History: The type of symptoms and physical signs described by the individual or an observer depend on which part of the brain is affected and may include confusion, a staring spell, jerking contractions of the muscles of the arms and legs, loss of consciousness, or psychic symptoms. An individual with epilepsy have almost the same type of seizure in each episode. The history is very important in the diagnosis of epilepsy. A detailed description of the seizure from the individuals themselves or an observer is noted. Since individuals often do not remember the event, information obtained from someone who has witnessed the seizure is a valuable part of the history. If the individual is conscious throughout the seizure, he or she may be able to recall symptoms or other details. Many individuals with epilepsy have no symptoms between seizures (the inter-ictal phase). Others may have an aura characterized by restlessness, irritability, or an uncomfortable feeling that precedes a seizure (pre-ictal state).
The documented seizures must be recurrent and chronic in order to confirm a diagnosis of epilepsy. An isolated seizure episode of any type is not necessarily an epileptic seizure. In fact, if there is no history of seizures, a single seizure or repeated seizures in a short period may be a sign of a serious underlying disease, chemical imbalance, drug or alcohol use, stroke, or a tumor. Epilepsy diagnosis requires two or more unprovoked (no identifiable cause) seizures separated by at least 24 hours.
The International League Against Epilepsy (ILAE) classifies epileptic seizures as focal (partial)- onset or generalized-onset seizures, based on how the abnormal brain activity begins. Focal-onset seizures involve a focal portion of one side of the brain (cerebral hemisphere), and generalized-onset seizures occur simultaneously in both sides of the brain. Unclassified seizures do not fit precisely into either class.
Focal seizures are produced by abnormal activity in only one area of the brain. There are two types of focal seizures: simple focal seizures, and complex (dyscognitive) focal seizures. Simple focal seizures do not result in loss of consciousness. Individuals may have altered emotions or perceive a change in the appearance, smell, feel, taste or sound of things (visual, olfactory, and auditory hallucinations), involuntary jerking of an arm or leg, and sensory symptoms such as dizziness (vertigo), tingling or numbness in a part of the body (paresthesias), and flashing lights. Individuals with complex focal seizures have altered consciousness or awareness, and may have transient loss of awareness, staring, and purposeless movements such as hand rubbing, chewing, swallowing, or walking in circles.
Generalized seizures appear to involve all areas of the brain. There are 6 types of generalized seizures: absence or cognitive seizures (petit mal seizures), tonic seizures, clonic seizures, myoclonic seizures, atonic seizures (drop seizures), and tonic-clonic seizures (grand mal seizures). An Individual with absence or cognitive seizures does not respond in a normal manner to his or her surroundings (e.g., staring and subtle body movement) for a brief period; there is a brief loss of consciousness. Tonic seizures cause stiffening of muscles, usually in the back, arms and legs, and may cause a fall to the ground. Clonic seizures usually affect the neck, face, and arms, and are associated with rhythmic, jerking muscle movements. Individuals with myoclonic seizures have sudden brief jerks or twitches of the arms and legs. In atonic seizures, there is loss of muscle control, which may cause a sudden collapse or fall. Tonic-clonic seizures, the most recognized type of seizure, are characterized by loss of consciousness, abnormal and sometimes violent movements of the body (e.g., body stiffening and shaking), and sometimes loss of bladder control or tongue biting. These seizures can start as a focal (partial) seizure and show secondary generalization. Physical exam: The exam may be entirely normal. If the individual is examined immediately after the seizure, a complete neurological exam may be postponed if the individual lost consciousness or is not alert. The period after the seizure is called the post-ictal phase. Some types of seizures leave the individual fatigued or confused and unable to follow directions. It is important to focus on findings that may indicate a brain lesion. Tests: The approach to testing depends on whether the seizure was the individual's first seizure. If it was the first episode, extensive testing is necessary. Comprehensive blood tests look for a metabolic or chemical cause for the seizures. Routine tests include EEG, skull x-rays, magnetic resonance imaging (MRI), computed tomography (CT), and possibly a cerebral angiogram. The EEG is the most useful test in classifying seizures and can direct the best approach to therapy. Positron emission tomography (PET) imaging can be used to identify areas of the brain that are producing seizures. Occasionally a 24- to 72-hour sleep study or epilepsy laboratory observation may be necessary to help classify the type of seizure, or to rule out pseudo-seizures (the manifestation of malingering, factitious disorder, or hysteria).
If the individual was previously seen for seizures and the diagnosis of a recurrent seizure disorder or epilepsy was established, then the testing is more limited. If the individual is on medication for seizures, measurement of blood drug levels can determine whether the individual has been taking the medications as indicated or if the dosage should be changed. |