Catamenial epilepsy

Epilepsy is a chronic neurological condition characterized by recurrent seizures.Catamenial epilepsy is a subset of epilepsy, which includes women whose seizures are exacerbated by their menstrual cycle. Women with catamenial epilepsy are unusually sensitive to endogenous hormonal changes. This seizure exacerbation has a statistically significant positive correlation to serum estradiol/estrogen levels and ratios.

Since at least the Greek times, there has been documented study of women with epilepsy and its correlation to the menstrual cycle. These patterns can easily be seen by charting out menses against seizure occurrence and type.

Our understanding of the major gonadal hormones, estrogen, progesterone, and testosterone, has significantly increased in the last century. These hormones are synthesized in various locations in the body, including the ovaries, adrenal gland, liver, subcutaneous fat, and brain. There is considerable research showing that these steroidal hormones take part in an important role in the pathophysiology of epilepsy. Broadly defined, estrogen and its many forms are thought to be “proconvulsant,” whereas progesterone is thought to be “anticonvulsant” by virtue of its conversion to the neurosteroid allopregnanolone.

Estrogen can be found in the female body in various forms, all of which affect women with catamenial epilepsy. Estrone (E1), estradiol (E2), and estriol (E3) are the three principal circulating estrogens in the body. These three forms influence neuronal excitability, but very little is known about their inter-hormone interactions, the relative concentrations and ratios of E1/E2/E3 and how that may influence the seizure frequency behavior in women with epilepsy. In normally menstruating women, serum estradiol levels are typically present by day 10 of the menstrual cycle, and persist until ovulation.

Similar to estrogen, progesterone receptors bind several molecules other than only progesterone. Progestogens are group of natural non-synthetic hormones, including progesterone, which binds to progesterone receptors. Other than progesterone, progestogens have several neuroactive metabolites, most notably allopregnanolone. Progesterone has been shown to lower the number of estrogen receptors, and thus act as an antagonist to estrogen actions. In trials, both progesterone and allopregnanolone administration have shown a neuroprotective effect on hippocampal neurons in seizure models induced by kainic acid.

...
Wikipedia