Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome
General description
Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome is a rare condition associated with opioid neurotoxicity, occurring exclusively in the context of intoxicant abuse. This syndrome is characterized by cytotoxic edema in regions with high opioid receptor expression, including the bilateral hippocampi, cerebellar cortices, and variably the basal ganglia.
Patients typically present with altered mental status or decreased consciousness following toxic opioid exposure, often raising concerns for anoxic injury. However, unlike acute ischemic infarction or hypoxic-ischemic encephalopathy, CHANTER syndrome has the potential for significant clinical and radiographic recovery with prompt and aggressive management.
Bilateral cerebellar and hippocampal edema
In CHANTER syndrome, the cerebellum is a hallmark site of involvement. MRI typically reveals diffuse cerebellar edema with restricted diffusion. This edema often causes crowding of the fourth ventricle, which is a distinguishing imaging feature of the syndrome.
Asymmetric basal ganglia diffusion restriction
The basal ganglia are also commonly affected, often asymmetrically. Imaging demonstrates edema and restricted diffusion in these regions, reflecting the areas of increased vulnerability due to high opioid receptor expression.
Hydrocephalus
Although not a direct feature of CHANTER syndrome, crowding of the fourth ventricle due to cerebellar edema can potentially lead to secondary hydrocephalus.