Seizures and Epilepsy
Epilepsy is a disorder of the brain characterized by repeated seizures. A seizure is usually defined as a sudden alteration of behavior due to a temporary change in the electrical functioning of the brain. Normally, the brain continuously generates tiny electrical impulses in an orderly pattern. These impulses travel along neurons — the network of nerve cells in the brain — and throughout the whole body via chemical messengers called neurotransmitters.
In epilepsy the brain's electrical rhythms have a tendency to become imbalanced, resulting in recurrent seizures. In patients with seizures, the normal electrical pattern is disrupted by sudden and synchronized bursts of electrical energy that may briefly affect their consciousness, movements or sensations.
Epilepsy is usually diagnosed after a person has had at least two seizures that were not caused by some known medical condition, such as alcohol withdrawal or extremely low blood sugar.
If seizures arise from a specific area of the brain, then the initial symptoms of the seizure often reflect the functions of that area. The right half of the brain controls the left side of the body, and the left half of the brain controls the right side of the body. For example, if a seizure starts from the right side of the brain in the area that controls movement in the thumb, then the seizure may begin with jerking of the left thumb or hand.
Focal seizures
When seizures appear to result from abnormal activity in just one area of your brain, they're called focal seizures. These seizures fall into two categories:
· Focal seizures without loss of consciousness. Once called simple partial seizures, these seizures don't cause a loss of consciousness. They may alter emotions or change the way things look, smell, feel, taste or sound. Some people experience deja vu. This type of seizure may also result in involuntary jerking of one body part, such as an arm or leg, and spontaneous sensory symptoms such as tingling, dizziness and flashing lights.
· Focal seizures with impaired awareness. Once called complex partial seizures, these seizures involve a change or loss of consciousness or awareness. This type of seizure may seem like being in a dream. During a focal seizure with impaired awareness, you may stare into space and not respond normally to your environment or perform repetitive movements, such as hand rubbing, chewing, swallowing or walking in circles.
Symptoms of focal seizures may be confused with other neurological disorders, such as migraine, narcolepsy or mental illness. A thorough examination and testing are needed to distinguish epilepsy from other disorders.
- Secondarily Generalized Seizure These seizures begin as a focal seizure and develop into a generalized seizure as the electrical abnormality spreads throughout the brain. You may be fully conscious when the seizure begins but then lose consciousness and experience convulsions as it develops.
Generalized seizures
Seizures that appear to involve all areas of the brain are called generalized seizures. Six types of generalized seizures exist.
· Tonic-clonic seizures (also called grand mal seizures). Tonic-clonic seizures, previously known as grand mal seizures, are the most dramatic type of epileptic seizure. They can cause an abrupt loss of consciousness and body stiffening, twitching and shaking. They sometimes cause loss of bladder control or biting your tongue.
· Absence seizures (also called petit mal seizures). Absence seizures, previously known as petit mal seizures, typically occur in children. They're characterized by staring into space with or without subtle body movements such as eye blinking or lip smacking and only last between 5-10 seconds. These seizures may occur in clusters, happening as often as 100 times per day, and cause a brief loss of awareness.
Childhood absence epilepsy shows up as brief staring episodes in children, usually starting between ages four and six. Children usually outgrow these. Juvenile absence epilepsy starts slightly later and can persist into adulthood; people with these kinds of seizures may develop tonic-clonic seizures in addition to absence of seizures in adulthood.
· Tonic seizures. Tonic seizures cause stiff muscles and may affect consciousness. These seizures usually affect muscles in your back, arms and legs and may cause you to fall to the ground.
· Akinetic or Atonic seizures (also called drop attacks). Atonic seizures, also known as drop seizures, cause a loss of muscle control. Since this most often affects the legs, it often causes you to suddenly collapse or fall down.
· Clonic seizures. Clonic seizures are associated with repeated or rhythmic, jerking muscle movements. These seizures usually affect the neck, face and arms.
· Myoclonic seizures. Myoclonic seizures usually appear as sudden brief jerks or twitches and usually affect the upper body, arms and legs.
Infantile spasms. This rare type of seizure disorder occurs in infants from before six months of age. There is a high occurrence rate of this seizure when the child is awakening, or when they are trying to go to sleep. The infant usually has brief periods of movement of the neck, trunk, or legs that lasts for a few seconds. Infants may have hundreds of these seizures a day. This can be a serious problem, and can have long-term complications.
Febrile seizures. This type of seizure is associated with fever and is not epilepsy, although a fever may trigger a seizure in a child who has epilepsy. These seizures are more commonly seen in children between 6 months and 5 years of age and there may be a family history of this type of seizure. Febrile seizures that last less than 15 minutes are called "simple," and typically do not have long-term neurological effects. Seizures lasting more than 15 minutes are called "complex" and there may be long-term neurological changes in the child.
Progressive Myoclonic Epilepsy
Progressive myoclonic epilepsy is rare and frequently results from hereditary metabolic disorders, such as neuronal ceroid lipofuscinosis and mitochondrial encephalopathy. In addition to seizures, symptoms may include unsteadiness, muscle rigidity, and intellectual disability.
Reflex Epilepsy
In reflex epilepsy, seizures are triggered by specific environmental stimuli. If flashing lights trigger a seizure, for instance, this is called photosensitive epilepsy. Reflex epilepsy usually begins in childhood and is often outgrown by adulthood.
Environmental triggers may also include sounds. The ringing of church bells, a certain song or type of music, or the sound of a person’s voice may prompt seizures in adults with this type of epilepsy.
For some people, activities such as reading, writing, solving math problems, and even thinking about a certain subject can provoke a seizure. These nonvisual stimuli may trigger generalized or focal seizures.
Symptoms
The child may have varying degrees of symptoms depending on the type of seizure. The following are general symptoms of a seizure or warning signs that your child may be experiencing seizures. Symptoms or warning signs may include:
· Staring
· Jerking movements of the arms and legs
· Stiffening of the body
· Loss of consciousness
· Breathing problems or breathing stops
· Loss of bowel or bladder control
· Falling suddenly for no apparent reason, especially when associated with loss of consciousness
· Not responding to noise or words for brief periods
· Appearing confused or in a haze
· Nodding the head rhythmically, when associated with loss of awareness or even loss of consciousness
· Periods of rapid eye blinking and staring
During the seizure, the child's lips may become bluish and breathing may not be normal. The movements are often followed by a period of sleep or disorientation.
The symptoms of a seizure may resemble other problems or medical conditions. Always consult your child's doctor for a diagnosis.
Causes
A child may experience one or many different types of seizures. While the exact cause of the seizure may not be known, the more common seizures are caused by the following:
· In newborns and infants:
o Birth trauma
o Congenital (present at birth) problems
o Fever/infection
o Metabolic or chemical imbalances in the body
· In children, adolescents, and young adults:
o Alcohol or drugs
o Trauma to the head or brain injury
o Infection
o Congenital conditions
o Genetic factors
o Unknown reasons
· Other possible causes of seizures may include:
o Brain tumor
o Neurological problems
o Drug withdrawal
o Medications
o Use of illicit drugs