What is the management for a patient with preeclampsia experiencing sudden unilateral vision loss?

Management of Sudden Unilateral Vision Loss in Preeclampsia

Sudden unilateral vision loss in a patient with preeclampsia requires immediate ophthalmologic consultation and urgent delivery to prevent permanent blindness and other severe maternal complications.

Initial Assessment and Stabilization

• Immediately evaluate for signs of severe preeclampsia:

  • Blood pressure measurements (target: diastolic BP of 85 mmHg and systolic <160 mmHg) 1
  • Neurological symptoms (headache, hyperreflexia, clonus)
  • Laboratory tests (platelet count, liver enzymes, creatinine)
  • Proteinuria assessment

• Urgent ophthalmologic consultation for:

  • Dilated fundoscopic examination
  • Assessment for retinal detachment, retinal arteriole occlusion, or acute angle-closure glaucoma 2, 3, 4
  • Point-of-care ocular ultrasound if available 4

Medical Management

1. Antihypertensive therapy:

   • For severe hypertension (BP ≥160/110 mmHg):
     • IV labetalol: 20 mg IV bolus, then 40 mg 10 minutes later, followed by 80 mg every 10 minutes for 2 additional doses to maximum of 220 mg 1
     • Hydralazine: 5 mg IV bolus, then 10 mg every 20-30 minutes to maximum of 25 mg 1
     • Oral nifedipine: 10 mg, repeat every 20 minutes to maximum of 30 mg (caution when used with magnesium sulfate) 1

2. Seizure prophylaxis:

   • Administer magnesium sulfate for convulsion prophylaxis 1
   • Standard dosing: 4-6 g IV loading dose over 15-20 minutes, followed by 1-2 g/hour continuous infusion

3. Corticosteroids:

   • If <34 weeks gestation, administer betamethasone or dexamethasone for fetal lung maturity 1
   • Complete 48-hour course if maternal and fetal condition permits

Obstetric Management

The definitive treatment for preeclampsia with visual complications is delivery:

1. Timing of delivery:

   • Visual loss represents an abnormal neurological feature and is an absolute indication for delivery regardless of gestational age 1
   • Do not delay delivery to complete steroid course if maternal condition is deteriorating

2. Mode of delivery:

   • Vaginal delivery is preferable if feasible 1
   • Cesarean section if:
     • Fetal distress
     • Unfavorable cervix with need for expedited delivery
     • Other obstetric indications

Post-delivery Management

1. Continue antihypertensive medications after delivery 5

   • Monitor BP at least every 4-6 hours for at least 3 days postpartum
   • First-line oral medications: labetalol, extended-release nifedipine, or methyldopa

2. Ophthalmologic follow-up:

   • Arrange close follow-up with ophthalmology
   • Visual symptoms may persist despite delivery and BP control 2, 3
   • Some cases of visual loss may be irreversible despite appropriate management

3. Long-term follow-up:

   • Continue BP monitoring for at least 6 weeks postpartum
   • Complete evaluation at 3 months including BP measurement, urinalysis, and laboratory tests 5
   • Counsel regarding increased future risk of cardiovascular disease and recurrent preeclampsia

Pitfalls and Caveats

• Visual loss in preeclampsia is often attributed to cerebral edema, but retinal pathology (detachment, arteriole occlusion) can cause permanent blindness 3
• Do not delay ophthalmologic evaluation or delivery when visual symptoms occur
• Avoid NSAIDs for postpartum pain relief in patients with preeclampsia 5
• Avoid diuretics as plasma volume is already reduced in preeclampsia 5
• Do not attempt to diagnose mild versus severe preeclampsia clinically as all cases may become emergencies rapidly 1

Visual loss in preeclampsia represents a medical emergency that requires immediate intervention to prevent permanent disability. The combination of prompt ophthalmologic evaluation, aggressive blood pressure control, seizure prophylaxis, and timely delivery offers the best chance for visual recovery and maternal safety.