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Encephalitis

Inflammation of the brain.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Encephalitis

Infections, and less commonly other causes, in the brain and spinal cord can cause dangerous inflammation. This inflammation can produce a wide range of symptoms, including fever, headache, seizures, change in behavior or confusion and, in extreme cases, can cause brain damage, stroke, or even death.

Infection of the meninges, the membranes that surround the brain and spinal cord, is called meningitis and inflammation of the brain itself is called encephalitis. Myelitis refers to inflammation of the spinal cord. When both the brain and the spinal cord are involved, the condition is called encephalomyelitis....Read more about Encephalitis NIH - National Institute of Neurological Disorders and Stroke

What works? Research summarized

Evidence reviews

Vaccines for preventing tick‐borne encephalitis

Tick‐borne encephalitis (TBE) is a disease of the central nervous system caused by a tick‐borne viral infection. TBE can lead to severe neurological syndromes, which can result in death. Many species of wild and domestic animals act as hosts of ticks; transmission to humans occurs often in woodland areas, especially during the summer, which is the time of greatest human outdoor activity. TBE is particularly prevalent in Central and Eastern Europe.

Two doses of an inactivated vaccine can help prevent Japanese encephalitis disease for at least one year; however, comparisons with other widely used vaccines are not available

Japanese encephalitis is a viral disease of the central nervous system with general symptoms of headache, fever, vomiting, and diarrhoea. Most people recover within a week without further complications, but approximately 1 in 300 suffers additional and severe symptoms such as disorientation, seizures, paralysis, and coma. Around thirty per cent of the severe cases are fatal and most survivors are left with serious and often chronic disabilities such as mental impairment, limb paralysis, and blindness. In this review of randomized controlled trials, a commercially available inactivated vaccine given in two doses was shown to provide disease protection for at least one year after vaccination, but with some adverse events. Disease protection by two vaccines, widely used in China but presently commercially unavailable, has not been investigated in randomized controlled trials. Further research is needed on all currently used as well as newly developed vaccines.

Antiepileptic drugs for the primary and secondary prevention of seizures in viral encephalitis

Viral encephalitis is characterised by inflammation and swelling of the brain and is caused by viral infection. Seizures can occur both during viral encephalitis and as a later consequence following resolution of the infection. Patients who have seizures during encephalitis are more likely to die or have a disability; some may also develop prolonged or repeated seizures, which can be very difficult to treat. As not all patients will develop seizures, it is unclear whether the use of antiepileptic drugs in patients with viral encephalitis before they have seizures can prevent further seizures and improve their outcome. It is also not clear whether the use of these drugs after the first seizure can prevent the occurrence of further seizures and long‐term epilepsy.

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Summaries for consumers

Vaccines for preventing tick‐borne encephalitis

Tick‐borne encephalitis (TBE) is a disease of the central nervous system caused by a tick‐borne viral infection. TBE can lead to severe neurological syndromes, which can result in death. Many species of wild and domestic animals act as hosts of ticks; transmission to humans occurs often in woodland areas, especially during the summer, which is the time of greatest human outdoor activity. TBE is particularly prevalent in Central and Eastern Europe.

Two doses of an inactivated vaccine can help prevent Japanese encephalitis disease for at least one year; however, comparisons with other widely used vaccines are not available

Japanese encephalitis is a viral disease of the central nervous system with general symptoms of headache, fever, vomiting, and diarrhoea. Most people recover within a week without further complications, but approximately 1 in 300 suffers additional and severe symptoms such as disorientation, seizures, paralysis, and coma. Around thirty per cent of the severe cases are fatal and most survivors are left with serious and often chronic disabilities such as mental impairment, limb paralysis, and blindness. In this review of randomized controlled trials, a commercially available inactivated vaccine given in two doses was shown to provide disease protection for at least one year after vaccination, but with some adverse events. Disease protection by two vaccines, widely used in China but presently commercially unavailable, has not been investigated in randomized controlled trials. Further research is needed on all currently used as well as newly developed vaccines.

Antiepileptic drugs for the primary and secondary prevention of seizures in viral encephalitis

Viral encephalitis is characterised by inflammation and swelling of the brain and is caused by viral infection. Seizures can occur both during viral encephalitis and as a later consequence following resolution of the infection. Patients who have seizures during encephalitis are more likely to die or have a disability; some may also develop prolonged or repeated seizures, which can be very difficult to treat. As not all patients will develop seizures, it is unclear whether the use of antiepileptic drugs in patients with viral encephalitis before they have seizures can prevent further seizures and improve their outcome. It is also not clear whether the use of these drugs after the first seizure can prevent the occurrence of further seizures and long‐term epilepsy.

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Terms to know

Brain
The part of the central nervous system that is contained within the skull (cranium).
Inflammation
Redness, swelling, pain, and/or a feeling of heat in an area of the body. This is a protective reaction to injury, disease, or irritation of the tissues.
Meninges
The three thin layers of tissue that cover and protect the brain and spinal cord.
Meningitis
Inflammation of the meninges (three thin layers of tissue that cover and protect the brain and spinal cord). Meningitis is usually caused by a bacterial or viral infection, but sometimes is caused by cancer, drug allergies, or inflammatory diseases.
Spinal Cord
A column of nerve tissue that runs from the base of the skull down the back. It is surrounded by three protective membranes, and is enclosed within the vertebrae (back bones). The spinal cord and the brain make up the central nervous system, and spinal cord nerves carry most messages between the brain and the rest of the body.

More about Encephalitis

Photo of an adult woman

Other terms to know: See all 5
Brain, Inflammation, Meninges

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