The effect of menopause and perimenopause on the course of epilepsy

Fertility treatment for people with epilepsy

Fertility treatment, including assisted reproductive technology (ART), is increasingly used. Sex hormones influence seizure control as well as interacting with antiseizure medications, and so the hormonal manipulation involved in fertility treatments has direct implications for people with epilepsy. Here, we summarise the various fertility treatments and consider their important influences on epilepsy care. While early observations raised concerns about seizure exacerbation associated with ART, there are limited data to guide best practice in people with epilepsy, and further research is needed.

Sex steroid hormones and epilepsy: Effects of hormonal replacement therapy on seizure frequency of postmenopausal women with epilepsy-A systematic review

BACKGROUND AND PURPOSE

Hormonal replacement therapy (HRT) is used for symptomatic treatment of menopause. Some evidence suggests a proconvulsant effect of estrogen and an anticonvulsant role of progesterone. Thus, the use of exogenous sex steroid hormones might influence the course of epilepsy in peri- and postmenopausal women with epilepsy (WWE). We conducted a systematic review on the impact of HRT on the frequency of seizures of WWE.

METHODS

PubMed and Scopus were searched for articles published from inception until August 2022. Abstracts from the past 5 years from the European Academy of Neurology and European Epilepsy Congresses were also reviewed. Article reference lists were screened, and relevant articles were retrieved for consultation. Interventional and observational studies on WWE and animal models of estrogen deficiency were included. Critical appraisal was performed using the revised Cochrane risk-of-bias tool for randomized trials and ROBINS-E tool.

RESULTS

Of 497 articles screened, 13 studies were included, including three human studies. One cross-sectional study showed a decrease in seizure frequency in WWE using combined HRT, a case-control study showed an increase in comparison with controls, and a randomized clinical trial found a dose-dependent increase in seizure frequency in women with focal epilepsy taking combined HRT. Ten studies addressing the impact of HRT in rat models were also included, which showed conflicting results.

CONCLUSIONS

There is scarce evidence of the impact of HRT in WWE. Further studies should evaluate the harmful potential, and prospective registries are needed for monitoring this population.

Gender Issues in Epileptic Patients

Treatment approaches for epilepsy for both women and men are similar, however, there are special aspects that must be considered when caring for women with epilepsy. This includes how hormonal fluctuations may affect seizure frequency, contraception, and potential drug-drug interactions, and pregnancy planning to minimize and potentially mitigate any adverse neurodevelopmental outcomes and major congenital malformations. Adequate counseling for women across the lifespan can help prepare women for the future and optimize outcomes.

Sex and gender differences in epilepsy

Sex and gender differences in epilepsy are important influencing factors in epilepsy care. In epilepsy, the hormonal differences between the sexes are important as they impact specific treatment considerations for patients at various life stages particularly during early adulthood with establishment of the menstrual cycle, pregnancy, perimenopause and menopause. Choice of antiseizure medication may have direct consequences on hormonal cycles, hormonal contraception, pregnancy and fetal risk of major congenital malformation. Conversely hormones whether intrinsic or extrinsically administered may have direct impact on antiseizure medications and seizure control. This chapter explores these important influences on the management of persons with epilepsy.

GABA System Modifications During Periods of Hormonal Flux Across the Female Lifespan

The female lifespan is marked by periods of dramatic hormonal fluctuation. Changes in the ovarian hormones estradiol and progesterone, in addition to the progesterone metabolite allopregnanolone, are among the most significant and have been shown to have widespread effects on the brain. This review summarizes current understanding of alterations that occur within the GABA system during the major hormonal transition periods of puberty, the ovarian cycle, pregnancy and the postpartum period, as well as reproductive aging. The functional impacts of altered inhibitory activity during these times are also discussed. Lastly, avenues for future research are identified, which, if pursued, can broaden understanding of the GABA system in the female brain and potentially lead to better treatments for women experiencing changes in brain function at each of these hormonal transition periods.

Women's Issues in Epilepsy

PURPOSE OF REVIEW

Issues pertaining to women with epilepsy have advanced with a better understanding of multidirectional influences among hormones, seizures, and antiseizure medications, as well as pregnancy-related concerns around fertility, seizure destabilization, and antiseizure medication-associated teratogenicity. This article highlights important developments in this field and reviews best practices in the management of women with epilepsy.

RECENT FINDINGS

Important external hormonal influences may impact women with epilepsy particularly in the context of gender-affirming medications, hormonal replacement therapy, and fertility therapies. Fertility for women with epilepsy is influenced by multiple variables; however, in the absence of preexisting fertility issues, epilepsy per se is not associated with significantly impaired fertility. Once women with epilepsy are pregnant, the majority have a stable course. Antiseizure medication use in pregnancy is associated with major congenital malformations 2 to 5 times that of the general population and is highest with high-dose (≥1500 mg or greater total daily) valproate. Carefully considered changes in drug choice and dose may mitigate these risks. Therapeutic drug monitoring plays an important role in pregnancy care, and under expert supervision, women with epilepsy in pregnancy have similar seizure risks as women with epilepsy who are not pregnant. As women with epilepsy age, bone health and menopause may further be impacted by seizures and antiseizure medications.

SUMMARY

The care of women with epilepsy is a multifaceted discipline that recognizes the life-long impact of sex and gender influences on epilepsy care.

Effects of the Menstrual Cycle on Neurological Disorders

PURPOSE OF REVIEW

The menstrual cycle involves recurrent fluctuations in hormone levels and temperature via neuroendocrine feedback loops. This paper reviews the impact of the menstrual cycle on several common neurological conditions, including migraine, seizures, multiple sclerosis, stroke, and Parkinson's disease.

RECENT FINDINGS

The ovarian steroid hormones, estrogen and progesterone, have protean effects on central nervous system functioning that can impact the likelihood, severity, and presentation of many neurological diseases. Hormonal therapies have been explored as a potential treatment for many neurological diseases with varying degrees of evidence and success. Neurological conditions also impact women's reproductive health, and the cessation of ovarian function with menopause may also alter the course of neurological diseases. Medication selection must consider hormonal effects on metabolism and the potential for adverse drug reactions related to menstruation, fertility, and pregnancy outcomes. Novel medications with selective affinity for hormonal receptors are desirable. Neurologists and gynecologists must collaborate to provide optimal care for women with neurological disorders.

Progesterone modulates neuronal excitability bidirectionally

Progesterone acts on neurons directly by activating its receptor and through metabolic conversion to neurosteroids. There is emerging evidence that progesterone exerts excitatory effects by activating its cognate receptors (progesterone receptors, PRs) through enhanced expression of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs). Progesterone metabolite 5α,3α-tetrahydro-progesterone (allopregnanolone, THP) mediates its anxiolytic and sedative actions through the potentiation of synaptic and extrasynaptic γ-aminobutyric acid type-A receptors (GABAARs). Here, we review progesterone's neuromodulatory actions exerted through PRs and THP and their opposing role in regulating seizures, catamenial epilepsy, and seizure exacerbation associated with progesterone withdrawal.

The interactions between reproductive hormones and epilepsy

There are complex interactions between hormones, epilepsy, and antiepileptic drugs (AEDs). While there is ample evidence that hormones influence epilepsy, it is also apparent that epileptic activity influences hormones in both women and men. In addition, AEDs may disturb endocrine function. The clinical importance of these interactions is primarily related to the effects on reproductive hormones, which is the focus of this article. Reproductive endocrine dysfunction is common among women and men with epilepsy. Menstrual disorders, polycystic ovaries, and infertility have been described among women with epilepsy, while reduced potency and sperm abnormalities have been found in men. Sexual problems and endocrine changes have been frequently described in both sexes. Epilepsy and AEDs can target a number of substrates to impact hormone levels. These include the limbic system, hypothalamus, pituitary, peripheral endocrine glands, liver, and adipose tissue. AEDs may also alter the synthesis of steroids and binding proteins, as well as hormone metabolism, and produce direct gonadal effects.

Treatment of Women With Epilepsy

PURPOSE OF REVIEW

This article provides the latest information to guide practitioners in counseling and treating women with epilepsy.

RECENT FINDINGS

There is an increasing body of literature on the multidirectional effects of sex hormones on seizure frequency and severity and of seizures altering areas of the brain involved in neuroendocrine function. Ongoing pregnancy outcome data from pregnancy registries and meta-analysis of observational studies have provided key information on the safety of using antiseizure medications during pregnancy and the risk to the fetus.

SUMMARY

In treating and counseling women with epilepsy from puberty to menopause, it is important to understand the complex interactions of sex hormones, seizures, and antiseizure medications on reproductive health and pregnancy outcomes.

Oestrogen receptor ERα and ERβ agonists ameliorate oxidative brain injury and improve memory dysfunction in rats with an epileptic seizure

NEW FINDINGS

What is the central question of this study? Could different hormonally active substances, including oestrogen receptor (ER) agonists, protect against oxidative brain damage and memory impairment induced by a single epileptic seizure in rats? If so, which signalling mechanisms are involved in their anti-inflammatory effects? What is the main finding and its importance? Chronic administration of oestrogen, progesterone, ER modulators/agonists or blockade of testosterone exhibited anti-inflammatory and antioxidant actions on single seizure-induced neuronal injury, while ER agonists additionally improved memory function and up-regulated CREB signalling and hippocampal GABA(A)α1 receptor density, suggesting that ERα or ERβ receptor activation may be beneficial in protecting against seizure-related oxidative brain injury and cognitive dysfunction.

ABSTRACT

The susceptibility to epileptic seizures is dependent on sex as well as fluctuations in oestrogen levels, while exogenous oestrogen was shown to have no effect or to facilitate or to inhibit seizure activity. Oestrogen receptors (ERs) mediate antioxidant and anti-inflammatory actions in several inflammatory models, but the involvement of ERs in seizure-induced neuronal injury has not been evaluated previously. In order to assess the effects of resveratrol, progesterone, oestradiol (E2), an anti-testosterone (cyproterone acetate; CPA), a selective ER modulator (tamoxifen; TMX) and ERα/ERβ agonists (propyl pyrazole triol (PPT), diarylpropionitrile (DPN)) on oxidative brain damage and memory impairment due to epileptic seizure, male Wistar rats (n = 120) received one of the treatment choices either in drinking water or intraperitoneally for 31 days, and epileptic seizure was induced on the 28th day by injection of a single-dose of pentylenetetrazole (45 mg kg^-1 ). The results demonstrate that chronic pretreatment with resveratrol, progesterone, E2, CPA or TMX suppressed most of the inflammatory parameters indicative of oxidative neuronal injury, while treatment with the ER agonists DPN or PPT were found to be even more effective in limiting the oxidative damage. Treatment with DPN resulted in the up-regulation of cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) expression, while PPT up-regulated expression of CREB without affecting BDNF levels. Moreover, both ER agonists provided protection against seizure-induced memory loss with a concomitant increase in hippocampal GABA(A)α1-positive cells. In conclusion, ER agonists, and more specifically ERβ agonist, appear to provide maximum protection against seizure-induced oxidative brain injury and associated memory dysfunction by up-regulating the expression of CREB, BDNF and GABA(A)α1 receptors.

Dealing with the storm: An overview of seizure precipitants and spontaneous seizure worsening in drug-resistant epilepsy

In drug-resistant epilepsy, periods of seizure stability may alternate with abrupt worsening, with frequent seizures limiting the individual's independence and physical, social, and psychological well-being. Here, we review the literature focusing on different clinical scenarios related to seizure aggravation in people with drug-resistant epilepsy. The role of antiseizure medication (ASM) changes is examined, especially focusing on paradoxical seizure aggravation after increased treatment. The external provocative factors that unbalance the brittle equilibrium of seizure control are reviewed, distinguishing between unspecific triggering factors, specific precipitants, and 'reflex' mechanisms. The chance of intervening surgical or medical conditions, including somatic comorbidities and epilepsy surgery failure, causing increased seizures is discussed. Spontaneous exacerbation is also explored, emphasizing recent findings on subject-specific circadian and ultradian rhythms. Awareness of external precipitants and understanding the subject-specific spontaneous epilepsy course may allow individuals to modify their lifestyles. It also allows clinicians to counsel appropriately and to institute suitable medical treatment to avoid sudden loss of seizure control.

Neuropathological complications associated with hypertensive disorders of pregnancy

Objective: Hypertensive disorders in pregnancy particularly severe preeclampsia and eclampsia result in significant maternal and neonatal morbidity and mortality. Many of these misfunctions can aggravate some of the neuropathological complications of hypertensive disorders during pregnancy. Method: In this review article, we described some of the neuropathological complications associated with hypertensive disorders of pregnancy. Results and conclusion: It is explained how the possible mechanism of neuropathological events triggers some of the complications associated with hypertensive disorders of pregnancy. Conclusion: A strong plea is made for the early detection of high blood pressure, its immediate control with rapid acting anti-hypertensive agents if necessary and timeous delivery of fetus as the exact pathogenesis of preeclampsia remains unknown.

Estrogen-related seizure exacerbation following hormone therapy for assisted reproduction in women with epilepsy

PURPOSE

Exogenous estrogens might lead to seizure worsening in women with epilepsy (WWE) by lowering the seizure threshold and inducing glucuronidation in women taking lamotrigine. Assisted reproduction techniques are increasingly used and often require estrogenic and estrogen raising hormone therapy. We aimed at reporting their possible impact on seizures in WWE.

METHODS

We describe two cases of seizure exacerbation following hormone therapy for assisted reproduction in WWE.

RESULTS

Patient 1: 46 years old woman, with right temporal dysplasia. At 40 years she had monthly focal seizures, possibly progressing to bilateral tonic-clonic seizures, she took levetiracetam 3000/day and she underwent gonadotropin therapy for ovarian stimulation. Estrogen blood levels showed a sudden and significant rise, up to 1019 pg/ml and she had a concomitant cluster of three tonic-clonic seizures in 24 h. Patient 2: 41 years old woman with focal epilepsy of unknown etiology. At 38 years she was taking lamotrigine 450 mg/day and had been seizure free for three years. She took estradiol valerate 4 mg for 10 days for endometrial preparation for embryo transfer and had the only seizure over six years, with the exception of auras during advanced pregnancy, related to marked decrease of lamotrigine blood levels. During adjunctive concomitant therapy with clobazam, neither patient had seizures while on hormone therapy.

CONCLUSIONS

Our data suggest that hormone therapy for assisted reproduction could exacerbate seizures and should be carefully monitored in WWE, especially those taking drugs inactivated by glucuronidation. Adjunctive concomitant antiepileptic therapy should be considered.

Estrogen Protects Neurotransmission Transcriptome During Status Epilepticus

Women with epilepsy commonly have premature onset of menopause. The decrease in estrogen levels is associated with increased occurrence of neurodegenerative processes and cognitive decline. Previously, we found that estradiol (E2) replacement in ovariectomized (OVX) female rats significantly reduced the seizure-related damage in the sensitive hilar region of hippocampal dentate gyrus (DG). However, the complex mechanisms by which E2 empowers the genomic fabrics of neurotransmission to resist damaging effects of status epilepticus (SE) are still unclear. We determined the protective effects of the estradiol replacement against kainic acid-induced SE-associated transcriptomic alterations in the DG of OVX rats. Without E2 replacement, SE altered expression of 44% of the DG genes. SE affected all major functional pathways, including apoptosis (61%), Alzheimer's disease (47%), cell cycle (59%), long-term potentiation (62%), and depression (55%), as well as synaptic vesicle cycle (62%), glutamatergic (53%), GABAergic (49%), cholinergic (52%), dopaminergic (55%), and serotonergic (49%) neurotransmission. However, in rats with E2 replacement the percentage of significantly affected genes after SE was reduced to the average 11% (from 8% for apoptosis to 32% for GABAergic synapse). Interestingly, while SE down-regulated most of the synaptic receptor genes in oil-injected females it had little effect on these receptors after E2-replacement. Our novel Pathway Protection analysis indicated that the E2-replacement prevented SE-related damage from 50% for GABA to 75% for dopaminergic transmission. The 15% synergistic expression between genes involved in estrogen signaling (ESG) and neurotransmission explains why low E2 levels result in down-regulation of neurotransmission. Interestingly, in animals with E2-replacement, SE switched 131 synergistically expressed ESG-neurotransmission gene pairs into antagonistically expressed gene pairs. Thus, the ESG pathway acts like a buffer against SE-induced alteration of neurotransmission that may contribute to the E2-mediated maintenance of brain function after the SE injury in postmenopausal women. We also show that the long-term potentiation is lost in OVX rats following SE but not in those with E2 replacement. The electrophysiological findings in OVX female rats with SE are corroborated by the high percentage of long-term potentiation regulated genes (62%) in oil-injected while only 13% of genes were regulated following SE in E2-replaced rats.

High risk of developing subsequent epilepsy in patients with sleep-disordered breathing

Purpose

Sleep-disordered breathing (SDB) is often associated with other medical disorders. Whether SDB interacts with other factors for developing subsequent epilepsy remains unclear.

Methods

This population-based cohort study was conducted using the National Health Insurance Research Database of Taiwan. Patients aged >20 years and diagnosed with SDB between 2000 and 2010 comprised the SDB cohort (n = 138,507), and their data were compared with those of the comparison cohort (n = 138,507). The adjusted hazard ratio (aHR) for epilepsy was calculated using a multivariate Cox proportional hazards model.

Results

The SDB cohort had an increased risk of epilepsy (aHR = 1.50, 95% confidence interval [CI] = 1.36–1.66). The sex-stratified analysis revealed a significant adjusted hazard ratio (aHR) for epilepsy with a 1.51-fold higher risk for female patients, and also a significantly 1.49-fold higher risk for male patients in the SDB cohort. Although epilepsy incidence increased with age in both cohorts, different age groups in the SDB cohort all had a significantly higher risk of developing epilepsy than comparison cohort.

Conclusion

This population-based cohort study indicates that patients with SDB are at a high risk of developing subsequent epilepsy, in both sexes and all age groups.

Women with epilepsy: clinically relevant issues

Women with epilepsy (WWE) face specific challenges throughout their lifespan due to the effects of seizures and antiepileptic drugs on hormonal function, potentially affecting both sexual and reproductive health. This review article addresses the most common issues of practical relevance to clinicians treating WWE: epidemiology and clinical presentations (including catamenial epilepsy), contraception, reproductive and sexual dysfunction, pregnancy, lactation, menopause-related issues (including bone health), and mental health aspects. Awareness of these gender-specific issues and implementation/adaptation of effective interventions for WWE results in significantly improved health-related quality of life in this patient population.

Oestradiol Regulates Neuropeptide Y Release and Gene Coupling with the GABAergic and Glutamatergic Synapses in the Adult Female Rat Dentate Gyrus

Neuropeptide Y (NPY) is an endogenous modulator of neuronal activity affecting both GABAergic and glutamatergic transmission. Previously, we found that oestradiol modifies the number of NPY immunoreactive neurones in the hippocampal dentate gyrus. In the present study, we investigated which oestrogen receptor type is responsible for these changes in the number of NPY-positive neurones. Furthermore, we determined the effects of oestrogen receptor activation on NPY release. Finally, we examined the contribution of oestrogen toward the remodelling of the GABAergic and glutamatergic gene networks in terms of coupling with Npy gene expression in ovariectomised rats. We found that activation of either oestrogen receptor type (ERα or ERβ) increases the number of NPY-immunopositive neurones and enhances NPY release in the dentate gyrus. We also found that, compared to oestrogen-lacking ovariectomised rats, oestrogen replacement increases the probability of synergistic/antagonistic coupling between the Npy and GABAergic synapse genes, whereas the glutamatergic synapse genes are less likely to be coupled with Npy under similar conditions. The data together suggest that oestrogens play a critical role in the regulation of NPY system activity and are also involved in the coupling/uncoupling of the Npy gene with the GABAergic and glutamatergic synapses in the female rat dentate gyrus.

