Exam 4 Flashcards
Full Consciousness
Cognitive cerebral function, fully aroused, fully aware
A state of awareness of both oneself and the environment and a set of responses to that environment.
- The fully conscious person responds to external stimuli with many responses
- Any decreased state of this awareness and responses is a decrease in consciousness
Consciousness involves
- Arousal
- Awareness
Arousal
an individual’s state of awakeness (mediated by the reticular activating system: RAS)
Can vary in an individual from day to night as someone’s level of awakeness.
Vegetative State
NO cerebral function, but crude awakened state
A crude awakening state characterized by loss of cerebral function
- its like “being in a fog” - you’re not able to fully respond to what’s happening; some can hear you but they cannot respond
- this is maintained by the reticular activating system and the brain stem
Vegetative State maintained by
Reticular activating system and brain stem.
Types of alterations in arousal (3)
- Structural
- Metabolic
- Psychogenic
Structural Alterations in Arousal types and causes
Can be above or below tentorial plate.
Causes include:
- infections
- Vascular
- Neoplasms
- Traumatic (brain bleeds)
- Congenital
- Degenerative
- Polygenic
Awareness
Content of thought. Encompasses all cognitive functions.
Reticular Activating System
Mediates arousal/maintains consciousness.
Responsible for regulating aspects of attention and information processing.
When someone looses cerebral function, the RAS has to work harder to maintain a level of consciousness. RAS and brainstem will compensate by maintaining a vegetative state.
Manifestations of a structural alteration of arousal
Depend on if the problem is above or below the tentorial plate. (don’t have to differentiate)
Metabolic alterations in arousal causes
Causes include:
- Hypoxia
- Electrolite disturbances
- Hypoglycemia (low blood sugar)
- Drugs
- Endogenous (from within) and exogenous (injested) toxins.
Psychogenic alterations in arousal
Unresponsiveness that might be present in some psychiatric disorders.
Different than metabolic and structural alterations, because the person is actually awake. They “choose” not to respond to the environment.
Evaluation points of neurologic function (5)
- Level of Consciousness
- Patterns of breathing
- Pupillary reaction
- Oculormotor responses
- Motor responses
Level of Consciousness (evaluation of neurologic function)
The most critical index of nervous system function. A Change in level of consciousness (LOC) can indicate either improvement or deterioration of the individual’s condition.
Alert and oriented x4 refers to person, place, time, and situation. If a person is aware of all of these things then they are considered to be functioning at the highest level of consciousness.
From the highest state it can decrease to confusion and even coma.
Patterns of breathing (eval of neuro function)
Helps evaluate the level of brain dysfunction and coma.
- Rate
- Rhythm
- Pattern
Cheyne-Stokes Respirations:
abnormal pattern of ventilation that have alternating periods of Tachypnea (elevated resp. rate) and Apnea (lack thereof). Commonly see Cheyne-Stokes in very depressed levels of Consciousness.
Pupillary reactions (eval of neuro function)
Can indicate the level and presence of brainstem dysfunction because brainstem areas that control arousal are adjacent to areas that control pupils.
Pupillary reactions can be a variety of changes, so we must take a look at what is causing it; example is Drugs
Causes of fixed pupils
- Severe ischemia
- Hypoxia
- Hypothermia
Oculomotor responses (eval of neuro function)
-Resting
-Spontaneous
-Reflexive
:eye movements that can change at various levels of brain dysfunction in comatose individuals.
If a person is in a metabolic induced coma, they may retain reflective eye movements even when other signs of brainstem damage are present.
Motor Responses (eval of neuro function)
help evaluate the level of brain dysfunction and determine the most severely damaged side of the brain.
Ex. If someone has a stroke and the right side of their body is not functioning properly, then we know it is the left side of the brain that is most damaged. ( see page 351 to see DOLL’S EYES PHENOMENON )
Patterns of motor responses
- Purposeful movements
- Inappropriate movements
- No motor movements
Motor responses associated with decreased consciousness
- Rigidity
- Reflex grasping
- reflux sucking
- snout reflex
- palmo-mental reflex
Posturing types
Occur with neurologic dysfunction
- Decorticate
- Decerebrate
Decorticate Posturing
(raptor arms)
- Flexion of arms, wrists and fingers
- Adduction in upper extremities
- Extension, internal rotation and plantar flexion in lower extremities
Decerebrate Posturing
(Straight arms)
- All four extremities in rigid extension
- Hyperpronation of forearms
- Plantar extension of feet
Types of neurologic death
Two forms of neurologic death that result from severe pathologic conditions and are associated with irreversible coma.
- Cerebral Death
- Brain Death
Brain death
Occurs when the brain is damaged so completely that it can never recover and cannot maintain the body’s internal homeostasis.
- Cessation of function of the entire brain including brain stem and cerebellum.
- Must be on life support because the brain doesn’t sustain life.
Brain death has occurred when there is no evidence of brain function for an extended period of time (flat EEG for 6-12 hours) and resulted from structural or known metabolic disease, not drugs, alcohol, or hypothermia.
Cerebral Death
Irreversible coma.
Death of the cerebral hemispheres exclusive of the brainstem and cerebellum. Internal homeostasis may be maintained (ie body temperature, cardio, etc.)
Damage is permanent, and the individual is forever unable to respond behaviorally in any significant way to the environment.
Alterations in awareness
- Selective Attention Deficit
- Executive Attention Deficit
- Alterations in Image Processing
- Sensory Inattentiveness
- Deficiencies in Memory
Selective Attention Deficit
This rarely occurs as an isolated event, it is usually associated or caused by other deficits including seizures, contusions, hematomas, strokes, gliomas, alzheimers, tumors, and dementia.
It refers to the ability to select certain information and focus on it for processing and can be temporary, permanent, or progressive depending on its cause.
Manifestations of selective attention deficit
- Cannot focus attention
- