Encephalitis refers to inflammation of the brain associated with memory loss, confusion, and even seizures. It is traditionally attributed to infections, as fever, headaches, and vomiting are also some of the symptoms. However, a recent study published in Annals of Neurology suggests that it could be caused by an autoimmune disease. This means that brain inflammation could be a result of the immune system attacking the brain.
This idea is not new. Doctors had suspected autoimmune causes even earlier and coined the term autoimmune encephalitis. However, it was a less known viewpoint, and considering the symptoms, doctors traditionally treated their patients for infections, which is ineffective for patients with autoimmune encephalitis. Since encephalitis is a progressive disease, improper treatment can cause the condition to worsen and even become life-threatening.
Encephalitis risk factors
Scientists have found certain groups of the population to be vulnerable to developing encephalitis. These include:
- Elderly people, infants, and children under the age of one
- People who have a weak immune system either genetically or due to an illness, including those who have contracted HIV/AIDS and people on immune-suppressing medications
Since viruses are also spread by mosquitos and ticks, people living in regions where these insects are common are at risk of contracting the disease. The risk is seasonal in countries such as the United States, where mosquito and tick-borne infections spread more rampantly in summer. Therefore, geographical location and the time of year are encephalitis risk factors.
In an attempt to understand encephalitis and its diagnosis better, researchers from Mayo Clinic studied the medical records database of Olmsted County in Minnesota as well as data collected during the Rochester Epidemiology Project.
Tools and data analysis
Researchers used the diagnostic criteria developed in 2016 to identify cases of autoimmune encephalitis. They tested blood and spinal fluid for neural autoantibodies and identified antibody markers in several samples. These samples indicated when someone had autoimmune encephalitis.
For cases that were not identified in the 2016 diagnostic criteria, researchers tested samples for infectious pathogens.
Analysis of this data revealed 14 in 100,000 people suffered from autoimmune encephalitis, whereas 12 in 100,000 people had infectious encephalitis.
Researchers also estimated that one million people suffer from autoimmune encephalitis worldwide and each year, 90,000 people develop the condition.
Findings and their significance
The comparative data shows that the number of people who suffered from autoimmune encephalitis and those suffering from infectious encephalitis are virtually the same. According to Eoin Flanagan, senior author of the study, the data shows that doctors are detecting an increasing number of cases of autoimmune encephalitis lately. Michel Toledano, a co-investigator in the study, recommends that all doctors should evaluate patients for both autoimmune encephalitis as well as infections. This would ensure appropriate treatment is given in time to avert long-lasting damage.
Estimates show that the prevalence of the condition is increasing worldwide, and awareness needs to be spread. World Encephalitis Day falls on February 22 and is the perfect time to educate yourself on the condition.