Case 2: Epilepsy A 19-year-old college student comes to student health services complaining of sporadic loss of memory. The periods of amnesia occur

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Austin Hudson
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1 Case 2: Epilepsy A 19-year-old college student comes to student health services complaining of sporadic loss of memory. The periods of amnesia occur while the student is awake and occasionally in class. During those times, his classmates report that he begins smacking his lips and fumbling around, disrupting the class. When confronted by his teacher, the student has no recollection of those events and was confused and disoriented. He rests for about 30 minutes and then feels fine. There is no family history of seizures. The student did suffer a head injury while playing sports 6 months earlier, but he does not indicate any cognitive defects. Physical examination: Vital Signs: Temperature: 37 C, Pulse: 76/min, Respiratory rate 18/min, BP 118/76 mm Hg Physical Examination: No abnormalities noted Laboratory studies: EEG: Normal, MRI: Normal The EEG in this patient is normal because the abnormal brain wave activity only occurs during seizures and not during the interval between seizures This patient s symptoms are tied to abnormal function of the central nervous system. Inability to remember activities (amnesia), disorientation, and confusion indicate a disruption of the higher cognitive processes. The mechanisms underlying the inability to remember events during the seizure (transient epileptic amnesia) are poorly understood. The major structures involved in memory the hippocampus, limbic system, and temporal lobe are most likely involved. Treatments can be used to diminish or completely eliminate seizures. There are a wide variety of antiepileptic drugs, the efficacy of which varies by the type and the severity of epilepsy. Surgery may be an option when the seizures originate from a well-defined area of damaged neurons. Vagal nerve stimulation diminishes the frequency and intensity of seizures in some patients. Finally, a ketogenic diet can be used to treat epilepsy, particularly in children Objectives: 1. Discuss the meaning of seizures 2. Discuss the meaning of Epilepsy 3. Explain the pathophysiology 4. Explain mechanism of Epilepsy 5. Discuss the different types of partial Epilepsy 6. Discuss the different types of generalized Epilepsy Questions: 1. What are the main differences between seizures and epilepsy? 2. What are the main epidemiological and impact factor of epilepsy? 3. Who could the primary and secondary cause differ initiation of epilepsy? 4. What are the difference between partial and complex Seizures? 5. What are the main types of partial and complex Seizures? 6. What the main criteria of complex Seizures? 7. What do you mean by Tonic-clonic attack? 1

2 8. Explain the main types of generalized Epilepsy 9. What do you mean by Petit Mal, Myoclonic, Atonic Seizures? Differences between Epilepsy and seizures Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. Seizures are transient signs and/or symptoms of abnormal, excessive or synchronous neuronal activity in the brain. Epidemiology The incidence of epilepsy in USA 35 to 75 cases/ 100,000 person per year while in developing countries, the incidence is higher at 100 to 190 cases per 100,000 persons per year, possibly related to poor health care and prenatal care, increased risk of neurologic trauma, and increased rates of infections. Social Impact Epilepsy is a disorder with profound impact on a patient s lifestyle. 1. Limiting driving: 2. Education: Individuals with persistent seizures have poor school attendance cognitive difficulties 3. Employment: Transportation and educational difficulties combine cause unemployed 4. Dependent on others: dependent upon care-givers to assist with medications, transportation, and ensuring their safety Etiology Primary: For nearly 80% of patients with epilepsy the underlying etiology is unknown. Hereditary factors appear to be important, although a specific cause cannot be identified in many patients Secondary: The most common recognized causes of epilepsy are: 1. Head trauma and stroke. 2. Developmental and genetic defects (5% of cases), 3. Central nervous system (CNS) tumors, central nervous system infections, and neurodegenerative diseases.4. Human immunodeficiency virus infection or neuro-cysticercosis infection. Isolated seizures that are not epilepsy can be caused by: Secondary Epilepsy can be caused by multiple neurological or medical conditions, such as acute electrolyte disorders, hypoglycemia, drugs (e.g., cocaine), eclampsia, kidney failure, hypertensive encephalopathy, meningitis, and so forth. If these underlying causes of seizures are not corrected, they may lead to the development of recurrent seizures or epilepsy. Pathophysiology Seizures Regardless of the underlying etiology, all seizures involve a sudden electrical disturbance of the cerebral cortex. A population of neurons fires rapidly and repetitively for seconds to minutes. Cortical electrical discharges become excessively rapid, rhythmic, and synchronous. This phenomenon is presumably related to an excess of excitatory neurotransmitter action, a failure of inhibitory neurotransmitter action, or a combination of the two. In the individual patient, however, it is usually impossible to identify which neuro -chemical factors are responsible. 2

