Cerebellar Hippocampal and Basal Nuclei Transient Edema with Restricted diffusion (CHANTER) Syndrome

Neurocrit Care. 2019 Oct;31(2):288-296. doi: 10.1007/s12028-018-00666-4.


Background: Abnormal restricted diffusion on magnetic resonance imaging is often associated with ischemic stroke or anoxic injury, but other conditions can present similarly. We present six cases of an unusual but consistent pattern of restricted diffusion in bilateral hippocampi and cerebellar cortices. This pattern of injury is distinct from typical imaging findings in ischemic, anoxic, or toxic injury, suggesting it may represent an under-recognized clinicoradiographic syndrome. Despite initial presentation with stupor or coma in the context of obstructive hydrocephalus, patients may have acceptable outcomes if offered early intervention.

Methods: We identified an ad hoc series of patients at our two institutions between years 2014 and 2017 who presented to the neurocritical care unit with severe, otherwise unexplained cerebellar edema and retrospectively identified several commonalities in history, presentation, and imaging.

Results: Between two institutions, we identified six patients-ages 33-59 years, four male-with similar presentations of decreased level of consciousness in the context of intoxicant exposure, with acute cytotoxic edema of the cerebellar cortex, hippocampi, and aspects of the basal nuclei. All patients presented with severe cerebellar edema which led to obstructive hydrocephalus requiring aggressive medical and/or surgical management. The five patients who survived to discharge demonstrated variable degrees of physical and memory impairment on discharge and at follow-up.

Conclusions: We present findings of a potentially novel syndrome involving a distinct pattern of cerebellar and hippocampal restricted diffusion, with imaging and clinical characteristics distinct from ischemic stroke, hypoxic injury, and known toxidromes and leukoencephalopathies. Given the potential for favorable outcome despite early obstructive hydrocephalus, early identification and treatment of this syndrome are critical.

Keywords: Acute brain injuries; Cerebellar syndromes; Cerebral edema; Drug overdose; Hippocampus proper.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Alcoholic Intoxication / complications
  • Amphetamines / adverse effects
  • Basal Ganglia / diagnostic imaging*
  • Benzodiazepines / adverse effects*
  • Brain Edema / chemically induced
  • Brain Edema / diagnostic imaging*
  • Brain Edema / physiopathology
  • Brain Edema / therapy
  • Central Nervous System Stimulants / adverse effects*
  • Cerebellar Cortex / diagnostic imaging*
  • Cerebellum / diagnostic imaging
  • Cocaine / adverse effects
  • Coma / etiology
  • Female
  • Heroin / adverse effects
  • Hippocampus / diagnostic imaging*
  • Humans
  • Hydrocephalus / diagnostic imaging*
  • Hydrocephalus / etiology
  • Hydrocephalus / physiopathology
  • Hydrocephalus / therapy
  • Hydromorphone / adverse effects
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Opiate Alkaloids / adverse effects*
  • Pain, Postoperative / drug therapy
  • Stupor / etiology
  • Substance-Related Disorders
  • Syndrome


  • Amphetamines
  • Central Nervous System Stimulants
  • Opiate Alkaloids
  • Benzodiazepines
  • Heroin
  • Cocaine
  • Hydromorphone