Comparison of precipitating factors for mania and partial seizures: Indicative of shared pathophysiology?

OBJECTIVES

Mania in bipolar disorder (BD) and partial (focal) seizures (PS) arising from the temporal lobes, have a number of similarities. Typically, a chronic course of the disorders is punctuated by acute illness episodes. Common features of episodes may include sensory, perceptual, cognitive and affective changes. Both respond to anticonvulsant treatment. Common mechanisms imputed include neurotransmitters and kindling processes. Further investigation may improve understanding of the occurrence of both mania and PS, casting light on the relevance of temporal lobe mediated processes and pathology. One avenue of investigation is to compare aetiological factors and determine the extent of overlap which may indicate shared brain localization or pathophysiology. Aetiology includes predisposing, precipitating or perpetuating factors. This paper examines the literature on precipitating factors of mania, first or subsequent episode, and of PS in diagnosed epilepsy, which is the second or subsequent seizure, to identify the extent and nature of their overlap.

METHOD

Narrative review based on a literature search of PubMed and Google Scholar.

RESULTS

Precipitating factors for both mania and PS were stress, sleep deprivation, antidepressant medication and, tentatively, emotion. For mania alone, goal-attainment events, spring and summer season, postpartum, and drugs include steroids and stimulants. For PS alone, winter season, menstruation and specific triggers in complex reflex epilepsies. Those not substantiated include lunar phase and menopause. A wide range of chemicals may provoke isolated seizures but by definition epilepsy requires at least two seizures.

CONCLUSIONS

The overlap of precipitating factors in mania and PS imply that common brain processes may contribute to both, consistent with findings from neuroscience research.

Age-dependent sex difference of the incidence and mortality of status epilepticus: a twelve year nationwide population-based cohort study in Taiwan

Status epilepticus (SE) is a serious neurologic emergency associated with a significant mortality. The objective of this study is to investigate its epidemiology in terms of age- and sex-specific incidences and mortality. By using the Taiwan National Health Insurance Research Database during 2000 to 2011, we identified hospitalized patients with a discharged diagnosis of SE and calculated the incidence and in-hospital mortality of SE with respect to age and sex. The overall incidence of SE was 4.61 per 100,000 person-years, which displayed a "J-shaped" distribution by age with a little higher under the age of 5 and highest over 60 years. The male-to-female rate ratio was 1.57 and it demonstrated a "mountain-shape" across ages with the peak at 45 to 49 years old. The in-hospital mortality was significantly lower in males (7.38%) than in females (11.12%) with an odds ratio of 0.64 (95% CI 0.56-0.72). Notably, the in-hospital mortality for females increased rapidly after the age of 40 to 45 years. The multivariate analysis found males had a significantly lower risk of mortality than females after, but not before, 45 years of age with an odds ratio of 0.56 (95% CI 0.49-0.65). Sex and age are crucial factors associated with the incidence and in-hospital mortality of SE. The females over 45 years of age have a higher risk of occurrence and mortality from SE. The underlying mechanism deserves further study.

Neurosteroids and their role in sex-specific epilepsies

Neurosteroids are involved in sex-specific epilepsies. Allopregnanolone and related endogenous neurosteroids in the brain control excessive neuronal excitability and seizure susceptibility. Neurosteroids activate GABA-A receptors, especially extrasynaptic αγδ-GABA-A receptor subtypes that mediate tonic inhibition and thus dampen network excitability. Our studies over the past decade have shown that neurosteroids are broad-spectrum anticonvulsants and confer seizure protection in various animal models. Neurosteroids also exert antiepileptogenic effects. There is emerging evidence on a critical role for neurosteroids in the pathophysiology of the sex-specific forms of epilepsies such as catamenial epilepsy, a menstrual cycle-related seizure disorder in women. Catamenial epilepsy is a neuroendocrine condition in which seizures are clustered around specific points in the menstrual cycle, most often around the perimenstrual or periovulatory period. Apart from ovarian hormones, fluctuations in neurosteroid levels could play a critical role in this gender-specific epilepsy. Neurosteroids also regulate the plasticity of synaptic and extrasynaptic GABA-A receptors in the hippocampus and other regions involved in epilepsy pathology. Based on these studies, we proposed a neurosteroid replacement therapy for catamenial epilepsy. Thus, neurosteroids are novel drug targets for pharmacotherapy of epilepsy.

