|Year : 2014 | Volume
| Issue : 2 | Page : 111-112
Posterior reversible encephalopathy syndrome
Sumana J Kamath, Priyansha Multani, Madhurima A Nayak
Department of Ophthalmology, Kasturba Medical College, Mangalore, Karnataka, India
|Date of Submission||11-May-2013|
|Date of Acceptance||19-Sep-2013|
|Date of Web Publication||11-Apr-2014|
Madhurima A Nayak
Department of Ophthalmology, Kasturba Medical College Hospital, Attavar, Mangalore - 575 001, Karnataka
Source of Support: None, Conflict of Interest: None
Posterior reversible encephalopathy is a relatively newly recognized disorder, which presents as a complication of pregnancy induced hypertension. Its usual presentation is blurred vision, headache, seizures and disturbance of consciousness. A 20-year-old primigravida presented with seizures, headache and loss of vision in both eyes. She was drowsy and blood pressure was 120/100 mm Hg. Ocular examination was fairly normal, except that her vision was a perception of light and fundus showed early papilledema. She was started on antihypertensives and anticonvulsants. The pregnancy was terminated. A magnetic resonance imaging revealed hyperintense areas in bilateral posterior occipitoparietal regions in T2 weighted images suggestive of posterior reversible encephalopathy syndrome (PRES). She had an improvement of vision starting from the very next day of the presentation. Treatment of this condition involves recognition of the offending factor and its removal. PRES is clinico-neuroradiological diagnosis and its knowledge can help prompt reversal and relief of anxiety to the patient.
Keywords: Pareito occipital cortex, preeclampsia, reversible encephalopathy
|How to cite this article:|
Kamath SJ, Multani P, Nayak MA. Posterior reversible encephalopathy syndrome. J Clin Ophthalmol Res 2014;2:111-2
Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity, which occurs due to edema of the white matter of the parietal and occipital lobes. It was first reported by Hinchey et al. in 1996, in conditions like hypertensive encephalopathy. It can occur following use of immunosuppressants, nephritic syndrome, sepsis and systemic lupus erythematosus. ,, The pathogenesis is thought to be loss of auto regulatory mechanism in the central nervous system vasculature leading to increased blood flow and breakdown of the blood brain barrier leading to vasogenic edema during elevated blood pressure states. The occipitoparietal areas are predisposed to this condition as the vasculature arising from the basilar artery lacks sympathetic tone. Pregnancy itself can pre-dispose to this condition.  We describe a case of PRES in a 20-year-old primigravida.
| Case Report|| |
A 20-year-old primigravida presented in a drowsy state, Glasgow Coma Scale of 14, at 39 weeks of gestation with multiple episodes of convulsions and vomiting associated with headache and loss of vision in both eyes of 1 day duration. At admission, her blood pressure (BP) was 120/100 mm Hg and had thrombocytopenia and proteinuria. Her visual acuity was a perception of light in both eyes. Both pupils were reacting to direct and consensual light. Fundus showed features of early papilledema and arterial attenuation. Visual-evoked potential and fundus photography could not be done as she was in intensive care unit. She was started on intravenous fluids and anticonvulsants. An emergency cesarean section was performed to terminate the pregnancy. Her BP rose to 160/100 mm Hg and was started on amlodipine 2.5 mg twice a day. Computed tomography (CT) brain was normal; however, magnetic resonance imaging (MRI) brain showed typical T2/fluid attenuated inversion recovery hyperintense areas in the parietal and occipital regions with no evidence of diffusion restriction suggestive of posterior leukoencephalopathy [Figure 1], [Figure 2], [Figure 3]. Her BP decreased and vision started improving from day 2 [Table 1]. After 2 weeks, her vision improved to 20/20, N 6 (both eyes). Furthermore, she developed dissociative disorder in the recovery period and ocular examination showed resolution of papilledema.
|Figure 1: Axial fluid attenuated inversion recovery image showing hyperintense area in the occipital lobe|
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|Figure 2: Axial T2 weighted image showing hyperintense area in the occipital lobe|
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|Figure 3: Axial fluid attenuated inversion recovery image showing hyperintense area in parietal cortex|
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| Discussion|| |
PRES can occur in various clinical settings such as pre-eclampsia, eclampsia, hypertensive encephalopathy, infections, electrolyte imbalance, hypercalcemia and use of several drugs. ,,, It occurs due to loss of autoregulatory mechanisms of the posterior circulation, as the latter has a poor sympathetic innervation. Normally, when BP increases, there is autoregulation of the blood vessels causing vasoconstriction and preventing fluid movement across the capillary bed to the interstitium. In PRES, this mechanism is abnormal leading to vasogenic edema.  In chronic hypertension, the autoregulatory mechanism is shifted to left, thus protecting from developing PRES. This mechanism is absent in pregnancy induced hypertension.  This patient also had bilateral disc edema as a part of hypertensive retinopathy.
Pregnancy predisposes brain to vasogenic edema. Although, pre-eclampsia and eclampsia are disorders of pregnancy, PRES has been reported in the postpartum period as well.  Our case report was in the peripartum period, which resolved following termination of pregnancy and control of BP.
PRES can present with various features. Headache is the most common presentation, accompanied by alterations in consciousness. Other reported features are seizures or status epilepticus, visual diminution, papilledema and motor dysfunctions. Furthermore, memory deficits and brain stem dysfunctions can be a part of the presentation. Our patient had an additional dissociative disorder in the recovery period.
Recognition of this syndrome by imaging is important. CT is negative in most cases and when positive can mimic stroke. Differential diagnoses for PRES include neoplasms, encephalitis, inflammatory and infectious processes, demyelinating pathology and cerebrovascular accidents.  MRI is the investigation of choice. The typical features are hyperintense regions in the parieto-occipital areas. Treatment of PRES is treating the underlying cause, like decreasing the BP as in this case. General measures of treatment include antihypertensive therapy and anticonvulsant therapy. Specific treatment options are termination of pregnancy, dialysis and toxic agent withdrawal depending on the underlying cause.
The importance of knowledge of PRES lies in early recognition of the symptoms and instituting treatment in the form of reversal of the precipitating condition. This can lead to avoidance of unnecessary fear and long term complications that associate with this condition.
| References|| |
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[Figure 1], [Figure 2], [Figure 3]