Seizures, generalized tonic-clonic

Seizures, generalized tonic-clonic: Excerpt from Professional Guide to Signs & Symptoms (Fifth Edition)

Like other types of seizures, generalized tonic-clonic seizures are caused by the paroxysmal, uncontrolled discharge of central nervous system (CNS) neurons, leading to neurologic dysfunction. Unlike most other types of seizures, however, this cerebral hyperactivity isn’t confined to the original focus or to a localized area but extends to the entire brain.

A generalized tonic-clonic seizure may begin with or without an aura. As seizure activity spreads to the subcortical structures, the patient loses consciousness, falls to the ground, and may utter a loud cry that’s precipitated by air rushing from the lungs through the vocal cords. His body stiffens (tonic phase), then undergoes rapid, synchronous muscle jerking and hyperventilation (clonic phase). Tongue biting, incontinence, diaphoresis, profuse salivation, and signs of respiratory distress may also occur. The seizure usually stops after 2 to 5 minutes. The patient then regains consciousness but displays confusion. He may complain of headache, fatigue, muscle soreness, and arm and leg weakness.

Generalized tonic-clonic seizures usually occur singly. The patient may be asleep or awake and active. (See What happens during a generalized tonic-clonic seizure.) Possible complications include respiratory arrest due to airway obstruction from secretions, status epilepticus (occurring in 5% to 8% of patients), head or spinal injuries and bruises, Todd’s paralysis and, rarely, cardiac arrest. Life-threatening status epilepticus is marked by prolonged seizure activity or by rapidly recurring seizures with no intervening periods of recovery. It’s most commonly triggered by abrupt discontinuation of anticonvulsant therapy.

Generalized seizures may be caused by a brain tumor, vascular disorder, head trauma, infection, metabolic defect, drug or alcohol withdrawal syndrome, exposure to toxins, or a genetic defect. Generalized seizures may also result from a focal seizure. With recurring seizures, or epilepsy, the cause may be unknown.

Emergency interventions

If possible, turn the patient to one side during the seizure to allow secretions to drain and to prevent aspiration. Otherwise, do this at the end of the clonic phase when respirations return. (If they fail to return, check for airway obstruction and suction the patient if necessary. Cardiopulmonary resuscitation, intubation, and mechanical ventilation may be needed.)

Protect the patient after the seizure by providing a safe area in which he can rest. As he awakens, reassure and reorient him. Check his vital signs and neurologic status. Be sure to carefully record these data and your observations during the seizure.

If the seizure lasts longer than 4 minutes or if a second seizure occurs before full recovery from the first, suspect status epilepticus. Establish an airway, start an I.V. line, give supplemental oxygen, and begin cardiac monitoring. Draw blood for appropriate studies. Turn the patient on his side, with his head in a semi-dependent position, to drain secretions and prevent aspiration. Periodically turn him to the opposite side, check his arterial blood gas levels for hypoxemia, and administer oxygen by mask, increasing the flow rate if necessary. Administer diazepam or lorazepam by slow I.V. push, repeated two or three times at 10- to 20-minute intervals, to stop the seizures. If the patient isn’t known to have epilepsy, an I.V. bolus of dextrose 50% (50 ml) with thiamine (100 mg) may be ordered. Dextrose may stop the seizures if the patient has hypoglycemia. If his thiamine level is low, also give thiamine to guard against further damage.

If the patient is intubated, expect to insert a nasogastric (NG) tube to prevent vomiting and aspiration. Be aware that if the patient hasn’t been intubated, the NG tube itself can trigger the gag reflex and cause vomiting. Be sure to record your observations and the intervals between seizures.

History and physical examination

If you didn’t witness the seizure, obtain a description from the patient’s companion. Ask when the seizure started and how long it lasted. Did the patient report any unusual sensations before the seizure began? Did the seizure start in one area of the body and spread, or did it affect the entire body right away? Did the patient fall on a hard surface? Did his eyes or head turn? Did he turn blue? Did he lose bladder control? Did he have any other seizures before recovering?

If the patient may have sustained a head injury, observe him closely for loss of consciousness, unequal or nonreactive pupils, and focal neurologic signs. Does he complain of headache and muscle soreness? Is he increasingly difficult to arouse when you check on him at 20-minute intervals? Examine his arms, legs, and face (including tongue) for injury, residual paralysis, or limb weakness.

Next, obtain a history. Has the patient ever had generalized or focal seizures before? If so, do they occur frequently? Do other family members also have them? Is the patient receiving drug therapy? Is he compliant? Ask about sleep deprivation and emotional or physical stress at the time the seizure occurred.

Medical causes

Alcohol withdrawal syndrome

i> Sudden withdrawal from alcohol dependence may cause seizures 7 to 48 hours later as well as status epilepticus. The patient may also be restless and exhibit hallucinations, profuse diaphoresis, and tachycardia.

Brain abscess

Generalized seizures may occur in the acute stage of abscess formation or after the abscess disappears. Depending on the size and location of the abscess, decreased level of consciousness (LOC) varies from drowsiness to deep stupor. Early signs and symptoms reflect increased intracranial pressure (ICP) and include constant headache, nausea, vomiting, and focal seizures. Typical later features include ocular disturbances, such as nystagmus, impaired vision, and unequal pupils. Other findings vary with the abscess site but may include aphasia, hemiparesis, abnormal behavior, and personality changes.

Brain tumor

Generalized seizures may occur, depending on the tumor’s location and type. Other findings include a slowly decreasing LOC, morning headache, dizziness, confusion, focal seizures, vision loss, motor and sensory disturbances, aphasia, and ataxia. Later findings include papilledema, vomiting, increased systolic blood pressure, widening pulse pressure, and (eventually) decorticate posture.

Cerebral aneurysm

Occasionally, generalized seizures may occur with an aneurysmal rupture. Premonitory signs and symptoms may last several days, but onset is typically abrupt with severe headache, nausea, vomiting, and decreased LOC. Depending on the site and amount of bleeding, related signs and symptoms vary but may include nuchal rigidity, irritability, hemiparesis, hemisensory defects, dysphagia, photophobia, diplopia, ptosis, and unilateral pupil dilation.

Chronic renal failure

End-stage renal failure produces rapid onset of twitching, trembling, myoclonic jerks, and generalized seizures. Related signs and symptoms include anuria or oliguria, fatigue, malaise, irritability, decreased mental acuity, muscle cramps, peripheral neuropathies, anorexia, and constipation or diarrhea. Integumentary effects include skin color changes (yellow, brown, or bronze), pruritus, and uremic frost. Other effects include ammonia breath odor, nausea and vomiting, ecchymoses, petechiae, GI bleeding, mouth and gum ulcers, hypertension, and Kussmaul’s respirations.

Eclampsia

Generalized seizures are a hallmark of this disorder. Related findings include severe frontal headache, nausea and vomiting, vision disturbances, increased blood pressure, fever of up to 104° F (40° C), peripheral edema, and sudden weight gain. The patient may also exhibit oliguria, irritability, hyperactive deep tendon reflexes (DTRs), and decreased LOC.

Encephalitis

Seizures are an early sign of this disorder, indicating a poor prognosis; they may also occur after recovery as a result of residual damage. Other findings include fever, headache, photophobia, nuchal rigidity, neck pain, vomiting, aphasia, ataxia, hemiparesis, nystagmus, irritability, cranial nerve palsies (causing facial weakness, ptosis, dysphagia), and myoclonic jerks.

Epilepsy (idiopathic)

In most cases, the cause of recurrent seizures is unknown.

Head trauma

In severe cases, generalized seizures may occur at the time of injury. (Months later, focal seizures may occur.) Severe head trauma may also cause a decreased LOC, leading to coma; soft-tissue injury of the face, head, or neck; clear or bloody drainage from the mouth, nose, or ears; facial edema; bony deformity of the face, head, or neck; Battle’s sign; and lack of response to oculocephalic and oculovestibular stimulation. Motor and sensory deficits may occur along with altered respirations. Examination may reveal signs of increasing ICP, such as decreased response to painful stimuli, nonreactive pupils, bradycardia, increased systolic pressure, and widening pulse pressure. If the patient is conscious, he may exhibit visual deficits, behavioral changes, and headache.

Hepatic encephalopathy

Generalized seizures may occur late in this disorder. Associated late-stage findings in the comatose patient include fetor hepaticus, asterixis, hyperactive DTRs, and a positive Babinski’s sign.

Hypertensive encephalopathy

This life-threatening disorder may cause seizures along with severely increased blood pressure, decreased LOC, intense headache, vomiting, transient blindness, paralysis, and (eventually) Cheyne-Stokes respirations.

Hypoglycemia

Generalized seizures usually occur with severe hypoglycemia, accompanied by blurred or double vision, motor weakness, hemiplegia, trembling, excessive diaphoresis, tachycardia, myoclonic twitching, and decreased LOC.

