uncal herniation /ung″kəl/ [L, uncus, hook, hernia, rupture] , a condition in which the medial part of the temporal lobe protrudes over the tentorial edge as a result of increased intracranial pressure. If uncorrected, the progressive disorder causes pressure on the brainstem after first impinging on the third cranial nerve. ▪ OBSERVATIONS: The characteristic signs of uncal herniation are an acute loss of consciousness, hemiparesis, and a dilated pupil on the side of the herniation. ▪ INTERVENTIONS: A CT or MRI is obtained to determine if there is a need for surgical intervention. The head of the bed should be elevated to 30 degrees or higher to facilitate cerebral venous drainage. Noxious stimuli, such as tracheal suctioning that may elevate intracranial pressure, should be minimized. High-dose corticosteroid therapy is initiated to reduce the pressure. ▪ PATIENT CARE CONSIDERATIONS: Uncal herniation is a life-threatening emergency requiring the coordinated efforts of a team focused on monitoring and intervening to prevent further neurologic deterioration.
