Neurotoxicity After Pediatric Opioid Overdose: A Toddler With CHANTER Syndrome

Introduction: An estimated 13% of opioid overdoses occur in pediatric patients. These children are at risk of respiratory depression and anoxic brain injury. Direct neurotoxicity has been described in adults, with emerging evidence in pediatrics. CHANTER syndrome (cerebellar, hippocampal, and basal nuclei transient edema with restricted diffusion) was first described in 2019 and has since been reported in one pediatric patient. We present an additional pediatric case who required neurosurgical intervention for CHANTER syndrome after opioid overdose.


Description: A 16-month-old girl transferred from an outside facility after being found unresponsive by her parents. Her examination was notable for hypopnea and pinpoint pupils. Respiratory and mental status improved with naloxone and a continuous infusion was started. Initial head CT revealed cerebellar edema with symmetric, hypodense appearance of the bilateral basal ganglia and hippocampi, consistent with CHANTER syndrome. She developed tachycardia with episodic lower extremity stiffness and was placed on EEG, found to have subclinical seizures, and loaded with antiepileptics. Several hours later, she was intubated for worsening respiratory failure. A repeat CT showed progressive cerebellar edema with new posterior fossa mass effect and obstructive hydrocephalus, so she underwent urgent ventricular drain placement. After 72 hours of neuroprotective care her cerebellar edema resolved, and she was eventually extubated and discharged to inpatient rehab with improving functional status.


Discussion: CHANTER syndrome may exist on a spectrum of neurotoxidromes secondary to regional differences in opioid receptor density. Unlike global hypoxic injury from prolonged respiratory depression, CHANTER syndrome seems to be associated with a greater degree of recovery if secondary injury from obstructive hydrocephalus or cerebellar tonsillar herniation can be avoided, with generally favorable neurologic outcomes. Further investigation is needed into the time course of edema progression, optimal surgical management of posterior fossa hypertension, the role of additional opioid exposure during routine PICU care, and optimal neuroprotective strategies. Greater awareness of CHANTER syndrome will improve early management after severe opioid intoxication in children.