Imagine an inflammation so powerful that it can play havoc with your brainstem, cerebrum, cerebellum, spinal cord, and peripheral nerves.
That’s the neurological damage that can happen as a result of encephalitis.
The good news is that it’s rare.
The bad news is that it causes the brain tissue to swell (cerebral edema), which may destroy nerve cells, cause bleeding in the brain (intracerebral hemorrhage), and brain damage.
Seizures are common during the initial stages of encephalitis.
And because they occur as a symptom, they’re referred to as “acute symptomatic seizures.”
Seizures may also occur at a later stage, as well, after the acute illness is over.
That’s because the after-effects of encephalitis’ inflammation may leave brain cells liable to the long-term “electrical storm” we know as epilepsy.
Those unlucky few who develop epilepsy after encephalitis will be plagued with what they call “unprovoked seizures”.
And there are others who may not have had any seizures at all, or maybe just a few which seemed to have settled down.
Suddenly they have the surprise of unwelcome unprovoked seizures, after the encephalitis seems to have exited.
The cumulative risk for later unprovoked seizures among those who had seizures during the initial acute stage of encephalitis is about 10% at 5 years and 22% by 20 years.
If there were no early seizures, the 20 year risk of unprovoked seizures is around 10%.
Up to 50% of people with encephalitis may have seizures at some point.
Of course, the question is WHEN?
The risk depends on the type of encephalitis involved.
Most people who develop epilepsy after encephalitis have focal or secondarily generalized seizures.
Because encephalitis is commonly a diffuse process involving both sides of the brain, seizures may sometimes arise from several different locations and result in multifocal epilepsy.
The goal of treatment is to achieve the best possible control of the seizures, while at the same time avoiding unacceptable side-effects from the medication.
Children aged one year or less and adults aged 55 years and over are more vulnerable to life threatening complications or chronic conditions from encephalitis.
And of course, one of these chronic conditions includes epilepsy.
There are two types of encephalitis — primary and secondary.
In primary encephalitis, a virus attacks the brain and spinal cord directly.
Secondary or post-infectious encephalitis, causes the virus to invade another part of your body and then travel to your brain.
Some of the reasons include:
Infectious – inflammation as a direct result of an infection, which is often viral
Post-infectious – inflammation is caused by the immune system reacting to a previous infection, and can occur days, weeks or sometimes months after the initial infection
Autoimmune – inflammation caused by the immune system reacting to a non-infectious cause, such as a tumor
Chronic — inflammation developing slowly over many months, and can be the result of a condition such as HIV, though in some cases there is no obvious cause
Aside from encephalitis being caused by inflammation, there are other possibilities:
Traveling to areas where viral encephalitis is common
An allergic reaction to vaccinations for polio, rabies and chickenpox
Bacteria, such as Lyme disease, syphilis, and tuberculosis
Parasites like roundworms
Mosquitoes, ticks and rabies
(Conversely, the introduction of the vaccination for measles, mumps and rubella has greatly lowered the rate of encephalitis from those diseases.)
Herpes Simplex Encephalitis and Epilepsy
HSE occurs at any age, to either sex and at any time of year.
Early in the infection, the virus shows a predisposition for certain parts of the brain.
Typically it goes to the limbic cortices.
It may then spread to the adjacent frontal and temporal lobes.
The destruction of tissue in these areas, together with brain swelling from the inflammation, causes many of the symptoms associated with HSE.
Seizures may occur in 50% patients with HSE, because of a degenerative condition in the front part of the brain.
Japanese Encephalitis (JE) is most common and is associated with acute symptomatic seizures, especially in children.
The prognosis is poor.
In addition, chronic and relapsing forms of HSE have been described and may be associated with antiepileptic drug-resistant seizures.
The reported frequency of acute symptomatic seizures in JE is 7-46%.
Some patients may have symptoms of a cold or stomach infection before encephalitis symptoms begin.
When a case of encephalitis is not very severe, the symptoms may be similar to those of other illnesses, including:
Fever that is not very high
Low energy and a poor appetite
Clumsiness, unsteady gait
Irritability or poor temper control
Stiff neck and back (occasionally)
Symptoms in NEWBORNS and younger infants may not be as easy to recognize, such as:
Irritability and crying more often (these symptoms may get worse when the baby is picked up)
Soft spot on the top of the head may bulge out more
Memory loss (amnesia), impaired short-term or long-term memory
Loss of consciousness, poor responsiveness, stupor, coma
Sudden change in mood and mental functions
Inflexibility, extreme self-centeredness, inability to make a decision
Less interest in daily activities
Withdrawal from social interaction
Muscle weakness or paralysis
Complications with Encephalitis
The complications resulting from encephalitis depend on several factors, including age, the cause of the infection, the severity of the initial illness and the time from disease onset to treatment.
In most cases, people with relatively mild form of the illness recover within a few weeks with no long-term complications.
