FRCA Notes

Posterior Reversible Encephalopathy Syndrome

This topic is absent from the curriculum and probably beyond the purview of the exam, but is included for interest.

Resources

  • Posterior, reversible encephalopathy syndrome is an uncommon, clinical-radiological neurotoxic state
  • Marked female preponderance
  • Peripartum patients with PET
  • Renal disease inc. AKI
  • Sepsis
  • Exposure to immunosuppressant drugs e.g. chemotherapy, post-organ transplant
  • Autoimmune disease
  • Acute hypertension

  • The underlying mechanism is unclear
  • Theories include:
    • Increased CBF from impaired autoregulation
    • Endothelial dysfunction and thus cerebral hypoperfusion
  • In either case, there is a failure of the BBB and subsequent cerebral vasogenic oedema

  • Rapid development of symptoms without prodrome
  • Features include:
    • Headache
    • Hypertension
    • Visual disturbance e.g. diplopia, scotoma, field defects
    • Altered conscious level
    • Confusion
    • Seizures (although does not cause long-term epilepsy)

  • Need to exclude other pathologies:
    • Bloods to exclude infection and check for electrolyte derangements
    • CT to exclude intracerebral haemorrhage, venous thrombosis and SOL
  • T2-weighted MRI is the investigation of choice, demonstrating focal parieto-occipital and cerebellar vasogenic oedema

  • Blood pressure control:
    • GTN infusion
    • Calcium channel blockers
    • Beta-blockers
    • Magnesium sulphate

  • 40% require I&V

  • Seizure management
    • Benzodiazepines
    • Phenytoin
    • Magnesium if pre-eclamptic aetiology

  • Fluid balance and electrolyte control
    • Avoid positive fluid balance
    • Correct electrolyte disturbances

Complications

  • Cerebral haemorrhage
  • Cerebral ischaemia
  • Trans-tentorial cerebral herniation from posterior oedema