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Symptoms of Increased ICP: Change in LOC
Result of impaired CBF which deprives cells of the cerebral cortex and the reticular activating system (RAS)-in brainstem of oxygen. Interruptions of impulses from the RAS can cause unconsciousness
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Symptoms of Increased ICP: Changes in vitals
- caused by increase pressure on hypothalamus, thalamus, pons, & medulla
- Cushing's Triad appears after ICP has been increased for some time. Change in temp also possible
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Symptoms of Increased ICP: Ocular signs
- compression of cranial nerve III (oculamotor nerve) results in dilation of pupil on same side as lesion; sluggish or no response to light, inability to move eye upward, & ptosis of eyelid.
- -These can be signs of brain moving away from midline (a fixed unilateral dilated pupil is a neuro emergency-herniation!)
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Symptoms of Increased ICP: Decrease in motor function
- Changes in motor ability as ICP rises.
- A contralateral (oppisite side of lesion), hemiparesis may develop. Noxious stimuli may elecit decorticate (flexion) or decerebrate (extension) posturing
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Decorticate posturing
Internal rotation and adduction of arms with flexion of elbow, wrists, and fingers as a result of interruption of volunatary motor tracts in cerebral cortex
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Decerebrate posturing
- disruption of motor fibers in midbrain and brainstem
- Arms stiffly extended, adducted and hyperpronated, Indicates more serious damage!
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CPP (Cerebral perfusion pressure)
- Reflects amount of blood flow from systemic circulation required to provide adequate glucose and oxygen for brain metabolism
- Done at bedside by decreasing the MAP from the ICP
- Normal CPP=60-100mmHg
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