National Institute of Neurological Disorders and Stroke

What is encephalitis?

Encephalitis is inflammation of the brain. Myelitis refers to inflammation of the spinal cord. When both the brain and the spinal cord are involved, the condition is called encephalomyelitis.

Infections and other disorders affecting the brain and spinal cord can activate the immune system, which leads to inflammation. This inflammation can produce a wide range of symptoms and, in extreme cases, cause brain damage, stroke, or even death.

Individuals with encephalitis often show mild flu-like symptoms. In more severe cases, people may experience:

• Problems with speech or hearing
• Double vision
• Hallucinations
• Personality changes
• Loss of consciousness
• Loss of sensation in some parts of the body

• Muscle weakness
• Partial paralysis in the arms and legs
• Impaired judgment
• Seizures
• Memory loss

Important signs of encephalitis to watch for in an infant include fever, lethargy, not waking for feedings, vomiting, body stiffness, unexplained/unusual irritability, and a full or bulging fontanel (the soft spot on the top of the head).

Who is more likely to get encephalitis?

Anyone—from infants to older adults—can get encephalitis. People with weakened immune systems, including those persons with HIV or those taking immunosuppressant drugs, are at increased risk.

Some forms of encephalitis are contagious and can be spread through contact with:

• Saliva
• Nasal discharge
• Feces
• Respiratory and throat secretions (often spread through kissing, coughing, or sharing drinking glasses, eating utensils, or such personal items as toothbrushes, lipstick, or cigarettes)

For example, people sharing a household, at a day care center, or in a classroom with an infected person can become infected. College students living in dormitories—in particular, college freshmen—have a higher risk of contracting meningococcal meningitis than college students overall.

Because the disease can occur suddenly and progress rapidly, anyone who is suspected of having encephalitis should immediately contact a doctor or go to the hospital.

Causes of encephalitis

Infectious causes of encephalitis include bacteria, viruses, fungi, and parasites. For some individuals, environmental exposure (such as a parasite), recent travel, or an immunocompromised state (such as HIV, diabetes, steroids, chemotherapy treatment) are important risk factors. There are also non-infectious causes such as autoimmune/rheumatological diseases and certain medications.

Up to 60 percent of cases of encephalitis remain undiagnosed. Several thousand cases are reported each year, but many more may occur since the symptoms may be mild to non-existent in most individuals.

Most diagnosed cases in the U.S. are caused by herpes simplex virus types 1 and 2, arboviruses (such as the West Nile Virus), which are transmitted from infected animals to humans through the bite of an infected tick, mosquito, or other blood-sucking insect, or enteroviruses. Lyme disease, a bacterial infection spread by tick bite, occasionally causes meningitis, and very rarely encephalitis. Rabies virus, which is transmitted by bites of rabid animals, is an extremely rare cause of human encephalitis.

Herpes simplex encephalitis (HSE) is responsible for about 10 percent of all encephalitis cases, with a frequency of about two cases per million people per year. More than half of untreated cases are fatal. About 30 percent of cases result from the initial infection with the herpes simplex virus; the majority of cases are caused by reactivation of an earlier infection. Most people acquire herpes simplex virus type 1 (the cause of cold sores or fever blisters) in childhood.

HSE due to herpes simplex virus type 1 can affect any age group but is most often seen in persons under age 20 or over age 40. This rapidly progressing disease is the single most important cause of fatal sporadic encephalitis in the country. Symptoms can include headache and fever for up to five days, followed by personality and behavioral changes, seizures, hallucinations, and altered levels of consciousness.  Brain damage in adults and in children beyond the first month of life is usually seen in the frontal lobes (leading to behavioral and personality changes) and temporal lobes (leading to memory and speech problems) and can be severe. 

Type 2 virus (genital herpes) is most often transmitted through sexual contact. Many people do not know they are infected and may not have active genital lesions. An infected mother can transmit the disease to her child at birth, through contact with genital secretions. In newborns, symptoms such as lethargy, irritability, tremors, seizures, and poor feeding generally develop between four and 11 days after delivery.

