World Encephalitis Day will be observed Tuesday, Feb. 22, which makes this a good time to learn about treating this infectious disease.
Encephalitis affects nearly 500,000 people of all ages worldwide each year, according to the Encephalitis Society, with young children and older adults most vulnerable. Other risk factors include having a compromised immune system, living in certain areas of the world and the season of the year.
Encephalitis is inflammation of the brain. The inflammation can be caused by an infection, most often a virus, invading the brain, but it also can be caused by the immune system attacking the brain in error, called autoimmune encephalitis. Sometimes the immune attack can be triggered by an infection in the body without the infection itself invading the brain.
Viruses that can cause encephalitis include herpes viruses and enteroviruses. Childhood infections, such as measles, mumps and rubella, used to be a common cause of secondary encephalitis, but this is rare now in the U.S. due to the availability of vaccinations for these diseases.
Encephalitis also can be caused by viruses carried by mosquitoes or ticks. Wearing appropriate clothing and using insect repellent while outdoors is the best way to prevent exposure to these viruses.
Symptoms of encephalitis evolve over days to weeks and include fever, confusion, headache, vomiting, weakness and seizures.
“This is a very serious condition; encephalitis can lead to coma and death,” says Dr. Sebastian Lopez, a Mayo Clinic neurologist. “So early diagnosis and prompt treatment is critical for achieving better neurologic outcomes. Diagnosing the cause of encephalitis is vital because treatments vary depending on whether patients have and underlying infection or a reaction caused by the immune system."
Despite significant progress, encephalitis is still associated with high mortality. Those who recover from the initial illness may struggle with fatigue, paralysis, language impairment, memory difficulties, personality changes and memory problems that may persist for months or be permanent.
Treatment for mild encephalitis usually consists of bed rest, fluids and anti-inflammatory medications to relieve headache and fever. Encephalitis caused by certain viruses usually also requires treatment with antiviral medications. Treatment of autoimmune encephalitis usually involves medications that suppress the immune system.
People who are hospitalized with severe encephalitis might need breathing assistance, IV fluids, anti-inflammatory drugs to reduce swelling and pressure within the skull, and anti-convulsant medications to stop or prevent seizures.
Connect with others talking about encephalitis in the Brain & Nervous System support group and the Autoimmune Diseases support group on Mayo Clinic Connect, an online patient community moderated by Mayo Clinic.