Encephalitis

Acute encephalitis causes fever and a change in the mental status of a person. It may also lead to the onset of seizures for the first time, especially in children, once infected. Most individuals suffering from the condition do not exhibit any symptoms. However, some may experience the following:

• Headache
• Vomiting
• Neck stiffness
• Weakness
• Increased irritability
• Confusion
• Disorientation
• Coma
• Hallucinations
• Aphasia (inability to talk or speak)
• Ataxia (loss of balance)
• Involuntary movements
• Personality changes

The infection progresses to illness in less than 1% of those infected. In individuals who develop symptoms, it usually takes around 5-15 days for the symptoms to appear after the infection. In severe cases, acute encephalitis syndrome (AES) can present with symptoms such as:

• Hearing loss
• Vision impairment
• Seizures
• Unconsciousness
• Paralysis
• Coma

The main cause of encephalitis in India is known to be viruses; however, bacteria, parasites, fungi, chemicals, toxins, and cancer (paraneoplastic encephalitis) can also cause the disease. Various causes are discussed below:

• Viruses: Arboviruses, transmitted through insect bites, are among the most common causes of viral encephalitis. These include Japanese encephalitis and tick-borne encephalitis viruses. Individuals suffering from dengue, mumps, measles, scrub typhus, Nipah, and Zika virus are at high risk of encephalitis. Other viruses that can cause encephalitis include herpes simplex virus (HSV), enteroviruses, Epstein-Barr virus, mosquito-borne viruses, tick-borne viruses, and rabies virus.
• Autoimmunity: Autoimmune encephalitis occurs when a person's own antibodies or immune cells attack the brain. It can be caused by autoimmune disorders such as systemic lupus erythematosus and Behçet's disease.
• Cancer: Encephalitis associated with cancer is known as paraneoplastic encephalitis. It can be caused by the metastasis of cancer cells to the nervous system or by complications of cancer, such as coagulopathy, stroke, metabolic and nutritional conditions, and side effects of cancer therapy.
• Other causes: Rarely, bacteria and parasites can cause encephalitis. Severe forms of leptospirosis and toxoplasmosis are associated with encephalitis. The causative agent may vary with season and geographical location. In some cases, the causative agent may remain unidentified.

Various risk factors associated with encephalitis are:

• Age: Infants, young children, and the elderly are at a higher risk of most types of viral encephalitis.
• Compromised immunity: Individuals with weakened immune systems, such as those suffering from HIV or cancer, undergoing chemotherapy, or taking immune-suppressing drugs, are at increased risk of encephalitis.
• Geographical areas: Certain geographical areas with a high prevalence of mosquito or tick-borne viruses report more cases of encephalitis.
• Season of the year: Mosquito and tick-borne diseases tend to be more common in the summer or rainy seasons when these insects are most active.

Acute encephalitis constitutes a medical emergency. The diagnosis of acute encephalitis is suspected in a febrile patient presenting altered consciousness. To diagnose encephalitis, your healthcare provider might order tests, perform a medical exam, and discuss medical history.

A. Clinical History

Before confirming the patient has encephalitis, it is essential to rule out conditions that may mimic the symptoms of encephalitis. A physician performs a detailed overview checkup, reviewing the patient’s history and the onset of symptoms to exclude other potential causes.

B. Lab Tests and Imaging Studies

• Imaging Tests: Tests like magnetic resonance imaging (MRI) or computed tomography (CT) can be used to view the cross-sectional area of the brain. Single photon emission computed tomography (SPECT) can also be performed depending on availability. Imaging tests can reveal abnormalities in the brain, as well as the cause of seizure-like tumors, lesions, and cerebral dysfunction. These tests can also check for any problems that may make performing a lumbar puncture or spinal tap risky.
• Lumbar Puncture: Also known as a spinal tap, this test is done to obtain a sample of cerebrospinal fluid (CSF), a protective fluid that flows through the meninges covering the brain and spinal cord. When the brain and meninges are inflamed, the number of white cells in the CSF increases. Sometimes, samples of CSF can be tested to identify the virus or other infectious agents causing encephalitis.
• Cerebrospinal Fluid (CSF) Polymerase Chain Reaction (PCR): PCR produces many copies of a gene, helping to detect the genetic material of viruses in a sample of CSF. It has become the primary diagnostic test for central nervous system (CNS) infections caused by viruses such as cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), and enteroviruses.
• Electroencephalogram (EEG): EEG records the brain's electrical activity. While it does not detect the virus that causes encephalitis, certain abnormal patterns on the EEG may indicate a diagnosis of encephalitis.
• Other Lab Tests: Blood tests, including complete blood count (CBC) along with urine or serum toxicology screening tests, may be conducted to test for viruses or other infectious agents.
• Intracranial Pressure Monitoring (ICP): Any brain swelling can be diagnosed by an increase in pressure inside the skull.
• Brain Biopsy: In very rare cases, a small sample of brain tissue might be removed for testing. This procedure is not preferred due to its high risk of complications and is usually performed only if other tests do not provide answers or if symptoms worsen despite treatment.
• Detection of Intrathecal Synthesis of Antibodies: This test may be useful in the detection of herpes simplex virus (HSV), West Nile virus, and varicella zoster virus encephalitis.

