Seizures

September 26, 2011

Epileptic seizures are episodic and sudden attacks that impair some aspect of a person’s function. These attacks consist of an alteration of one or more spheres of the brain functions such as sensory perception, motor activity, autonomic control, and level of consciousness. Epileptic seizures are caused by abnormal electrical discharges occurring in the brain. There are a variety of different manifestations of seizures. Although there are specific names given to characterize these various seizures, such as generalized tonic-clonic seizures, complex partial seizures, absence seizures, the manifestation of seizures between individuals can be quite varied, even of seizures in the same category. Within the same individual, however, the seizures are very consistent. Indeed this stereotypic nature of epileptic seizures is one characteristic sought out by physicians to help differentiate epileptic seizures from other paroxysmal events that are not caused by epileptic discharges in the brain.

SEIZURE TYPES

There are some commonly used terms that have been given to various types of seizures. These terms are derived from the International League Against Epilepsy’s (ILAE) classification of epileptic seizures. While this is an imperfect classification system and the particulars are clinically insignificant, the terms are widely used and its usage has become generalized. Therefore, we will briefly review some of the more common seizure types in this classification system. Generalized tonic-clonic seizures, previously known as “grand mal seizures,” are seizures in which there is a sudden and complete loss of consciousness by the individual, quickly followed by a tensing up of the entire body shortly followed by rhythmic jerking of the extremities. These seizures typically last less than 2 min in duration. These seizures are often associated with a loud groan in the beginning of the seizure called the “epileptic cry” as well as other associated symptoms such as tongue biting and urinary incontinence.

Complex partial seizures are seizures in which there is a loss of awareness that is associated with a blank stare. In contrast to generalized tonic-clonic seizures, the involuntary motor activities during these seizures are less dramatic and often very subtle. These movements may include minor mouth chewing movements, and picking movements of the hands, which are termed “automatisms.” During the seizure, the patient is typically unable to respond to questions or interact with persons or their environment usually for a period of 1-2 min. Following these seizures, there is usually a period of confusion that can last seconds to 1-2 hr.

Absence seizures, previously called “petit mal seizures,” on the other hand are similar to complex partial seizures in which again there is a loss of awareness with a stare but usually there is a paucity of any other movements expect perhaps some minor eye fluttering. Absence seizures are usually shorter in duration than complex partial seizures and usually are not associated with a period of confusion following the seizure. There are a number of other types of seizures that also occur but are less widely recognized by the general population. (Please refer to the Suggested Reading material at the end of this entry for more information about other seizure types.)

SEIZURE PRECAUTIONS

The most important thing to do if you witness a person having a seizure is to try to minimize the circumstances in which physical injury could result from the seizure. These precautions include clearing the area around the person and rolling the person onto their side if they have fallen, which allows any saliva or vom-itus to escape their mouth easily without falling back into their lungs. Do not put your fingers or other objects in a seizing person’s mouth as this can result in accidental laceration or amputation of your fingers and damage to the person’s dentition or oral cavity. Once the person has stopped seizing, they may often be confused and even agitated. It is useful not to provide too much stimulation to the person in this setting as they may become combative in some circumstances. If a seizure has lasted for longer than 2 min and it does not appear that the person is coming out of the seizure, then it should be considered a medical emergency and a call to 911 should be made. Otherwise, following a typical seizure, the patient’s physician may be contacted for further management.

General precautions that the seizure patient can follow include surrendering driving privileges, avoiding tub baths (as seizures even in small pools of water can result in drowning), avoiding sharp moving objects, avoiding hot surfaces, avoid being at heights, swimming only in groups and with individuals who are aware of

the patient’s medical history of seizures and can rescue the patient from the water if they have a seizure while swimming. General health precautions that apply not only to seizure patients but to all people include wearing seat belts as a passenger in a car and using helmets while bicycling or skating.

PSEUDOSEIZURE AND OTHER PAROXYSMAL EVENTS

There are many paroxysmal events that individuals can exhibit that may be confused as seizures. During these events, a person has what appears to be a seizure but there is no associated electrical abnormality originating from the brain. These types of events may occur in the setting of other disorders such as migraine headaches, strokes, cardiac disorders, fainting, or pseu-doseizures. Pseudoseizures are episodes that may masquerade as seizures but result from a psychiatric disturbance such as a conversion disorder, mood disorder, somatization disorder, or malingering. In these cases, treatment with drugs made to control true seizures (anticonvulsants) is not helpful.

