Encephalitis Symptoms

Quick Glance: Common Encephalitis Symptoms

Encephalitis may show some common symptoms, such as:

• Fever

• Seizures

• Difficulty thinking clearly

• Severe or persistent headache

• Unusual tiredness

• Nausea or vomiting

• Behaviour or personality changes

• Difficulty speaking or walking

Although symptoms usually develop over hours or days, some people experience neurological issues without having a flu-like illness first.

Encephalitis Symptoms That Should Not Be Ignored

The following changes indicate affected brain function and require prompt medical assessment:

These symptoms can also occur with stroke, meningitis, seizures, metabolic disorders or other brain conditions. Hence, they should not be self-diagnosed.

Why Do Encephalitis Symptoms Occur?

Encephalitis develops when brain tissue becomes inflamed. This may happen when a virus infects the brain or when the immune system mistakenly attacks healthy brain cells. During this process, the immune response releases white blood cells and inflammatory chemicals. They help fight infection, but may also disrupt communication between nerve cells.

As a result, inflammation can affect different parts of the brain, including:

• The temporal lobes and hippocampus are involved in memory, language and behaviour.

• The frontal lobes help control judgement, personality and movement.

• The cerebellum supports balance and coordination.

• The brainstem helps control breathing, swallowing and consciousness.

If left unchecked, severe inflammation may cause brain swelling and increased pressure inside the skull. Ultimately, this can lead to worsening headache, vomiting, drowsiness, seizures or loss of consciousness.

Encephalitis Symptoms That Require Immediate Medical Attention

Encephalitis is a medical emergency as it can lead to permanent neurological damage. Seek immediate medical care if any of the following develop:

• Sudden confusion or severe disorientation

• Any new, prolonged, or repeated seizures

• Loss of consciousness or difficulty waking

• Partial paralysis in arms and legs

• Difficulty speaking or understanding speech

• Severe headache with neck stiffness or repeated vomiting

• New problems with breathing or swallowing

• Severe agitation, hallucinations or abnormal behaviour

• High fever with a rapid decline in alertness

Symptoms of Encephalitis Based on Type

Encephalitis symptoms vary depending on whether the inflammation stems from a direct viral attack or an autoimmune reaction. Here is how symptoms typically differ based on the types of encephalitis:

Encephalitis Symptoms in Children

Parents should seek urgent care when a child with a fever becomes unusually sleepy, confused, difficult to wake or develops a seizure. Encephalitis symptoms vary by age, and thus, parents can look out for the following:

Can You Have Encephalitis Without Symptoms?

No, encephalitis rarely occurs without symptoms. As it involves inflammation of brain tissue, it almost always triggers physical or neurological changes. However, early symptoms are usually mild.

Some infections that can cause encephalitis cause no symptoms in most infected people. For example, most Japanese encephalitis virus infections are mild or asymptomatic, while only a small proportion progress to encephalitis.

Infants, toddlers, older adults and people with reduced immunity may initially show less typical signs. These may include poor feeding, unusual sleepiness, subtle confusion or behaviour changes.

When Can Encephalitis Symptoms Become Life-Threatening?

Encephalitis can become life-threatening when inflammation affects consciousness, breathing or other essential brain functions. Some of these life-threatening symptoms of encephalitis include:

How are Encephalitis Symptoms Diagnosed?

Encephalitis cannot be diagnosed from symptoms alone. Doctors combine neurological assessment with brain scans and laboratory tests to confirm a case. Some of these diagnostic tests used to detect encephalitis include: