is a serious complication of pregnancy
and is characterised by convulsions
. Usually eclampsia occurs after the onset of pre-eclampsia
though sometimes no pre-eclamptic symptoms are recognisable.
The convulsions may appear before, during or after labour
, though cases of eclampsia after just 20 weeks of pregnancy have been recorded.
The pathogenesis of eclampsia is poorly understood.
Signs and symptoms
The majority of cases are heralded by pregnancy-induced hypertension
but the only true sign of eclampsia is an eclamptic convulsion, of which there are four stages. Patients with edema
may develop renal failure
or pulmonary edema
.Premonitory stage: this stage is usually missed unless constantly monitored, the woman rolls her eyes while her facial and hand muscles twitch slightly.Tonic stage: soon after the premonitory stage the twitching turns into clenching. Sometimes the woman may bite her tongue as she clenches her teeth, while the arms and legs go rigid. The respiratory
muscles also spasm, causing the woman to stop breathing, leading to cyanosis. This stage continues for around 30 seconds.Clonic stage: the spasm stops but the muscles start to jerk violently. Frothy, slightly bloodied saliva appears on the lips and can sometimes be inhaled. After around two minutes the convulsions stop, leading into a temporary unconscious stage.Comatose stage: the woman falls deeply unconscious and needs airway management
to allow breathing and prevent hypoxia
. This can last only a few minutes or may persist for hours.
Eclampsia is usually treated well in the majority of cases with just under one in 50 affected women and one in 14 fetuses of affected women developing complications.
The treatment of eclampsia consists of preventing further convulsions, controlling elevated blood pressure and delivering the fetus.
Prevention of convulsion is usually done using magnesium sulfate with a loading of Magnesium sulfate 20% solution, 4g IV over 5 minutes, followed by 1g of magnesium sulfate an hour.
The blood pressure may be controlled by hydralazine 5mg IV slowly every 5 minutes until blood pressure is lowered . In less well resourced healthcare settings hydralazine 12.5 mg IM every 2 can be given as needed.
Delivery should take place as soon as the woman’s condition has stabilized. Delaying delivery to increase fetal maturity is unsafe for both the woman and the fetus, after delivery the woman's health will begin to improve. Delivery should occur regardless of the gestational age.
In severe pre-eclampsia, delivery should occur within 24 hours of the onset of symptoms. In eclampsia, delivery should occur within 12 hours of the onset of convulsions. If vaginal delivery is not anticipated within 12 hours (for eclampsia) or 24 hours (for severe pre-eclampsia), deliver by caesarean section.
- Mayes, M., Sweet, B. R. & Tiran, D. (1997). Mayes' Midwifery - A Textbook for Midwives 12th Edition, pp. 533–545. Baillière Tindall. ISBN 0-7020-1757-4