns into illness in less than 1% of those infected. In people who develop symptoms, it usually takes around 5-15 days for the symptoms to appear after the infection. 

In severe cases, AES can show symptoms such as:

  • Hearing loss

  • Vision impairment

  • Seizures

  • Unconsciousness

  • Paralysis

  • Coma

Causes Of Encephalitis

The main cause of encephalitis in India is known to be viruses however, even bacteria, parasites, fungi, chemicals, toxins and cancer (paraneoplastic encephalitis) can also cause the disease. Various causes are discussed below:

1. Viruses

Arboviruses, viruses transmitted through insect bites, are one of the most common causes of viral encephalitis. These include Japanese encephalitis and tick-borne encephalitis viruses. It is reported that people suffering from dengue, mumps, measles, scrub typhus, nipah, and zika virus are at high risk of encephalitis. Also, other viruses that can cause encephalitis include herpes simplex virus (HSV), enteroviruses, Epstein Barr virus, mosquito borne viruses, tick borne viruses, and rabies virus.

2. Autoimmunity 

Autoimmune encephalitis occurs when a person’s own antibodies or immune cells start to attack the brain. It can be caused by autoimmune disorders like systemic lupus erythematosus and Behcet's disease.

3. Cancer

Encephalitis associated with cancer is known as paraneoplastic encephalitis. It is caused by metastasis of cancer cells to the nervous system or by any complication of cancer such as coagulopathy, stroke, metabolic and nutritional conditions, and side effects of cancer therapy.

4. Other causes

Rarely, bacteria and parasites can cause encephalitis. A severe form of leptospirosis and toxoplasmosis are associated with encephalitis. The causative agent might vary with season and geographical status. Surprisingly, in some cases, the causative agent may also remain unidentified.

Risk Factors For Encephalitis

Various risk factors associated with encephalitis are:


Mostly, infants, young children and elderly are at a higher risk of most types of viral encephalitis. 


Compromised immunity

People with weakened immune system like those suffering from HIV or cancer, undergoing chemotherapy or taking immune-suppressing drugs are at increased risk of encephalitis.


Geographical areas

Certain geographical areas which have high prevalence of mosquito or tick borne viruses see more cases of encephalitis.


Season of the year

Mosquito and tick borne diseases tend to be more common in summer or rainy seasons when these insects are most active.

Litchi And Encephalitis: What’s The Link?
Every year, many children in India, especially in Bihar, fall prey to this disease. Encephalitis seems to affect mostly children from impoverished rural families, and has often been attributed to natural toxins found in litchis which grow in abundance all around the district. Several studies have also revealed that eating litchi on an empty stomach or at night can cause encephalitis. Read the article to know more about it.

Diagnosis Of Encephalitis

Acute encephalitis constitutes a medical emergency. The diagnosis of acute encephalitis is suspected in a febrile patient presenting altered consciousness. To diagnose encephalitis, your healthcare provider might order tests, perform a medical exam and discuss medical history. 

A. Clinical history 

Before confirming the patient is having encephalitis, it is essential to rule out the conditions that may mimic the symptoms of encephalitis. A physician performs a detailed overview checkup, reviewing the patient’s history, and the onset of symptoms to rule out other potential causes.

B. Lab tests and imaging studies

1. Imaging tests: Tests like magnetic resonance imaging (MRI) or computed tomography (CT) can be used to view the cross-sectional area of the brain. Single photon emission computed tomography (SPECT) can also be performed depending on availability. Imaging tests can reveal the abnormalities in the brain and the cause of the seizure-like tumor, lesions, and causes of cerebral dysfunction. These tests can also check for any problems that can make performing a lumbar puncture or a spinal tap risky.

2. Lumbar puncture: Also known as a spinal tap, this test is done to obtain a sample of CSF (cerebrospinal fluid), a protective fluid that flows through the meninges that cover the brain and spinal cord. When the brain and meninges are inflamed, the number of white cells in cerebrospinal fluid increases. Sometimes, samples of CSF can be tested to identify the virus or other infectious agent that is causing encephalitis.

3. Cerebrospinal fluid (CSF) polymerase chain reaction (PCR): PCR produces many copies of a gene which helps in detecting the genetic material of viruses in a sample of cerebrospinal fluid. It has become the primary diagnostic test for central nervous system (CNS infections) caused by viruses such as cytomegalovirus (CMV), Epstein Barr virus (EBV), human herpesvirus 6 (HHV-6) and enteroviruses.

