Alpha-pattern coma in a 2-year-old child.

Area of Science:

• Pediatric Neurology
• Neurophysiology
• Critical Care Medicine

Background:

• Reye's syndrome is a rare but serious condition that causes swelling in the liver and brain.
• Hypoglycemia, or low blood sugar, can lead to severe neurological complications.
• Alpha activity on an electroencephalogram (EEG) typically indicates wakefulness, making its presence during coma unusual.

Observation:

• A two-year-old child with Reye's syndrome and prolonged hypoglycemia presented with continuous, diffuse 8- to 9-Hz alpha activity while comatose.
• Serial EEG monitoring demonstrated a gradual decrease in alpha activity and the emergence of delta waves over 18 hours.
• Subsequent EEGs revealed electrocerebral silence, indicating a severe decline in brain function.

Findings:

• The observed EEG pattern, characterized by diffuse alpha activity in a comatose patient, closely resembled the "alpha-pattern coma" previously described in adults post-anoxia.
• This suggests a potential shared mechanism of diffuse cortical-subcortical insult, possibly triggered by hypoglycemia in this pediatric case.
• The transient nature of this EEG pattern is a critical observation.

Implications:

• The findings suggest that diffuse alpha activity in pediatric coma may represent a specific, albeit transient, neurophysiological response to severe cerebral insults.
• Prompt and serial EEG examinations are crucial for identifying this pattern in children following acute brain injury.
• This could aid in earlier diagnosis and potentially guide management strategies for severe pediatric encephalopathies.