Epilepsy in children
What is epilepsy?
To answer this, first we need to understand a little bit about the brain. It
controls and regulates all voluntary and involuntary responses in the body. The
brain consists of nerve cells that normally communicate with each other through
electrical activity. Seizures are altered behavior that occurs when part(s) of
the brain receives a burst of abnormal electrical signals that temporarily
interrupts normal electrical brain function. Epilepsy is defined as two or more
seizures that occur without a special cause.
Different kinds of epilepsy are classified according to their signs and
symptoms, the child's age when they begin to occur, their EEG pattern,
neurologic findings on examination and special kinds of imaging (x-ray-type)
tests including magnetic resonance imaging (MRI) and computerized tomography
(CT) scans.
The incidence of epilepsy in kids
Approximately 4-6% of children have a single seizure during their childhood,
and approximately 1% have two or more. Of those who have two or more seizures,
70-80% of them eventually "outgrow" the condition.
How are seizures classified?
Partial seizures (also known as focal) take place when abnormal
electrical brain function occurs in one or more areas of one side of the brain.
If the child does not lose consciousness throughout the seizure, the seizure is
classified as a simple partial seizure. If the child loses consciousness or does
not respond appropriately, the seizure is classified as a complex partial
seizure.
Partial seizures may include one-sided jerking movements of the arms or legs,
stiffening, eye deviation to one side, or twisting of the body, sometimes
preceded by seeing visions, hearing noises, tasting and smelling things,
dizziness, a rapid heart rate, dilated pupils, sweating, flushing, stomach
fullness and psychic symptoms such as a sense of deja-vu, distortions, illusions
and hallucinations.
Generalized seizures involve both sides of the brain. As a result,
the seizures are less variable than focal seizures. Typically, they may involve
brief staring spells; sudden, quick, muscle jerks; generalized and rhythmic
jerking of the extremities; generalized stiffening episodes, or generalized
stiffness followed by rhythmic jerking of the extremities, or a sudden loss of
muscle tone resulting in a head drop or sudden fall to the ground.
What causes seizures?
- Fever (febrile seizures): These are caused by fever in children age 3
months to 5 years of age, and no other underlying neurologic problems are
present. Febrile seizures are common and occur in 2-5% of all children. Simple
febrile seizures are brief (usually less than 5 minutes) generalized
convulsions that only occur once in the course of an illness.
- Metabolic or chemical imbalances in the body: These may include
hypoglycemia (low blood sugar) hypo/hypernatremia (too little or too much
sodium in the blood), and hypocalcemia (too little calcium). In addition,
meningitis or encephalitis (brain infections) may induce seizures. Other acute
problems that can cause seizures include toxins, trauma, and strokes. In
children with epilepsy, a common reason for sudden increase in seizures is
that the youngsters are not taking their medications as directed.
- Trauma at birth or brain abnormalities such as tumors: This may include a
lack of adequate oxygen near the time of birth, trauma, infection, and stroke.
Sometimes the seizures appear suddenly although the brain abnormality may have
been present for a long time.
- Neurodegenerative diseases. While neurodegenerative diseases are rare,
they can be devastating.
How is epilepsy diagnosed?
The best tool the doctor has to evaluate the spells is the child's history.
This includes knowing what happened immediately before the spell, the first
indication that something was wrong, a complete description of the event, the
level of responsiveness of the child, how long the spell lasted, how it resolved
and what the child did after the event. All or some of the following tests may
be used:
- Blood tests
- Electroencephalogram (EEG) - A procedure that records the brain's
continuous, electrical activity by means of electrodes attached to the scalp.
- Magnetic resonance imaging (MRI) - A diagnostic procedure that uses a
combination of large magnets, radiofrequencies, and a computer to produce
detailed images of organs and structures within the body.
- Computed tomography scan (Also called a CT or CAT scan.) - A diagnostic
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 CT scan shows detailed images of any part of the
body, including the bones, muscles, fat, and organs. CT scans are more
detailed than general x-rays.
- Lumbar puncture (spinal tap) - A special needle is
placed into the lower back, into the spinal canal. This is the area around
(but not into) the spinal cord. The pressure in the spinal canal and brain can
then be measured. A small amount of cerebral spinal fluid (CSF) can be removed
and sent for testing to determine if there is an infection or other problems.
CSF is the fluid that bathes your child's brain and spinal cord.