Herniation protrusion of brain tissue through an opening in the supporting dura

Herniation protrusion of brain tissue through an

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Herniation: protrusion of brain tissue through an opening in the supporting dura of the brain; deadly Types of herniation syndromes: o Subfalcine o Tentorial o Uncal o Tonsillar Manifestations of brain injury: Level of Consciousness (LOC) Change in LOC is most sensitive indicator of altered brain function State of alertness and attentiveness to one’s environment and situation Dependent on activity in the RAS neurons LOC may fluctuate; important to monitor and treat changes Complete loss of consciousness : coma Glasgow Coma Scale 34
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Standardized tool for assessing LOC in acutely brain-injured persons Numeric scores given to arousal-directed responses of eye opening, verbal utterances, and motor reactions Mild (>12), moderate (9 to 12), to severe (<8) Motor response most powerful predictor of patient outcome Decorticate posturing, abnormal flexor; decerebrate posturing, abnormal extension Pupil Reflex Indicates the function of the brainstem and cranial nerves (CN) II and III Changes in size, shape, and reactivity of the pupil early indicator of ICP and possible brain herniation Eye movements controlled by CN III, IV, and VI may be impaired with increased ICP Nystagmus, dysconjugate movement, and ocular palsies may be present Oculovestibular Reflex Impaired reflex implies brainstem dysfunction Doll’s-eyes/oculocephalic maneuver entails rotating the patient’s head from side to side Cold calorics/oculovestibular: inject cold water into ear Both tests have many contraindications Corneal Reflex Wisp of cotton touches cornea of the eye to elicit a blink response Absence of blink response: indictor of severely impaired brain function Brain Hemodynamics and Metabolism Hypothermia may be used to reduce brain metabolism Increased brain metabolism (fever, seizures, agitation, and pain) should be avoided TRAUMATIC BRAIN INJURY: TBI = leading cause of death and disability in U.S. Most head injuries incurred in transportation-related accidents, falls, fire arms, and sports accidents Severity of TBI is classified by the Glasgow coma scale (GCS) as: Mild GCS score 13 to 15 Moderate GCS score 9 to 12 Severe GCS score 8 or below Types of TBI o Primary injury o Focal o Polar o Diffuse Intracranial hematomas o Epidural o Subdural o Subarachnoid Primary Injury Result of initial trauma/injury on brain cells Focal injuries (coup) localized to site of impact Polar injuries (coup contrecoup) due to acceleration-deceleration movement of the brain within the skull, resulting in double injury (usually opposite focal injury) Diffuse injury due to movement of the brain within the skull, resulting in widespread axonal injury Mechanisms of injury: Mild traumatic brain injury; most common injury encountered by military personnel and athletes Alteration or loss of consciousness (< 30 minutes) but no evidence of brain damage on CT Headache, nausea, vomiting, dizziness, fatigue, blurred vision, cognitive and emotional disturbances Mechanisms of injury
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