Some women with eclampsia may develop severe cerebral edema, hemorrhage, or both. The edema can be vasogenic or cytotoxic, leading to increased intracerebral pressure. Suspect edema or hemorrhage if the patient remains unresponsive, continues to experience convulsions despite therapy, or exhibits sensory or motor neurologic deficits. In such cases, neuroimaging is indicated, and the patient should be managed in consultation with neurology or neurosurgery.
Once the patient has been stabilized—and not before—initiate the induction process. Be aware that during and after the convulsion, changes in fetal heart rate (FHR) and uterine monitoring will usually be evident:
- prolonged deceleration or bradycardia (3–10 minutes)
- compensatory tachycardia, decreased beat-to-beat variability
- transient recurrent decelerations
- increased uterine tone and greater frequency of uterine activity.
These changes in FHR and uterine activity usually last 3 to 15 minutes. For this reason, it is important to avoid rushing the patient for cesarean delivery, as FHR and uterine activity are likely to return to normal after maternal resuscitation and stabilization. If not, consider other causes, such as abruptio placentae.
Eclampsia itself is not an indication for cesarean delivery. The selection of mode of delivery should be based on the presence or absence of labor, the cervical Bishop score, fetal gestational age, fetal presentation, and overall fetal condition.
Regional analgesia/anesthesia is the method of choice for most women with eclampsia. However, regional anesthesia is to be avoided in the presence of disseminated intravascular coagulation or thrombocytopenia (the threshold platelet count is usually less than 75 x 103 µL. In such a case, IV analgesia can be used during labor, and general anesthesia may be appropriate for cesarean delivery. Both spinal and epidural analgesia and anesthesia are appropriate for women with eclampsia.
A hypertensive emergency during pregnancy or postpartum involves acute-onset, persistent (>15 minutes), severe systolic BP (≥160 mm Hg) or severe diastolic BP (≥110 mm Hg), or both. The first step in such an emergency is to ensure the accurate measurement of BP using standard techniques.
Patients with acute-onset, persistent, severe BP should be hospitalized promptly for evaluation and treatment to prevent organ damage. Once such a patient is hospitalized, BP should be recorded every 15 minutes, with continuous FHR monitoring to ensure fetal viability.
Related article: Failure to diagnose preeclampsia and more (Medical Verdicts, February 2013)
The timing of initiation of antihypertensive medications, as well as determination of the type of medication best suited for the patient, should be based on:
- systolic and diastolic BP levels
- maternal clinical and laboratory findings
- presence of associated symptoms
- preexisting medical comorbidities
- whether the patient is antepartum or postpartum.
For example, a sustained BP level of 200/120 mm Hg requires therapy after 15 minutes, whereas observation may be suitable for as long as 60 minutes for a sustained BP of 160/72 mm Hg during labor.
Rapid reduction of systolic BP can lead to marked reductions in uteroplacental blood flow and a nonreassuring FHR tracing. Moreover, a rapid reduction of severe systolic BP in patients who have constricted plasma volume can reduce perfusion to the kidney, brain, and placenta. However, sustained BP of 165/100 mm Hg in association with central nervous system signs or symptoms, congestive heart failure, thrombocytopenia, or postpartum status requires therapy within 1 hour.
In general, it is difficult to obtain accurate BP recordings using noninvasive electronic instruments during labor because of the effects of labor on systolic BP and the lack of standardized methods for positioning of the arm cuff and the patient.
For these reasons, the decision about when to start acute antihypertensive therapy, based on systolic or diastolic BP, or both, should be individualized. And the choice of antihypertensive agent should be based on maternal clinical findings.
Because both hydralazine and nifedipine are associated with tachycardia, avoid them in patients with a heart rate above 110 bpm, using labetalol instead.10
In patients with bradycardia (heart rate <60 bpm), asthma, or congestive heart failure, however, labetalol should be avoided. In these populations, hydralazine or nifedipine is the drug of choice. Nifedipine is associated with improved renal blood flow and a resultant increase in urine output, making it preferable for patients with decreased urine output or severe postpartum hypertension.10
One theoretical concern is that the combined use of nifedipine and magnesium sulfate can cause excessive hypotension and neuromuscular blockage. As a result, some experts recommend that nifedipine be avoided in patients receiving magnesium sulfate. However, a recent review of this subject concluded that combined use of these drugs does not increase the risks of excessive hypotension and neuromuscular blockage in patients with severe hypertension or preeclampsia.
