Seizures and epilepsy

40 Seizures and epilepsy




Overview/pathophysiology


Seizures result from an abnormal, uncontrolled electrical discharge from the neurons of the cerebral cortex in response to a stimulus. If the activity is localized in one portion of the brain, the individual will have a partial seizure, but when it is widespread and diffuse, a generalized seizure occurs. Symptoms vary widely, depending on the involved area of the cerebral cortex. Seizures are generally manifested as an alteration in sensation, behavior, movement, perception, or consciousness lasting from seconds to several minutes. A seizure can be an isolated incident that may not recur once the underlying cause is corrected (e.g., fever, alcohol withdrawal). Epilepsy is the term used for recurrent, unprovoked seizures.


Seizure threshold refers to the amount of stimulation needed to cause neural activity. Although anyone can have a seizure if the stimulus is sufficient, the seizure threshold is lowered in some individuals and this may result in spontaneous seizures. Potential causes for lowered seizure threshold include congenital defects; craniocerebral trauma, particularly that from a penetrating wound; subarachnoid hemorrhage; stroke; intracranial tumors; infections, such as meningitis or encephalitis; exposure to toxins, such as lead; hypoxia; alcohol or other drug withdrawal; and metabolic and endocrine disorders, such as hypoglycemia, hypocalcemia, uremia, hypoparathyroidism, excessive hydration, and fever. Phenothiazine, tricyclic antidepressants, and alcohol usage increase risk of seizure by lowering the seizure threshold. For susceptible individuals, triggers may include emotional tension or stress; physical stimulation, such as loud music, bright flashing lights, and some videos; lack of sleep or food; fatigue; menses or pregnancy; and excessive drug/alcohol use. If a trigger stimulus is identified, the individual has what is termed reflex epilepsy.


Although a seizure itself generally is not fatal, individuals can be injured by hitting their heads or breaking bones if they lose consciousness and fall to the ground. Seizure activity increases cerebral O2 consumption by 60% and cerebral blood flow by 250%. Instances of prolonged and repeated generalized seizures, status epilepticus (SE), can be life threatening because apnea, hypoxia, acidosis, cerebral edema, dysrhythmias, and cardiovascular collapse can occur.



Health care setting


Primary care with possible hospitalization for complications of therapy, continuous diagnostic video electroencephalogram (EEG) monitoring during pharmacologic or surgical interventions, or intensive care unit (ICU) for SE



Assessment


It is important to obtain an accurate description of seizure characteristics and duration, as well as any antecedent events, precipitating factors, and postictal phase. There are many clinical types of seizures, but the following are the most serious or common.




Generalized tonic-clonic (grand mal):


Caused by bilateral electrical activity, usually symmetrical from onset, and always involves loss of consciousness. A possible prodromal phase of increased irritability, tension, mood changes, or headache may precede the seizure by hours or days. Patients may experience an aura (a sensory warning, such as a sound, odor, or flash of light) immediately preceding the seizure by seconds or minutes. The seizure usually does not last more than 2-5 min and includes the following phases:


• Tonic (rigid/contracted muscles /extended limbs): Often lasts only 15 sec, usually subsiding in less than 1 min. Symptoms include loss of consciousness, clenched jaws (potential for tongue to be bitten), apnea (may hear a cry as air is forced out of the lungs), and cyanosis. The patient may be incontinent, and pupils may dilate and become nonreactive to light.

• Clonic (rhythmic contraction and relaxation of extremities and muscles): May subside in 30 sec but can last 2-4 min. Eyes roll upward, and excessive salivation results in foaming at the mouth. During this phase, the potential is greatest for biting the tongue.

• Postictal: The first few minutes after the seizure, the individual may be limp and nonresponsive. Pupils begin to react to light and return to their normal size. After about 5 min, patients may be sleepy, semiconscious, confused, unable to speak clearly, and uncoordinated; have a headache; complain of muscle aches; and have no recollection of the seizure event. This phase usually lasts less than 15 min. Temporary weakness, dysphasia, or hemianopia lasting up to 24 hr after the seizure may be experienced.


Generalized absence (petit mal):


Patient has momentary loss of awareness and consciousness with abrupt cessation of voluntary muscle activity. Patient may appear to be daydreaming with a vacant stare and may experience facial, eyelid, or hand twitching. Patient usually does not lose general body muscle tone and so does not fall. The individual resumes previous activity when the seizure ends. There is usually no memory of the seizure, and patients may have difficulty reorienting after the seizure event. This type of seizure can last 1-10 sec, may occur up to 100 times/day, and usually resolves by puberty.



Generalized myoclonic:


Sudden, very brief contraction or jerking of muscles or muscle groups. Individuals may have a very brief, momentary loss of consciousness with some postictal confusion.



Partial simple motor (focal motor seizures):


An irritative focus located in the motor cortex of the frontal lobe causes clonic movement in a particular part of the body, such as the hands or face. If the seizure activity spreads or marches in an orderly fashion to an adjacent area (e.g., hands to arms to shoulders), the seizure is termed a focal motor seizure with jacksonian march. The seizure usually lasts several seconds to minutes. There is no loss of consciousness. Other simple, partial seizures include those with somatosensory symptoms (e.g., smells, sounds), autonomic symptoms (e.g., tachycardia, tachypnea, diaphoresis, goose bumps [piloerection], pallor, flushing), or psychic symptoms (e.g., fear, déjà vu).



Partial complex seizure (psychomotor, “temporal lobe”):


Generally lasts 1-4 min and involves impaired consciousness and a postictal state of confusion lasting several minutes. However, the individual does not fall to the ground, is able to interact with the environment, exhibits purposeful but inappropriate movements or behavior, and has no memory of the event. The individual will perform such automatisms as lip smacking, chewing, facial grimacing, picking, or swallowing movements. These patients may experience and remember various sensory or emotional hallucinations or sensations that occur immediately before the seizure, such as smells; ringing or hissing sounds; or feelings of déjà vu, fear, or pleasure.



Status epilepticus:


State of continuous seizure activity lasting more than 5 min or two or more recurring seizures in which the individual does not completely recover baseline neurologic functioning between seizures. Individuals who suddenly stop taking their antiepilepsy medication are likely to develop this condition. Other common causes are drug withdrawal (e.g., alcohol, sedatives) and fever. This is a medical emergency, especially with tonic-clonic seizures, resulting in such potential complications as cerebral anoxia and edema, aspiration, rhabdomyolysis, hyperthermia, and exhaustion. Brain injury may occur in 20-30 min, and irreversible damage may occur in 60 min. Death may ensue. SE can occur in the absence of movement. The patient does not regain consciousness. This nonconvulsive SE may not be life threatening, but it can cause brain damage and will require continuous EEG monitoring. Expect patients in SE to be transferred to ICU.



Other classifications:


Seizures also can be classified according to epileptic syndrome (e.g., generalized epilepsies, idiopathic with age-related onset). Establishing the correct diagnosis of seizure type and, when possible, epilepsy syndrome, will help tailor effective antiepilepsy drugs (AEDs) and treatment.



Diagnostic tests


Because a variety of problems can precipitate seizures, testing may be extensive. Common tests for initial workup include the following:




Laboratory tests:


To rule out metabolic causes, such as hypoglycemia, hyponatremia, or hypocalcemia; kidney and liver problems; toxicology screens; and AED level.



EEG—both sleeping and awake:


To reveal abnormal patterns of electrical activity, particularly with such stimuli as flashing lights or hyperventilation. Ambulatory EEGs may record brain activity for 48-72 hr, and 24-hr continuous EEG monitoring with video recording may show association of brain activity with the observed seizure. Generalized tonic-clonic seizures show up as high, fast-voltage spikes in all leads. A normal EEG does not rule out seizures.



Magnetic resonance imaging (MRI) scan:


To show structural lesions causing seizures; also may reveal a space-occupying lesion such as a tumor or hematoma. Fast fluid-attenuated inversion-recovery (FLAIR) MRI may be particularly sensitive in finding tumors.



Positron emission tomography:


To check for areas of cerebral glucose hypometabolism that correlate with the irritative seizure-causing focus. This test is useful in partial seizures but is available only in a few centers.



Computed tomography (CT) scan:


To check for presence of a space-occupying lesion, such as a tumor or hematoma.



Skull x-ray examination:


To reveal fractures, tumors, calcifications, or congenital anomalies (pineal shift, ventricular deformity).



Lumbar puncture and cerebrospinal fluid analysis:


If infection such as meningitis is suspected. It also can rule out increased intracranial pressure and determine brain levels of gamma-aminobutyric acid.



New diagnostic technologies and combining of technologies:


Have aided in localizing epileptic activity more precisely. Some of these include the following:


• Functional MRI (fMRI): Enables direct observation of cerebral blood flow (CBF) changes associated with cognitive, sensory, and motor processes and generally has replaced the intracarotid sodium amytal (Wada’s) test to determine hemispheric dominance and function.

• Simultaneous EEG-correlated functional MRI (EEG/fMRI): During this test, blood oxygen level–dependent MRI focal changes match up to changes in blood flow.

• Subtraction ictal and postictal imaging single photon emission computed tomography (SPECT) co-registered on MRI: To assess focal changes in cerebral perfusion, which may identify eleptogenic areas.

• Magnetic source imaging: Magnetoencephalography [MEG] information is superimposed on a co-recorded MRI scan for a noninvasive functional/anatomic imaging technique.

• EEG dipole source modeling: Data from EEG and MEG are taken to locate origin of epileptic paroxysm.

• Methohexital suppression test: Can distinguish the primary focus in temporal lobe epilepsy with multifocal discharges.

• Optical imaging: Noninvasive tool to analyze seizure activity by measuring dynamic changes in blood flow and oxygen during epileptic activity.

• Invasive intracranial EEG monitoring: Depth electrodes are placed in brain tissue, and a subdural “grid” is applied directly to the cortical surface to evaluate deep epileptic sources. This may be performed in patients considering surgical treatment of their epilepsy.




Nursing diagnosis:


Risk for trauma

related to oral, musculoskeletal, and airway vulnerability occurring with seizure activity


Desired Outcomes: Patient exhibits no signs of oral or musculoskeletal tissue injury or airway compromise after the seizure. Before hospital discharge, patient’s significant other verbalizes knowledge of actions necessary during seizure activity.













































ASSESSMENT/INTERVENTIONS RATIONALES
Seizure Precautions
Assess patient’s environment. Pad side rails with blankets or pillows. Keep side rails up and bed in its lowest position when patient is in bed. Keep bed, wheelchair, or stretcher brakes locked. These actions promote safety and protect the patient from trauma in case a seizure occurs.
Tape a soft rubber oral airway to the bedside. Remove wooden tongue depressors (if used, they may splinter). Keep suction and oxygen equipment readily available. These measures enable a patent airway, prevent hypoxia, and protect patient from trauma in case a seizure occurs.
Consider a saline lock for intravenous (IV) access for high-risk patient. Some AEDs must be administered IV, especially as a loading dose or in case of sustained seizure activity.
Use electronic tympanic thermometers for patients at high risk for seizure. If only breakable thermometers are available, take temperature via axillary or rectal route. Glass or other breakable oral thermometers should be avoided when taking patient’s temperature because of the harm they could cause patient if they break.
Caution patients to lie down and push call button if they experience prodromal or aural warning. Keep call light within reach. Prodromal or aural warnings precede seizures in many patients.
Encourage patient to empty mouth of dentures or foreign objects. This helps prevent choking in case a seizure occurs.
Do not allow unsupervised smoking. This restriction prevents fire damage to patient and surroundings if a seizure occurs.
Evaluate need for and provide protective headgear as indicated. This protects patient’s head in case of a seizure.
During the Seizure  
Remain with patient and stay calm. Assess for, record, and report type, duration, and characteristics of seizure activity and any postseizure response. Seizure activity should be documented in detail to aid in management and differentiation of seizure type and identification of triggering factors. This should include, as appropriate, precipitating event, aura, initial location and progression, automatisms, type and duration of movement, changes in level of consciousness, eye movement (e.g., deviation, nystagmus), pupil size and reaction, bowel and bladder incontinence, head deviation, tongue deviation, or teeth clenching.
Prevent or break the fall and ease patient to floor if seizure occurs while patient is out of bed. These actions promote patient’s physical safety.
Keep patient in bed if seizure occurs while there, and lower head of bed to a flat position.
Flattening patient’s position reduces risk of falling out of bed during
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Jul 18, 2016 | Posted by in NURSING | Comments Off on Seizures and epilepsy

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