Four common forms of mosquito-transmitted viral encephalitis are seen in the United States:

1. Equine encephalitis affects horses and humans  
   • Eastern equine encephalitis also infects birds that live in freshwater swamps of the eastern U.S. seaboard and along the Gulf Coast. In humans, symptoms are seen within four days or up to two weeks following transmission and include sudden fever, general flu-like muscle pains, and headache of increasing severity, followed by coma and death in severe cases.  About half of infected individuals die from the disorder. Fewer than 10 human cases are seen annually in the United States. 
   • Western equine encephalitis is seen in farming areas in the western and central plains states. Symptoms begin within five and up to 10 days following infection. Children, particularly those under 12 months of age, are affected more severely than adults and may have permanent neurologic damage. Death occurs in about three percent of cases. 
   • Venezuelan equine encephalitis is very rare in the U.S. Children are at greatest risk of developing severe complications, while adults generally develop flu-like symptoms. Epidemics in Central and South America have killed thousands of people and left others with permanent, severe neurologic damage.
2. LaCrosse encephalitis occurs in the upper midwestern states (Illinois, Wisconsin, Indiana, Ohio, Minnesota, and Iowa) but has been reported in the southeastern and mid-Atlantic regions of the country.  Most cases are seen in children under the age of 16. Symptoms such as vomiting, headache, fever, and lethargy appear up to 10 days following infection. Severe complications include seizures, coma, and permanent neurologic damage. About 100 cases of LaCrosse encephalitis are reported each year.
3. St. Louis encephalitis is most prevalent in temperate regions of the U.S. but can occur throughout most of the country. The disease is generally milder in children than in adults, with elderly adults at highest risk of severe disease or death. Symptoms typically appear within seven days and up to 10 following infection and include headache and fever. In more severe cases, confusion and disorientation, tremors, convulsions (especially in the very young), and coma may occur.
4. West Nile encephalitis is usually transmitted by a bite from an infected mosquito but can also occur after transplantation of an infected organ or transfusions of infected blood or blood products. Symptoms are flu-like and include fever, headache, and joint pain. Some individuals may develop a skin rash and swollen lymph glands, while others may not show any symptoms. At highest risk are older adults and people with weakened immune systems.

Outside the U.S., Japanese encephalitis is one of the most common causes of encephalitis worldwide. It is widespread in Asia and transmitted by a mosquito. A vaccine is available so travelers to at-risk areas should discuss this with their healthcare provider.

Powassan encephalitis is rare but is the only well-documented tick-borne arbovirus in the U.S. and Canada. Symptoms are noticed seven to 10 days following the bite (most people do not notice tick bites) and may include headache, fever, nausea, confusion, partial paralysis, coma, and seizures.

It is also possible to develop encephalitis that has non-infectious or autoimmune causes. Some cases of encephalitis are caused by an autoimmune disorder that may in some instances be triggered by an infection (“post infectious”) or by a cancer—even one that is microscopic and cannot be found (so-called paraneoplastic neurological syndromes).  NMDA-Receptor encephalitis is a type of autoantibody-mediated encephalitis and is being increasingly recognized; it was the most documented form of non-bacterial meningitis reported in the long-term study and follow-up of participants in the California Encephalitis project. Treatment involves immunosuppression and/or tumor removal if such a cause is found.

How is encephalitis diagnosed and treated?

Diagnosing encephalitis

Following a physical exam and medical history to review activities of the past several days or weeks (such as recent exposure to insects, ticks or animals, any contact with ill persons, or recent travel; preexisting medical conditions and medications), the doctor may order various diagnostic tests to confirm the presence of infection or inflammation. Early diagnosis is vital, as symptoms can appear suddenly and escalate to brain damage, hearing and/or speech loss, blindness, or even death.

