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Posterior Reversible Encephalopathy Syndrome (PRES)

Reversible vasogenic edema syndrome with characteristic posterior brain changes

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

References (5)

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Nöroloji department. Book Appointment →

What is Posterior Reversible Encephalopathy Syndrome (PRES)?

PRES is caused by failure of cerebral autoregulation leading to vasogenic edema, predominantly in the posterior cerebral circulation territory.

Despite the name, lesions can occur anywhere in the brain (frontal, brainstem, cerebellum, basal ganglia) — the posterior predominance reflects sympathetic innervation patterns.

Common triggers include hypertensive crisis (most frequent), eclampsia, immunosuppressants (calcineurin inhibitors, chemotherapy), autoimmune diseases (SLE, vasculitis), sepsis and renal failure.

Most patients have full clinical recovery and resolution of imaging findings within days to weeks if the underlying cause is addressed promptly.

Severe forms may have permanent residual deficits or, rarely, fatal outcome from cerebral hemorrhage or massive edema.

Symptoms

Severe headache (often the first symptom)
Seizures (focal, generalized or status epilepticus) — often the presenting feature
Visual disturbances: cortical blindness, visual hallucinations, hemianopia, blurred vision
Altered mental status, confusion, lethargy, encephalopathy
Focal neurologic deficits: hemiparesis, ataxia, brainstem signs
Severely elevated blood pressure in many cases (though not all)
Symptoms develop acutely over hours to days

Risk Factors

Severe or rapidly rising hypertension (hypertensive emergency)
Eclampsia and pre-eclampsia
Immunosuppressants: cyclosporine, tacrolimus, sirolimus, after solid organ or stem cell transplantation
Cytotoxic chemotherapy: bevacizumab, cisplatin, gemcitabine, others
Autoimmune diseases: SLE, ANCA vasculitis, scleroderma renal crisis
Sepsis and septic shock
Acute or chronic renal failure
Hypercalcemia, electrolyte disturbances
Massive blood transfusion, IVIG
Cocaine and other sympathomimetic drugs

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Acute severe headache, especially with elevated blood pressure
  • New seizures with confusion or visual symptoms
  • Acute visual disturbances or cortical blindness
  • Encephalopathy in pregnant or postpartum patient
  • Acute neurologic symptoms in patient on immunosuppressants or chemotherapy
  • Severe hypertension with neurologic symptoms
  • Status epilepticus with associated severe hypertension

Treatment Methods

01
Diagnosis: clinical features plus brain MRI showing T2/FLAIR hyperintensity predominantly in parieto-occipital subcortical white matter, often bilateral and symmetric
02
Distinguish from infarction: PRES lesions typically do not show restricted diffusion (vasogenic, not cytotoxic edema)
03
CT may show low-attenuation areas; MRI is more sensitive
04
Identify and treat underlying cause — the cornerstone of management
05
Severe hypertension: gradual blood pressure reduction (target 25 percent decrease in first hour, then to 160/100 over 6 hours) using IV labetalol, nicardipine, hydralazine — avoid sudden severe drops
06
Eclampsia: magnesium sulfate plus blood pressure control plus prompt delivery
07
Immunosuppressant-induced: reduce or change offending drug if clinically feasible
08
Treat seizures: levetiracetam, lacosamide or other anticonvulsants; benzodiazepines for status epilepticus
09
Supportive care: ICU monitoring, electrolyte correction, fluid balance
10
Avoid hypoperfusion: do not lower blood pressure too aggressively, especially if chronic hypertension
11
Repeat MRI at 1–2 weeks to confirm resolution
12
Prognosis: 70–90 percent achieve complete recovery; mortality 5–15 percent in severe forms
13
Long-term: monitor blood pressure, manage underlying conditions, prevent recurrence

Which Department to Visit?

You can visit our Nöroloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.