All You Need to Know About Acute Encephalitis Syndrome

Introduction:

There have been more than 188 cases of acute encephalitis syndrome reported since January 2019 in India. This disease has claimed the lives of more than 45 children so far. These deaths have been caused due to low blood sugar levels in the body. The recent outbreak of Acute Encephalitis Syndrome in India is believed to be due to children consuming unripe or rotten lychee fruit. Consuming lychee is not directly linked to death and AES. Animal experiments have shown that methylene cyclopropyl glycine (MCPG), a toxin present in lychee, causes hypoglycemia (low blood sugar). The kids who died are believed to be suffering from AES and hypoglycemia (as they are malnourished and skip meals), which on consuming lychee made the blood sugar levels drop to fatal levels, resulting in coma and death.

What Is Acute Encephalitis Syndrome?

Acute encephalitis syndrome (AES) is a group of neurological disorders that affects the brain and limbs. The condition is caused by viruses, bacteria, fungi, parasites, or chemical toxins. An inflammation of the brain tissue is called encephalitis. It is commonly seen in children younger than 15 years. The outbreak of this disease is common during monsoon. The causative organism varies depending on the season and geographical variation.

What Is the Most Common Cause of AES?

The cause of AES is not clearly understood as it is a very complex condition. It is known to be caused by many factors and microorganisms like viruses, bacteria, fungi, parasites, and environmental chemicals, or it can be autoimmune.

Viral Causes: Viruses are known to cause most cases of AES. The common viruses include:

• West Nile encephalitis virus (infectious disease).

• Tick-borne encephalitis.

• Measles (viral respiratory illness).

• Nipah virus (zoonotic virus spread through animals to humans).

• Zika virus (mosquito-borne virus).

• Herpes simplex virus (HSV) (infection spread through the blood of an infected person).

• EBV (Ebstein-Barr virus spread through saliva).

• Mumps (a viral infection causing swelling of parotid glands).

• Enterovirus (feco-oral transmission).

Infections:

• Bacterial Infections: The known bacterial infections that can lead to the development of AES are Streptococcus pneumoniae and Hemophilus influenzae. Through the bloodstream, these bacteria enter the brain and affect the brain. Vaccinations may help in preventing these infections.

• Fungal Infections: The species that can cause fungal infections is the Aspergillus species. People with weakened immune systems are more susceptible to fungal infections. Antifungal treatment may help in preventing these infections.

• Parasitic Infections: The Japanese encephalitis (JE) virus (the infection spread through the bite of an infected mosquito) is known to cause AES. Vaccination against these infections helps prevent this infection.

How Does AES Spread?

AES can be caused by a variety of infectious and non-infectious factors, such as viruses, fungi, parasites, and bacteria. The mode of spread of AES is described below:

• Viral Causes: The viruses are transmitted to humans through the bite of a mosquito. The mosquito feeds on infected animals and serves as a reservoir. In addition, some viruses spread through direct contact with infected people or contaminated surfaces.

• Bacterial Causes: The bacterial droplets spread through direct contact with infected individuals or through respiratory droplets, like sneezing and coughing.

• Other Infectious Diseases: Infectious diseases, such as fungal and parasitic infections spread through environmental exposure to contaminated soil, water, or vectors.

• Non-Infectious Diseases: The non-infectious diseases caused by non-infectious factors, such as metabolic disorders, autoimmune reactions, chemical toxins, and adverse drug reactions.

What Are the Symptoms of AES?

The disease spreads rapidly and affects the cells in the brain. The symptoms include:

• High fever (above 103 degrees Fahrenheit).

• Drowsiness.

• Mental confusion.

• Hallucinations.

• Light sensitivity.

• Unconsciousness.

• Irritability.

• Coma.

• Seizures.

What Are the Signs of AES to Look for in Infants?

Signs in infants are:

• Vomiting.

• Bulging of the soft spot on the head (fontanel).

• Body stiffness.

• Crying continuously.

• Not taking feeds properly.

Who Is at Risk of AES?

AES generally affects children in rural areas. It is mainly due to malnourishment and low blood sugar levels. This results in poor immunity and the condition progresses rapidly, leading to death. People with weakened immune systems or individuals receiving immunotherapy are at high risk of developing the condition. Lack of vaccination against vaccine-preventable diseases or people engaging in outdoor activities can lead to the development of encephalitis.

How is AES Diagnosed?

The diagnosis of AES involves clinical evaluation, laboratory tests, cerebrospinal fluid analysis, and imaging studies. The diagnostic evaluation of AES is described below:

• Clinical Assessment: The healthcare provider may assess the patient's symptoms, medical history, and neurological status. The experienced symptoms include fever, seizures, altered mental status, and neck stiffness.

• Laboratory Tests: The healthcare provider may perform blood tests to detect infectious agents and inflammatory markers. The Serological tests are performed to find bacterial, viral, fungal, and parasitic pathogens.

• Imaging Tests: The imaging tests, including computed tomography (CT) and magnetic resonance imaging (MRI), are performed to check structural abnormalities of the brain and signs of inflammation. MRI is used to distinguish between infectious and non-infectious causes of AES.

• Cerebrospinal Fluid Analysis: The healthcare provider may do lumbar puncture and take cerebrospinal fluid to find infectious agents and inflammatory markers. The findings include increased protein levels and increased white blood cell count.

How Is AES Treated?

As it is caused by a viral or bacterial infection, antivirals or antibiotics are used. Fever and seizures are managed with medicines. Steroids and anti-inflammatory medications are used to reduce pain and other symptoms. Supportive care measures include intravenous fluids, and medications to control fever, and seizures. The prognosis is good if the disease is caught in the early stage. In addition, rehabilitation therapy, such as speech therapy and physical therapy is recommended to help patients regain lost function.

How Can AES Be Prevented?

It can be prevented by:

• Vector Control: People should use mosquito nets, insecticide spray, and elimination of breeding sites to reduce the risk of mosquito-borne viral infections.

• Vaccination: Administration of vaccines against bacterial or viral infections. Get the child vaccinated for all childhood viral infections.

• Practice Good Hygiene: Promoting good hygiene practices by handwashing and safe food handling may reduce the transmission of infectious agents. Consume fruits and vegetables after washing them thoroughly.

• Stay Hydrated: Drink a lot of water to flush out toxins from the body.

• Take a Balanced Diet: Eat healthy and a balanced diet.

What Are the Complications of AES?

The complications include:

• Memory loss.

• Personality changes.

• Fatigue.

• Vision problems.

• Epilepsy.

• Difficulty hearing.

• Difficulty speaking.

• Coma.

• Breathing becomes difficult.

• Death.

Conclusion:

In conclusion, acute encephalitis syndrome is a challenging condition in regions where infectious diseases are endemic. The management of AES requires a coordinated approach that addresses the underlying cause, and symptoms, and prevents complications. Timely diagnosis and appropriate treatment are crucial to improve patient outcomes. Continued research into the epidemiology, pathogenesis, and treatment of AES is necessary to advance the understanding of the condition and develop more effective strategies for its prevention and management