Diagnostic tests include:

• A neurological examination involves a series of physical examination tests designed to assess motor and sensory function, nerve function, hearing and speech, vision, coordination and balance, mental status, and changes in mood or behavior.
• Laboratory screening of blood, urine, and body secretions can help detect and identify brain and/or spinal cord infection and determine the presence of antibodies and foreign proteins. Such tests can also rule out metabolic conditions that may have similar symptoms.
• Analysis of the cerebrospinal fluid that surrounds and protects the brain and spinal cord can detect infections in the brain and/or spinal cord, acute and chronic inflammation, and other diseases. A small amount of cerebrospinal fluid is removed by a special needle that is inserted into the lower back and the fluid is tested to detect the presence of bacteria, blood, and viruses. The testing can also measure glucose levels (a low glucose level can be seen in bacterial or fungal meningitis) and white blood cells (elevated white blood cell counts are a sign of inflammation), as well as protein and antibody levels.

Brain imaging can reveal signs of brain inflammation, internal bleeding or hemorrhage, or other brain abnormalities. Two imaging procedures are routinely used to diagnose meningitis.

1. Computed tomography (CT)
2. Magnetic resonance imaging (MRI)

Additionally, electroencephalography (EEG) can identify abnormal brain waves by monitoring electrical activity in the brain.

Treating encephalitis

People who are suspected of having encephalitis should receive immediate, aggressive medical treatment. The disease can progress quickly and has the potential to cause severe, irreversible neurological damage.

Antiviral drugs used to treat viral encephalitis include acyclovir and ganciclovir. For most encephalitis-causing viruses, no specific treatment is available.

Autoimmune causes of encephalitis are treated with additional immunosuppressant drugs and screening for underlying tumors when appropriate. Acute disseminated encephalomyelitis, a non-infectious inflammatory brain disease mostly seen in children, is treated with steroids.

Anticonvulsants may be prescribed to stop or prevent seizures.  Corticosteroids can reduce brain swelling. Affected individuals with breathing difficulties may require artificial respiration.

Once the acute illness is under control, comprehensive rehabilitation should include cognitive rehabilitation and physical, speech, and occupational therapy.

Prevention

People should avoid sharing food, utensils, glasses, and other objects with someone who may be exposed to or have the infection. People should wash their hands often with soap and rinse under running water.

To lessen the risk of being bitten by an infected mosquito or other arthropod, people should limit outdoor activities at night, wear long-sleeved clothing when outdoors, use insect repellents that are most effective for that particular region of the country, and rid lawn and outdoor areas of free-standing pools of water (where mosquitoes like to breed). Repellants should not be overapplied, particularly on young children and especially infants, as chemicals like DEET may be absorbed through the skin.

The outlook for individuals with encephalitis generally depends on the particular infectious agent involved, the severity of the illness, and how quickly treatment is given. In most cases, people with very mild encephalitis can make a full recovery, although the process may be slow.

In more serious cases, the disease can cause hearing and/or speech loss, blindness, permanent brain and nerve damage, behavioral changes, cognitive disabilities, lack of muscle control, seizures, and memory loss. These individuals may need long-term therapy, medication, and supportive care. 

file-medical

Learn About Clinical Trials

Clinical trials are studies that allow us to learn more about disorders and improve care. They can help connect patients with new and upcoming treatment options.

How can I or my loved one help improve care for people with encephalitis?

Consider participating in a clinical trial so clinicians and scientists can learn more about encephalitis and related disorders.  Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with encephalitis at Clinicaltrials.gov.

Where can I find more information about encephalitis?

Information may be available from the following resources:

Centers for Disease Control and Prevention (CDC)
Phone: 800-232-4636

HHV-6 Foundation
Phone: 888-530-6726

MedlinePlus

National Institute of Allergy and Infectious Disease (NIAID)
Phone: 301-496-5717 or 866-284-4107

Learn about related topics

• Meningitis

Encephalitis | Johns Hopkins Medicine

Encephalitis is a serious condition affecting the brain that requires prompt treatment to lower the risk of lasting complications or death.

