[Brain death in secondary brain lesion]

Area of Science:

• Neurology
• Forensic Medicine
• Critical Care Medicine

Background:

• Established brain death criteria often require a primary, destructive brain lesion.
• Secondary brain lesions (e.g., post-anoxia, intoxication) have historically been excluded from brain death determination due to insufficient data.
• Clarifying the etiology of coma is crucial for diagnosing brain death, but this is not always possible.

Purpose of the Study:

• To investigate if a universal clinico-pathological entity of brain death exists, irrespective of the underlying cause.
• To determine clinical methods for defining brain death in cases of secondary brain lesions.

Main Methods:

• Selection of 25 patients exhibiting a "brain death-like state" (coma, dilated nonreactive pupils, respiratory arrest > 6 hours) due to non-destructive, secondary brain lesions.
• Inclusion of diverse etiologies: post-anoxia, CO intoxication, poisoning, near-drowning, hepatic coma, hypothermia, sepsis, with or without cardiac arrest.
• Monitoring clinical signs and electroencephalogram (EEG) activity over time.

Main Results:

• Clinical signs of the brain death-like state were not consistently irreversible in all patients.
• Isoelectric EEG (no activity) was recorded in 11 patients, with no return of activity upon retesting.
• Five patients demonstrated EEG activity despite strong clinical suspicion of brain death.

Conclusions:

• The clinical presentation of a "brain death-like state" may not always indicate irreversible cessation of brain function, particularly in secondary brain lesions.
• Current diagnostic criteria may need re-evaluation to encompass a broader range of etiologies.
• Further research is essential to establish universal clinical and pathological definitions for brain death.