Women and epilepsy: review and practical recommendations

Individuals with epilepsy experience a number of sex-specific problems. In women, pregnancy and delivery are obvious issues, fertility problems are more often encountered and they also seem to have a higher frequency of sexual problems. A large number of women with epilepsy experience seizure exacerbation in relation to the menstrual cycle and have higher frequencies of menstrual disturbances and polycystic ovaries. Cosmetic problems affecting skin, hair or weight may also be drug induced. The use of antiepileptic drugs may influence the effect of contraceptives leading to unplanned pregnancies and contraceptives may affect the serum levels of antiepileptic drugs. The care of pregnant women with epilepsy requires attention to a number of guidelines and close cooperation between neurologist and gynecologist is recommended. Although the majority of the women with epilepsy experience normal pregnancies and deliveries, their children have a higher risk of birth defects. At menopause, their seizure pattern may change and some antiepileptic drugs may increase the risk of osteoporosis. The optimal treatment of women with epilepsy should take into account these gender-specific issues in the different stages of life.

Are patterns of cortical hyperexcitability altered in catamenial epilepsy?

OBJECTIVE

We used transcranial magnetic stimulation to determine menstrual cycle-related changes in cortical excitability in women with and without catamenial epilepsy and investigated whether these changes differed between ovulatory and anovulatory cohorts.

METHODS

Healthy nonepilepsy women and women with generalized and focal epilepsy were investigated during ovulatory (n=11, 46, and 43, respectively) and anovulatory (n=9, 42, and 41) cycles. Patients were divided based on seizure pattern into catamenial (C1=perimenstrual, C2=periovulatory, C3=luteal seizure exacerbation), noncatamenial, and seizure free. Cortical excitability was assessed using motor threshold (MT) and paired pulse stimulation at short (2-15 milliseconds) and long (100-300 milliseconds) interstimulus intervals twice, at the (1) late follicular and (2) mid luteal phases of the menstrual cycle.

RESULTS

In controls, cortical excitability was greatest in the follicular study, where intracortical facilitation was increased (p<0.05). The opposite was seen in women with epilepsy, where intracortical facilitation was greatest and intracortical inhibition was least in the luteal studies (p<0.05). There were no differences between the ovulatory and anovulatory groups in any of the cohorts. No changes were observed in MT.

INTERPRETATION

Nonhormonal factors are involved in the cyclicity of cortical excitability across the menstrual cycle. Normal menstrual cycle variations in cortical excitability are altered in a similar pattern in ovulatory and anovulatory women with epilepsy regardless of seizure patterns. The underlying neural changes associated with epilepsy may alter responses to sex hormones. This may be an important underlying mechanism for catamenial seizure clustering.

Tamoxifen mimics the effects of endogenous ovarian hormones on repeated seizures induced by pentylenetetrazole in rats

In the present study, the effects of tamoxifen on pentylenetetrazole (PTZ)-induced repeated seizures and hippocampal neuronal damage in ovariectomized rats were investigated. Thirty seven virgin female Wistar rats were divided to: (1) control, (2) sham-PTZ, (3) sham-PTZ-tamoxifen (sham-PTZ-T), (4) Ovariectomized -PTZ (OVX-PTZ) and (5) OVX-PTZ-tamoxifen (OVX-PTZ-T) groups. The animals of groups 3 and 5 were injected by tamoxifen (10 mg/kg) on 7 consecutive days. After 7 days of tamoxifen injection, they also were then injected by tamoxifen 30 min prior each PTZ injection. PTZ (40 mg/kg) was injected on 6 consecutive days and the animal behaviors were observed for 60 min. The histological methods were then used to determine dark neurons in hippocampus. A significant decrease in the seizure score was seen in OVX-PTZ group compared to Sham-PTZ. The animals of OVX-PTZ-T group had a significant higher seizure score compared to OVX-PTZ group. The dark neurons in DG of OVX group were lower than sham group (p<0.01). The numbers of dark neurons in CA1 area of OVX-PTZ-T group was higher than OVX-PTZ group (p<0.05) compared to control, the numbers of dark neurons in CA3 area showed a significant increase in Sham-PTZ and OVX-PTZ group (p<0.05 and p<0.01 respectively). Dark neurons in OVX-PTZ-T group were higher than OVX-PTZ group (p<0.05). It is concluded that pretreatment of the ovariectomized rats by tamoxifen increased PTZ-induced seizure score and dark neurons. It might be suggested that tamoxifen has agonistic effects for estrogen receptors to change the seizure severity.

Pregnancy, epilepsy, and women's issues

PURPOSE OF REVIEW

Optimal treatment of women with epilepsy includes consideration of the complex interactions of sex steroid hormones with epilepsy and antiepileptic drugs, and of the potential risks of any antiepileptic drug prescribed during a pregnancy.

RECENT FINDINGS

Clinical studies in women with epilepsy have provided a better foundation of knowledge about the complex relationships between cycling sex steroid hormones, seizure frequency, antiepileptic drugs, contraception, and neuroendocrine abnormalities. Pregnancy registries and observational studies have provided key data that allow for a better estimation of risks to the developing fetus.