The seizures themselves may cause Some damage to the cortex; Loss of neurons, especially inhibitory neurons, has been demonstrated in tissue from seizure foci.

3 The seizures themselves may cause Some damage to the cortex; Loss of neurons, especially inhibitory neurons, has been demonstrated in tissue from seizure foci. Reorganization of connections between groups of neurons may strengthen excitatory connections and weaken inhibitory connections, making the occurrence of future seizures more likely. Mechanism of Epilepsy Epilepsy is the tendency to have seizures on a chronic, recurrent basis. Epilepsy may be that an originally small group of abnormal neurons causes adjacent or connected neurons to gradually become abnormal as well, by bombarding them over time with frequent, repeated electrical impulses. When the network of abnormal neurons becomes sufficiently large, it becomes capable of sustaining an excessive firing pattern for at least several seconds: a seizure. This hyperexcitable network of neurons is then the seizure focus. The International Classification of Epileptic Seizures: The International Classification of Epileptic Seizures combines the clinical description with certain electro-physiologic findings to classify epileptic seizures. Seizures are divided into two main patho-physiologic groups: partial seizures and generalized seizures by EEG recordings and clinical symptomatology A. Partial Seizures When the seizure begins in a localized area of the brain, it is defined as partial. These lesions can promote extremely rapid discharges in the local neurons; when the discharge rate rises above several hundred per second, synchronous waves begin to spread over adjacent cortical regions or more remotely to the contralateral cortex and subcortical areas of the brain through projections to the thalamus, which has widespread connections to both hemispheres. Partial Epileptic Seizures classified into: 1. Simple (formally called focal): Focal seizures originate in one area of the brain, usually the cortex or limbic system. The person having a focal seizure will not lose consciousness during the seizure, but will be unable to control various body movements. People experiencing a simple partial seizure can talk and answer questions. They will remember what happened during the seizure 3

Simple partial seizures usually last two to 10 seconds, although they may last longer. If there are no convulsions, they may not be obvious to the onlooker. The type of simple partial seizure A.

Partial (focal) somatosensory seizure (jacksonian motor seizures) The person may see lights, hear a buzzing sound, or feel tingling or numbness in a part of the body. C.

4 Simple partial seizures usually last two to 10 seconds, although they may last longer. If there are no convulsions, they may not be obvious to the onlooker. The type of simple partial seizure A. Partial (focal) motor seizure (jacksonian motor seizures) Simple partial seizures typically begins in one area of the body the face, arm, leg, or trunk and may spread to other parts of the body. B. Partial (focal) somatosensory seizure (jacksonian motor seizures) The person may see lights, hear a buzzing sound, or feel tingling or numbness in a part of the body. C. Partial psychomotor (temporal lobe) seizure One may see or hear things that are not there objects looking strange or appearing bigger or smaller than usual. One feels emotions, often fear, but sometimes sadness, anger, or joy. D. Autonomic Seizures Autonomic symptoms or signs, such as abdominal discomfort or nausea, stomach pain, (borborygmi), belching, flatulence, and vomiting. 2. Complex partial seizures (formerly Psychomotor or Temporal Lobe Seizures) A complex partial seizure occurs when epileptic activity spreads to both temporal lobes in the brain. A complex partial seizure often occurs after a simple partial seizure originating in the temporal lobe. A complex partial seizure usually lasts about two to four minutes A complex partial seizure does not involve convulsions, but it impairs consciousness. During the seizure, the person will no longer respond to questions. Someone experiencing a complex partial seizure may become frightened and try to run and struggle. Following the seizure, there will be no memory of it. During a complex partial seizure, the person stops and has a blank look or empty stare. S/he will appear unaware of the environment and may seem dazed. The seizure may progress to manifest any of the following inappropriate automatic behaviours: chewing movements, uncoordinated activity 2. Generalized Seizures Generalized epileptic seizures are characterized by diffuse, excessive, and uncontrolled neuronal discharges that at the outset spread rapidly and simultaneously to both cerebral hemispheres through interconnections between the thalamus and cortex. However, it is sometimes difficult clinically to distinguish between a primary generalized seizure and a focal seizure that rapidly spreads. Generalized seizures are subdivided primarily on the basis of the ictal motor manifestations, which, in turn, depend on the extent to which subcortical and brain stem regions participate in the seizure. 4

