What are the diagnosis and management strategies for Posterior Reversible Encephalopathy Syndrome (PRES)?

Posterior Reversible Encephalopathy Syndrome (PRES): Diagnosis and Management

PRES is a cliniconeuroradiologic syndrome requiring immediate identification and removal of triggering factors, stringent blood pressure control, and management of neurological symptoms for optimal outcomes and prevention of permanent neurological sequelae. 1

Diagnosis

Clinical Presentation

• Acute neurological deficits including:
  • Altered consciousness/encephalopathy
  • Visual disturbances or blindness
  • Headaches
  • Seizures 1, 2

Risk Factors and Etiology

• Severe hypertension/hypertensive emergency (most common cause)
• Pre-eclampsia/eclampsia
• Immunosuppressive drugs
• Chemotherapy agents (especially anti-angiogenic therapy)
• Autoimmune disorders
• Renal impairment/failure
• Allogeneic stem-cell transplantation
• Solid organ transplantation with associated immunosuppression 1

Diagnostic Imaging

• MRI is the gold standard diagnostic tool showing:
  • T2-weighted hyperintensities indicating vasogenic edema
  • Predominant involvement of bilateral parieto-occipital lobes
  • White matter more affected than gray matter 1, 2
• CT may be used initially but is less sensitive than MRI 2

Laboratory Studies

• Primarily useful for excluding alternative diagnoses
• Monitor renal function, electrolytes, and complete blood count
• In cases of suspected eclampsia, check liver enzymes and urine protein 2

Management Algorithm

Step 1: Immediate Interventions

1. Identify and remove triggering factors:

   • Discontinue offending medications (immunosuppressants, chemotherapy)
   • Immediate delivery for eclampsia cases 1
   • Address underlying autoimmune conditions

2. Blood pressure management:

   • Initiate very stringent blood pressure control
   • Target gradual reduction to avoid cerebral hypoperfusion
   • Use IV antihypertensives for severe hypertension
   • First-line agents: Labetalol, followed by hydralazine, nifedipine, nicardipine 1, 3
   • For refractory cases: Urapidil, nitroglycerin (avoid sodium nitroprusside if possible) 3
   • In hemodialysis patients, strict volume control may be key 4

3. Seizure management:

   • Administer antiepileptic treatment for active seizures
   • Magnesium sulfate is the drug of choice for eclampsia-related seizures 3
   • Consider prophylactic anticonvulsants in high-risk patients
   • Use benzodiazepines for acute seizure control 1

Step 2: Supportive Care

• Elevate head of bed to decrease hydrostatic pressure and cerebral edema
• Implement aspiration precautions
• Provide IV hydration as needed
• Avoid medications that cause CNS depression 1
• Monitor neurological status closely with frequent neurological examinations

Step 3: Monitoring and Follow-up

• Regular neurological assessments
• Repeat neuroimaging to document resolution (typically within 2 weeks)
• Monitor patients on immunosuppressive therapy for early detection of recurrence 1

Prognosis and Complications

• PRES is typically reversible with appropriate management within 2 weeks
• Factors associated with poor outcomes:
  • Altered sensorium
  • Extensive cerebral edema
  • Presence of hemorrhage on imaging
  • Delayed control of causative factors 1
• Delayed diagnosis and treatment may lead to permanent neurological sequelae 1, 5

Special Considerations

• Early diagnosis is crucial to prevent irreversible neurological damage
• For chemotherapy-induced PRES, carefully consider the risk-benefit ratio before reintroducing therapy 1
• Angiotensin converting enzyme inhibitors and angiotensin receptor blockers are contraindicated in pregnancy-related PRES 3
• In hemodialysis patients, strict volume control may be particularly important for both treatment and prevention 4

Common Pitfalls to Avoid

• Delaying diagnosis due to nonspecific clinical presentation
• Failing to promptly control blood pressure
• Continuing offending medications
• Reducing blood pressure too rapidly, which can cause cerebral hypoperfusion
• Missing atypical presentations or alternative diagnoses with similar presentations
• Neglecting to repeat neuroimaging to confirm resolution