causes of coma caused by diffuse lesions

causes of coma caused by diffuse lesions:

generally speaking, unilateral or localized chronic or subacute cerebral hemisphere damage will not directly cause coma. these damages generally do not damage the midbrain reticular formation or the non-specific projection system of the thalamus. the impulses of the ascending reticular activating system can maintain the arousal state through the other cerebral hemisphere. however, if there is a relatively large lesion in one cerebral hemisphere, and the edema around the lesion is severe, or even brain herniation is formed, it can cause coma. acute, bilateral, and extensive brain damage can cause disturbance of consciousness or long-term coma.

if the diffuse damage to both cerebral hemispheres progresses slowly, causing extensive degeneration and atrophy of both hemispheres, but the arousal system is not compressed or damaged, coma will generally not occur, such as alzheimer's disease. however, due to various diseases, extensive and serious diffuse damage to both cerebral hemispheres, brain tissue ischemia, hypoxia, edema, necrosis, etc., leading to damage to the arousal system and causing coma, such as various encephalitis, severe subarachnoid hemorrhage , diffuse metabolic encephalopathy, cerebral hypoxia after cardiac arrest, etc.

in addition, increased intracranial pressure caused by various reasons can reduce cerebral blood flow, cause cerebral ischemia and hypoxia, and lead to coma. in addition, some toxins, metabolic disorders, etc. can also damage the ascending reticular activating system and cause coma.