Case: Woman Presents to ED With Headache and Hypertension

Prevention of Seizures

In addition to treating her hypertension, prevention of seizures (eclampsia) is also important. Intravenous magnesium sulfate is the choice for prevention and treatment of eclampsia-induced seizure in the peripartum period. ACOG recommends the use of magnesium sulfate for women with new-onset hypertension associated with headache or blurred vision or preeclampsia with severe hypertension in the postpartum period. Common dosing of magnesium sulfate includes: IV bolus of 4-6 g over 20-30 minutes, followed by IV infusion of 1-2 g per hour continued for 24 hours. If no IV access has been established, an alternative loading dose is to use 10 g of 50% solution IM (5 g in each buttock), followed by 5 g every 4 hours.

The adverse effects of magnesium sulfate come largely from its action as a smooth-muscle relaxant. Clinical monitoring for magnesium toxicity can include monitoring of urine output and respiratory status, and ensuring presence of deep tendon reflexes. Patients with renal insufficiency (serum creatinine 1.0-1.5 mg/dL) or oliguria (< 30 mL urine output/4 hours) need a reduced maintenance dose (1 g/hour). In women with renal dysfunction, laboratory determination of serum magnesium levels every 4 hours becomes necessary.^[3]

Patient safety groups recommend that healthcare facilities that care for pregnant and postpartum patients should have standardized education and protocols for monitoring and treating preeclampsia and eclampsia.

Additional Testing

Additional diagnostic testing should be guided by the clinical presentation. Characteristics that should prompt neuroimaging and/or consultation with neurology include thunderclap headaches, any headache associated with altered mental status, seizures, visual disturbances, or focal neurologic deficits, and refractory headaches after treatment of severe hypertension. Neuroimaging studies to consider include CT scan to exclude hemorrhage or mass; MRI to detect acute ischemia, posterior reversible encephalopathy syndrome (PRES), or hemorrhage; CT or MR angiography of head and neck to detect vasospasm or dissection; and CT or MR venography to detect venous thrombosis. It is important to note that contrast (CT or MRI) is not contraindicated in lactating patients.

Several studies have noted the prevalence of clinical signs and symptoms of volume overload, such as shortness of breath and peripheral edema, among women with postpartum preeclampsia. Brain natriuretic peptide (BNP) is commonly used in the diagnosis, prognosis, and risk stratification of heart failure for non-pregnant patients (upper limit of normal < 100 pg/mL). It may be a useful adjunct to confirm the diagnosis of volume overload for symptomatic women with postpartum preeclampsia.^[1]

Ongoing Case Management

After intravenous access was established, this patient was treated with intravenous labetalol and received magnesium sulfate for seizure prophylaxis for 24 hours. Her blood pressure normalized and her headache resolved. She was transitioned to oral labetalol 400 mg two times a day with a blood pressure goal of 140-150/90 mm Hg and was discharged on hospital day 3. She was given a blood pressure monitor for home use and received education in self-monitoring of blood pressure, including when and how to reach her obstetrician/gynecologist (ob/gyn).

She was seen by her ob/gyn 1 week after discharge and continued her antihypertensive medications. Her ob/gyn continued to monitor her hypertension, and her medications were discontinued at her comprehensive postpartum visit 10 weeks following her delivery. She was counseled about the increased lifetime risk for cardiometabolic disease associated with preeclampsia, and her care was transitioned to a primary care provider.

Current guidelines do not specify standardized management with specific antihypertensive agents or parameters for medication titration in the postpartum period.^[3] Physician preference, experience, cost of drug, safety during breastfeeding, and frequency of administration become important factors that affect the choice of therapy. Of note, both nifedipine and labetalol are safe in breastfeeding women.^[1]

Summary

Healthcare professionals should routinely ask if patients are pregnant or were pregnant in the past year. This information is important to consider for making an accurate and timely diagnosis and for identifying appropriate treatment and management. Many peripartum complications (including preeclampsia) may present with low-acuity complaints such as headache. The initial delays in this patient's care illustrate the importance of healthcare professionals recognizing the signs and symptoms of pregnancy-related complications such as preeclampsia.

Obstetric professionals should also educate patients about the potential for pregnancy-related complications up to a year after pregnancy and provide take-home materials at discharge. Encourage patients to tell or remind medical staff at future medical appointments of their recent pregnancy status.