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A delayed methadone encephalopathy: clinical and neuroradiological findings

Anna Zanin1, Susanna Masiero, Maria Savina Severino

  • 1Paediatric Emergency Unit, Paediatric Department, University of Padua, 35100 Padua, Italy. anna.zanin@unipd.it

Journal of Child Neurology
|October 8, 2009
PubMed

Insights

A child experienced delayed encephalopathy after methadone poisoning, showing neurological symptoms days later. Subsequent MRI revealed abnormalities in brain regions, a novel finding for synthetic opioid intoxication.

Area of Science:

  • Neurology
  • Toxicology
  • Pediatrics

Background:

  • Opioid receptors are densely located in brain areas such as the cerebellum and limbic system.
  • Methadone poisoning has been linked to severe cerebellitis in pediatric cases.
  • Synthetic opioids are potent analgesics with potential for severe toxicity.

Observation:

  • A 30-month-old girl presented with coma following methadone intoxication, recovering after naloxone administration.
  • Five days post-intoxication, she developed delayed neurological symptoms including agitation, ataxia, and abnormal movements.
  • Initial neuroimaging was negative, but a follow-up MRI showed signal abnormalities.

Findings:

  • Delayed encephalopathy occurred 5 days after methadone intoxication.
  • Magnetic resonance imaging (MRI) revealed signal abnormalities in the temporomesial regions, basal ganglia, and substantia nigra 19 days after intoxication.
  • These specific delayed MRI findings are unprecedented in cases of synthetic opioid intoxication.

Implications:

  • This case highlights the potential for delayed neurological complications following synthetic opioid intoxication in children.
  • The findings suggest that certain brain regions may be particularly vulnerable to delayed toxicity from methadone.
  • Further research is warranted to understand the mechanisms behind these delayed neurotoxic effects and inform clinical management.

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