Encephalitis

Overview

Encephalitis is a serious medical issue, caused by certain viruses, bacteria, fungi or the body's autoimmune process. It leads to a brain infection that causes inflammation and swelling. An individual may experience fever, headache, confusion, seizures, or personality changes. Treatment often involves hospitalisation, ensuring the patient receives proper medical care including life support equipment. Lastly, its prevention includes vaccinations and protecting oneself from insect bites.

What is Encephalitis?

Encephalitis is a serious, life-threatening and rare infection of the brain that causes swelling and inflammation. It can be caused by viruses, bacteria, fungi, or even the body's autoimmune process where the immune system attacks brain cells. Symptoms of this disease often include fever, headache, confusion, seizures, and changes in behaviour or personality.

Types of Encephalitis

The following are the different types of Encephalitis:

Viral or Infectious Encephalitis: It is the most common type of encephalitis that is caused by various viruses including the West Nile virus, herpes simplex virus, Epstein-Barr virus or varicella zoster virus. An individual may experience symptoms ranging from mild flu-like illness to severe neurological problems.

Autoimmune Encephalitis: This is a rare condition where the body's immune system mistakenly attacks the brain cells due to a tumour or infection. While symptoms can vary widely, signs may include cognitive impairment, behavioural changes, and seizures.

Bacterial or Fungal Encephalitis: While this type of encephalitis is less common, it can be life-threatening, especially for individuals with compromised immune systems. It may occur due to a complication caused by some other infections, such as meningitis. Symptoms can include high fever, severe headache, stiff neck, confusion, and seizures.
The other type of encephalitis includes arbovirus encephalitis in which fleas, mosquitoes and ticks spread the encephalitis-causing infection.

Symptoms of Encephalitis

The symptoms of encephalitis depend on its type. Infectious encephalitis may exhibit symptoms more quickly than other types of encephalitis such as autoimmune encephalitis. However, the early warning signs of this infectious disease include high fever, fatigue, mild to moderate neck stiffness and fatigue.

On the contrary autoimmune disease, which exhibits neurological symptoms slowly, includes signs such as drowsiness, confusion, memory problems, loss of consciousness, vision changes, bowel and bladder symptoms, sensation loss, muscle weakness, hallucinations, agitation, vomiting and nausea, speech impairment, seizure, noticeable personality changes, and loss of movement or weakness in some body parts.

Symptoms in young children and infants may include irritability, nausea and vomiting, not waking for a feeding or poor feeding, stiffness affecting the entire body, and bulging of an infant's skull’s soft spots.

Causes of Encephalitis

Certain viruses affecting the brain contribute to the cause of encephalitis. Herpes simplex virus (HSV) is often the major cause of this disease. However, an individual can also develop it if they have other viruses or certain infectious diseases such as mumps, rubella, varicella chickenpox and measles. Other viruses that can lead to this condition include rabies-causing RABV virus, Epstein-Barr virus, human immunodeficiency virus (HIV), and cytomegalovirus (CMV).

Encephalitis can also be caused by viruses spread by insects including eastern equine encephalitis (EEE), dengue viruses, tick-borne encephalitis (TBE), poliovirus, coxsackievirus, St. Louis encephalitis (SLE) virus, western equine encephalitis and West Nile virus (most prevalent mosquito-borne virus that causes encephalitis). Encephalitis, in some cases, may also be caused when the immune cells of the body attack the brain mistakenly.

The risk factors for encephalitis include being in exposure to insect-borne viruses or having certain viral infections. Young children, individuals with weakened immune systems and older adults are at an increased risk of developing encephalitis. Living in geographical regions where cases of mosquito or tick-borne infectious diseases are common is another risk factor. Other risk factors include going out frequently during the summer season, having an autoimmune condition, and smoking.

Diagnosis of Encephalitis

Healthcare providers physically examine the patient to determine the cause of encephalitis. The examination deals with answering about their symptoms and the duration of them. Following that, the doctor may recommend certain tests including complete blood count (CBC) and comprehensive metabolic panel (CMP) blood tests, lumbar puncture, imaging tests such as CT scan, MEG and MRI, and neurological examination.

Treatment for Encephalitis

The treatment options available for encephalitis help in treating its symptoms and underlying conditions. Many patients are kept under a doctor's surveillance, in a hospital, to keep their symptoms monitored and take prompt action if symptoms worsen. However, the common treatment options include antiviral medications such as acyclovir (Zovirax®), mechanical ventilation or supplemental oxygen, anti-seizure medication, corticosteroids, immune globulin, enteral nutrition, and physical therapy. A doctor may also recommend reaching out for mental health support from a psychologist, taking intravenous (IV) fluids, speech therapy and plasmapheresis.

Prevention of Encephalitis

The risk of getting encephalitis can be reduced by protecting oneself from mosquito bites and staying up-to-date with vaccinations. One must ensure getting vaccinated against mumps, chickenpox, measles and rubella. The one-and-done vaccination, MMR vaccinations are given to people early in their childhood.

In addition, one must use mosquito repellents containing DEET when they are outside, especially when mosquitoes are most active; wear protective clothes such as pants, hats and long-sleeve shirts; use window screens and fans to keep mosquitoes away from one's house; and spray areas with insecticide and dry out items with standing water to prevent the development of this condition.

Myths and Facts Related to Encephalitis

Following are the common myths and facts surrounding Encephalitis:

Myth 1: Encephalitis is a Rare Disease
Fact: While it is a less common disease than other illnesses, it can affect people of every age group and cause severe complications such as brain damage or memory loss.

Myth 2: Encephalitis is Caused Only by Mosquito Bites
Fact: While mosquito-borne viruses such as West Nile virus, eastern equine encephalitis and Japanese encephalitis virus are common causes of encephalitis, other factors can also trigger it. These include bacterial infections, viral infections such as herpes simplex virus, fungal infections, and autoimmune disorders.

Myth 3: Encephalitis is Always Dangerous and Severe
Fact: No, encephalitis is not always fatal as only about 10% of patients die from the disease while the rest fully recover. However, the recovery time may range from months to years.

Myth 4: Diagnosing Encephalitis is Very Easy
Fact: Diagnosing encephalitis can be challenging as it is a reaction to something, and its symptoms vary widely and mimic other conditions. A combination of tests, including blood tests, spinal fluid analysis, and imaging studies like CT scans and MRIs may be required for proper diagnosis.