4. Electroencephalogram (EEG): EEG helps to record the brain's electrical activity. It does not detect the virus that causes encephalitis, but certain abnormal patterns on the EEG may indicate a diagnosis of encephalitis. 

5. Other lab tests: Blood tests including complete blood count (CBC) along with urine or serum toxicology screening tests may be done to test for viruses or other infectious agents.

6. Intracranial pressure monitoring (ICP): Any brain swelling can be diagnosed by increase in pressure inside the skull.

7. Brain biopsy: In very rare cases, a small sample of brain tissue might be removed for testing. This procedure is not preferred because of its high risk of complications. A brain biopsy is usually done only if the other tests do not give an answer or symptoms are worsening and treatments are having no effect.

8. Detection of intrathecal synthesis of antibodies: This test may be useful in detection of HSV, west nile virus and varicella zoster virus encephalitis.

Prevention Of Encephalitis

As encephalitis can be spread from one person to another, here are few tips to prevent the infection.

Avoid sharing items with a sick person: Be it food, utensils, glasses, or any other objects, it is advised to not share anything, especially personal items, with someone who may be exposed to or have the infection.  

Hand hygiene: Wash hands frequently and properly with soap and water, particularly after using the washroom and before and after meals.

Prevent mosquito bites: Eliminate the risk of being bitten by an infected mosquito or another arthropod by the following steps:

  • Wear clothes that cover arms, legs, and feet

  • Avoid sleeping or staying long in open areas

  • Use mosquito repellents in your home and clothes

  • Use mosquito screens on doors windows to prevent entry of mosquitoes in the homes

  • Use bed nets for all members of the family during night time

  • Use mosquito zapping devices like electric bats

  • Invest in mosquito-repelling plants like tulsi and lemongrass 

Get vaccinated: Vaccines are the most effective way of reducing the risk of developing encephalitis. These include vaccines for measles, mumps, and rubella. If the specific virus is prevalent in your region, vaccines for Japanese encephalitis and tick-borne encephalitis are recommended. Vaccines have been developed for people who travel to high-risk areas as well.

Do not self medicate: Take antibiotics (only after consulting with a doctor) if you live, work, or go to school with someone who has been diagnosed with bacterial encephalitis.

Should a person with encephalitis be quarantined?
Some of the causes of encephalitis such as enterovirus, COVID-19, or herpes are contagious while other forms are not. This is one reason, it is important to find out the underlying cause when a patient has encephalitis. The vast number of patients with encephalitis would not require quarantine. Consult your doctor to get clarity.
Should a person with encephalitis be quarantined?

Specialist To Visit

Patients exhibiting the symptoms of encephalitis are not capable enough to take their decisions on their own. Thus, the family or caregivers must approach the emergency care team if they suspect any abnormal activities of the brain in the patient. The following doctors can be consulted:

  • Neurologist

  • Internal medicine specialist

  • Infectious disease specialist

  • Pediatrician

Treatment Of Encephalitis


The key to surviving encephalitis is early detection and effective treatment of the underlying cause. Encephalitis treatment depends on the underlying cause and symptoms and may include:

1. Antiviral medications

The following antiviral medications are prescribed in case of viral encephalitis:

  • Acyclovir: It is commonly used in patients suspected with viral encephalitis, especially in case of HSV encephalitis. 

  • Ganciclovir and foscarnet: Both these drugs can be used either individually or in combination for the treatment of CMV encephalitis.

  • Ribavirin: It might be of benefit in children with severe adenovirus or rotavirus encephalitis. 

2. Antibiotics 

This class of medicines are used to address underlying bacterial infections causing encephalitis. Some of the common examples include:

3. Immunotherapy 

Immunotherapy is mostly recommended to address certain types of autoimmune encephalitis.

  • Steroids: It is usually used as an adjunctive therapy in the treatment of tuberculosis (TB) encephalitis, bacterial encephalitis (before an antibiotic shot is given), and autoimmune encephalitis. It helps in reducing the inflammation of the brain tissue and intracranial pressure (ICP). 
  • IV antibodies (IVIG): Viral encephalitis and autoimmune encephalitis have shown benefit after the use of IV antibodies. Due to the lack of sufficient evidence in the favor of IVIG, this treatment cannot be used as a part of the standard treatment of encephalitis
  • Plasma exchange: Therapeutic plasma exchange has shown promise especially in severe refractory cases of autoimmune encephalitis, not responding to steroids or IVIG.

