Central/Downward Transtentorial Herniation
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Overview
Plain-Language Overview
Central/Downward Transtentorial Herniation is a serious brain condition where increased pressure inside the skull pushes brain tissue downward through a natural opening called the tentorial notch. This affects the brainstem, which controls vital functions like breathing and heart rate. The pressure can cause headache, altered consciousness, and problems with eye movement. It often results from swelling or bleeding in the brain due to injury, stroke, or tumors. This condition can rapidly worsen and lead to life-threatening complications if not recognized quickly.
Clinical Definition
Central/Downward Transtentorial Herniation is a type of brain herniation characterized by the downward displacement of the diencephalon and midbrain through the tentorial notch due to increased intracranial pressure. It commonly occurs secondary to diffuse cerebral edema, large supratentorial mass lesions, or global brain swelling. The herniation compresses the midbrain, basilar artery, and reticular activating system, leading to impaired consciousness and autonomic dysfunction. Clinically, it presents with bilateral small reactive pupils, decorticate or decerebrate posturing, and progressive coma. This herniation pattern is a neurosurgical emergency due to the risk of brainstem ischemia and death.