SUMMARY

Understanding these key factors should enable informed treatment recommendations that can reduce adverse health effects in women with epilepsy and improve both seizure control and maternal and fetal outcomes.

Neuroendocrine aspects of catamenial epilepsy

This review describes the neuroendocrinological aspects of catamenial epilepsy, a menstrual cycle-related seizure disorder in women with epilepsy. Catamenial epilepsy is a multifaceted neuroendocrine condition in which seizures are clustered around specific points in the menstrual cycle, most often around perimenstrual or periovulatory period. Three types of catamenial seizures (perimenstrual, periovulatory and inadequate luteal) have been identified. The molecular pathophysiology of catamenial epilepsy remains unclear. Cyclical changes in the circulating levels of estrogens and progesterone (P) play a central role in the development of catamenial epilepsy. Endogenous neurosteroids such as allopregnanolone (AP) and allotetrahydrodeoxycorticosterone (THDOC) that modulate seizure susceptibility could play a critical role in catamenial epilepsy. In addition, plasticity in GABA-A receptor subunits could play a role in the enhanced seizure susceptibility in catamenial epilepsy. P-derived neurosteroids such as AP and THDOC potentiate synaptic GABA-A receptor function and also activate extrasynaptic GABA-A receptors in the hippocampus and thus may represent endogenous regulators of catamenial seizure susceptibility. Experimental studies have shown that neurosteroids confer greater seizure protection in animal models of catamenial epilepsy, especially without evident tolerance to their actions during chronic therapy. In the recently completed NIH-sponsored, placebo controlled phase 3 clinical trial, P therapy proved to be beneficial only in women with perimenstrual catamenial epilepsy but not in non-catamenial subjects. Neurosteroid analogs with favorable profile may be useful in the treatment of catamenial epilepsy.

Sex and hormonal influences on seizures and epilepsy

Epilepsy is the third most common chronic neurological disorder. Clinical and experimental evidence supports the role of sex and influence of sex hormones on seizures and epilepsy as well as alterations of the endocrine system and levels of sex hormones by epileptiform activity. Conversely, seizures are sensitive to changes in sex hormone levels, which in turn may affect the seizure-induced neuronal damage. The effects of reproductive hormones on neuronal excitability and seizure-induced damage are complex to contradictory and depend on different mechanisms, which have to be accounted for in data interpretation. Both estradiol and progesterone/allopregnanolone may have beneficial effects for patients with epilepsy. Individualized hormonal therapy should be considered as adjunctive treatment in patients with epilepsy to improve seizure control as well as quality of life.

Neuroendocrine considerations in the treatment of men and women with epilepsy

Complex, multidirectional interactions between hormones, seizures, and the medications used to control them can present a challenge for clinicians treating patients with epilepsy. Many hormones act as neurosteroids, modulating brain excitability via direct binding sites. Thus, changes in endogenous or exogenous hormone levels can affect the occurrence of seizures directly as well as indirectly through pharmacokinetic effects that alter the concentrations of antiepileptic drugs. The underlying structural and physiological brain abnormalities of epilepsy and the metabolic activity of antiepileptic drugs can adversely affect hypothalamic and gonadal functioning. Knowledge of these complex interactions has increased and can now be incorporated in meaningful treatment approaches for men and women with epilepsy.

Females, their estrogens, and seizures

Estrogens are essential for normal brain functions. The effects of estrogens on seizures are contradictory. More studies are necessary to determine under which conditions the estrogens have proconvulsant effects and when the estrogens may have beneficial action in patients with epilepsy.

Effects of female sex hormones on caffeine-induced epileptiform activity in rats

Research on female sex hormones has demonstrated that estrogen aggravates epileptogenesis. Theoretically, this means that the frequency of epileptic attacks should be decreased in epileptic women during menopause. However, although epilepsy attacks are reported to decrease in some women during menopause, they may not change in others. Increases in attack frequency have even been reported during menopause in some epileptic women. This study has investigated the effects of estrogen, progesterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH) on caffeine-induced epileptiform activity in rats. Estrogen was found to increase epileptiform activity in a dose-dependent manner via its own receptors. In contrast, progesterone had no effect on epileptiform activity. FSH and LH suppressed epileptiform activity at low doses; however, at high doses they enhanced it. In conclusion, we suggest that the occurrence or aggravation of epilepsy, despite estrogen deficiency in the menopausal or post-menopausal period, is related to excessive accumulation of FSH and LH.

Treatment of epilepsy in postmenopausal women

Menopausal women represent a rapidly growing proportion of the population. Epidemiologic evidence for the increased incidence of epilepsy in elderly patients suggests that with global aging of the population, there is likely to be a growing need for healthcare workers to manage seizures in older women. Unfortunately, there has been relatively little scientific investigation into the unique concerns of postmenopausal woman with epilepsy. There is some evidence that women may experience increased seizure activity during the menopausal transition owing to the effects of estrogen and progesterone on neuronal excitability. During perimenopause and menopause, use of hormone-replacement therapy can also worsen seizure control. Menopausal women are particularly vulnerable to osteoporosis and fragility fractures, both of which demonstrate increased risk following exposure to antiepileptic drugs. Optimization of epilepsy therapy to avoid both seizures and falls caused by antiepileptic drug-induced imbalance is crucial in order to minimize fracture risk in this group of women. Elderly patients are more susceptible to adverse medication side effects owing to drug interactions and the physiologic changes of aging that result in altered drug pharmacokinetics.