What is encephalitis?

Encephalitis is inflammation of the active tissues of the brain caused by an infection or an autoimmune response. The inflammation causes the brain to swell, which can lead to headache, stiff neck, sensitivity to light, mental confusion and seizures.

Encephalitis strikes 10–15 people per 100,000 each year, with more than 250,000 patients diagnosed in the last decade alone in the U.S. The condition can affect anyone, but more often occurs in younger people.

Encephalitis Causes and Types

Encephalitis can be caused by infections or autoimmune conditions where the body’s own immune responses attack the brain. Even with extensive testing, the specific cause of encephalitis remains unknown in about 30%–40% of cases.

Cases of encephalitis are likely to continue to rise as more and more autoimmune causes are recognized. Emerging infections such as Zika, chikungunya and Powassan viruses can also contribute to this trend.

Infectious Encephalitis

Infectious encephalitis is typically caused by a viral infection. Vaccines for measles, mumps, rubella and chickenpox have reduced the rate of encephalitis from these diseases, but other viruses can cause encephalitis. The most common causes of viral encephalitis are herpes simplex virus types 1 and 2, varicella zoster virus and enteroviruses, which cause gastrointestinal illness.

Encephalitis can also result from certain viruses carried by mosquitoes, ticks and other insects or animals such as:

• West Nile virus
• Japanese encephalitis virus
• La Crosse virus
• St. Louis virus
• Equine viruses
• Powassan virus
• Zika
• Chikungunya

Other infectious microorganisms such as bacteria, fungi and parasites can also cause encephalitis, though rarely.

Autoimmune Encephalitis

Autoimmune encephalitis occurs when a person’s own antibodies or immune cells attack the brain. Antibodies may target specific proteins or receptors in the brain, which determine the type of autoimmune encephalitis:

• In anti-NMDA receptor encephalitis, the immune system targets the NMDA receptors in the brain.
• In VGKC-complex antibody encephalitis, the immune system targets the VGKC brain protein complex that includes subtypes LGI-1 and CASPR2.
• GABA-A and GABA-B receptors may also be targeted.

While the causes of autoimmune encephalitis are not well understood, it can sometimes result from a tumor (benign or cancerous). Some types of autoimmune encephalitis such as acute disseminated encephalomyelitis (ADEM) are typically triggered by an infection (post-infectious encephalitis).

Encephalitis Symptoms

Acute encephalitis shows up with an onset of symptoms that get worse over the course of days to weeks. Infectious encephalitis often starts with flu-like symptoms or headache and evolves to altered mental status and problems with thinking, remembering and reasoning. Autoimmune encephalitis typically progresses over the course of weeks.

Symptoms of encephalitis vary according to the area of the brain affected and, in autoimmune encephalitis, depending on the associated antibody.

Physical Symptoms

• Fever
• Seizures
• Headache
• Movement disorders
• Sensitivity to light
• Sensitivity to sound
• Neck stiffness
• Loss of consciousness

In severe cases, encephalitis symptoms may include:

• Weakness or partial paralysis in the arms and legs
• Double vision
• Impairment of speech or hearing
• Coma

Cognitive Symptoms

• Excessive sleepiness
• Confusion and disorientation
• Irritability
• Anxiety
• Psychosis
• Hallucinations
• Memory loss
• Other behavioral changes
• Cognitive impairment

Symptoms Due to Specific Types of Encephalitis

Encephalitis caused by certain infections or autoimmune processes can show up with characteristic symptoms.

• A sensation of déjà vu (the feeling that one is reliving something already experienced) is a common finding in early stages of herpes simplex virus encephalitis.
• A type of autoimmune encephalitis affecting NMDA receptors can start with a flu-like illness. It can then lead to behavioral changes and unusual movement patterns affecting the mouth and face, cognitive decline and impaired function of the autonomic nervous system.
• Another type of autoimmune encephalitis (LGI1) is associated with seizures or other abnormal movement of the face or arm.

