(1356) CHANTER Syndrome: From Emergent Intubation to Walking out With No Deficits

Introduction: Chanter syndrome, or Cerebellar Hippocampal and Basal Nuclei Transient Edema with Restricted Diffusion, is a newly emerging syndrome categorized by diffuse cerebellar edema with restricted diffusion and crowding of the fourth ventricle following toxic opioid exposure. The cerebral cortex, thalamus, and subcortical white matter are usually spared. Patients typically present in an obtunded state, which may be attributed to the positive urine drug screen, thus the diagnosis may be missed. The degree of recovery appears to be variable; however, patients typically experience greater recovery than with other clinical manifestations of toxic opioid exposure, such as hypoxic-ischemic encephalopathy.

Description: A 27-year-old male with no past medical history presented after being found unresponsive. Initial workup showed a urine drug screen positive for benzodiazepines and fentanyl. Computed tomography (CT) head showed patchy and confluent hypodensities in the bilateral cerebellar hemispheres with mass effect likely reflecting bilateral cerebellar infarcts with significant edema as well as additional bilateral pallidal hypodensities, likely reflecting toxic-metabolic insult. The patient required emergent intubation and initiation of vasopressor support. He underwent emergent placement of a right frontal external ventricular drain followed by a suboccipital craniectomy for cerebellar decompression. Postoperative magnetic resonance imaging showed acute restricted diffusion within both cerebellum consistent with bilateral cerebellar infarcts as well as left greater than right posterior medial temporal lobe and bilateral basal ganglia restricted diffusion consistent with infarcts reflecting sequela of toxic-metabolic insult. Ultimately, the patient made a full recovery and was able to be discharged with no deficits.

Discussion: Prompt recognition and diagnosis of CHANTER syndrome is essential to preventing long-term sequelae. In patients presenting in an altered or obtunded state, rapid opioid reversal and aggressive management in the intensive care unit to avoid further ICP elevation is essential to survival and potential recovery. This case demonstrates the potential for symptom resolution and reversal with prompt recognition and appropriate elevation of care.