Viral Encephalitis: Symptoms, Causes & Treatment

Viral encephalitis is inflammation of the brain caused by a virus. It can lead to symptoms such as a very severe headache, fever, confusion, or seizures.

This condition mainly affects babies and children. It can also occur in adults with weakened immune systems and may be caused by relatively common viruses such as herpes simplex, adenovirus, or cytomegalovirus.

Treatment for viral encephalitis is usually managed by a neurologist, infectious disease specialist, or pediatrician. It typically requires hospitalization and medications, and should be started as soon as possible to help reduce the risk of long-term complications.

Main symptoms

The main symptoms of viral encephalitis are:

• Very severe headache

• Fever above 38ºC (100.4ºF)

• Extreme tiredness

• Nausea or vomiting

• Muscle or joint pain

• Confusion or hallucinations

• Agitation or disorientation

In more severe cases, symptoms can also include neck or back stiffness, extreme sensitivity to light, paralysis or muscle weakness, and seizures.

According to the CDC, severe encephalitis may also cause confusion and trouble speaking.

Viral encephalitis often occurs together with meningitis, because both conditions can be triggered by the same viruses and share many of the same signs.

Symptoms in babies

Signs of viral encephalitis in babies include irritability, high-pitched crying, difficulty breastfeeding, refusal to eat, stiffness throughout the body, or a bulging soft spot.

In older children, vomiting or difficulty walking may also occur in addition to the common symptoms.

Confirming a diagnosis

Viral encephalitis is diagnosed by a neurologist, infectious disease specialist, primary care provider, or pediatrician based on symptoms, risk factors, and a physical exam.

Blood tests, an electroencephalogram (EEG), magnetic resonance imaging (MRI), or a CT scan may also be recommended.

Another test that may be done to confirm viral encephalitis is a lumbar puncture (spinal tap). According to the National Institute of Neurological Disorders and Stroke, cerebrospinal fluid obtained through a lumbar puncture can help detect encephalitis and other neurologic conditions.

Possible causes

Viral encephalitis can be caused by viruses such as:

• Herpes simplex virus types 1, 2, or 6.

• Enteroviruses, such as Coxsackievirus, poliovirus, or echovirus.

• Cytomegalovirus or Epstein-Barr virus.

• Viruses that cause chickenpox, measles, mumps, or rubella.

• Dengue, Zika, Chikungunya, or rabies viruses.

These viruses cause an initial infection in the body and may reach the brain or spinal cord through the bloodstream or by traveling along the nerves.

Encephalitis mainly affects babies, older adults, and people with weakened immune systems, including people with HIV infection or those receiving chemotherapy for cancer.

Is viral encephalitis contagious?

Viral encephalitis itself is not contagious. However, because it is a complication of a viral infection, the virus that caused it may still be spread to other people.

These viruses may be transmitted through contact with the respiratory secretions of an infected person or through contaminated utensils such as forks, knives, or cups.

In these cases, the person who catches the virus usually develops the infection itself, not the complication of viral encephalitis.

Treatment options

Treatment for viral encephalitis should be guided by a neurologist, infectious disease specialist, or pediatrician to help the body fight the infection and relieve symptoms.

The main treatments for viral encephalitis include:

1. Medications

A doctor may prescribe medications to help relieve symptoms of the infection.

The main medications used for viral encephalitis are:

• Pain relievers and fever reducers, such as acetaminophen, to reduce fever and relieve headache.

• Anticonvulsants, such as phenytoin, to prevent or treat seizures.

• Corticosteroids, such as dexamethasone, to reduce brain swelling.

In infections caused by herpes viruses or cytomegalovirus, the doctor may also prescribe antivirals such as acyclovir, ganciclovir, or foscarnet to help prevent the viruses from multiplying, since these infections can cause severe brain damage.

2. Hospital admission

Hospital admission is recommended in more severe cases of viral encephalitis. It is usually done in the intensive care unit (ICU) to monitor vital signs and provide IV fluids and medications.

Breathing support may also be needed, including oxygen therapy or mechanical ventilation, if breathing is affected.

3. Surgery

Surgery for viral encephalitis may be recommended in cases of severe brain swelling that does not improve with corticosteroids.

This procedure is done to decompress the brain and allow it to expand, which helps reduce intracranial pressure.

Possible complications

The main complications of viral encephalitis are:

• Muscle paralysis

• Problems with memory and learning

• Speech and hearing difficulties

• Vision changes

• Epilepsy

• Involuntary muscle movements

These complications usually appear only when the infection lasts a long time and treatment does not produce the expected results.