July 02, 2020
6 min read
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Young preeclamptic woman presents with vision loss

OCT confirmed a serous retinal detachment of the right macula with some focal disruption of the retinal pigment epithelium.

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A 20-year-old primigravid woman was admitted to the labor and delivery ward at Tufts Medical Center for monitoring of preeclampsia. She was at 32 weeks of gestation.

The patient was referred from an outside hospital because of peripheral edema, systolic blood pressure greater than 160 mm Hg and proteinuria. Her medical history was pertinent only for anemia. She was started on oral nifedipine and given intravenous magnesium for seizure prophylaxis as well as betamethasone to promote fetal lung maturity. After admission, her blood pressure measurements were in the normal to mildly elevated range.

Alison J. Lauter
Alison J. Lauter
Sarah E. Thornton
Sarah E. Thornton

On the fifth day of admission, the patient developed right-sided blurry vision. She was initially evaluated by the inpatient neurology team, which did not note any neurologic deficits and recommended brain MRI/MRV, which was unremarkable. Ophthalmology was consulted for evaluation. Upon questioning, the patient described a few days of worsening right-sided blurry vision without pain, metamorphopsia, flashes, floaters or black spots. She felt that the vision in her left eye was at baseline at this initial visit.

Examination

Upon examination in the office, the patient’s best corrected visual acuity was 20/25-1 in the right eye and 20/25-2 in the left eye. Her color vision was intact in each eye. Confrontation visual fields as well as extraocular muscle motility were full bilaterally, and pupils were equal in size without evidence of an afferent pupillary defect. Anterior segment evaluation showed bilateral conjunctival chemosis greater in the temporal quadrants. The patient refused dilated fundus examination. An undilated view of the right optic nerve revealed sharp borders without edema and a small cup-to-disc ratio. The right macular details appeared less discrete compared with the left macula.

OCT on initial presentation
Figure 1. OCT of the right eye (a) and left eye (b) on initial presentation. OCT of the right eye demonstrates a serous retinal detachment with disruption of the RPE. The left eye has normal contour and retinal architecture.

Source: Chelsea Gottschalk, MD, Thomas R. Hedges III, MD, and Melina I. Morkin, MD

Imaging

OCT of the macula confirmed a serous retinal detachment of the right macula with some focal disruption of the retinal pigment epithelium (RPE) and revealed an area of outer retina tethered to the RPE nasally (Figure 1a). OCT of the left eye was within normal limits (Figure 1b). OCT of the retinal nerve fiber layer (RNFL) demonstrated right temporal edema secondary to adjacent serous fluid.

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Retinal detachment

Based on the smooth appearance of the detachment, the location in the nasal macula, the lack of pigment in the vitreous, and the absence of subjective flashes or floaters, it was felt that this detachment did not represent a rhegmatogenous retinal detachment even though a detailed dilated exam was not possible due to the patient’s refusal.

Serous, also known as exudative, retinal detachment can be associated with a wide range of etiologies including infections (tuberculosis, syphilis), inflammation (Vogt-Koyanagi-Harada disease, posterior scleritis, sympathetic ophthalmia), neoplasia (melanoma, lymphoma), congenital causes (optic nerve pit), vascular causes (Coats disease, vein occlusion, preeclampsia, or hemolysis, elevated liver enzymes, low platelet syndrome) and idiopathic conditions (central serous chorioretinopathy). The patient’s medical history included only anemia. During her pregnancy, she had a negative rapid plasma reagin test, making syphilis less likely. Her examination did not reveal anterior chamber or vitreous inflammation. While a neoplastic process can cause serous retinal detachment, no masses or lesions were noted in the macula, and the patient’s complete blood count did not suggest malignancy. Additionally, her optic nerve exam and OCT RNFL did not show any abnormalities suggestive of an optic nerve pit.

While both pregnancy and glucocorticoids, given to this patient to promote fetal lung maturity, are risk factors for central serous chorioretinopathy, it was thought that this patient’s acute presentation was more likely related to her diagnosis of preeclampsia. Serous retinal detachments occur in about 1% of preeclamptic patients, with higher risk in patients with hemolysis, elevated liver enzymes, low platelet syndrome and eclampsia. The detachments almost always resolve in the postpartum period with blood pressure control and delivery.