Generalized Tonic-Clonic (Grand Mal) Seizures) 1. Tonic-clonic: Characterized by: The duration of the seizure is usually 1 to 3 minutes. These seizures are often described as grand mal.

body or rigidly pushed away from it, which will cause the person to fall if standing,usually lasting only a few seconds.

These may range from exaggerated twitches of the limbs to violent shaking or vibrating of the stiffened extremities. The person may roll and stretch as the seizure spreads.

5 Generalized Tonic-Clonic (Grand Mal) Seizures) 1. Tonic-clonic: Characterized by: The duration of the seizure is usually 1 to 3 minutes. These seizures are often described as grand mal. The seizures are divided into two phases Tonic phase The person will quickly lose consciousness, and the skeletal muscles will suddenly tense, often causing the extremities to be pulled towards the body or rigidly pushed away from it, which will cause the person to fall if standing,usually lasting only a few seconds. Clonic phase The person's muscles will start to contract and relax rapidly, causing convulsions. These may range from exaggerated twitches of the limbs to violent shaking or vibrating of the stiffened extremities. The person may roll and stretch as the seizure spreads. The eyes typically roll back or close and the tongue often suffers bruising sustained by strong jaw contractions. What Initiates a Generalized Tonic-Clonic Seizure? (1) strong emotional stimuli, (2) alkalosis caused by overbreathing, (3) drugs, (4) fever, and (5) loud noises or flashing lights. What Stops the Generalized Tonic-Clonic Attack? The extreme neuronal overactivity during a tonicclonic attack is presumed to be caused by massive simultaneous activation of many reverberating neuronal pathways throughout the brain. Although the factors that terminate the attack are not well understood, it is likely that active inhibition occurs by inhibitory neurons that have been activated by the attack. Absence Seizures (Petit Mal Seizures) Absence seizures, formerly called petit mal seizures, usually begin in childhood or early adolescence and account for 15 to 20 percent of epilepsy cases in children. Absence seizures almost certainly involve the thalamocortical brain activating system. They are usually characterized by 3 to 30 seconds of unconsciousness or diminished consciousness, during which time the person often stares and has twitchlike contractions of muscles, usually in the head region, especially blinking of the eyes; this phase 5

6 is followed by a rapid return of consciousness and resumption of previous activities. This total sequence is called the absence syndrome or absence epilepsy. The patient may have one such attack in many months or, in rare instances, may have a rapid series of attacks, one after the other. The usual course is for the absence seizures to appear first during childhood or adolescence and then to disappear by the age of 30 years. On occasion, an absence seizure will initiate a generalized tonic-clonic (grand mal) attack. 3. Myoclonic(infantile spasm): Seen in children or infants, caused by cerebral pathology, often with mental retardation Infantile spasms usually disappear by age 4, but child may develop other types of seizures. 4. Atonic: Characterized by: A. The patient loses consciousness and muscle tone. B. No muscle movements are typically noted, and the patient will fall when they are not lying down or sitting in a chair. C. These seizures may be described as falling out. D. Usually accruing in children, this type is associated with complete loss of consciousness and muscle tone. 6

Child Neurology. The Plural. of anecdote. is not evidence. University of Texas Health Science Center at San Antonio

Child Neurology. The Plural. of anecdote. is not evidence. University of Texas Health Science Center at San Antonio Child Neurology Management of Seizure Disorders The stated goal of advocacy groups for patients with seizures, is to have the patient seizure free. S W Atkinson, MD Management of When to pharmacologically