Posterior Reversible Encephalopathy Syndrome (PRES) Overview



Clinico-Radiological Syndrome, characterized by:

 • Headache

 • Seizures

 • Altered mental status

 • Visual disturbance

 • White matter vasogenic edema affecting the posterior occipital and parietal lobes of the brain



PRES Clinical Presentation:

 • Altered mental status

 • Headache

 • Seizures

 • Vision changes

 • Hypertensive crisis may precede the neurologic syndrome by 24 hours or longer/BP fluctuations



PRES-Associated Clinical Conditions:

 • Preeclampsia, Eclampsia, Infection/Sepsis/Shock, Autoimmune disease, Cancer chemotherapy, Immunosuppressive agents, Renal failure, Transplantation including bone marrow or stem cell transplantation, Hypertension/Hypertensive emergency, Blood transfusion, Hypercalcemia



Etiology:

 • Pathophysiology remains unclear, endothelial dysfunction is key, with hypertension being the most common precipitating factor



PRES Diagnosis:

1. Neurological symptoms: Acute onset

2. Risk factors

3. Imaging Patterns in PRES:

	• Increased signal on T2-weighted images

	• Vasogenic edema visualized as a hypo- or isointense signal on DWI

	• White matter edema - both posterior cerebral hemispheres

	• (FLAIR) sequences improve sensitivity showing cortical lesions

	• Vascular narrowing on MRA/CTA

	• Anterior circulation: MCA ACA watershed territories signal changes

4. Reversible course



Differential Diagnosis:

 • Infection, Electrolyte abnormality, Medication/Drug toxicity, Metabolic disturbance, External lines/devices, Constipation, Seizures, Stroke, Paraneoplastic syndrome, ADEM, Acute toxic leukoencephalopathy, Cerebral venous thrombosis



Testing:

 • Imaging: White matter vasogenic edema affecting the posterior occipital and parietal lobes of the brain

 • CSF: Modestly elevated protein level (mean 58 mg/dL in one study) but no pleocytosis. An elevated white blood cell count in the CSF should prompt consideration of other diagnoses.

 • EEG: With persistent altered level of consciousness to exclude nonconvulsive status epilepticus



Treatment:

 • Address the underlying cause

 • Treatment of HTN is the mainstay of therapy in patients

	- 10-25% BP reduction initially, Avoid overaggressive BP lowering

	- Lower the diastolic pressure to 100-105 mmHg within 2 to 6 hours

	- Use easily titratable parenteral agents: clevidipine, nicardipine, or labetalol.

 • Magnesium correction: Levels 2-3 mEq/L

 • Seizures: Treat with AEDs until cause identified



#PRES #Posterior #Reversible #Encephalopathy #Syndrome #diagnosis #management #neurology