Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome in the setting of opioid and phencyclidine use

Cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion (CHANTER) syndrome is a constellation of specific imaging findings characterized by cytotoxic edema in the bilateral hippocampi, cerebellar cortices, and basal ganglia in patients presenting with altered mental status in the setting of substance intoxication. Previous case reports have demonstrated a strong correlation between CHANTER syndrome and polysubstance abuse, particularly with opioid intoxication. The patient we present in this case was found unresponsive following opioid use and demonstrated a constellation of findings on initial and follow-up imaging, consistent with CHANTER syndrome. While cases of irreversible brain damage or death during hospitalization have been reported in the literature, our patient demonstrated near-full recovery a few days after admission to the hospital. We aim to highlight the presentation and progression of CHANTER syndrome and alert clinicians and radiologists to include this entity in their diagnostic checklist for patients with polysubstance abuse and altered mental status.