The symptoms of encephalitis may resemble other problems or medical conditions. Always consult your health care provider for a diagnosis.

Encephalitis Diagnosis

You may need to be evaluated for encephalitis if you are experiencing a combination of symptoms such as fever, altered state of awareness, seizures or changes in behavior or movement. It is very important to identify encephalitis promptly to decrease the risk of death or lasting complications.

To diagnose encephalitis, your healthcare provider might order tests, perform a medical exam and discuss your medical history. The doctor may ask about your vaccinations, recent colds and other respiratory illnesses or gastrointestinal illness. He or she will want to know if you have recently had a tick bite, have been around pets or other animals, or have traveled to certain locations.

Tests for encephalitis can include:

• Neuroimaging, such as a brain MRI or CT scan
• A lumbar puncture (spinal tap) to check for signs of infection in the brain or spinal cord
• Electroencephalogram (EEG) to look for seizures or specific patterns of electrical activity in the brain
• Blood tests or urine and stool tests to identify organisms or antibodies responsible for an infection

Additional tests may include:

• A sputum culture tests the material that is coughed up from the lungs to see if certain infections are present.
• In rare cases, a biopsy of affected brain tissue may be performed to allow for examination under a microscope.
• Intracranial pressure monitoring (ICP) measures the pressure inside the skull to monitor the brain swelling.

Encephalitis Treatment

The key to surviving encephalitis is early detection and effective treatment of the underlying cause. A team of specialists working together is an important factor in optimal care.

Encephalitis patients might require a stay in the ICU so that health care providers can watch for seizures, brain swelling, respiratory failure or heart rhythm changes.

Encephalitis treatment depends on the underlying cause and symptoms, and may include:

• Antiviral medications to fight viral infections affecting the brain.
• Antibiotics to address underlying bacterial infections causing encephalitis.
• Immunotherapy, such as steroids, intravenous antibodies (IVIg) or plasma exchange, to address certain types of autoimmune encephalitis.
• Medications or other therapies to control seizures.
• A breathing tube, urinary catheter, or feeding tube may be necessary if the person’s encephalitis has caused loss of consciousness.

Patients with encephalitis who have seizures that don’t respond well to anti-seizure medications could benefit from a ketogenic diet, which is high in fat and low in carbohydrates. It has been effective in reducing seizures in drug-resistant epilepsy in children and adults, as well as in patients with autoimmune encephalitis such as anti-NMDA receptor encephalitis.

Encephalitis Prognosis

Encephalitis is very serious. Both the acute stage and the aftermath can be overwhelming for patients and their families.

During the encephalitis attack, the inflamed brain tissue can suffer damage, which varies greatly between patients. In general, the brain doesn’t bounce back as quickly as other body parts such as bone, skin and muscles, but it does have some capacity to recover.

Mild cases of encephalitis are usually short and result in a full recovery. However, despite improvements in diagnosis and treatment, encephalitis still leads to death in about 10% of patients.

Survivors of severe cases of encephalitis can be left with permanent problems such as fatigue, irritability, impaired concentration, seizures, hearing loss, memory loss and blindness.

The recovery process may take months to even years. Intensive rehabilitation, involving specialists in neurology, occupational therapy, speech and language therapy, nutrition and neuropsychology, can help patients make the best possible recovery.

Can encephalitis be prevented?

These measures can help prevent certain types of infectious encephalitis:

• Keep your vaccinations up to date, especially when traveling to areas known to have encephalitis-causing viruses.
• Use proper hygiene and hand-washing to help prevent the spread of viruses and bacteria.
• Avoid mosquito and tick exposure.

If you are exposed to someone with bacterial encephalitis, contact your doctor. You may be offered a course of antibiotics to prevent you from getting the disease.

