Background: anticonvulsants

Background:

Epidemiology | Etiology | Seizures | Seizure types | Treatment

hairless human head with areas marked up in black

You are working on a ten-year old boy in the dental office. During the procedure the child makes a high-pitched sound, then begins to convulse. The seizure goes on for about two minutes, although it seems longer because of your concern.

Seizures are ranked the fifth most likely medical emergency faced in the dental office. Are you prepared to deal with a patient having a seizure? Do you know the types of questions to ask if a patient indicates they have a history of seizures? Are you aware of the oral side effects of some anticonvulsant drugs?

This unit on anticonvulsant drugs will answer these questions and prepare you to provide the highest level of dental care to the patient with a seizure disorder.

Pharmacology for Dental Hygiene Practice,
ch. 20, pp. 266-276

Epidemiology

Anticonvulsant drugs are used primarily to treat seizure disorders known as epilepsy.

Nearly 1.4 million Americans have epilepsy (1996)
The majority of these Americans are under age 45 (1996)
More people in the South have epilepsy than in any other region (1996)

Source: Vital and Health Statistics Series 10, No. 200
For more information on Epilepsy Statistics visit the
Epilpesy Foundation. (This link opens up in a new browser window. To return to this lesson, just close the other window.)

Etiology & pathogenesis

The etiologies of epilepsy are classified into two broad categories:

Symptomatic (an identifiable cause)
Idiopathic (no obvious cause can be found)

Symptomatic etiologies	Idiopathic characteristics
Congenital abnormalities & perinatal injuries	Generally starts between the ages of 2-14 with no identifiable cause or other neurologic abnormality.
Metabolic disorders	.
Head trauma is... an important cause of seizures in general the most common cause of seizures in young adults.	.
Neoplasms tend to affect patients in middle and later life.	.
Infectious diseases, including ... bacterial meningitis herpetic encephalitis & others	.
Degenerative diseases (e.g. Alzheimer's disease): are causes of seizures in older adult	.

Seizures

A seizure is a sudden, uncontrolled disturbance of the central nervous system that is characterized by varying symptoms. In some patients, seizures are sometimes evoked by a specific stimulus.

Symptoms of seizure

Possible stimuli

impaired consciousness
abnormal motor function
sensory disturbances
autonomic dysfunction

flickering lights
monotonous sounds
music
a loud noise

Note: Patients often know what type of stimuli can bring on a seizure. Many patients report a feeling or “aura” that precedes a seizure.

Types of seizure

We’ll look at four different seizure types:

Petit Mal
Grand Mal (Generalized Tonic Clonic)
Single Focal
Partial Complex

The table below contains descriptions of each seizure type:

These types	may be manifested by...
Petit Mal (occur most often during childhood)	minimal or no movements (usually, except for "eye blinking") an appearance like a blank stare brief sudden loss of awareness or conscious activity (may only last seconds) recurring many times throughout childhood decreased learning (child often thought to be daydreaming)
Grand Mal (Generalized Tonic-Clonic)	generalized, violent muscle contractions & rigidity patient emitting a sudden cry Breathing stopping temporarily, followed by sigh(s) loss of consciousness consciousness returning within a few minutes, followed by ... weakness stupor headache confusion incontinence of urine tongue or cheek biting
Single Focal	muscle contractions of a specific body part abnormal sensations (numbness, unusual taste & smell) nausea sweating skin flushing dilated pupils other focal (localized) symptoms
Partial Complex	automatism (automatic performance of complex behaviors, i.e. Walking in circles, smacking lips, sitting and standing) nausea sweating skin flushing dilated pupils loss of consciousness changes in personality or alertness (laughing, hallucinations) other focal (localized) symptoms

For more information on the seizure types and how to recognize the difference between them, consult Medline's Seizure Information (opens in new window).

Treatment

sketch of human head with pill placed strategically as on a game board The medical management of epilepsy is based on drug therapy. Anticonvulsant drugs are central nervous system depressants. These agents work by preventing the spread of abnormal electric discharges in the brain, although the exact mechanism of action is unknown.

Anticonvulsant drugs are used singly or in combinations depending on the type and degree of seizure activity. Generally, these drugs are taken for life to control seizures, so the toxicity and side effects may be chronic and/or cumulative!

The most commonly used as a first line of treatment is phenytoin (Dilantin).

Other anticonvulsants commonlty used are...

carbamazepine
phenobarbital
valproic acid