Encephalitis – Symptoms and Causes

Overview

Encephalitis is a condition where the brain becomes inflamed. This inflammation can have different causes, including:

• Viral infections
• Bacterial infections
• Immune system malfunction (autoimmune encephalitis)
• Unknown causes (in some cases)

Insects like mosquitos and ticks can spread viruses that lead to encephalitis.

When the inflammation comes from an infection directly in the brain tissue, doctors call it infectious encephalitis.

The impact of encephalitis varies widely from person to person, making it impossible to predict exactly how it will affect someone. This unpredictable nature makes quick diagnosis and treatment very important.

Encephalitis can be serious and sometimes fatal.

Signs and Symptoms

Encephalitis can show up in many ways. People may feel confused, have changes in their personality, get seizures, or have trouble moving. It can also affect how well they see or hear.

Most people with infectious encephalitis first get symptoms like:

• Headache
• Fever
• Muscle or joint pain
• Feeling tired or weak

Within hours or days, more serious symptoms may appear:

• Stiff neck
• Confusion or seeing things that aren’t there
• Seizures
• Numbness or paralysis in parts of the face or body
• Strange movements
• Muscle weakness
• Problems with talking or hearing
• Passing out or falling into a coma

Babies and young children might show different signs:

• Bulging soft spots on the skull
• Throwing up
• Whole-body stiffness
• Poor eating or not waking up to eat
• Being very fussy

For autoimmune encephalitis, symptoms often develop more slowly over weeks. These may include:

• Personality changes
• Memory problems
• Trouble knowing what’s real (psychosis)
• Seeing or hearing things that aren’t there (hallucinations)
• Seizures
• Vision changes
• Sleep problems
• Weak muscles
• Loss of feeling
• Walking difficulties
• Unusual movements
• Bladder and bowel issues

When to Get Medical Help

Don’t wait to seek medical care if you notice the serious symptoms of encephalitis. A severe headache with fever and any changes in awareness needs emergency treatment.

For babies and young children, any sign of encephalitis requires immediate medical attention. Early treatment can make a big difference in recovery.

What Causes Brain Inflammation?

The brain can become inflamed when certain viruses attack it. These viruses can enter the brain directly and cause damage. Here are some common viral causes:

• Herpes simplex viruses can lead to serious brain inflammation. Type 1 (which causes cold sores) and Type 2 (which causes genital herpes) can both affect the brain. When Type 1 reaches the brain, though rare, it can cause severe damage or even death.
• Other herpes family viruses that can cause brain inflammation include:
  • Epstein-Barr virus (known for causing mono)
  • Varicella-zoster virus (responsible for chickenpox and shingles)
• Enteroviruses may also trigger brain inflammation. These typically cause flu-like symptoms first, with eye inflammation and stomach pain. This group includes:
  • Poliovirus
  • Coxsackievirus
• Mosquito-transmitted viruses include:
  • West Nile virus
  • La Crosse virus
  • St. Louis virus
  • Western equine virus
  • Eastern equine virus
    • Symptoms usually appear within 2 weeks after a mosquito bite.
• Tick-transmitted viruses like the Powassan virus affect people mainly in the Midwest. Symptoms typically develop about a week after being bitten by an infected tick.
• Rabies virus can cause brain inflammation when transmitted through the bite of an infected animal. Once symptoms begin, the disease progresses quickly. Thankfully, rabies rarely causes brain inflammation in the United States.

In about half of all cases, doctors cannot identify the exact cause of brain inflammation. When they do find a cause, it typically falls into two main categories:

1. Infection-based inflammation – usually from viruses attacking brain tissue.
2. Immune system attacks – when your own immune system mistakenly targets brain cells.

The immune system attacks can happen because of:

• Tumors (cancerous or non-cancerous)
• Previous infections elsewhere in the body
• Unknown triggers (in many cases)

Risk Factors

Several factors can increase a person’s chance of getting encephalitis:

• Age: Young children and older adults face higher risks for most viral encephalitis types. Some autoimmune forms affect children and young adults more often, while others are more common in older people.
• Weak Immune System: People with HIV/AIDS or those taking medications that suppress the immune system have higher encephalitis risk.
• Location: Where you live matters. Some areas have more mosquitoes or ticks carrying encephalitis-causing viruses.
• Time of Year: In many parts of the United States, summer brings increased risk for mosquito and tick diseases.
• Existing Autoimmune Conditions: Having one autoimmune disease may make a person more likely to develop autoimmune encephalitis.
• Smoking: Smokers face higher lung cancer risk, which increases the chance of developing certain types of encephalitis related to paraneoplastic syndromes.

Health Risks

Brain inflammation can cause severe damage, sometimes leading to coma or even death. For those who survive serious encephalitis, several lasting problems may develop:

• Ongoing tiredness that doesn’t improve with rest
• Physical difficulties like muscle weakness or poor coordination
• Changes in how someone acts or thinks
• Trouble remembering things from the past or learning new information

People might also experience:

• Changes in how well they can hear or see
• Problems speaking clearly or finding the right words

The seriousness of these problems depends on your age, what caused the infection, how severe the illness was, and how quickly treatment began. People with mild cases typically recover fully within a few weeks without lasting issues.

Ways to Prevent Infection

Avoiding mosquito and tick bites is crucial for preventing viral encephalitis. Here are some effective steps you can take:

Dress Properly for Protection

• Wear long sleeves and pants when outdoors
• Choose light-colored clothing to spot ticks more easily
• Tuck pants into socks in tick-heavy areas

Use Effective Repellents

• Apply repellents with DEET to skin and clothing
• Spray repellent on your hands first, then apply to your face
• Apply sunscreen first, then repellent if using both products

Treat Clothing and Gear

• Use permethrin products on clothes, tents and outdoor equipment
• Never apply permethrin directly to skin
• Treat camping gear before trips to high-risk areas

Control Your Environment

• Remove standing water from your yard where mosquitoes breed
• Fix broken screens and windows
• Limit outdoor activities during peak mosquito times (dusk to dawn)
• Report dead birds or animals to local health officials

Check Yourself Regularly

• Examine your body for ticks after being outdoors
• Pay special attention to underarms, ears, hair, and behind knees
• Remove ticks promptly with fine-tipped tweezers

Protecting Young Children

Children need special care to prevent insect bites that could lead to encephalitis:

For Babies Under 2 Months:

• Never use insect repellent
• Cover strollers and carriers with fine mesh mosquito netting
• Dress infants in lightweight clothing that covers arms and legs

For Older Children:

• Use repellents with 10-30% DEET
• Avoid products combining DEET and sunscreen
• Always help children apply repellent

Safe application tips:

1. Apply repellent outdoors to reduce inhalation risk
2. Spray onto your hands first, then apply to your child’s face
3. Keep repellent away from eyes, mouth, and hands of young children
4. Wash treated skin with soap and water after coming indoors

Additional protection measures:

• Teach children to avoid areas where insects gather
• Ensure children wear protective clothing during outdoor activities
• Check children for ticks thoroughly after they’ve been outdoors

Good hygiene practices also help prevent other forms of encephalitis. Teach children to wash hands properly, especially before eating and after using the bathroom.

Avoid sharing utensils and drinks with others. Stay current with all recommended vaccinations, particularly before traveling to regions where encephalitis is common.