Rapidly reversible visual loss in posterior reversible encephalopathy syndrome: An ophthalmologist's enigma.

Posterior reversible encephalopathy Syndrome (PRES) may present with a sudden onset reversible visual loss under special visual conditions. Such patients' may initially be misdiagnosed as Malingering. Ophthalmologists may be the first physicians to be confronted by such patients. Hence, a knowledge of this condition is vital to diagnosis and management of such conditions.

Introduction

An 18-year-old female presented to our clinic with sudden onset decrease of vision in both eyes 10 days postpartum. She complained of headache and was irritable. Her best corrected visual acuity was hand movements close to face with an accurate projection of rays. Her anterior segment was normal. Extra-ocular movements were full. Pupils were briskly reacting to light and fundus examination was normal in both eyes [Figure 1].

Figure 1

Color fundus photograph of the patient showing a normal fundus

Visual evoked potential showed extinguished response [Figure 2]. She was advised magnetic resonance imaging (MRI) brain which showed presence of multiple round to oval lesions which were hyperintense on the T1-, T2- and fluid attenuated inversion recovery (FLAIR) weighted images in the posterior parietal, temporal and occipital lobes and cerebellum [Figures 3–6]. Corresponding diffusion weighted scans did not show the presence of a corresponding restriction suggesting cerebral edema. A diagnosis of the posterior reversible encephalopathy syndrome (PRES) was made. Patient's antenatal, natal and postnatal periods were uneventful. It was decided to observe the patient and patient had a spontaneous recovery of visual acuity to 20/20 over 3 days.

Figure 2

Visual evoked potential of both eyes of the case showing bilateral extinguished pattern but reproducible flash visual evoked potential suggestive of visual pathway lesions

Figure 3

Axial T1-weighted image of the magnetic resonance imaging brain showing the presence of the hyperintense lesions suggestive of edema in the bilateral occipital and temporal lobes (white arrows)

Figure 6

Diffusion weighted scan of the magnetic resonance imaging brain showing no restriction of diffusion suggestive of lesions being vasogenic edema rather than infarcts

Axial fluid attenuated inversion recovery weighted image of the magnetic resonance imaging brain showing the presence of the hyperintense lesions in the medial temporal lobes (white arrows)

Axial T2-weighted image of the magnetic resonance imaging brain showing the presence of the hyperintense lesions in the cerebellum and medial temporal lobes (white arrows)

Discussion

PRES is characterized by neurotoxic manifestations such as headache, visual disturbances, aphasia, facial numbness, seizure, and ataxia.[1] It results from the edematous lesions of the central nervous system and brainstem, especially parietooccipital lobes. These lesions result from a disruption of the cerebral perfusion auto-regulation leading to a vasogenic cerebral edema.[1] The presence of blood pressure fluctuations, toxemia of pregnancy (eclampsia or preeclampsia), connective tissue disorders, systemic inflammatory response syndrome, medications may lead to this condition.[23] The characteristic MRI findings of T2 and FLAIR hyperintense lesions that may take three patterns (holohemispheric watershed, superior frontal sulcus or parietooccipital).[2] Visual disturbances are common and usually resolve without a permanent deficit. The ophthalmologists and radiologists should be aware of this condition to diagnose and manage patients.

Financial support and sponsorship

Hyderabad Eye Research Foundation, HERF, Hyderabad, Andhra Pradesh, India.

Conflicts of interest

There are no conflicts of interest.