What is posterior reversible encephalopathy syndrome (PRES)?

From the Guidelines

Posterior reversible encephalopathy syndrome (PRES) is a rare but increasingly diagnosed neurological disorder characterized by acute neurological deficits, including altered consciousness, visual disturbances, blindness, headaches, and seizures, due to a disruption of the blood-brain barrier caused by endothelial injury from abrupt blood pressure changes. The condition typically presents with symptoms such as headache, confusion, seizures, visual disturbances, and occasionally focal neurological deficits, and is usually triggered by acute hypertension, certain medications, eclampsia or pre-eclampsia, kidney disease, or autoimmune disorders 1.

Key Characteristics of PRES

• Acute onset of neurological symptoms
• Characteristic white matter edema in the posterior cerebral regions on brain imaging, typically MRI
• Disruption of the blood-brain barrier due to endothelial injury from abrupt blood pressure changes
• Usually reversible with appropriate supportive management within 2 weeks

Treatment and Management

• Treatment is purely symptomatic and includes discontinuation of offending medications, correction of electrolytes, and symptomatic treatment with benzodiazepines 1
• Very stringent control of blood pressure is crucial, especially when PRES is present 1
• Antiepileptic treatment may be necessary in case of seizures 1
• Most patients recover completely within days to weeks with prompt treatment, though neurological symptoms may persist in some cases 1

From the Research

Definition and Characteristics of Posterior Reversible Encephalopathy Syndrome (PRES)

• Posterior reversible encephalopathy syndrome (PRES) is an acute neurotoxic syndrome characterized by a spectrum of neurological and radiological features resulting from various risk factors 2.
• Common neurological symptoms include headache, impairment in level of consciousness, seizures, visual disturbances, and focal neurological deficits 2, 3.
• The syndrome is often associated with acute hypertension, renal disease, preeclampsia/eclampsia, and immunosuppressive therapy 3, 4.

Radiographic Findings and Pathophysiology

• Classic radiographic findings include bilateral subcortical vasogenic edema predominantly affecting the parieto-occipital regions, but atypical features can involve other regions, cortical involvement, restricted diffusion, hemorrhage, and contrast enhancement 2.
• The pathophysiology is theorized to involve dysfunction of cerebral autoregulation leading to vascular leak or endothelial dysfunction resulting in vasogenic edema 3, 5.
• The lesions in PRES are thought to be due to vasogenic edema, predominantly in the posterior cerebral hemispheres, and are reversible with appropriate management 4, 5.

Diagnosis, Treatment, and Outcome

• Diagnosis involves clinical findings suggestive of PRES, laboratory studies to exclude alternative diagnoses, and neuroimaging modalities such as computed tomography (CT) and magnetic resonance imaging (MRI) 3.
• Treatment involves management of seizures, control of blood pressure if elevated, and treatment of any underlying trigger 3, 5.
• PRES is typically reversible if recognized on presentation and promptly and appropriately managed, but long-standing morbidity and mortality can occur in severe forms 2, 6.