Posterior reversible encephalopathy syndrome

Background

• Abbreviation: PRES
• Risk factors include: malignant hypertension, immunosuppression, eclampsia
• Poorly understood entity, but thought to be due to failure of cerebral auto-regulation in which the brain sees too high of systemic pressures leading to vasogenic edema
• Somewhat of a misnomer as changes seen on MRI are not limited to the posterior fossa and symptoms are not always reversible
  • Renamed reversible posterior leukoencephalopathy syndrome (RPLS) by the American Academy of Neurology

Magnetic resonance image showing multiple cortico-subcortical areas of hyperdense signal involving the occipital and parietal lobes bilaterally and pons in a patient with posterior reversible encephalopathy syndrome

Clinical Features

• Seizures
• Hypertension
• Encephalopathy/Altered Mental Status
• Visual Disturbances
• Vomiting
• Headache

Differential Diagnosis

• Eclampsia
• Vascular
  • Hypertensive Encephalopathy
  • CVA
  • Intracranial Hemorrhage
  • Cerebral Venous Thrombosis
• Infectious
  • Encephalitis
  • Meningitis
• Metabolic
  • Hepatic Encephalopathy
  • Hyponatremia
  • Porphyria
• Demyelinating Disorders (e.g. MS)
  • SLE
• Psychiatric disorder

Seizure

• Epileptic seizure
  • First-time seizure
  • Seizure with known seizure disorder
  • Status epilepticus
  • Temporal lobe epilepsy
  • Non-compliance with anti-epileptic medications
  • Hyponatremia
  • INH toxicity
• Non-epileptic seizure
  • Meningitis
  • Encephalitis
  • Brain abscess
  • Intracranial hemorrhage
  • Alcohol withdrawal
  • Benzodiazepine withdrawal
  • Barbiturate withdrawal
  • Baclofen withdrawal
  • Metabolic abnormalities: hyponatremia, hypernatremia, hypocalcemia, hypomagnesemia, hypoglycemia, hyperglycemia, hepatic failure, uremia
  • Eclampsia
  • Neurocysticercosis
  • Posterior reversible encephalopathy syndrome
  • Impact seizure (head trauma)
  • Acute hydrocephalus
  • Arteriovenous malformation
  • Seizure with VP shunt
  • Toxic ingestion (amphetamines, anticholinergics, cocaine, INH, organophosphates, TCA, salicylates, lithium, phenothiazines, bupropion, camphor, clozapine, cyclosporine, fluoroquinolones, imipenem, lead, lidocaine, metronidazole, synthetic cannabinoids, theophylline, Starfruit)
  • Psychogenic nonepileptic seizure (pseudoseizure)
• Intracranial mass
• Syncope
• Hyperventilation syndrome
• Migraine headache
• Movement disorders
• Narcolepsy/cataplexy
• Post-hypoxic myoclonus (Status myoclonicus)

Evaluation

• Focus on altered mental status workup, with PRES as diagnosis of exclusion
• MRI shows cerebral edema, especially in posterior circulation

Management

• Control Blood Pressure
• Discontinue immunosuppressants

Disposition

• Admit

See Also

• Hypertensive emergency
• Eclampsia