EPILEPSY

Epilepsy is a common disorder affecting approximately 1% of the U.S. population. The diagnosis of epilepsy simply means that the person has a tendency for recurrent seizures. The possibility of having one seizure in a person’s lifetime is not unusual. Indeed up to 10% of the U.S. population will have a seizure in their lifetime; however, only 10% of those persons who have had their first seizure will go on to have another seizure. This distinction is important when a physician is considering when to start a medication. In fact, many physicians may not start a seizure medication after a single seizure. The indication to start treating seizures is usually reserved for a person who has had his or her second seizure or history of several seizures in the past. This places them at a higher risk for future seizures. Epilepsy occurs in both women and men in equal percentages. There are some particular issues that affect women who have epilepsy that are unique. These include issues relating to pregnancy, breast-feeding, fertility, birth control, hormonal influences, anticonvulsant effect on female health, and propensity to pass on the disease to their offspring. These are some of the issues that will be discussed in the remainder of this section.

EPILEPSY AND PREGNANCY

There are many unwarranted social stigmas that have been attached to epilepsy. One of the most disturbing is the fallacy that women with epilepsy cannot bear healthy children. Nothing could be further from the truth. Indeed, the vast majority of women with epilepsy who take anticonvulsants bear completely normal children who grow up to be healthy and lead fulfilling lives. Another misconception is the notion that all anticonvul-sants should be stopped during pregnancy. The discontinuation of anticonvulsants during pregnancy could lead to increased number of seizures and potential injury to the fetus, which could result in birth defects or miscarriage. Women with epilepsy taking anticonvulsant medications are considered to have high-risk pregnancies but it does not mean that pregnancy itself or anticonvulsants are contraindicated. The high-risk status is to underscore the necessity and importance of frequent, regular doctor visits early in the pregnancy. Ideally each pregnancy should be planned and medical care coordinated with a team of medical specialists, including an obstetrician, a seizure specialist, and a primary care physician. This is to ensure that women with epilepsy’s anticonvulsant medications can be optimized and the appropriate prenatal vitamin regimen initiated.

In general, the goal for the medical treatment of epilepsy during pregnancy is to achieve optimal seizure control, defined as no seizures, with the fewest medications, preferably one anticonvulsant, at the lowest dose possible. During pregnancy, anticonvulsant levels are often closely monitored because anticonvulsant levels of both the older anticonvulsants such as phenytoin, car-bamazepine, or valproic acid and some of the newer anticonvulsants such as lamotrigine can fall during pregnancy. Among all the established anticonvulsant medications, valproic acid carries the highest risk of fetal malformation, almost a 1-2% risk of neural tube defects. In spite of this, however, valproic acid is considered the drug of choice for particular types of epilepsy, such as Juvenile Myoclonic Epilepsy. Some physicians may suggest that this medication be continued if the highest degree of seizure control for these individuals was seen with valproic acid rather than other medications. In general it appears that the new-generation anticonvulsant

medications carry a lower rate of fetal malformation than the older anticonvulsant medications although the data are still incomplete. The preliminary data from lamotrig-ine appear to carry no more increased risk than the general population.

Most anticonvulsant medications are minimally secreted in breast milk and should not affect the infant. Therefore, breast-feeding is not generally contraindicated (advised against).

HORMONAL INFLUENCES IN EPILEPSY

Catamenial epilepsy is the cyclic increase in seizure frequency near the time of the menstrual cycle. This pattern was first documented over 100 years ago and is ascribed to normal fluctuation of the female hormones, estrogen and progesterone, during the menstrual cycle. In general, estrogens decrease seizure threshold by inhibiting a neurotransmitter substance in the brain called 7-aminobutyric acid (GABA) and potentiating glutamate, which results in increased excitability. On the other hand, progesterone (a hormone) appears to have the opposite effect. The by-products of progesterone appear to increase GABA’s function, which in turn results in increased inhibition and thereby decreasing the propensity for seizures. This “protection” that progesterone may provide is the basis for its use in some people with catamenial epilepsy.

