Seizures (Convulsions, Epilepsy)

– Paroxysmal episodes of sudden, involuntary muscle contractions and alterations in consciousness, behavior, sensation, and autonomic functioning. The episodes may be partial (simple, complex) or generalized (absence,myoclonic, tonic, clonic, tonic-clonic) and are labeled epilepsy if they are recurrent.

Causes and Incidence

The etiology of seizures may be idiopathic or symptomatic. Identified causes include pathologic processes in the brain (e.g., vascular anomalies or lesions, space-occupying lesions, trauma, acute cerebral edema, infection, degeneration, and neuronal injury); endogenous or exogenous toxic substances (e.g., uremia, lead ingestion, alcohol intoxication, or phenothiazides); metabolic disturbances; febrile states; developmental abnormalities; or birth defects. Seizures affect about 2% of the U.S. population, and 25% of those have chronically recurring seizures (epilepsy).

Disease Process

Seizures result from a generalized disturbance in cerebral function. An internal or external stimulus causes abnormal hypersynchronous discharges in a focal area in the cerebrum that spread throughout the cerebrum. During the seizure, neuropeptides and neurotransmitters are released and blood flow is increased. Extracellular concentrations of potassium are increased, and concentrations of calcium are decreased. Changes occur in pH and utilization of glucose increases. It is hypothesized that the seizure ceases when the neuronal cell membrane hyperpolarizes and causes the neuronal cells to cease firing, suppressing the surface potentials of the cerebrum. Partial seizures begin locally with a specific aberration of sensory, motor, or psychic origin, reflecting the cerebellar origin of the seizure. A complex partial seizure progresses to impairment of consciousness. A generalized seizure affects both consciousness and motor function from the onset. Absence seizures last 10 to 30 seconds and involve twitching and loss of contact. Myo-clonic seizures involve intermittent contraction of muscles without loss of consciousness. Tonic seizures are marked by prolonged involuntary muscle contraction with a 30- to 60-second loss of consciousness. Clonic seizures involve intermittent muscle contractions and loss of consciousness for several minutes. Tonic-clonic seizures involve loss of consciousness with sustained muscle contractions, followed by intermittent muscle contractions and then a limp body state.

Symptoms

Simple partial
Motor: recurrent involuntary muscle contractions of one body part (e.g., face, finger, hand, or arm) that may spread to other, same-side body parts Sensory: auditory or visual hallucinations, paresthesias, vertigo Psychic: sensation of deja vu, complex hallucinations or illusions, unwarranted anger or fear, pupillary dilation, sweating

Complex partial
Onset: may have aura before onset Motor: automatisms (patting body parts, smacking lips, aimless walking, picking at clothes), unintelligible muttering, staggering gait Sensory: 1 to 2 minutes of loss of contact with surroundings, hallucinations

Generalized
Absence: transient loss of consciousness, flickering of eyelids or intermittent jerking of hands Myoclonic: rapid, jerky movements in extremities or over entire body, which may cause a fall Tonic: sudden abnormal dystonic posture, deviation of eyes and head to one side Clonic: symmetric jerking of extremities for several minutes with loss of consciousness Tonicclonic: aura of epigastric discomfort, outcry, loss of consciousness, cyanosis, fall; tonic then clonic contractions, then limpness, sleep, headache, muscle soreness, confusion, and lethargy; loss of bowel and bladder control

Potential Complications

Complications may occur as a result of the onset of seizure activity and can include injury from a fall or from jerking, as well as airway occlusion and aspiration. A condition known as status epilepticus, in which motor sensory or psychic seizures follow one another with no intervening periods of consciousness, is a medical emergency. Failure to get immediate treatment can lead to hypoxia, hyperthermia, hypoglycemia, acidosis, and death.

Diagnostic Tests

The presence of seizures is diagnosed by clinical history and examination. The diagnostic priority is to distinguish idiopathic seizure activity from symptomatic activity.

Computed tomography/ magnetic resonance imaging/positron emission tomography
Structural changes

Skull x-ray
Evidence of fractures; shift in calcified pineal gland; bony erosion; separated sutures

Cerebral angiography
Vascular abnormalities; subdural hematoma

Echoencephalography
Midline shifts in brain structures

Urine
To detect medication toxicity

Serum
Hypoglycemia; electrolyte imbalance; increased blood urea nitrogen; increased blood alcohol levels

Electroencephalography
Tonicclonic: high, fast voltage spiked in all leads Absence: 3/s, rounded, spiked wave complexes in all leads Complex partial: squaretopped, 4-6/s spike wave complexes over involved lobe Inherited pattern: 2.5 to 3/s spike and wave pattern; presence of delta waves indicates destroyed brain tissue

Treatments

Surgery
Resection of epileptic focus or stereotactic lesions in the brain.

Drugs
Anticonvulsants to prevent or control seizure activity.

General
During seizure: safety precautions to prevent injury (i.e., loosen restrictive clothing, roll on side to prevent aspiration, place a small pillow under the head, ease from a standing or sitting position to the floor) Do not place a finger or other object into the person’s mouth to protect or straighten the tongue–it is unnecessary and dangerous; do not try to hold the person still because you may injure the individual or yourself Maintain a patent airway; note frequency, type, time, involved body parts, and length of seizure; monitor vital signs and neurologic status; reorient individual as seizure ceases Other: eliminate causative or precipitating factors; encourage normal lifestyle, moderate exercise, and participation in sports with proper safeguards; a driver’s license is permitted in most states if the person is seizure free for 1 year; alcohol is contraindicated; medical and laboratory monitoring of anticonvulsant blood levels and possible side effects; information about the importance of taking medications as directed and not deleting doses; individual and family support to adapt to seizure disorder; wearing a Medic-Alert tag.