SHM Converge Scientific Abstract ePoster Gallery-Beyond Radiology: Chanter Syndrome From a Hospitalist's Perspective

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This case describes a 49-year-old woman with intravenous drug use who presented with acute confusion, retrograde and anterograde amnesia, and behavioral changes. She was tearful, oriented only to self, but had no focal neurologic deficits, normal strength/sensation/coordination, and no gait abnormality.<br /><br />Initial non-contrast CT of the head showed symmetric hypodensities in the basal ganglia and cerebellum, raising concern for toxic-metabolic encephalopathy. Because the CT findings did not clearly explain the clinical picture, MRI was obtained the next day and showed restricted diffusion and T2 hyperintensity in the bilateral cerebellar dentate nuclei, hippocampi, and basal nuclei. Neuroradiology felt the pattern was consistent with CHANTER syndrome.<br /><br />CHANTER stands for Cerebellar-Hippocampal-and-basal Nuclei Transient Edema with Restricted diffusion. It is a rare opioid-associated toxic encephalopathy first described in 2019 and is increasingly recognized, especially with fentanyl exposure. It can mimic stroke, seizure, infection, trauma, intoxication, medication effects, or psychiatric illness, making diagnosis challenging.<br /><br />The workup was notable for a urine drug screen positive for fentanyl and amphetamines. Other testing, including electrolytes, renal function, CBC, inflammatory markers, vitamin B12, RPR, ceruloplasmin, chest X-ray, and broad serum/CSF infectious, metabolic, toxic, and inflammatory studies, was unrevealing aside from mild transaminitis attributed to chronic hepatitis C and a UTI treated with ceftriaxone.<br /><br />Management was supportive and included orientation aids, PT/OT, speech therapy for cognitive rehabilitation, and discharge planning for outpatient rehabilitation and substance-use follow-up. Her cognition improved significantly over about two months.<br /><br />Key takeaways: consider CHANTER in patients with opioid exposure and encephalopathy, obtain early MRI with neurology/neuroradiology input, recognize that the syndrome is often transient, and arrange rehabilitation and addiction follow-up.

Asset Subtitle

Kassidy Lovins

Meta Tag

Author List Aaron Fried, Dominic K. Lal, Emily Sturkie, Kassidy Lovins

Category Clinical Vignettes

Concept CHANTER Syndrome

Concept Opioid Exposure

Concept Neuroimaging Pattern

Concept Fentanyl

Concept Toxic Encephalopathy

Distinguished Non-Finalist

Presenter Organization University of North Carolina at Chapel Hill School of Medicine

Presenting Author Kassidy Lovins

Track Adult

Keywords

CHANTER syndrome

opioid-associated encephalopathy

fentanyl exposure

restricted diffusion

MRI brain

basal ganglia

cerebellar dentate nuclei

hippocampal involvement

toxic-metabolic encephalopathy

intravenous drug use

CHANTER Syndrome

Opioid Exposure

Neuroimaging Pattern

Fentanyl

Toxic Encephalopathy