Preeclampsia and eclampsia: 7 management challenges (and zero shortcuts)
From making the diagnosis to treating atypical eclampsia, management of preeclampsia involves serious, often unpredictable challenges
IN THIS ARTICLE
The authors report no financial relationships relevant to this article.
CASE: At risk, or just very pregnant?
At her first prenatal visit, a 31-year-old gravida has blood pressure (BP) of 100/60 mm Hg, no proteinuria, and normal weight for her gestational age. As she enters the third trimester, however, her BP rises to 138/86 mm Hg, she now has proteinuria of 1+, and she has gained 10 lb in the past 2 weeks.
Does she have preeclampsia, or do these findings reflect normal development in the last trimester?
These findings, in and of themselves, may not indicate preeclampsia—but they do suggest a serious risk of developing the disease.
Preeclampsia complicates approximately 3% to 7% of nulliparous pregnancies in the United States, and about 0.8% to 5% of multiparous pregnancies.
Although severe preeclampsia represents only a fraction of those amounts, and eclampsia an even lower percentage, they are potentially catastrophic complications of pregnancy and one of the leading causes of maternal death. They also are responsible for a large percentage of infants born prematurely as a result of a worsening maternal or fetal condition.
Preeclampsia and eclampsia are obstetric diseases, and obstetricians are the group best equipped to diagnose, evaluate, and manage them. In this article, we highlight seven challenges that obstetricians face when managing preeclampsia and eclampsia, and offer useful strategies to help minimize morbidity and mortality in both mother and infant.
CHALLENGE NO. 1: Making the diagnosis
Good prenatal care is a prerequisite
We can’t overemphasize the importance of early and adequate prenatal care! Although the diagnostic criteria for preeclampsia have been widely established—persistent BP elevation above 140/90 mm Hg and proteinuria exceeding 300 mg over a 24-hour collection period—the condition does not always play by the rules. With close monitoring of weight, urine protein, and BP, the clinician can identify and follow potentially worrisome trends.
Earlier diagnostic criteria—which included a rise in systolic BP of 30 mm Hg or a rise in diastolic BP of 15 mm Hg above initial baseline BP, as well as the presence of pathologic edema—may have been revised, but it remains important for clinicians to put all pieces of clinical information together at each visit. For example, given her rising BP, proteinuria, and weight gain, the patient in the opening case must be considered at risk for preeclampsia. Suspicion also is justified if the patient has any of the risk factors for preeclampsia in TABLE 1.
Risk factors for preeclampsia
Early detection is critical
Early identification of preeclampsia may allow for interventions, including delivery, that will lessen the risk of progression to severe preeclampsia and eclampsia and reduce fetal and maternal morbidity and mortality. It is, therefore, essential for the clinician to ask specifically about signs and symptoms of preeclampsia and to listen carefully to the answers.
Signs and symptoms may sometimes be typical:
- weight gain
- increasing edema
- persistent headache
- blurred vision.
At times, however, they may also be nonspecific:
- epigastric discomfort
- right upper-quadrant discomfort.
Although a number of tests have been proposed to predict who may be at greatest risk for preeclampsia, none have risen to the level that they can be recommended for general population screening.
The diagnosis of preeclampsia is based on persistent BP elevation above 140/90 mm Hg and proteinuria exceeding 300 mg over a 24-hour collection period.1 Other criteria have been applied, such as a rise in systolic or diastolic BP above baseline and urine dipstick criteria for proteinuria, but BP above 140/90 mm Hg and proteinuria above 300 mg are most frequently used in medical centers in the United States.2
Gestational hypertension and chronic hypertension do sometimes coexist with superimposed preeclampsia, but should not be confused with preeclampsia or lead to management decisions that should apply only to patients with preeclampsia.3
Before severe preeclampsia can be diagnosed, the initial criteria for preeclampsia should have been fulfilled, along with one or more of the findings listed in TABLE 2.
Attempts to predict preeclampsia have met with poor results. Measurement of the ratio of uterine artery systolic to diastolic flow has not been informative in the general healthy population of pregnant women. Nor has uric acid determination been useful; it generally has very poor predictive value and should be interpreted with caution.
13 criteria for establishing severe preeclampsia
Hospitalization is essential for severe disease
Mild preeclampsia can be managed expectantly until fetal maturity or 37 weeks’ gestation. Severe preeclampsia can be managed expectantly in the mid trimester or early third trimester if both mother and fetus are stable, but hospitalization is necessary in a tertiary care facility that has critical-care OB expertise, an ICU facility, and a NICU facility and personnel on site.
Distinguish an existing condition from superimposed preeclampsia
One of the most difficult management challenges is the diagnosis of superimposed preeclampsia. Patients who have chronic hypertension often have underlying renal disease as well; in these patients, it may be difficult, if not impossible, to distinguish a worsening underlying medical condition from superimposed preeclampsia.
Our advice is not to agonize about this difference too much in the patient at or near term, as delivery may be indicated and the patient’s postpartum course may help resolve the question, with rapid resolution tending to favor a diagnosis of superimposed preeclampsia.
It also is important to note whether these patients are receiving antihypertensive therapy. If they are, hospitalization is recommended until delivery once the diagnosis of superimposed preeclampsia is made.
Given that the use of antihypertensive agents removes one of the major indicators of disease progression (i.e., rising BP), it is our practice to deliver these patients according to our severe preeclampsia management protocol and not to carry such pregnancies beyond 34 weeks. In carefully selected cases, the pregnancy can be continued to 37 weeks, but the decision to do so should be weighed carefully—ideally, with input from a maternal–fetal medicine specialist.
