Pediatric encephalopathy (encephalitis)

Pediatric encephalopathy (en·​ceph·​a·​lop·​a·​thy) or encephalitis (en·​ceph·​a·​li·​tis) is inflammation (swelling) of the brain, most often caused by a viral infection.

What is pediatric encephalopathy (encephalitis)?

Inflammation of the brain due to encephalitis can be caused by a viral or bacterial infection. In most cases, encephalitis only causes mild flu-like symptoms. In rare cases, however, encephalitis can be life threatening. 

What are the different types of pediatric encephalopathy (encephalitis)?

There are two main types of encephalitis:

Primary encephalitis

Primary encephalitis occurs when a virus or other agent directly infects the brain. The infection may be concentrated in one area or it could be widespread.

Secondary encephalitis

Secondary encephalitis occurs when a person’s immune system fails to react to an infection elsewhere in the body effectively. Instead of attacking the cells that have caused the infection, the immune system attacks healthy brain cells by mistake.

What are the signs and symptoms of encephalopathy (encephalitis)?

Common symptoms

In most cases, babies and children with encephalitis experience mild, flu-like symptoms, including:

  • Aches in muscles or joints
  • Body stiffness
  • Bulging in the soft spots (fontanels) of the infant’s skull
  • Fatigue or weakness
  • Fever
  • Headache
  • Irritability
  • Nausea and vomiting
  • Poor feeding or not waking up for a feeding

Severe symptoms

In more severe cases, babies and children with encephalitis experience these signs and symptoms:

  • Confusion, agitation or hallucinations
  • Loss of consciousness
  • Loss of sensation or paralysis in certain regions of the face or body
  • Muscle weakness
  • Problems with speech or hearing
  • Seizures

Long-term complications

Several other complications related to encephalitis can persist for months or even for the rest of a person’s life.

These complications include:

  • Hearing or vision defects
  • Memory problems
  • Paralysis
  • Persistent fatigue
  • Personality changes
  • Speech impairments
  • Weakness or lack of muscle coordination

What are the causes of encephalopathy (encephalitis)?

Pediatric encephalopathy may be caused by several factors. In infants (birth to 1 year), it is usually a genetic condition involving high levels of glycine (amino acid) in the brain.

Other causes of encephalopathy include:

Bacterial meningitis

Epstein-Barr virus (the virus that causes mononucleosis, chicken pox and shingles)


Hashimoto’s disease

Herpes simplex virus 1 and 2

High blood pressure


Kidney failure

Lack of oxygen to the brain

Liver disease

Lyme disease


Mosquito-borne viruses


Prenatal drug exposure

Prion diseases (protein disorders)


Rubella (German measles)

Tick-borne viruses

Traumatic injury to the brain (TBI)

Vitamin B-1 deficiency

West Nile virus

Pediatric encephalopathy (encephalitis) doctors and providers