Low dose aspirin is recommended to prevent pre-eclampsia and eclampsia in those at high risk.[12] Other preventative recommendations include calcium supplementation in areas with low calcium intake and treatment of prior hypertension with anti-hypertensive medications.[2][3] Exercise during pregnancy may also be useful.[1] The use of intravenous or intramuscular magnesium sulfate improves outcomes in those with severe pre-eclampsia and eclampsia and is generally safe.[4][13] Treatment options include blood pressure medications such as hydralazine and emergency delivery of the baby either vaginally or by cesarean section.[1]
eclampsia
Pre-eclampsia is estimated to globally affect about 5% of deliveries while eclampsia affects about 1.4% of deliveries.[5] In the developed world eclampsia rates are about 1 in 2,000 deliveries due to improved medical care whereas in developing countries it can impact 10-30 times as many women.[1][14] Hypertensive disorders of pregnancy are one of the most common causes of death in pregnancy.[14] They resulted in 46,900 deaths in 2015.[6] Maternal mortality due to eclampsia occurs at a rate of approximately 0-1.8% of cases in high-income countries and up to 15% of cases in low- to middle- income countries.[15] The word eclampsia is from the Greek term for lightning.[16] The first known description of the condition was by Hippocrates in the 5th century BC.[16]
Eclampsia is a disorder of pregnancy characterized by seizures in the setting of pre-eclampsia.[17] Most women have premonitory signs/symptoms in the hours before the initial seizure. Typically the woman develops hypertension before the onset of a convulsion (seizure).[18] Other signs and symptoms to looks out for include:[19]
The seizures of eclampsia typically present during pregnancy and prior to delivery (the antepartum period),[22] but may also occur during labor and delivery (the intrapartum period) or after the baby has been delivered (the postpartum period).[17][21][23] If postpartum seizures develop, it is most likely to occur within the first 48 hours after delivery. However, late postpartum seizures of eclampsia may occur as late as 4 weeks after delivery.[17][21]
There are risks to both the mother and the fetus when eclampsia occurs. The fetus may grow more slowly than normal within the womb (uterus) of a woman with eclampsia, which is termed intrauterine growth restriction and may result in the child appearing small for gestational age or being born with low birth weight.[27] Eclampsia may also cause problems with the placenta. The placenta may bleed (hemorrhage) or begin to separate early from the wall of the uterus.[28] It is normal for the placenta to separate from the uterine wall during delivery, but it is abnormal for it to separate prior to delivery; this condition is called placental abruption and can be dangerous for the fetus.[29] Placental insufficiency may also occur, a state in which the placenta fails to support appropriate fetal development because it cannot deliver the necessary amount of oxygen or nutrients to the fetus.[28] During an eclamptic seizure, the beating of the fetal heart may become slower than normal (bradycardia).[27][30] If any of these complications occurs, fetal distress may develop. Treatment of the mother's seizures may also manage fetal bradycardia.[22][31] If the risk to the health of the fetus or the mother is high, the definitive treatment for eclampsia is delivery of the baby. Delivery by cesarean section may be necessary, especially if the instance of fetal bradycardia does not resolve after 10 to 15 minutes of resuscitative interventions.[22][32] It may be safer to deliver the infant preterm than to wait for the full 40 weeks of fetal development to finish, and as a result prematurity is also a potential complication of eclampsia.[28][33]
In the mother, changes in vision may occur as a result of eclampsia, and these changes may include blurry vision, one-sided blindness (either temporary due to amaurosis fugax or potentially permanent due to retinal detachment), or cortical blindness, which affects the vision from both eyes.[34][35] There are also potential complications in the lungs. The woman may have fluid slowly collecting in the lungs in a process known as pulmonary edema.[28] During an eclamptic seizure, it is possible for a person to vomit the contents of the stomach and to inhale some of this material in a process known as aspiration.[27] If aspiration occurs, the woman may experience difficulty breathing immediately or could develop an infection in the lungs later, called aspiration pneumonia.[21][36] It is also possible that during a seizure breathing will stop temporarily or become inefficient, and the amount of oxygen reaching the woman's body and brain will be decreased (in a state known as hypoxia).[21][37] If it becomes difficult for the woman to breathe, she may need to have her breathing temporarily supported by an assistive device in a process called mechanical ventilation. In some severe eclampsia cases, the mother may become weak and sluggish (lethargy) or even comatose.[35] These may be signs that the brain is swelling (cerebral edema) or bleeding (intracerebral hemorrhage).[28][35]
Eclampsia, like pre-eclampsia, tends to occur more commonly in first pregnancies than subsequent pregnancies.[38][39][40] Women who have long term high blood pressure before becoming pregnant have a greater risk of pre-eclampsia.[38][39] Patients who have gestational hypertension and pre-eclampsia have an increased risk of eclampsia.[41] Furthermore, women with other pre-existing vascular diseases (diabetes or nephropathy) or thrombophilia disease such as the antiphospholipid syndrome are at higher risk to develop pre-eclampsia and eclampsia.[38][39] Having a placenta that is enlarged by multiple gestation or hydatidiform mole also increases risk of eclampsia.[38][39][42] In addition, there is a genetic component: a woman whose mother or sister had the condition is at higher risk than otherwise.[43] Patients who have experienced eclampsia are at increased risk for pre-eclampsia/eclampsia in a later pregnancy.[39] The occurrence of pre-eclampsia was 5% in white, 9% in Hispanic, and 11% in African American patients and this may reflect disproportionate risk of developing pre-eclampsia among ethnic groups.[44] Additionally, black patients were also shown to have a disproportionately higher risk of dying from eclampsia.[44]
The mechanisms of eclampsia and preeclampsia are not definitively understood, but following provides some insight. The presence of a placenta is required, and eclampsia resolves if it is removed.[45] Reduced blood flow to the placenta (placental hypoperfusion) may be a key feature of the process. It is typically accompanied by increased sensitivity of the maternal vasculature to agents which cause constriction of the small arteries, leading to reduced blood flow to multiple organs. Vascular dysfunction-associated maternal conditions such as Lupus, hypertension, and renal disease, or obstetric conditions that increase placental volume without an increase in placental blood flow (such as multifetal gestation) may increase risk for pre-eclampsia.[46] Also, activation of the coagulation cascade can lead to microthrombi formation, which may further impair blood flow. Thirdly, increased vascular permeability results in the shift of extracellular fluid from the blood to the interstitial space which reduces blood flow and causes edema. These events can lead to hypertension, renal dysfunction, pulmonary dysfunction, hepatic dysfunction, and cerebral edema with cerebral dysfunction and convulsions.[45] In clinical context, increased platelet and endothelial activation may be detected before symptoms appear.[45]
If a pregnant woman has already been diagnosed with pre-eclampsia during the current pregnancy and then develops a seizure, she may be assigned a 'clinical diagnosis' of eclampsia without further workup. While seizures are most common in the third trimester, they may occur any time from 20 weeks of pregnancy until 6 weeks after birth.[50] Because pre-eclampsia and eclampsia are common conditions in women, eclampsia can be assumed to be the correct diagnosis until proven otherwise in pregnant or postpartum women who experience seizures.[51] However, if a woman has a seizure and it is unknown whether or not they have pre-eclampsia, testing can help make the diagnosis clear.
Pre-eclampsia is diagnosed when repeated blood pressure measurements are greater or equal to 140/90mmHg, in addition to any signs of organ dysfunction, including: proteinuria, thrombocytopenia, renal insufficiency, impaired liver function, pulmonary edema, cerebral symptoms, or abdominal pain.[52]
One of the core features of pre-eclampsia is the new onset of high blood pressure. Blood pressure is a measurement of two numbers: systolic blood pressure and diastolic blood pressure. A systolic blood pressure (the top number) of greater than 140 mmHg and/or a diastolic blood pressure (the bottom number) of greater than 90 mmHg is higher than the normal range. If the blood pressure is high on at least two separate occasions after the first 20 weeks of pregnancy and the woman has signs of organ dysfunction (e.g. proteinuria), then they meet the criteria for a diagnosis of pre-eclampsia.[33] If the systolic blood pressure is greater than 160 or the diastolic pressure is greater than 110, the hypertension is considered to be severe.[17]
Another common feature of pre-eclampsia is proteinuria, which is the presence of excess protein in the urine. To determine if proteinuria is present, the urine can be collected and tested for protein; if there is 0.3 grams of protein or more in the urine of a pregnant woman collected over 24 hours, this is one of the diagnostic criteria for pre-eclampsia and raises the suspicion that a seizure is due to eclampsia.[17]
In cases of severe eclampsia or pre-eclampsia, the woman can have low levels of platelets in the blood, a condition termed thrombocytopenia.[53][30] A complete blood count, or CBC, is a test of the blood that can be performed to check platelet levels. 2ff7e9595c
Comments