Workup and management

The decision was made to observe the patient and continue preeclampsia management. Improvement of the serous detachment was expected to occur with time.

The patient remained in the hospital for monitoring with a plan to induce labor when the fetus reached 34 weeks of gestation. However, a few days before the induction and less than 1 week after initial ophthalmologic evaluation, the patient’s systolic blood pressure rose to 175 mm Hg despite continued antihypertensive therapy. Shortly thereafter, the patient had an eclamptic seizure lasting 1 minute. The decision was made by the obstetrics team to induce labor, which did not progress despite induction. Given nonreassuring fetal monitoring, the patient was taken to the operating room for an emergent cesarean section. She gave birth to a girl with low initial Apgar scores who was taken to the neonatal intensive care unit for monitoring.

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Less than 2 days after delivery, the patient reported worsening vision in both eyes. At that point, her blood pressure was well controlled on medical therapy. BCVA was 20/70-1 in the right eye and 20/50-1 in the left eye. Color vision remained intact in each eye, and anterior segment exam showed improved temporal chemosis bilaterally. Dilated fundus exam revealed increased obscuration of the macula in the right eye and new superonasal and inferonasal mottling in the left eye (Figures 2a and 2b). There were no retinal tears on peripheral examination. OCT of the right eye demonstrated worsening serous retinal detachment now involving the temporal macula, while the left OCT showed a new serous retinal detachment with shallow fluid in the nasal macula (Figures 2c and 2d).

 Fundus photos and macular OCT after the patient’s eclamptic seizure
Figure 2. Fundus photos and macular OCT after the patient’s eclamptic seizure. There is blunting of the foveal reflex in the right eye (a) and hypopigmented mottling surrounding the optic nerve head and in the nasal macula in the left eye (b). OCT shows a worsening serous detachment in the right eye (c) and a new shallow serous detachment in the left eye (d).

At this point, due to the patient’s discomfort after her cesarean section and concerns for unnecessary exposure in the setting of the COVID-19 pandemic, the patient did not undergo further imaging or testing. The subretinal fluid was expected to slowly improve after delivery with continued observation and blood pressure control.

At the patient’s 5-week follow-up visit, her blood pressure remained well controlled. Her BCVA measured 20/30 bilaterally. Fundus examination demonstrated bilateral macular mottling without blunting of the foveal reflex. OCT showed resolved serous retinal detachments bilaterally with outer retinal disruption in the region of the ellipsoid and interdigitation zones (Figure 3).

resolved serous detachments bilaterally
Figure 3. Macular OCT of the right eye (a) and left eye (b) shows resolved serous detachments bilaterally with subtle residual outer retinal disruption (see insets).

Discussion

Preeclampsia is thought to be secondary to abnormal placentation resulting in endothelial dysfunction that leads to increased peripheral vascular resistance, hypertension, proteinuria and generalized edema. This condition can progress to eclampsia, which is characterized by seizures or coma and is associated with a worse outcome for both mother and infant. The most common ocular manifestations of preeclampsia include retinal arteriolar narrowing, which can precede preeclampsia diagnosis, hypertensive retinopathy with hemorrhages and cotton wool spots, vein or artery occlusions, and Elschnig spots (focal choroidal ischemia). Affected patients can also experience cerebral infarction leading to cortical blindness, which is why it is imperative to perform neurological imaging when indicated.

In the setting of preeclampsia, serous retinal detachments are believed to result from increased systemic vascular resistance causing choroidal and RPE ischemia, followed by disruption of the blood-retinal barrier and extravasation of serous fluid into the subretinal space. This is similar to proposed mechanisms for the development of central serous chorioretinopathy. Our patient was at higher risk because she had preeclampsia with severe features that eventually progressed to eclampsia. OCT angiography may show choroidal flow defects in these patients, and intravenous fluorescein angiography may demonstrate early choroidal filling defects followed by late leakage. Additionally, choroidal ischemia in these patients is associated with a thickened choroid, best evaluated by enhanced depth imaging OCT.

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Preeclampsia-associated serous retinal detachments are often diagnosed postpartum and resolve within a few months of delivery. Interim treatment includes observation, blood pressure management and early delivery if there is fetal compromise or progression to eclampsia. The role of steroids in recovery remains controversial.