Seizure Disorders PDF

10/24/23, 3:34 PM Realizeit for Student Seizure Disorders Seizures are episodes of abnormal motor, sensory, autonomic, or psychic activity (or a combination of these) that result from sudden excessive discharge from cerebral neurons (Hickey & Strayer, 2020). A localized area or all of the brain ma...

10/24/23, 3:34 PM Realizeit for Student Seizure Disorders Seizures are episodes of abnormal motor, sensory, autonomic, or psychic activity (or a combination of these) that result from sudden excessive discharge from cerebral neurons (Hickey & Strayer, 2020). A localized area or all of the brain may be involved. The International League Against Epilepsy (ILAE) has defined epilepsy as more than one unprovoked seizure (Fisher, Cross, French, et al., 2017). The ILAE differentiates between three main seizure types: focal onset, generalized onset, and unknown onset seizures (see Chart 61-4) . Focal (or partial) seizures are thought to originate within a localized area of the brain. Generalized seizures occur in and rapidly engage bilaterally distributed networks. Unknown onset seizures can be described as “unclassified,” so termed because of incomplete data surrounding the event, but they may also be described from their clinical features (Fisher et al., 2017). Seizures may also be characterized as “provoked,” or related to acute, reversible conditions such as structural, metabolic, immune, infectious, or unknown etiologies. Pathophysiology The underlying cause is an electrical disturbance (arrhythmia) in the nerve cells in one section of the brain; these cells emit abnormal, recurring, uncontrolled electrical discharges. The characteristic seizure is a manifestation of this excessive neuronal discharge. Associated loss of consciousness, excess movement or loss of muscle tone or movement, and disturbances of behavior, mood, sensation, and perception may also occur. The specific causes of seizures are varied and can be categorized as genetic, due to a structural or metabolic condition, or the cause may be yet unknown etiologies (Fisher et al., 2017). Causes of seizures include: Allergies Brain tumor Cerebrovascular disease CNS infections Drug and alcohol withdrawal Fever (childhood) Head injury Hypertension Hypoxemia of any cause, including vascular insufficiency Metabolic and toxic conditions (e.g., kidney injury, hyponatremia, hypocalcemia, hypoglycemia, pesticide exposure) https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IUAYD8aTcEKqA9iFsBPwk2RFvtNozNlLKTVk0W5HMqg… 1/3 10/24/23, 3:34 PM Realizeit for Student Clinical Manifestations Depending on the location of the discharging neurons, seizures may range from a simple staring episode (generalized absence seizure) to prolonged convulsive movements with loss of consciousness. The initial pattern of the seizures indicates the region of the brain in which the seizure originates (see Chart 61-4) . Only a finger or hand may shake, or the mouth may jerk uncontrollably. The person may talk unintelligibly; may be dizzy; and may experience unusual or unpleasant sights, sounds, odors, or tastes, but without loss of consciousness (Hickey & Strayer, 2020). Generalized seizures often involve both hemispheres of the brain, causing both sides of the body to react. Intense rigidity of the entire body may occur, followed by alternating muscle relaxation and contraction (generalized tonic–clonic contraction). The simultaneous contractions of the diaphragm https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IUAYD8aTcEKqA9iFsBPwk2RFvtNozNlLKTVk0W5HMqg… 2/3 10/24/23, 3:34 PM Realizeit for Student and chest muscles may produce a characteristic epileptic cry. The tongue is often chewed, and the patient can be incontinent of urine and feces. After 1 or 2 minutes, the convulsive movements begin to subside; the patient relaxes and lies in deep coma, breathing noisily. The respirations at this point are chiefly abdominal. In the postictal state (after the seizure), the patient is often confused and hard to arouse and may sleep for hours. Many patients report headache, sore muscles, fatigue, and depression (AANN, 2016a). Other generalized seizures may be absence types of seizures (Hickey & Strayer, 2020). Focal seizures are subdivided into events characterized by both motor and nonmotor symptoms. There may be an impairment of consciousness or awareness or other dyscognitive features, localization, and progression of symptoms (Fisher et al., 2017). Assessment and Diagnostic Findings The diagnostic assessment is aimed at determining the type of seizures, their frequency and severity, and the factors that precipitate them. A developmental history is taken, including events of pregnancy and childbirth, to seek evidence of preexisting injury. The patient is also questioned about illnesses or head injuries that may have affected the brain. In addition to physical and neurologic evaluations, diagnostic examinations include biochemical, hematologic, and serologic studies. MRI is used to detect structural lesions such as focal abnormalities, cerebrovascular abnormalities, and cerebral degenerative changes (AANN, 2016a). The EEG furnishes diagnostic evidence for a substantial proportion of patients with epilepsy and assists in classifying the type of seizure. Abnormalities in the EEG usually continue between seizures or, if not apparent, may be elicited by hyperventilation or during sleep (AANN, 2016a). Microelectrodes (depth electrodes) can be inserted deep in the brain to probe the action of single brain cells. Some people with clinical seizures have normal EEGs, whereas others who have never had seizures have abnormal EEGs. Telemetry and computerized equipment are used to monitor electrical brain activity while the patient pursues their normal activities and to store the readings on computer tapes for analysis. Video recording of seizures taken simultaneously with EEG telemetry is useful in determining the type of seizure as well as its duration and magnitude (Hickey & Strayer, 2020). SPECT is an additional tool that is sometimes used in the diagnostic workup. It is useful for identifying the epileptogenic zone so that the area in the brain giving rise to seizures can be removed surgically (AANN, 2016a). https://herzing.realizeithome.com/RealizeitApp/Student.aspx?Token=0Dn26kXyU%2f6F5gOCz4%2f2IUAYD8aTcEKqA9iFsBPwk2RFvtNozNlLKTVk0W5HMqg… 3/3