Seizure disorders; convulsions; absence seizures, generalized seizures, partial seizures, grand mal epilepsy, petit mal epilepsy, tonic-seizures
* Epilepsy Introduction:
Normally, our brains coordinate the intricate affairs of our bodies with an orchestra of electrical impulses. Occasionally this harmonious energy is interrupted by the clash of many brain cells sounding off at once in a disorganized storm of electro-chemical noise. This burst of simultaneous, contradictory signals is called a seizure or convulsion. The seizure impulses override the normal functioning of the brain.
* What is it?
The most common cause of seizures in childhood is the rapid onset of a high fever. Febrile seizures, while very frightening to parents, are not dangerous.
Head trauma is another common cause of seizures. Infections of various types (especially meningitis) are the other common known cause of seizures. Other less common causes include drugs, toxins, brain tumors, strokes, neurologic syndromes, altered blood sugar levels (too low or too high), or abnormalities of blood levels of sodium, calcium, or magnesium.
Night terrors, breath-holding spells, and Tourette syndrome can be confused with seizures, and vice versa.
Epilepsy is defined as recurrent seizures unrelated to fever or identifiable acute damage to the brain.
* Who gets it?
About 5 percent of children will have a seizure before the age of fifteen. Somewhere between 0.4 and 1 percent of people have epilepsy. Epilepsy can begin at any age, but it usually begins during childhood.
* What are the symptoms?
When most people think of seizures, they picture rhythmic jerking movements of the arms and legs. Seizures can look like this, but can also have many different appearances depending on which brain cells are affected. Often the actual appearance of a seizure is so different from what people expect that the diagnosis of seizure is missed.
Seizures are classified as generalized or partial depending on how much of the brain is involved. Seizure activity seizes control of normal brain function. Some partial seizures affect areas of the brain that direct movement; others stimulate areas of the brain that perceive reality or that regulate the body’s internal functions.
Generalized seizures are disruptions of both sides of the brain at once, and as a result, usually include an impairment or loss of consciousness. The classic tonic-clonic or grand mal seizure would be difficult not to notice. The individual suddenly loses consciousness, sometimes emitting a piercing cry or haunting moan. The eyes roll back in the head and muscles throughout the face, trunk, and limbs become rigid in a tonic contraction. The person falls, unprotected, to the ground. Often the tongue is bitten. Sometimes breathing stops and the person begins to turn blue. Sphincter control is lost; urine and sometimes stool are passed. This tonic phase usually lasts for tens of seconds. As the clonic phase begins, the muscles relax and then contract again with rhythmic jerks. It is not uncommon for this phase to last for 30 minutes or more. When the generalized tonic-clonic seizure is finally over, the entire body relaxes, and the person is unconscious.
Absence or petit mal seizures, by contrast, are often nothing more than brief, motionless, blank staring into space. The head may fall forward slightly and the eyelids may flicker, but the effect is not dramatic. After absence spells the people immediately resume whatever they were doing or saying just before the seizure interrupted them. They don’t even notice the pause.
Uncontrolled muscle activity is the most common form of partial seizure. This can either be tonic (increased muscle tone) or clonic (rhythmic muscle contractions). Usually this involves the face, neck, or limbs. One classic appearance is the forceful turning of the head and eyes to one side. Sometimes complex movements such as lip-smacking, sucking, or swallowing can occur. These might be confused with the tics of Tourette’s syndrome. Sometimes partial seizures can appear somewhat intentional, as when a seizure makes someone pull at clothing or caress an object. A partial seizure in the part of the brain that directs the “flight” response might even send someone running aimlessly.
Sensory seizures are more difficult to detect. An explosion of activity in the auditory centers of the brain might cause someone to suddenly hear things that aren’t there. If the seizure is in the back of the head, all manner of visual disturbance might occur, from temporary blindness, to flashes of light, to complex visual hallucinations. Auditory or visual hallucinations might even be misdiagnosed as schizophrenia or some other mental illness. Olfactory seizures, in which people smell aromas that are not present, may be either pleasant or revolting. Gustatory seizures, with bursts of taste sensation, are rare.
Paroxysmal vertigo is another type of partial seizure. Suddenly the world starts to spin out of control, and you are falling. Terror!!! Seizures in primitive reaches of the brain can produce states of absolute fear. States of vague anxiety can be partial seizures. Seizures in the limbic system of the brain can produce spasms of depression — or the sensation of total well-being.
Seizures can thrust vivid memories into consciousness, or distorted, mangled memories. They can create dream-like states, sudden nightmares, and states of unreality or detachment. Partial seizures can slow time to a syrupy pace, or make it seem to rush by in fast-action fury.
Sometimes partial sensory seizures are as subtle as periods of numbness, discomfort, or pain in parts of the body. Occasionally, rather than creating new sensations, they merely distort those that are already there.
Sometimes only the body’s internal regulatory parts of the brain are affected by a partial seizure — there might be a sudden increase in the amount of saliva, or in the speed of stool through the intestines.
Many of the symptoms that can be produced by partial seizures are common. Only when they are triggered outside the normal pathways of brain function are they considered seizures. The potential for each of them is, after all, present in each of our brains.
* Is it contagious?
Epilepsy is not contagious.
* How long does it last?
This varies widely among the different specific types of epilepsy. Children who have had 2 seizure-free years on treatment, and no specific risk factors, will often stay seizure-free once the medicine is slowly withdrawn.
* How is it diagnosed?
Often the story is compelling enough to clinch the diagnosis of seizure. When this is not the case, the hallmark test is the electroencephalogram or EEG. This painless, non-invasive test simply records brain waves to look for abnormalities. A positive test can make the diagnosis. A negative test though, unless it happens during the event, can’t completely rule out a seizure. Sometimes the situation that triggers the event is reproduced to try to capture it on video and/or EEG. Sometimes an MRI or CT is needed to look at the brain.
* How is it treated?
Anitconvulsant medications are used to treat epilepsy. Sometimes a special diet, the ketogenic diet, is prescribed. Rarely, surgery is needed if other forms of treatment are not effective.
Individual seizures may require specific therapy if they last longer than 2 or 3 minutes or are unusually severe.
* How can it be prevented?
Individual seizures can be prevented with appropriate treatment, but there are no routine preventive measures for epilepsy itself.
Date : 05 May 2016