3. Supportive care 

Supportive care includes careful monitoring of intracranial pressure, fluid restriction, suppression of fever, and monitoring of blood pressure. Also, use of a feeding tube, catheter, and breathing tube are required in some cases.

Note: Seizures should be treated with standard anticonvulsant treatment and prophylactic therapy should be considered in view of the high frequency of seizures in severe cases of encephalitis.

Did you know?
Patients with encephalitis who suffer from seizures and do not respond well to anti-seizure medications can benefit from a ketogenic diet. Keto diet is high in fat and low in carbohydrates. It has been found to be effective in reducing seizures in drug-resistant epilepsy in children and adults, as well as in patients with autoimmune encephalitis.
Did you know?

Home-care For Encephalitis 

Self-management can help in taking care of yourself. 

  • Know about your condition

  • Taking your medicine 

  • Talk with a doctor if you have questions

  • Good nutrition

  • Lower stress levels

  • Get enough sleep

Complications Of Encephalitis

Timely treatment after proper diagnosis of encephalitis can lead to better prognosis. However, if the encephalitis is left untreated, or even if the treatment is delayed, the damage to the brain can be fatal. Some of the common complications of encephalitis include:

  • Persistent fatigue

  • Persistent headache

  • Weakness or lack of muscle coordination

  • Movement disorders like tremors & involuntary muscle jerks

  • Post encephalitis (residual) seizure disorder

  • Paralysis

  • Hearing or vision defects

  • Speech impairments

  • Decreased concentration

  • Personality changes

  • Memory problems

  • Depression

Living With Encephalitis

Encephalitis is a serious condition. Both the acute stage of the disease and the after effects can be overwhelming for patients and their families. Recovery can take a long time. However, the following therapies can go a long way in helping the patients to make the best possible recovery:

  • Occupational therapy: Sometimes, encephalitis can dull the senses. An occupational therapist can help to adjust to this lack of sensation. They can also help a person improve their ability to carry out daily activities such as bathing, dressing, eating or reading.

  • Physical therapy: The goal of physical therapy (PT) or physiotherapy is to improve mobility, restore function, reduce pain, and prevent further injury by using a variety of methods, including exercises or yoga. A physical therapist can help to regain strength and relearn movement and coordination. 

  • Speech therapy: Speech therapy is a treatment that can help improve communication skills.  A speech and language therapist can help with problems producing speech. In case verbal communication is difficult, they can help in finding new and innovative ways of communication. Regular practice along with change in communication style can make communicating simpler.

  • Cognitive therapy: Post encephalitis, many patients may experience changes in their thinking or reasoning skills. This can also lead to behavioral and mood swings. Cognitive therapy can help to regain former patterns of behavior, along with management of emotional responses.

Frequently Asked Questions


  1. Ghosh S, Basu A. Acute Encephalitis Syndrome in India: The Changing Scenario. Ann Neurosci. 2016 Sep;23(3):131-133. Epub 2016 Sep 9.External Link
  2. Japanese encephalitis. Key facts. World Health Organization. External Link
  3. Narain JP, Dhariwal AC, MacIntyre CR. Acute encephalitis in India: An unfolding tragedy. Indian J Med Res. 2017 May;145(5):584-587.External Link
  4. Vashishtha VM, Ramachandran VG. Vaccination Policy for Japanese Encephalitis in India: Tread with Caution! Indian Pediatr. 2015 Oct;52(10):837-9.External Link
  5. Operational Guide for Japanese Encephalitis Vaccination in India, MoHFW, September 2010.External Link
  6. Encephalitis. Conditions and Diseases. Health. Johns Hopkins Medicine.External Link
  7. Encephalitis. Paediatr Child Health. 1998 Jan;3(1):47-52. External Link
  8. Ellul M, Solomon T. Acute encephalitis - diagnosis and management. Clin Med (Lond). 2018 Mar;18(2):155-159.External Link
  9. Encephalitis. Paediatr Child Health. 1998 Jan;3(1):47-52. External Link
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