Hyponatremia

Seizures develop
when serum sodium levels fall below 125 mEq/L, especially if the decrease is rapid. Hyponatremia also causes orthostatic hypotension, headache, muscle twitching and weakness, fatigue, oliguria or anuria, cold and clammy skin, decreased skin turgor, irritability, lethargy, confusion, and stupor or coma. Excessive thirst, tachycardia, nausea, vomiting, and abdominal cramps may also occur. Severe hyponatremia may cause cyanosis and vasomotor collapse, with a thready pulse.

Hypoparathyroidism

Worsening tetany causes generalized seizures. Chronic hypoparathyroidism produces neuromuscular irritability and hyperactive DTRs.

Hypoxic encephalopathy

Besides generalized seizures, this disorder may produce myoclonic jerks and coma. Later, if the patient has recovered, dementia, visual agnosia, choreoathetosis, and ataxia may occur.

Multiple sclerosis

This disorder rarely produces generalized seizures. Characteristic findings include vision deficits, paresthesia, constipation, muscle weakness, paralysis, spasticity, hyperreflexia, intention tremor, ataxic gait, dysphagia, dysarthria, impotence, and emotional lability. Urinary frequency, urgency, and incontinence may also occur.

Neurofibromatosis

Multiple brain lesions from this disorder cause focal and generalized seizures. Inspection reveals café-au-lait spots, multiple skin tumors, scoliosis, and kyphoscoliosis. Related findings include dizziness, ataxia, monocular blindness, and nystagmus.

Porphyria (intermittent acute)

Generalized seizures are a late sign of this disorder, indicating severe CNS involvement. Acute porphyria also causes severe abdominal pain, tachycardia, psychotic behavior, muscle weakness, and sensory loss in the trunk.

Sarcoidosis

Lesions may affect the brain, causing generalized and focal seizures. Associated findings include a nonproductive cough with dyspnea, substernal pain, malaise, fatigue, arthralgia, myalgia, weight loss, tachypnea, dysphagia, skin lesions, and impaired vision.

Stroke

Seizures (focal more often than generalized) may occur within 6 months of an ischemic stroke. Associated signs and symptoms vary with the location and extent of brain damage. They include decreased LOC, contralateral hemiplegia, dysarthria, dysphagia, ataxia, unilateral sensory loss, apraxia, agnosia, and aphasia. The patient may also develop visual deficits, memory loss, poor judgment, personality changes, emotional lability, urine retention or urinary incontinence, constipation, headache, and vomiting.

Other causes

Arsenic poisoning

Besides generalized seizures, arsenic poisoning may cause a garlicky breath odor, increased salivation, and generalized pruritus. GI effects include diarrhea, nausea, vomiting, and severe abdominal pain. Related effects include diffuse hyperpigmentation; sharply defined edema of the eyelids, face, and ankles; paresthesia of the extremities; alopecia; irritated mucous membranes; weakness; muscle aches; and peripheral neuropathy.

Barbiturate withdrawal

In chronically intoxicated patients, barbiturate withdrawal may produce generalized seizures 2 to 4 days after the last dose. Status epilepticus is possible.

Diagnostic tests

Contrast agents used in radiologic tests may cause generalized seizures.

Drugs

Toxic blood levels of some drugs, such as theophylline, lidocaine, meperidine, penicillins, and cimetidine, may cause generalized seizures. Phenothiazines, tricyclic antidepressants, amphetamines, isoniazid, and vincristine may cause seizures in patients with preexisting epilepsy.

Special considerations

Closely monitor the patient after the seizure for recurring seizure activity. Prepare him for a computed tomography scan or magnetic resonance imaging and EEG.

Pediatric pointers

Generalized seizures are common in children. In fact, between 75% and 90% of epileptic patients experience their first seizure before age 20. Many children between ages 3 months and 3 years experience generalized seizures associated with fever; some of these children later develop seizures without fever. Generalized seizures may also stem from inborn errors of metabolism, perinatal injury, brain infection, Reye’s syndrome, Sturge-Weber syndrome, arteriovenous malformation, lead poisoning, hypoglycemia, and idiopathic causes. The pertussis component of the DPT vaccine may cause seizures; although this is rare.

Patient counseling

Advise the patient’s family to observe and record his seizure activity to ensure proper treatment. Emphasize the importance of strict compliance with the drug regimen, and warn the patient about adverse reactions. Stress the importance of regular follow-up appointments for blood studies.

Pictures

Book Source Details

• Book Title: Professional Guide to Signs & Symptoms (Fifth Edition)
• Author(s): Springhouse
• Year of Publication: 2006
• Copyright Details: Professional Guide to Signs & Symptoms (Fifth Edition), Copyright © 2006 Lippincott Williams & Wilkins.

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More About This Book: Title: Professional Guide to Signs & Symptoms (Fifth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2006 ISBN: 1-58255-510-9

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