CHALLENGE NO. 2: Forgoing shortcuts
Evaluation and management of preeclampsia are relatively straightforward, but there are no shortcuts. Many patients who feel well initially may push for outpatient evaluation, but once a diagnosis of preeclampsia is established, in-hospital evaluation is preferable, at least until the degree of illness can be determined, fetal well-being can be established, and the patient’s candidacy for subsequent outpatient management can be more fully determined.
In-hospital management may be particularly useful for patients who have any of the risk factors for preeclampsia listed in TABLE 1.
Initial evaluation consists of:
- fetal nonstress testing
- amniotic fluid index
- serial BP determination
- 24-hour urine collection
- initial laboratory evaluation comprising a complete blood count with platelets and aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatinine levels.
Additional tests may be ordered as indicated but are of limited value in making management decisions.
If fetal and maternal evaluations are reassuring, and if the patient has remained stable, then outpatient management may be considered. In general, if proteinuria exceeds 1 g in 24 hours, in-hospital management is recommended, regardless of other parameters.
If outpatient management is considered, the level of care and surveillance must mirror what could be provided in the hospital. Hospitalization alone will not prevent all cases from progressing to severe preeclampsia or eclampsia, but daily and diligent observation and evaluation may minimize the risk.
CHALLENGE NO. 3: Treating the disease
Appropriate treatment of preeclampsia requires not only that the patient show up for prenatal care, but also that we:
- are certain of the diagnosis
- recognize the potential seriousness of the disease
- are thorough (remember, no shortcuts!).
Too often, aspects of the overall preeclamptic disease process are overlooked during evaluation and management of pregnant patients. For example, by focusing exclusively on epigastric pain, the clinician may lean toward a diagnosis of gallbladder disease rather than consider it as one component of preeclampsia.
Many experts in the field of preeclampsia have stated, on numerous occasions, that preeclampsia is more than simple hypertension. It is almost never advisable to initiate antihypertensive therapy for a patient in the third trimester when she was previously normotensive, because one runs the risk of masking a key clinical parameter used to assess disease progression.
In our institutions, any patient who is taking antihypertensive medication and in whom we are entertaining a diagnosis of preeclampsia is recommended for hospitalization for the duration of her pregnancy or until a diagnosis of preeclampsia can be ruled out with reasonable certainty.
Because preeclampsia is a multisystem disease, it has maternal, placental, and fetal consequences. The cure for preeclampsia remains delivery of the placenta. Expectant management offers no maternal benefit, but does offer some potential neonatal benefits if prematurity is a concern. Once concerns about prematurity have been largely eliminated, generally by achieving a gestational age of 37 weeks, further expectant management is not indicated, offers little or no additional benefit to the fetus, and leaves both mother and fetus at risk.
Therefore, once the pregnancy reaches 37 weeks, delivery is recommended.
When preeclampsia is severe, and when it is superimposed in a patient who is taking antihypertensive medication, we generally do not continue the pregnancy beyond 34 weeks.4 In our institutions, most patients who are being expectantly managed for severe preeclampsia remote from term—and who have remained stable—are delivered between 32 and 34 weeks’ gestation, depending on the specific clinical circumstances.
CHALLENGE NO. 4: Controlling blood pressure
Cerebrovascular accident (stroke) is the leading cause of maternal mortality from preeclampsia in the United States. Not all cases can be prevented, but one suggested preventive strategy is adequate BP control. Some cases of stroke in the setting of preeclampsia will occur despite systemic BP readings that are not considered to be in a dangerous range. One reason may be an override of normal cerebral blood flow autoregulatory mechanisms, resulting in increased cerebral blood flow, rising cerebral perfusion pressures, and vessel rupture. Such occurrences may sometimes, but not always, be related to coagulopathy.
When a patient has elevated BP, generally defined as persistent systolic pressures above 160 to 170 mm Hg and persistent diastolic pressures above 105 to 110 mm Hg, antihypertensive therapy is indicated and should be administered in a timely fashion.
Labetalol, nifedipine, and hydralazine have all been used effectively in such acute settings, when administered parenterally (except nifedipine, which may be given orally) and when given in proper dosages (TABLE 3).
Avoid oral use of labetalol or hydralazine to treat acute hypertensive emergencies.
Pharmacotherapy of acute hypertension
5 mg IV
Repeat in 10 min, then give 10 mg IV every 20 min until BP stabilizes (140–150/90–100 mm Hg)
10–20 mg IV push
Repeat every 10-20 min, doubling the dosage each time until a maximum total cumulative dosage of 300 mg has been given
Repeat in 20 min for four doses (maximum 40 mg); then give 10–20 mg orally every 4–6 h to achieve a stable BP of 140–150/90–100 mm Hg
* If target blood pressure is not reached after the maximum dosage of an agent is given, then additional or alternative pharmacotherapy must be utilized.
Goals for treatment
In the antepartum patient, the goal is to maintain systolic BP at 140 to 150 mm Hg and diastolic pressure at 90 to 100 mm Hg to keep from inadvertently inducing uteroplacental insufficiency secondary to reduced uterine blood flow.
In the delivered patient, the risk of mild hypotension is not quite as great, although an attempt to rapidly return the patient to her previous normal BP profile may cause symptomatic hypotension.
If a patient develops a true hypertensive crisis with hypertensive encephalopathy (which generally occurs at BPs exceeding 240/140 mm Hg), then emergent intervention with a rapidly acting agent such as sodium nitroprusside is necessary and should be managed by someone skilled in critical care and the use of such drugs.
CHALLENGE NO. 5: Preventing seizures