Hormonal aspects of epilepsy

The relationships among hormones, epilepsy, and the medications used to treat epilepsy are complex, with tridirectional interactions that affect both men and women in various ways. Abnormalities of baseline endocrine status occur more commonly in people with epilepsy. Abnormalities are most often described for the sex steroid hormone axis, commonly presenting as sexual dysfunction in men and women with epilepsy and lower fertility. Other signs and symptoms in women with epilepsy include menstrual irregularities, premature menopause, and polycystic ovarian syndrome. The evaluation and care of adult patients with epilepsy should include considerations of the common hormonal aberrations that occur in this patient population. Questions about reproductive health disorders, sexual function, symptoms of thyroid disorders, and bone health should be part of the evaluation of all adult patients with epilepsy. Further laboratory or radiologic testing and referral to other specialists to participate in collaborative care may be warranted if underlying disorders are suspected, especially given that many of these hormone abnormalities can result in long-term health risks as well as negatively affect quality of life. AEDs and hormones have a bidirectional interaction that can impair the efficacy of contraceptive hormone treatments and of the AEDs. Endogenous hormones can influence seizure severity and frequency, resulting in catamenial patterns of epilepsy. However, this susceptibility to hormonal influences can be used to develop hormonal strategies to improve seizure control in women with epilepsy with use of cyclic PROG supplementation or alteration of the endogenous hormone release. Additionally, development of the neurosteroid analog ganaxolone provides a novel approach that can potentially be used across both genders and all age groups.

Efeitos endócrinos e metabólicos das drogas antiepilépticas

As drogas antiepilépticas (DAE) são utilizadas por um enorme contingente de pessoas em todo o mundo - tanto no tratamento das epilepsias como para outros fins - frequentemente por um longo tempo. Por essas razões, torna-se fundamental o conhecimento sobre os potenciais efeitos adversos desses medicamentos, muitos deles envolvendo vários aspectos hormonais e metabólicos que devem ser do conhecimento do endocrinologista. Nesta revisão, foi abordada a relação das DAE com anormalidades no metabolismo mineral ósseo, balanço energético e peso corporal, eixo gonadal e função tireoideana, além de ter sido revisado o papel terapêutico dessas medicações no tratamento da neuropatia diabética.

The role of neurosteroids in the pathophysiology and treatment of catamenial epilepsy

Catamenial epilepsy is a multifaceted neuroendocrine condition in which seizures are clustered around specific points in the menstrual cycle, most often around perimenstrual or periovulatory period. Generally, a twofold or greater increase in seizure frequency during a particular phase of the menstrual cycle could be considered as catamenial epilepsy. Based on this criteria, recent clinical studies indicate that catamenial epilepsy affects 31-60% of the women with epilepsy. Three types of catamenial seizures (perimenstrual, periovulatory and inadequate luteal) have been identified. However, there is no specific drug available today for catamenial epilepsy, which has not been successfully treated with conventional antiepileptic drugs. Elucidation of the pathophysiology of catamenial epilepsy is a prerequisite to develop specific targeted approaches for treatment or prevention of the disorder. Cyclical changes in the circulating levels of estrogens and progesterone play a central role in the development of catamenial epilepsy. There is emerging evidence that endogenous neurosteroids with anticonvulsant or proconvulsant effects could play a critical role in catamenial epilepsy. It is thought that perimenstrual catamenial epilepsy is associated with the withdrawal of anticonvulsant neurosteroids. Progesterone and other hormonal agents have been shown in limited trials to be moderately effective in catamenial epilepsy, but may cause endocrine side effects. Synthetic neurosteroids, which enhance the tonic GABA-A receptor function, might provide an effective approach for the catamenial epilepsy therapy without producing hormonal side effects.

Gender-specific psychosocial impact of living with epilepsy

Although many psychosocial issues affect all people living with epilepsy, certain issues either are specific to one gender or have a different prevalence or significance between men and women with epilepsy. Most studies suggest that the incidence of epilepsy is slightly higher in males with epilepsy. Sexual dysfunction is common among men and women with epilepsy and has been related to epilepsy type and treatment. Women living with epilepsy are often prone to increased seizure frequency at certain phases of their menstrual cycles. Hormone replacement therapy in postmenopausal women may worsen seizures. Treatment during pregnancy is often a precarious balancing act between the teratogenic risks of AEDs and the maintenance of maternal seizure control. However, pregnancy registries and other prospective studies have given us invaluable information on how to optimize treatment regimens as well as information about safety of breastfeeding. These gender-specific factors should be a key consideration when counseling and treating patients with epilepsy.