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<< Seizures and Status Epilepticus: Diagnosis and Management in the Emergency Department
Seizures In Pregnancy
Seizures in pregnancy can be classified as one of three types: 1) those that can occur in epileptics who happen to be pregnant, 2) the new onset seizure in a pregnant patient, 3) seizures that are unique to the pregnant state: eclampsia
The most complete prospective observation study of pregnant women with epilepsy is the EURAP Pregnancy Registry. Of 1956 pregnancies, over half were seizure free during the pregnancy; 17.3% of women had an increase in seizure frequency and 15.9% had a decrease in frequency during the pregnancy.164 In a previous study, a larger increase in seizure frequency was attributed to the discontinuation of AEDs.165 Other factors that may lower the seizure threshold in pregnancy include sleep deprivation, nausea, and vomiting.
Epilepsy in pregnancy can affect the total blood levels of AED. The serum concentration tends to go down during the pregnancy due to an increase in hepatic and renal clearance of drug and a pregnancy related increase in the volume of distribution of the drug. 166, 167, 168 This decrease in serum drug level is balanced by the fact that free (unbound) drug levels may actually be increased due to the decrease in concentration of serum proteins that normally occurs in pregnancy.
Pregnant patients with new onset seizures (not ecamptic) should be worked-up as any new onset seizure patient with a metabolic profile and head CT with appropriate abdominal shielding. Precipitating etiologies, such as infections and drug toxicities, should also be investigated. If no source is identified, anticonvulsants should be withheld and the patient referred for close follow-up. In pregnant patients with epilepsy, noncompliance and sleep deprivation are common causes for seizures.
Patients who are actively seizing should be managed as the non-pregnant patient. The risks to the fetus from hypoxia and acidosis are greater than the potential teratogenicity of anticonvulsant medications. Arrange for fetal monitoring during and after a seizure in patients more than 24 weeks gestation.169 Eclampsia: Eclampsia is the major consideration in pregnant patients of more than 20-week gestation and up to 23 days postpartum170, 171 who present with new onset seizures. Magnesium has been demonstrated to be the therapy of choice in the treatment of acute eclamplic seizures and for prevention of recurrenteclampic seizures.172 A systematic review173 of four good quality trials involving 823 women found magnesium sulfate to be substantially more effective than phenytoin with regards to recurrence of convulsions and maternal death. Complications, such as respiratory depression and pneumonia, were also less for magnesium than for phenytoin. Magnesium showed a trend towards increased incidence of renal failure when compared to phenytoin; however, this was not statistically significant. Magnesium sulfate was alsoassociated with benefits for the baby, including fewer admissions to the NICU.
In the eclamptic patient, give 4 grams of intravenous magnesium sulfate followed by a 2 gm/h drip (some centers use intramuscular regimens.) Control the patient’s blood pressure if very high (SBP greater than 160 and/or DBP greater than 110) and contact an obstetrician. Agents of choice for blood pressure control according to the American College of Obstetrics and Gynecology (ACOG) and the National High Blood Pressure Education Program: Working Group Report on High Blood Pressure in Pregnancy174 in the emergency setting include hydralazine (first line) and labetalol. In resistant cases, nitroprusside may also be used, although fetal cyanide toxicity can occur after even a few hours of therapy.
The most complete prospective observation study of pregnant women with epilepsy is the EURAP Pregnancy Registry. Of 1956 pregnancies, over half were seizure free during the pregnancy; 17.3% of women had an increase in seizure frequency and 15.9% had a decrease in frequency during the pregnancy.164 In a previous study, a larger increase in seizure frequency was attributed to the discontinuation of AEDs.165 Other factors that may lower the seizure threshold in pregnancy include sleep deprivation, nausea, and vomiting.
Epilepsy in pregnancy can affect the total blood levels of AED. The serum concentration tends to go down during the pregnancy due to an increase in hepatic and renal clearance of drug and a pregnancy related increase in the volume of distribution of the drug. 166, 167, 168 This decrease in serum drug level is balanced by the fact that free (unbound) drug levels may actually be increased due to the decrease in concentration of serum proteins that normally occurs in pregnancy.
Pregnant patients with new onset seizures (not ecamptic) should be worked-up as any new onset seizure patient with a metabolic profile and head CT with appropriate abdominal shielding. Precipitating etiologies, such as infections and drug toxicities, should also be investigated. If no source is identified, anticonvulsants should be withheld and the patient referred for close follow-up. In pregnant patients with epilepsy, noncompliance and sleep deprivation are common causes for seizures.
Patients who are actively seizing should be managed as the non-pregnant patient. The risks to the fetus from hypoxia and acidosis are greater than the potential teratogenicity of anticonvulsant medications. Arrange for fetal monitoring during and after a seizure in patients more than 24 weeks gestation.169 Eclampsia: Eclampsia is the major consideration in pregnant patients of more than 20-week gestation and up to 23 days postpartum170, 171 who present with new onset seizures. Magnesium has been demonstrated to be the therapy of choice in the treatment of acute eclamplic seizures and for prevention of recurrenteclampic seizures.172 A systematic review173 of four good quality trials involving 823 women found magnesium sulfate to be substantially more effective than phenytoin with regards to recurrence of convulsions and maternal death. Complications, such as respiratory depression and pneumonia, were also less for magnesium than for phenytoin. Magnesium showed a trend towards increased incidence of renal failure when compared to phenytoin; however, this was not statistically significant. Magnesium sulfate was alsoassociated with benefits for the baby, including fewer admissions to the NICU.
In the eclamptic patient, give 4 grams of intravenous magnesium sulfate followed by a 2 gm/h drip (some centers use intramuscular regimens.) Control the patient’s blood pressure if very high (SBP greater than 160 and/or DBP greater than 110) and contact an obstetrician. Agents of choice for blood pressure control according to the American College of Obstetrics and Gynecology (ACOG) and the National High Blood Pressure Education Program: Working Group Report on High Blood Pressure in Pregnancy174 in the emergency setting include hydralazine (first line) and labetalol. In resistant cases, nitroprusside may also be used, although fetal cyanide toxicity can occur after even a few hours of therapy.
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