Treatment of inflammation of the brain or spinal cord (meningitis, encephalitis, myelitis)

Treatment of inflammation of the brain or spinal cord (meningitis, encephalitis, myelitis)

Myelitis is a general term for diseases and any inflammatory processes affecting the human spinal cord. Encephalitis is a group of diseases characterized by inflammation of the brain. In turn, meningitis is an infectious disease that affects the membranes of both the spinal cord and the brain.

Causes of inflammation

Encephalitis is caused by neurotropic viruses. The disease can also occur due to complications of rubella, smallpox and measles, and infection can also occur through ticks or mosquitoes. Meningitis is caused mainly by three types of bacteria – pneumococci, meningococci and Haemophilus influenzae. Thus, the cause of inflammation of the spinal cord or brain one way or another are infections of a viral, fungal or bacterial nature, or parasites.

Symptoms

The clinical picture is determined by the general extent and severity of the lesion. In most cases, patients experience the following symptoms:

• headache
• rise in body temperature
• nausea
• sensitivity to light
• general weakness
• in extreme manifestations, paralysis, epileptic seizures, impaired consciousness, etc. are possible.

Diagnosis

To diagnose and start treatment of inflammation of the spinal cord or brain, it is necessary to be examined by a neurologist. In addition to the examination, additional studies are carried out, including:

• computed tomography of the spinal cord and/or brain
• magnetic resonance imaging
• lumbar puncture for cerebrospinal fluid analysis, etc.

Treatment of inflammation of the brain or spinal cord

In such diseases, the doctors of the Viva clinic prescribe mainly drug therapy. As an additional treatment for inflammation of the brain and spinal cord, physiotherapy exercises, physiotherapy, and massage sessions are indicated.

Drug therapy involves taking antibiotics, vitamins, antiseptics, and other drugs. In addition, to ensure the effectiveness of the treatment of inflammation of the spinal cord and brain, an important role is played by:

• proper nutrition
• bed rest
• competent rehabilitation after recovery

Neurologists

Units where the procedure is performed

• Clinic at Vinogradarepr. V. Porika, 9a
• Clinic on Podoleul. Shchekavitskaya, 36
• Clinic on Troyeshchineul. Lavrukhina, 6
• Clinic on Lybidska st. Antonovicha, 155
• Clinic on Shulyavskaya st. Vadim Hetman, 1-in
• Clinic on Troyeshchineul. Honore de Balzac, 85a

Still have questions?

Inflammation of the meninges – diagnosis and treatment at 100med

What is this disease

Meningitis is often referred to as inflammation of the meninges. In the event of its occurrence, the protective layers of the spinal cord and brain become inflamed. This occurs under the influence of simple microorganisms, bacteria, fungal or viral infections. In some cases, the cause of inflammation can be medication or an injury.

Symptoms

Symptoms of inflammation of the meninges:

• increase in body temperature;

• the occurrence of hearing problems;

• significant headaches;

• nausea;

• loss of consciousness;

• vomit;

• the appearance of a rash on the skin;

• neck stiffness;

• drowsiness;

• convulsions;

• mental problems, including apathy, hallucinations, anxiety, agitation and other types.

Causes

Causes of inflammation of the meninges:

• influence of the simplest microorganisms;

• the presence of fungal infections;

• bacterial types of infections;

• viral diseases;

• a combination of several types of pathogens.

Diagnosis

Diagnosis of inflammation of the meninges is carried out as follows:

• general, PCR and biochemical blood tests;

• neurological examination;

• electroencephalography;

• puncture of the cerebrospinal type;

• CT study.

Write us an online chat

Our expert’s opinion

Meningitis occurs in acute, fulminant and chronic forms, so only with the right approach can a correct and timely diagnosis be made. Such a complex disease requires complex treatment and high professionalism of medical personnel.

Treatment

Therapy of inflammation of the meninges is carried out in the complex:

• the use of antiviral agents;

• the appointment of antipyretics;

• the use of painkillers;

• antifungal treatment;

• antibacterial therapy.