Encephalitis and meningitis are inflammatory conditions that affect the central nervous system. Encephalitis is inflammation of the brain, while meningitis is inflammation of the membranes protecting the brain and spinal cord.
Encephalitis and meningitis can occur as a result of certain viral, bacterial, fungal, and parasitic infections. Both conditions have similar symptoms, and both require prompt diagnosis and treatment to help prevent complications.
This article outlines the differences between encephalitis and meningitis, including their associated symptoms, causes, and risk factors. We also provide information on treating and helping prevent these conditions, and offer advice on when to contact a doctor.
Encephalitis is the medical term for inflammation of the brain. Meningitis is the medical term for inflammation of the meninges. The meninges are protective membranes that surround the brain and spinal cord.
The symptoms of encephalitis and meningitis are similar, but not identical. We outline these symptoms below.
Symptoms of encephalitis may include:
- mild flu-like symptoms
- sudden fever
- vision problems
- increased sensitivity to light
- stiff neck and back
- muscle weakness
- clumsy or unsteady gait
- difficulty with speech or hearing
- impaired judgment
- confusion or disorientation
- changes in personality or behavior
- sudden memory loss
- loss of consciousness
Symptoms of meningitis can occur very suddenly, and may
- high fever
- flu-like symptoms that develop within 1–2 days
- severe, persistent headache
- nausea or vomiting
- double vision
- sensitivity to bright light
- stiff neck
- difficulty waking
Signs of meningitis or encephalitis in an infant may include:
- not waking for feedings
- unusual or unexplained irritability
- body stiffness
- bulging of the soft spot on the top of the head
Both encephalitis and meningitis can occur as a result of infection with the following pathogens:
Common causes of encephalitis in the United States include:
- herpes simplex virus types 1 and 2
- arboviruses, such as West Nile virus, which spreads through bites from infected ticks or mosquitoes
- enteroviruses, which can spread between people via droplets in the air when coughing or sneezing
In some cases, encephalitis can develop as a result of an autoimmune condition.
Causes of meningitis depend on the type of meningitis a person has. Some examples are below.
Viruses that can cause viral meningitis include:
- varicella zoster, which causes chickenpox and shingles
- herpes simplex type 2
Bacteria that can cause bacterial meningitis include:
- Streptococcus pneumoniae: Causes pneumococcal meningitis.
- Neisseria meningitides: Causes meningococcal meningitis.
- Haemophilus influenzae: Causes Haemophilus influenzae meningitis.
- Listeria monocytogenes: Causes Listeria monocytogenes meningitis.
- Escherichia coli: Causes E. coli meningitis.
Fungi that can cause fungal meningitis
- Cryptococcus: Lives in the environment in most parts of the world.
- Histoplasma: Lives primarily in soil that contains large quantities of bird or bat droppings.
- Blastomyces: Lives in moist soil and decaying wood and leaves.
- Coccidioides:Lives in soil in the following parts of the world:
- Southwestern U.S.
- South Central Washington State
- parts of Mexico and Central and South America
According to the
The following parasites
- Angiostrongylus cantonensis: Can transmit to humans who eat raw or undercooked snails or slugs.
- Baylisascaris procyonis: Can transmit to humans who come into contact with raccoon feces contaminated with the parasite eggs.
- Gnathostoma spinigerum: Can transmit to humans who eat any of the following raw or undercooked animal produce:
- freshwater fish or eels
Encephalitis and meningitis can affect anyone. People have an
Additional risk factors of encephalitis
Some types of encephalitis are more likely to occur in certain areas of the U.S., such as:
- Western equine encephalitis: Occurs in farming areas of Western and Central Plains states.
- Eastern equine encephalitis: Occurs in birds along the Eastern U.S. seaboard and the Gulf Coast, although human cases are rare.
- LaCrosse encephalitis: Occurs mainly in the Upper Midwestern states, but can also occur in Southeastern and Mid-Atlantic parts of the U.S.