For women with ovulatory cycles, estrogen rises midcycle with ovulation and again during the luteal phase. Progesterone is low throughout the first half of the menstrual cycle, peaks during the luteal phase then rapidly declines, which trigger the menses. Therefore, women may notice increased seizures midcycle during ovulation due to high estrogen levels and perimenstrually due to dropping progesterone levels.

For women with anovulatory cycles, progesterone remains low during the luteal phase so these women may have an irregular pattern of increased seizures throughout the second half of the menstrual cycle due to the unopposed high levels of estrogen.

Furthermore, women taking the antiseizure medication phenytoin may have fluctuations in their medication levels around the time of menstruation (perimenstrual fluctuations) since both phenytoin and the hormone estrogen are metabolized by the same enzyme in the liver (hepatic cytochrome P-450 enzyme system). Increased liver clearance of the anticonvulsant plus the high estrogen levels may precipitate increased seizure activity.

ANOVULATION AND INFERTILITY

Whereas 10% of menstrual cycles are anovulatory (without ovulation) in normal women, up to 35% are anovulatory in women with complex partial seizures. In other studies of women with both complex partial seizures and generalized tonic-clonic seizures, some of the women had endocrine dysfunction consistent with primary ovarian failure (gonadal insufficiency), ovarian failure secondary to other medical causes (hypogo-nadotropic hypogonadism), or disorders of the ovaries (polycystic ovarian syndrome). While most of these endocrine disorders appear to be a product of seizure-induced hormonal changes, anticonvulsants can also affect hormonal function. For example, valproate has been associated with polycystic ovaries and abnormalities in hormone levels (hyperandrogenism).

Fertility rates for women with epilepsy are reduced by 15% in comparison to the general population. Women whose first seizure was before the age of 10 years are more likely to never have children. The reasons for these observations are not entirely clear but are certainly mul-tifactorial. Major depression may be more common in epileptics and tends to be associated with infertility. One study reported that 33% of women with epilepsy in an outpatient clinic had sexual dysfunction including dys-pareunia, vaginismus, and arousal insufficiency.

HORMONAL CONTRACEPTIVES

Despite estrogens being thought of as proconvul-sant, hormonal contraceptives have not been reported to increase seizure frequency. However, there is a higher rate of hormonal contraceptive failure in women taking hepatic enzyme-inducing anticonvulsant drugs. Women taking such medication, which includes barbiturates, phenytoin, and carbamazapine, need oral contraceptives with higher levels of the hormone estradiol (at least 50 f g of estradiol rather than the typical 20-35 fig). Contraception failure has also been reported with fixed subdermal levonorgestrel implants (Norplant) due to the increased hepatic metabolism of the medication. Medroxyprogesterone acetate (Depo-Provera) may be a better long-acting option but the injections should be given every 10 weeks, instead of every 12 weeks.

See Also: Breast-feeding, Headache, Migraine, Mood disorders, Oral contraception, Pregnancy

Suggested Reading

  • Liporace, J., & D’Abreau, A. (2003). Epilepsy and women’s health: Family planning, bone health, menopause, and menstrual-related seizures. Mayo Clinic Proceedings, 78, 497-506.
  • Luders, H., & Lesser, R. P. (1987). Clinical medicine and the nervous system: Epilepsy, electroclinical syndromes. London: Springer-Verlag.
  • Morrel, M. J. (1997). Sexuality in epilepsy. In J. Engle & T. A. Pedley (Eds.), Epilepsy (pp. 2021-2026). Philadelphia: Lippincott-Raven.
  • Rush, A., & Plum, F. (1998). Neurologic health and disorders. In L. A. Wallis et al. (Eds.), Textbook of women’s health (pp. 573-575). Philadelphia: Lippincott-Raven.
  • Woolley, C. S., & Schwartzkroin, P. A. (1998). Hormonal effects on the brain. Epilepsia, 39(Suppl. 8), S2-S8.
  • Wyllie, E. (1993). The treatment of epilepsy: Principles and practice. Philadelphia: Lea & Febiger.
  • Yerby, M. S. (2000). Quality of life, epilepsy advances, and the evolving role of anticonvulsants in women with epilepsy. Neurology, 55(Suppl. 1), S21-S31.

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