What is the best next step for a 35-week pregnant patient with preeclampsia, presenting with a severe headache, hypertension, and impaired renal function?

Magnesium Sulfate for Seizure Prophylaxis

The best next step is magnesium sulfate for seizure prophylaxis, followed by urgent blood pressure control with IV antihypertensives, and preparation for delivery after maternal stabilization. 1, 2

Clinical Presentation Analysis

This patient presents with severe preeclampsia with features of severe disease:

• Severe hypertension (BP 160/105 mmHg) 3
• Severe headache (neurological symptom indicating CNS involvement) 3
• Renal dysfunction (creatinine 1.8 mg/dL, significantly elevated) 3
• Significant proteinuria (2+ on urinalysis) 2
• No prenatal care at 35 weeks gestation 3

The presence of severe headache with severe hypertension constitutes an indication for immediate magnesium sulfate administration. 1, 2

Immediate Management Algorithm

Step 1: Magnesium Sulfate Administration (First Priority)

Magnesium sulfate must be administered immediately for seizure prophylaxis because this patient has severe hypertension (≥160/105 mmHg) with neurological symptoms (severe headache). 1, 4, 2

• Loading dose: 4-5g IV over 5 minutes 1
• Maintenance: 1-2g/hour continuous IV infusion 1
• Duration: Continue for 24 hours after delivery or last seizure 1
• Monitoring: Assess deep tendon reflexes, respiratory rate (must be >12/min), and urine output (>100mL over 4 hours) 1, 2

Critical precaution: Have injectable calcium salt immediately available to counteract potential magnesium toxicity. 1

Step 2: Urgent Blood Pressure Control (Concurrent Priority)

Blood pressure ≥160/105 mmHg requires urgent treatment in a monitored setting. 3, 2

First-line IV antihypertensive options:

• Labetalol IV: 20mg bolus, then 40mg after 10 minutes, then 80mg every 10 minutes to maximum 220mg 3, 1
• Nicardipine IV: Start at 5mg/h, increase by 2.5mg/h every 5-15 minutes to maximum 15mg/h 1, 5
• Hydralazine IV: 5mg bolus, then 10mg every 20-30 minutes to maximum 25mg 3

Target blood pressure: Diastolic 85 mmHg and systolic 110-140 mmHg 4, 2

Important caveat: Avoid combining magnesium sulfate with calcium channel blockers (like nicardipine or nifedipine) due to risk of severe hypotension. 3, 1 If using nicardipine, exercise extreme caution with concurrent magnesium administration. 3

Step 3: Preparation for Delivery

Delivery should be planned after maternal stabilization at this gestational age (35 weeks). 3, 1

Indications for immediate delivery in this case include:

• Severe headache (neurological feature) 3
• Deteriorating renal function (creatinine 1.8 mg/dL) 3
• Gestational age ≥34 weeks 1, 4

Vaginal delivery is preferred unless cesarean is indicated for obstetric reasons. 3, 4

Why Not the Other Options?

Ciprofloxacin (Incorrect)

While the urinalysis shows positive leukocyte esterase and nitrites suggesting UTI, this is NOT the priority. The patient has life-threatening severe preeclampsia with neurological symptoms requiring immediate seizure prophylaxis and blood pressure control. 1, 2 The UTI can be addressed after stabilization.

Emergent Delivery (Premature Without Stabilization)

Delivery should occur AFTER maternal stabilization with magnesium sulfate and blood pressure control, not emergently before stabilization. 3, 1 Attempting delivery without first controlling seizure risk and severe hypertension places both mother and fetus at unnecessary risk. 3

Nicardipine Alone (Incomplete Management)

While nicardipine is appropriate for blood pressure control, using it without magnesium sulfate ignores the critical need for seizure prophylaxis in a patient with severe preeclampsia and neurological symptoms. 1, 2 Additionally, combining nicardipine with magnesium sulfate requires extreme caution due to risk of precipitous blood pressure drop. 3, 1

Critical Monitoring Requirements

Continuous maternal monitoring must include:

• Blood pressure every 15 minutes during acute treatment, then every 4 hours 4, 2
• Deep tendon reflexes and respiratory rate (signs of magnesium toxicity) 1, 2
• Urine output (maintain >100mL per 4 hours) 1
• Oxygen saturation 2

Laboratory monitoring every 2 days minimum:

• Complete blood count (hemoglobin, platelets) 4, 2
• Liver enzymes (AST, ALT) 4, 2
• Creatinine 4, 2

Fetal monitoring:

• Continuous fetal heart rate monitoring 1, 2
• Ultrasound assessment of fetal status 1, 2

Common Pitfalls to Avoid

• Never delay magnesium sulfate while waiting for blood pressure control in patients with neurological symptoms. 1, 2
• Avoid rapid or excessive blood pressure reduction as this can compromise uteroplacental perfusion and cause fetal distress. 6
• Do not use sodium nitroprusside due to risk of fetal cyanide toxicity. 1
• Avoid diuretics as plasma volume is already reduced in preeclampsia. 3, 1
• Do not use NSAIDs for analgesia, especially with renal dysfunction. 4