Hypertensive Brainstem Encephalopathy

• Background:
  • Posterior reversible encephalopathy syndrome (PRES) typically involves the posterior parieto-occipital structures, but variations do occur. However, isolated brainstem involvement in PRES is unusual, with a few cases reported in the literature.
  • Over-distension of the cerebral vessels, breakdown of the blood brain barrier, and extravasation of fluid into the interstitium result in vasogenic edema.
• Clinical Presentation:
  • Hypertensive encephalopathy is a medical emergency.
  • Patients may present with headache, altered alertness/behavior, drowsiness, stupor, seizures, and/or vomiting.
• Key Diagnostic Features:
  • The most commonly observed abnormalities on MRI are punctuate or confluent areas of increased signal on FLAIR and T2-weighted images.
  • Restricted diffusion is usually not seen on DWI and ADC maps.
• Differential Diagnoses:
  • Pontine infarct
  • Osmotic demyelination syndrome
  • Pontine neoplasm
  • Demyelinating disease
• Treatment:
  • Control blood pressure and remove precipitating factors.
  • Delayed diagnosis/therapy can result in chronic neurologic sequelae.

Suggested Reading

1. Ruzek KA, Campeau NG, Miller GM. Early diagnosis of central pontine myelinolysis with diffusion-weighted imaging. AJNR Am J Neuroradiol 2004;25:210–13
2. Kitaguchi H, Tomimoto H, Miki Y, et al. A brainstem variant of reversible posterior leukoencephalopathy syndrome. Neuroradiology 2005;47:652–56, 10.1007/s00234-005-1399-z
3. Osman Y, Imam YZ, Salem K, et al. Isolated brainstem involvement in a patient with hypertensive encephalopathy. Case Rep Neurol Med 2013;2013:540947, 10.1155/2013/540947