By: Sofia Arreguin
Catamenial Epilepsy
Many individuals assigned female at birth struggle with a form of ‘pharmacoresistant epilepsy,’ a type of epilepsy that is inadequately managed by medication. Affecting around 10% to 70% of women, this form of epilepsyincludes an increased frequency of seizures relative to their menstrual cycle. Known as catamenial epilepsy, this change in the severity of seizures during certain phases of the menstrual cycle consists of proconvulsant estrogen, which increases neuronal excitability, and anticonvulsant progesterone, which increases GABA’s reduction of neuronal activity (Verrotti, et al., 2012). Alongside the worsening of seizures, these women can experience long-term effects on their reproductive health, such as infertility or polycystic ovarian syndrome (PCOS). Presumably, the cause of such reactions has been identified as the hormonal changes the female body undergoes during the menstrual cycle, specifically concerning the fluctuations of the sex hormones estrogen and progesterone. An increase in estrogen has been shown to cause seizures, while progesterone has been determined to prevent, or reduce, seizures. Therefore, it is believed that women with epilepsy seem to experience an increase in seizures during particular stages of their cycle because they lack a sufficient amount of progesterone; the supply of estrogen is disproportionate to that of progesterone.
Estrogen and Progesterone
The hormone estrogen, especially estradiol (E2), contains proconvulsant effects, meaning its neural excitability causes convulsions and seizures. It acts on neurons in the hippocampus to increase the excitability of neurotransmitter activity through N-methyl-D-aspartate receptors, while also suppressing gamma-aminobutyric (GABA) neurotransmitters that soothe the nervous system (Frank & A. Tyson, 2020). Ultimately, estrogen can cause an increase in seizures. Conversely, the hormone progesterone contains anticonvulsant effects, meaning it prevents convulsions or seizures, which arise through the reduced metabolites of progesterone, particularly allopregnanolone (AP) (Frank & A. Tyson, 2020). Allopregnanolone carries anticonvulsant and sedative characteristics and exerts these properties by helping enhance GABA neurotransmitters. Generally, progesterone guards against seizures.
Relationship between Catamenial Epilepsy and the Menstrual Cycle
The association of a woman’s menstrual cycle with catamenial epilepsy is expressed through the cycle’s different phases: the perimenstrual, periovulatory, and luteal phases (Nunez, 2021). The perimenstrual phase, a C1 pattern, is represented by the occurrence of seizures before the start of a woman’s period, and the decline in progesterone. In this phase, the hormone progesterone thickens the uterus lining in preparation for a fertilized egg, but if the egg remains unfertilized, the corpus luteum degenerates, causing a reduction in the production of progesterone and the start of menstruation. However, this decline in progesterone occurs at a more rapid pace than the fall in estrogen, leading to more estrogen than progesterone, and ultimately giving rise to increased seizures. Likewise, the luteal phase, a C3 pattern, experiences an insufficient secretion of progesterone, which also causes intense seizures. With the periovulatory phase, a C2 pattern, the increase in estrogen causes a worsening of seizures during ovulation. The sudden rise in estradiol, or estrogen, comes about as the female body gets ready for pregnancy. As a result, this accumulation of estrogen tends to trigger seizures in women with epilepsy since its proconvulsant properties excite neural activity in the brain.
Diagnosis
Doctors often advise female patients with epilepsy to monitor and track their seizures and menstrual cycle to diagnose catamenial epilepsy. If there appears to be a cluster of seizures around the time of their period, physicians are more inclined to determine their patient has catamenial epilepsy. For patients with irregular periods, doctors may recommend the use of ovulation kits, which detect when their patient is ovulating; this helps them better interpret whether their seizures frequently happen around the time of their period (Frank & A. Tyson, 2020). Physicians also diagnose patients using electroencephalograms, imaging scans, and holding a record of the patient’s temperature (Nunez, 2021). Electroencephalograms measure the electrical activity in the brain, allowing the physician to pinpoint any abnormal patterns caused by seizures. Similarly, imaging scans produce detailed illustrations of a patient’s brain, letting the doctor view any irregular brain activity. When it comes to temperature, a doctor may recommend a patient keep a record of their basal body temperature and seizures. Because there is often a rise in temperature in the body after the menstrual cycle, a doctor can determine if there is a connection between a person’s period and seizures.
Treatment
While there is no specific treatment for catamenial epilepsy, there are some forms of hormonal therapy that clinicians may provide. Natural progesterone supplements, for example, can aid in reducing the frequency of seizures (Frank & A. Tyson, 2020). Given in the form of a lozenge, natural progesterone contains, as the name suggests, progesterone, which is known for being able to suppress seizures. Synthetic progesterone, on the other hand, lowers allopregnanolone, preventing the reduction of seizures. Hormonal contraceptives are also considered for treatment, such as oral contraceptive pills that contain ethinyl estradiol (synthetic estrogen) and progesterone (Frank & A. Tyson, 2020). In many severe cases, a patient may need to undergo surgery for treatment, where the ovaries are removed and, as a result, menstruation stops (Nunez, 2021). Others may face epilepsy surgery that targets the part of the brain where the patient’s seizures develop; both forms of surgery can provide relief.
Conclusion
Women with catamenial epilepsy face an increased frequency of seizures surrounding their menstrual cycle. This is because of the fluctuations in hormones, specifically estrogen, which could be considered here as the “bad hormone,” and progesterone, the “good hormone.” Estrogen results in a growth in seizure frequency, while progesterone helps protect against seizures. While catamenial epilepsy is not well understood, there have been some hormonal and non-hormonal treatments suggested to benefit these women. However, more research is needed to definitively determine which therapies work best.
References
Frank, S., Tyson, N.A. (2020). A Clinical Approach to Catamenial Epilepsy: A Review. The Permanente Journal, 19(145). https://doi.org/10.7812/TPP/19.145
Nunez, K. (2021, July 14). Catamenial (Menstrual-Linked) Epilepsy Overview. Healthline. https://www.healthline.com/health/epilepsy/catamenial-epilepsy
Verrotti, A., et al. (2012). Diagnosis and management of catamenial seizures: a review. National Library of Medicine. https://doi.org/10.2147/IJWH.S28872
