to the editor: Although preeclampsia is typically diagnosed in the prenatal period, we would like to describe an unusual case of late-onset eclampsia presenting postpartum as sudden bilateral cortical blindness.

The patient was a healthy, 21-year-old black woman, gravida three, para one, with a previous normal pregnancy and no history of hypertension or preeclampsia. She had an unremarkable prenatal course and her blood pressure prenatally ranged from 98/62 mm Hg to 130/80 mm Hg one week before delivery. Urine protein was zero or trace at all visits. She delivered a healthy 2,670 g (5 lb, 8 oz) male infant at term. Blood pressures immediately postpartum were mostly 120s to 130s/60s to 70s mm Hg with occasional pressures of 140 to 150/80 to 90 mm Hg.

Eight days after delivery, the patient awoke with a severe bilateral frontal headache and blurry vision. Over several hours, this progressed to acute bilateral cortical blindness. Initial evaluation showed blood pressure of 169/99 but without proteinuria. Subsequent 24-hour urine collection showed 0.28 grams protein. Computed axial tomography of the brain demonstrated bilateral low attenuation lesions in the cerebral hemispheres; magnetic resonance imaging revealed diffuse altered T2 signals in a posterior distribution. Cerebral angiogram was normal. Twenty hours after the onset of symptoms the patient developed altered mental status and had two tonic-clonic seizures, at which point she was treated with phenytoin (Dilantin) and magnesium.

The patient’s headache and vision quickly improved and by 48 hours her vision had returned to 20/20 acuity. Her blood pressure continued to be elevated throughout her hospital stay, at one point reaching 200/110 mm Hg. Three days after admission, she was discharged home on metoprolol.

Preeclampsia in pregnancy is defined as new-onset elevated blood pressure (>140/90 mm Hg) along with proteinuria after 20 weeks of gestation.^1,2 Severe cases may progress to eclampsia characterized by seizures. A multicenter review³ of preeclampsia found up to one third of cases developed postpartum with 80 percent of these occurring three to 14 days after delivery. One case report⁴ describes onset 26 days after delivery.

Although visual changes such as blurry vision or scotoma are common, they may be more typical of late-onset disease.^3,5 One study reported visual symptoms in 44 percent of patients with late-onset preeclampsia.³ Acute cortical blindness has been estimated to occur in 1 to 3 percent of patients with eclampsia, although a review of 15 cases noted a prevalence of 15 percent.⁵ Our patient was similar to patients in that case series including the transient nature of visual loss (four hours to eight days in their review) and mental status changes (three of their 15 patients) but had minimal urine protein and relatively mild hypertension on initial presentation.

Because 90 percent of women presenting with late postpartum preeclampsia have a headache and close to one half have some type of visual disturbance, physicians providing obstetric care should be alert for these symptoms as an unusual presentation of this disease. This case demonstrates that preeclampsia is less common in multiparous patients, but it can be severe when it develops.