Neurointensivist & Division Chief, Inpatient Neurology Corewell Health, United States
Introduction: Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome is a rare opioid induced neurotoxicity with distinct clinicoradiologic features. The acute cerebellar edema can cause obstructive hydrocephalus, and MRI can show restricted diffusion in affected areas. Findings can often be mistaken for acute ischemia, hypoxic-ischemic encephalopathy, heroin-associated spongiform leukoencephalopathy, or opioid-associated amnestic syndrome (OAA). Prompt diagnosis and treatment are essential. Exact pathogenesis of CHANTER is still uncertain, but it appears direct opioid toxicity plays a key role and injury pattern is thought to be from a combination of hypoxia and neurotoxicity leading to mitochondrial failure with anoxic injury.
Description: A 45-year-old female with polysubstance abuse and alcohol use disorder presented with coma and incontinence. She received Narcan but required intubation for airway protection. Initial CT demonstrated edema of bilateral cerebellum. CTA did not show any abnormalities. Drug screen was positive for fentanyl. MRI brain demonstrated diffuse multifocal bilateral supratentorial and infratentorial regions of restricted diffusion and edema most prominent within cerebellar hemispheres and hippocampi. Patient was successfully extubated after repeated doses of Narcan but grew drowsy. Repeat HCT demonstrated obstructive hydrocephalus for which an EVD was placed. Hypertonic saline was given for cerebral and cerebellar edema with clinical signs of intracranial hypertension. She progressively improved and the EVD was removed one week after admission. After another week she was discharged alert and oriented without any neurologic deficits.
Discussion: CHANTER is a newly recognized phenomenon with distinct imaging features that if recognized early by providers and radiologists and treated early and aggressively patients can improve greatly from baseline. Treatment should be multidisciplinary utilizing medical management such as hypertonic in conjunction with neurosurgical approaches such as CSF diversion and/or surgical decompression. As the opioid epidemic continues to worsen it is important that we learn and understand the pathogenesis better as well as the course of the syndrome to improve outcomes.
