What is the initial workup and management for a patient suspected of having Posterior Reversible Encephalopathy Syndrome (PRES)?

Initial Workup and Management of Posterior Reversible Encephalopathy Syndrome (PRES)

The initial workup for suspected PRES should include an urgent brain MRI (gold standard for diagnosis), comprehensive neurological assessment, blood pressure monitoring, and identification of potential triggering factors, followed by immediate removal of offending agents and stringent blood pressure control. 1

Clinical Presentation and Initial Assessment

Key Clinical Features to Identify

• Acute neurological symptoms:
  • Headache
  • Altered mental status/confusion
  • Visual disturbances or blindness
  • Seizures (most common presenting symptom)
  • Focal neurological deficits

Immediate Diagnostic Workup

1. Neuroimaging:

   • Brain MRI (gold standard): Look for characteristic T2-weighted hyperintensities indicating vasogenic edema, predominantly in parieto-occipital regions 1
   • Brain CT: If MRI is not immediately available, to rule out other causes of neurological symptoms 1

2. Laboratory Tests:

   • Complete blood count
   • Comprehensive metabolic panel (with special attention to renal function)
   • Liver function tests
   • Urinalysis (especially in pregnancy to assess for preeclampsia)
   • Drug levels of immunosuppressants if applicable

3. Blood Pressure Monitoring:

   • Continuous monitoring is essential as severe hypertension is a common trigger 1, 2

Identification of Triggering Factors

Common Triggers to Evaluate

• Severe hypertension/hypertensive emergency
• Medications:
  • Immunosuppressants (cyclosporine, tacrolimus, mycophenolate mofetil) 3, 4
  • Chemotherapeutic agents
  • Anti-angiogenic therapy
• Medical conditions:
  • Preeclampsia/eclampsia
  • Renal failure
  • Autoimmune diseases
  • Solid organ or bone marrow transplantation 1

Immediate Management

1. Removal of Triggering Factors

• Discontinue offending medications immediately if identified 1
• For eclampsia: Consider immediate delivery if applicable 1
• For infections: Initiate appropriate antimicrobial therapy

2. Blood Pressure Management

• Target: Gradual reduction to avoid cerebral hypoperfusion 1
• Preferred medications:
  • IV labetalol (first-line)
  • Oral nifedipine (if IV access unavailable)
  • IV hydralazine (second-line) 1

3. Seizure Management

• For active seizures:
  • Benzodiazepines for acute control (IV lorazepam 2-4 mg or diazepam 5-10 mg)
  • Consider loading with levetiracetam or phenytoin if seizures persist 1
• Monitor for at least 24 hours for late seizures (tardive seizures) 1
• Obtain neurology consultation for recurrent or prolonged seizures 1

4. Supportive Care

• Elevate head of bed to 30 degrees to decrease hydrostatic pressure and cerebral edema 1
• For cerebral edema/increased intracranial pressure:
  • Mannitol: 0.5-1 g/kg IV initially, then 0.25-1 g/kg every 6 hours, or
  • Hypertonic 3% saline: 5 ml/kg IV over 15 minutes, then 1 ml/kg/hour to target serum sodium 150-155 meq/l 1

Monitoring and Follow-up

Neurological Monitoring

• Frequent neurological assessments (at least every 2-4 hours)
• Monitor for improvement or worsening of symptoms

Radiological Follow-up

• Follow-up MRI in 1-2 weeks to assess resolution of lesions 1, 5

Long-term Considerations

• PRES is typically reversible within 2 weeks with appropriate management 1, 2
• Delayed diagnosis and treatment may lead to permanent neurological sequelae 1, 5
• Consider long-term antiepileptic therapy only if seizures persist after resolution of PRES 5

Special Considerations

For Transplant Recipients

• Regular monitoring of patients on immunosuppressive therapy for early detection 1
• Consider switching immunosuppressants (e.g., from mycophenolate mofetil to everolimus) if PRES is attributed to these medications 4

For Patients with Renal Disease

• More aggressive blood pressure control may be needed
• Careful monitoring of fluid status and electrolytes 3

Early diagnosis and prompt management are crucial to prevent irreversible neurological damage in PRES. The condition is typically reversible when triggering factors are identified and addressed quickly 1, 2, 6.