CHANTER Syndrome: A Case Report of Delayed Diagnosis in Opioid Overdose
Location
LSUHSC-NO
Publication Date
April 2026
Start Date
9-4-2026 10:00 AM
End Date
9-4-2026 2:00 PM
Description
Cerebellar, Hippocampal, and Basal Nuclei Transient Edema with Restricted Diffusion (CHANTER) syndrome, which was first described in 2019, is a clinically distinct neuroimaging pattern found in cases of substance intoxication, particularly in the setting of opioid overdose. It is characterized by cytotoxic edema that may result in acute obstructive hydrocephalus. Patients may present with stupor or coma. Identification of CHANTER syndrome may portend a degree of reversibility and a more favorable prognosis when compared to similar neurologic insults, such as anoxic brain injury. In this case report, we describe a 63-year-old man with a history of opioid use disorder who was found with altered mental status following a suspected opioid overdose. He was stuporous and unresponsive to naloxone on arrival to the ED and was subsequently intubated. Toxicology was positive for oxycodone and fentanyl. CHANTER syndrome was identified on magnetic resonance imaging, albeit six days after initial presentation. The patient's hospital course was complicated by persistent encephalopathy, prompting psychiatric consultation for management of agitation, as well as the subacute development of a cerebellar hematoma. At the time of discharge, the patient had residual neurologic deficits, including cognitive impairment and limited mobility. This case suggests variability in the prognosis of this clinicoradiologic syndrome and demonstrates a need for further study to elucidate its clinical course, complications, and contributing and confounding factors. Familiarity with CHANTER syndrome among consultation-liaison psychiatrists may inform treatment approaches and guide prognostic discussions with patients and their families.
Recommended Citation
Mauch, Brendan J. MD and McCullough, Aaron MD Candidate 2026, "CHANTER Syndrome: A Case Report of Delayed Diagnosis in Opioid Overdose" (2026). Dept. of Psychiatry Research Symposium. 16.
https://digitalscholar.lsuhsc.edu/psych_rd/2026/posters/16
CHANTER Syndrome: A Case Report of Delayed Diagnosis in Opioid Overdose
LSUHSC-NO
Cerebellar, Hippocampal, and Basal Nuclei Transient Edema with Restricted Diffusion (CHANTER) syndrome, which was first described in 2019, is a clinically distinct neuroimaging pattern found in cases of substance intoxication, particularly in the setting of opioid overdose. It is characterized by cytotoxic edema that may result in acute obstructive hydrocephalus. Patients may present with stupor or coma. Identification of CHANTER syndrome may portend a degree of reversibility and a more favorable prognosis when compared to similar neurologic insults, such as anoxic brain injury. In this case report, we describe a 63-year-old man with a history of opioid use disorder who was found with altered mental status following a suspected opioid overdose. He was stuporous and unresponsive to naloxone on arrival to the ED and was subsequently intubated. Toxicology was positive for oxycodone and fentanyl. CHANTER syndrome was identified on magnetic resonance imaging, albeit six days after initial presentation. The patient's hospital course was complicated by persistent encephalopathy, prompting psychiatric consultation for management of agitation, as well as the subacute development of a cerebellar hematoma. At the time of discharge, the patient had residual neurologic deficits, including cognitive impairment and limited mobility. This case suggests variability in the prognosis of this clinicoradiologic syndrome and demonstrates a need for further study to elucidate its clinical course, complications, and contributing and confounding factors. Familiarity with CHANTER syndrome among consultation-liaison psychiatrists may inform treatment approaches and guide prognostic discussions with patients and their families.