Typically patients show signs of pregnancy-induced hypertension and proteinuria prior to the onset of the hallmark of eclampsia, the eclamptic convulsion. Other cerebral signs may precede the convulsion such as nausea, vomiting, headaches, and cortical blindness. In addition, with the advancement of the pathophysiological process, other organ symptoms may be present including abdominal pain, liver failure, signs of the HELLP syndrome, pulmonary edema, and oliguria. The fetus may have been already compromised by intrauterine growth retardation, and with the toxemic changes during eclampsia may suffer fetal distress. Placental bleeding and placental abruption may occur.
The eclamptic seizure
Chesley distinguishes these four stages of an eclamptic event: In the ''stage of invasion'' facial twitching can be observed around the mouth. In the ''stage of contraction'' tonic contractions render the body rigid; this stage may last about 15 to 20 seconds. The next stage is the ''stage of convulsion'' when involuntary and forceful muscular movements occur, the tongue may be bitten, foam appears at the mouth. The patient stops breathing and becomes cyanotic; this stage lasts about one minute. The final stage is a more or less prolonged ''coma''. When the patient awakens, she is unlikely to remember the event. In some rare cases there are no convulsions and the patient falls directly into a coma. Some patients when they awake from the coma may have temporary blindness.
During a seizure, the fetus may experience bradycardia. As per Lu and Nightingale , serum Mg2+ concentrations associated with maternal toxicity (also neonate depression or hypotonia and low Apgar scores) are:
- 7.0–10.0 mEq/L - loss of patellar reflex
- 10.0–13.0 mEq/L - respiratory depression
- 15.0–25.0 mEq/L - altered atrioventricular conduction and (further) complete heart block
- >25.0 mEq/L - cardiac arrest
Even with therapeutic serum Mg2+ concentrations, recurrent convulsions and seizures may occur—patients would receive additional MgSO4 but under close monitoring for respiratory, cardiac and neurological depression: 4–6 g loading dose in 100 mL IV fluid over 15–20 min., then 2 g/hr as a continuous infusion
Antihypertensive management
Antihypertensive management at this stage in pregnancy may consist of hydralazine (5–10 mg IV every 15-20 min until desired response is achieved) or labetalol (20 mg bolus iv followed by 40 mg if necessary in 10 minutes; then 80 mg every 10 up to maximum of 220 mg).
Delivery
If the woman has not yet been delivered, steps need to be taken to stabilize the patient and deliver her speedily. This needs to be done even if the fetus is immature as the eclamptic condition is unsafe for fetus and mother. As eclampsia is a manifestation of a multiorgan failure, other organs (liver, kidney, clotting, lungs, and cardiovascular system) need to be assessed in preparation for a delivery, often a cesarean section, unless the patient is already in advanced labor. Regional anesthesia for cesarean section is contraindicated when a coagulopathy has developed.
Invasive hemodynamic monitoring
Invasive hemodynamic monitoring may be useful in eclamptic patients with severe cardiac disease, renal disease, refractory hypertension, pulmonary edema, and oliguria.
Further Reading
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