What is the treatment for Posterior Reversible Encephalopathy Syndrome (PRES) caused by hypertension?

Treatment of Posterior Reversible Encephalopathy Syndrome (PRES) Caused by Hypertension

Immediate blood pressure reduction using intravenous labetalol or nicardipine with a target of 20-25% mean arterial pressure reduction within the first hour is the cornerstone of treatment for hypertension-induced PRES, requiring ICU admission with continuous arterial monitoring. 1, 2

Immediate Management Priorities

ICU Admission and Monitoring

• All patients with hypertensive PRES require immediate ICU admission (Class I recommendation) with continuous arterial blood pressure monitoring. 1, 2, 3
• Continuous neurological monitoring is essential, assessing for altered mental status, visual changes, seizure activity, and progression of symptoms. 2, 3
• MRI with FLAIR or T2-weighted sequences should be obtained to confirm the diagnosis, showing characteristic increased signal intensity in posterior white matter regions that are fully reversible with treatment. 1, 3

Blood Pressure Reduction Strategy

The rate of blood pressure rise is more critical than the absolute value in causing PRES, and overly aggressive reduction can precipitate cerebral, renal, or coronary ischemia. 1, 3

The European Heart Journal provides specific targets: 1, 2

• First hour: Reduce mean arterial pressure by 20-25% immediately
• Next 2-6 hours: If stable, reduce to 160/100 mmHg
• Following 24-48 hours: Cautiously normalize blood pressure

Critical pitfall: Avoid excessive acute drops exceeding 70 mmHg systolic, as patients with chronic hypertension have altered cerebral autoregulation and cannot tolerate acute normalization. 1, 2

First-Line Medication Selection

Preferred Agents

Nicardipine is the optimal first-line agent for hypertensive PRES because it maintains cerebral blood flow and does not increase intracranial pressure. 2, 3

• Initial dose: 5 mg/hr IV infusion
• Titration: Increase by 2.5 mg/hr every 15 minutes
• Maximum: 15 mg/hr 1, 2

Labetalol is an excellent alternative first-line agent. 1, 2

• Bolus dosing: 0.25-0.5 mg/kg IV bolus
• Continuous infusion: 2-4 mg/min until goal BP reached, then 5-20 mg/hr maintenance 1, 2

Agents to Avoid

Immediate-release nifedipine is contraindicated due to unpredictable precipitous blood pressure drops and reflex tachycardia. 2

Sodium nitroprusside should only be used as a last resort due to risk of cyanide toxicity and potential to increase intracranial pressure. 2

Pathophysiology Guiding Treatment

The European Heart Journal explains that PRES develops when markedly elevated blood pressure exceeds cerebral autoregulation capacity, particularly in posterior brain regions where sympathetic innervation is less pronounced, leading to less effective damping of blood pressure oscillations. 1, 4

This results in: 1

• Cerebral edema (vasogenic, not cytotoxic)
• Microscopic hemorrhages
• Potential infarctions if untreated

The white matter lesions are fully reversible with timely recognition and appropriate blood pressure management. 1, 3

Special Considerations and Complications

Severe Cases Requiring Surgical Intervention

While rare, some PRES cases develop refractory intracranial hypertension despite optimal medical management. 5, 6, 7

If severe brainstem compression or hydrocephalus develops, emergent posterior fossa decompression or ventriculostomy may be required. 6, 7

Signs indicating potential need for neurosurgical consultation: 6, 7

• Rapidly deteriorating neurological status despite blood pressure control
• Brainstem signs on examination
• Evidence of posterior fossa mass effect or hydrocephalus on imaging

Underlying Causes to Address

Screen for secondary hypertension causes after stabilization, as 20-40% of malignant hypertension cases have identifiable secondary causes. 2

Common contributing factors include: 2

• Medication non-adherence (most common trigger)
• Sympathomimetics or cocaine use
• NSAIDs, steroids, immunosuppressants
• Renal artery stenosis, pheochromocytoma, primary aldosteronism

Transition to Long-Term Management

After acute stabilization, transition to oral antihypertensive therapy should be gradual, using combination therapy with RAS blockers, calcium channel blockers, and diuretics. 2

Target systolic blood pressure of 120-129 mmHg for most adults to reduce long-term cardiovascular risk. 2

Prognosis

With timely recognition and appropriate blood pressure management, PRES is largely reversible with favorable long-term outcomes. 5, 8

However, delayed treatment or overly aggressive blood pressure reduction can result in: 1, 5

• Progressive cerebral edema and ischemia
• Permanent neurological deficits
• Severe disability or death in minority of cases

Early detection through frequent neurological evaluations and neuroimaging is key for rapid recovery and good prognosis. 8