As encephalitis can be spread from one person to another, here are a few tips to prevent the infection:

• Avoid sharing items with a sick person: Do not share food, utensils, glasses, or any personal items with someone who may be exposed to or have the infection.
• Hand hygiene: Wash hands frequently and properly with soap and water, particularly after using the washroom and before and after meals.
• Prevent mosquito bites: Eliminate the risk of being bitten by an infected mosquito or other arthropods by following these steps:
  • Wear clothes that cover arms, legs, and feet.
  • Avoid sleeping or staying long in open areas.
  • Use mosquito repellents on your skin and clothing.
  • Install mosquito screens on doors and windows to prevent entry into homes.
  • Use bed nets for all family members during nighttime.
  • Utilize mosquito zapping devices, such as electric bats.
  • Invest in mosquito-repelling plants like tulsi and lemongrass.
• Get vaccinated: Vaccines are the most effective way to reduce the risk of developing encephalitis. Recommended vaccines include those for measles, mumps, and rubella. If specific viruses are prevalent in your region, vaccines for Japanese encephalitis and tick-borne encephalitis are advised. Vaccines are also available for travelers to high-risk areas.
• Do not self-medicate: Take antibiotics only after consulting with a doctor if you live, work, or go to school with someone diagnosed with bacterial encephalitis.

The key to surviving encephalitis is early detection and effective treatment of the underlying cause. Encephalitis treatment depends on the underlying cause and symptoms and may include:

• Antiviral medications
  • Acyclovir: Commonly used in patients suspected of viral encephalitis, especially in cases of HSV encephalitis.
  • Ganciclovir and foscarnet: These drugs can be used either individually or in combination for the treatment of CMV encephalitis.
  • Ribavirin: May be beneficial in children with severe adenovirus or rotavirus encephalitis.
• Antibiotics
  • Ceftriaxone
  • Penicillin G
  • Vancomycin
• Immunotherapy
  • Steroids: Usually used as an adjunctive therapy in the treatment of tuberculosis (TB) encephalitis, bacterial encephalitis (before antibiotic administration), and autoimmune encephalitis. Helps reduce inflammation of brain tissue and intracranial pressure (ICP).
  • IV antibodies (IVIG): Viral encephalitis and autoimmune encephalitis may benefit from IV antibodies. However, due to insufficient evidence, this treatment is not part of the standard treatment for encephalitis.
  • Plasma exchange: Therapeutic plasma exchange shows promise, especially in severe refractory cases of autoimmune encephalitis that do not respond to steroids or IVIG.
• Supportive care
  • Supportive care includes careful monitoring of intracranial pressure, fluid restriction, suppression of fever, and monitoring of blood pressure. The use of a feeding tube, catheter, and breathing tube may be required in some cases.
  • Seizures should be treated with standard anticonvulsant treatment, and prophylactic therapy should be considered due to the high frequency of seizures in severe cases of encephalitis.

• Self-management can help you take care of yourself.
• Know about your condition.
• Taking your medicine.
• Talk with a doctor if you have questions.
• Good nutrition.
• Lower stress levels.
• Get enough sleep.

Timely treatment after proper diagnosis of encephalitis can lead to a better prognosis. However, if encephalitis is left untreated, or if treatment is delayed, the damage to the brain can be fatal. Some common complications of encephalitis include:

• Persistent fatigue
• Persistent headache
• Weakness or lack of muscle coordination
• Movement disorders such as tremors and involuntary muscle jerks
• Post-encephalitis (residual) seizure disorder
• Paralysis
• Hearing or vision defects
• Speech impairments
• Decreased concentration
• Personality changes
• Memory problems
• Depression

Encephalitis is a serious condition. Both the acute stage of the disease and the aftereffects can be overwhelming for patients and their families. Recovery can take a long time. However, the following therapies can significantly aid patients in making the best possible recovery:

• Occupational therapy: Encephalitis can dull the senses. An occupational therapist can assist in adapting to this lack of sensation and help improve the ability to perform daily activities such as bathing, dressing, eating, or reading.
• Physical therapy: The goal of physical therapy (PT) or physiotherapy is to improve mobility, restore function, reduce pain, and prevent further injury through various methods, including exercises or yoga. A physical therapist can help regain strength and relearn movement and coordination.
• Speech therapy: Speech therapy is designed to enhance communication skills. A speech and language therapist can assist with difficulties in producing speech. If verbal communication is challenging, they can help find new and innovative ways to communicate. Regular practice, along with adjustments in communication style, can simplify the process of communication.
• Cognitive therapy: Post-encephalitis, many patients may experience changes in their thinking or reasoning skills, which can lead to behavioral and mood swings. Cognitive therapy can help regain former patterns of behavior and manage emotional responses.