- St. Louis encephalitis: Occurs mainly in temperate areas of the U.S., but can occur throughout the country.
Outside of the U.S., Japanese encephalitis is one of the
Additional risk factors of meningitis
The following people may be at
- infants below 1 year of age
- people traveling to endemic areas
- college students, particularly freshmen
- military recruits
- people who live in dormitories
Other high-risk groups for meningitis include:
- Older adults and newborns: People in these groups have an increased risk for developing E. coli meningitis.
- Children under 2 years of age: Children in this age category are at increased risk for pneumococcal meningitis.
- People who do not have access to the Haemophilus influenzae b vaccine, or children in childcare environments: People in these groups may have a higher risk for developing Haemophilus influenzae meningitis.
Both encephalitis and meningitis are conditions that require immediate treatment. Medical professionals will typically administer these treatments in a hospital setting.
Treatment for encephalitis may include antivirals for viral encephalitis such as acyclovir and ganciclovir, and immunosuppressant medication if autoimmune disorders are causing the encephalitis.
Treatment for meningitis may include:
- antibiotics for
most typesof bacterial meningitis
- intravenous antifungal medication for fungal meningitis
- home treatment for symptoms of viral meningitis, as most cases are not life threatening
People will also require treatment for the symptoms of encephalitis or meningitis. Treatments may include:
- anticonvulsants for seizures
- corticosteroids to control inflammation and swelling of the brain or meninges
- over-the-counter medications to alleviate headache and fever
Vaccines are available that can help prevent certain types of meningitis or encephalitis. Examples include:
- pneumococcal vaccine
- meningococcal vaccine
- Haemophilus influenzae b vaccine
- Japanese encephalitis vaccine
Severe cases of encephalitis or meningitis may lead to the following complications:
- lack of muscle control
- loss of sensation in some areas of the body
- partial paralysis in the arms and legs
- loss of hearing or speech
- permanent brain and nerve damage
- changes to behavior or personality
- memory loss
- cognitive disabilities
The outlook for encephalitis and meningitis depends on the severity of the disease, and how quickly people receive a diagnosis and treatment.
In severe cases, encephalitis and meningitis can progress rapidly and may lead to permanent neurological damage or even death.
Recovery from encephalitis can depend on the severity of the condition and the level of brain inflammation.
People may experience symptoms of encephalitis for
With treatment, people with bacterial meningitis may show improvement within
Viral meningitis is not usually life threatening, and people with mild cases may recover fully in
It is possible to have both encephalitis and meningitis. Medical professionals refer to this as “meningoencephalitis.” People with meningoencephalitis have inflammation of both the brain and the meninges.
Symptoms of meningoencephalitis may include:
- altered mental state
In order to diagnose meningoencephalitis, a doctor will examine the cerebrospinal fluid. If the condition is present, the doctor will administer immediate treatment with either antibiotic or antiviral medications.
It is important that people contact a doctor straight away if they experience symptoms of encephalitis or meningitis.
To diagnose either condition, a doctor will ask about a person’s symptoms and medical history and carry out a physical examination.
If the doctor suspects encephalitis or meningitis, they may also request the following tests:
- blood tests to check for pathogens in the blood
- a cerebrospinal fluid analysis to check for pathogens in the central nervous system
- imaging tests of the head and chest to check for inflammation in the brain and spinal cord
Encephalitis is inflammation of the brain. Meningitis is inflammation of the protective membranes around the brain and spinal cord. Both conditions can occur as a result of infection with certain viruses, bacteria, fungi, or parasites.
People with mild cases of encephalitis and meningitis typically make a full recovery. In more severe cases, people may require hospitalization, and their recovery may take longer.
Early diagnosis and treatment of both encephalitis and meningitis are important to reduce the risk of complications. Anyone who experiences symptoms of either condition should contact their doctor as soon as possible.