Complications of severe illness:
Injury to the brain from inflammation
Some complications — may persist for many months or be permanent, like:
Lack of muscle coordination
Hearing or vision defects
The inflammation that is associated with encephalitis can also result in what’s known as Aquired Brain Injury which can lead to long-term complications, including:
Epilepsy with repeated seizures
Attention, concentration and problem solving problems
Behavioral and personality problems
Physical and motor difficulties
An examination may show:
Increased intracranial pressure
Signs in other organs, such as the liver and lungs
Diagnostic tests for encephatlitis
X-ray – which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
Magnetic resonance imaging (MRI) – using a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
Computed tomography scan (CAT or CT scan) — an imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body.
A CAT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CAT scans are more detailed than general x-rays.
Blood tests, urine and stool tests.
Sputum culture – performed on the material that is coughed up from the lungs and into the mouth. A sputum culture is often performed to determine if an infection is present.
Electroencephalogram (EEG) – recording the brain’s continuous, electrical activity by means of electrodes attached to the scalp.
Spinal tap (or lumbar puncture) – a special needle is placed into the lower back, around the spinal cord. The pressure in the spinal canal and brain can then be measured.
Cerebral spinal fluid (CSF) is the fluid that bathes the brain and spinal cord. A small amount of it can be removed and sent for testing to determine if there is an infection or other problems.
Brain biopsy — involves removing tissue or cells from the body for examination under a microscope. In rare cases, a biopsy of affected brain tissue may be removed for diagnosis.
Intracranial pressure monitoring (ICP) — measuring the pressure inside the skull. If there is a severe brain injury, head surgery, brain infection, or other problems, the brain may swell.
Since the brain is covered by the skull, there is only a small amount of room for it to swell.
This means that, as the brain swells, the pressure inside the skull increases.
If the pressure gets significantly higher than normal, it can cause damage to the brain.
People who have hydrocephalus or brain tumors may also have their intracranial pressure monitored.
Prevention from encephalitis
The most effective way to protect against encephalitis is to make sure that you receive the MMR vaccine (for measles, mumps and rubella).
The first MMR vaccination should be given to all children at around 13 months of age, with a booster dose given before they start school (between three and five years old).
Between 5 and 10% of children are not fully immune after the first dose, so the booster increases protection and results in less than 1% of children remaining at risk.
Vaccinations are also available for Japanese encephalitis, tick-borne encephalitis and encephalitis caused by rabies.
The key to treating encephalitis properly is early detection and treatment.
A person with encephalitis requires immediate hospitalization and close monitoring.
The goal of treatment is to reduce the swelling in the head and to prevent other related complications.
Medications to control the infection, seizures, fever, or other conditions may be used.
The extent of the problem is dependent on the severity of the encephalitis and the presence of other organ system problems that could affect the person.
In severe cases, a breathing machine may be required to help you breathe easier.
As you recover, physical, occupational, or speech therapy may be necessary to help regain muscle strength and/or speech skills.
The healthcare team will educate your family after hospitalization on how to best care for you at home, and outline specific clinical problems that require immediate medical attention by your physician.
Reorientation and emotional support for confused or delirious people may be helpful.
Treatment depends on the type of encephalitis you have, but may include:
Anti-seizure medications (such as phenytoin) — to prevent seizures
Immunosuppressants – medicines that stop the immune system from attacking healthy tissue
Immunoglobulin therapy – a type of donated blood product that contains a number of specific antibodies, which help regulate the immune system’s abnormal function
Steroid injections (such as dexamethasone) — to reduce brain swelling
Antiviral medications, like acyclovir (Zovirax) and foscarnet (Foscavir) — to treat herpes encephalitis or other severe viral infections (however, no specific antiviral drugs are available to fight encephalitis)
Plasmapharesis – removing the blood and discarding the parts that contain antibodies. After the blood has been treated, it is returned to your body
Antibiotics – if the infection is caused by certain bacteria
Sedatives – to treat irritability or restlessness
Acetaminophen –for fever and headaches
According to the CDC (Centers for Disease Control and Prevention), USA, encephalitis occurs in approximately 0.5 in every 1000,000 individuals, most of them children, elderly people and individuals with weakened immune systems.
And the outcome varies. Some cases are mild and short, and the person fully recovers.
Other cases are severe, and permanent impairment or death is possible.
The acute phase normally lasts for 1-2 weeks. Fever and symptoms gradually or suddenly disappear. Some people may take several months to fully recover.
Research is an important priority towards of the treatment of the epileptic encephalopathies, since these patients may not respond to standard anti-seizure medications.
Research scientists are studying the effects of high-dose benzodiazepines and pulse intravenous corticosteroids on the EEG, the neuropsychologic manifestations of electrical status, epilepticus of sleep, and the genetics of the epileptic encephalopathies.
Hopefully, a clinical treatment will be available in the near future.
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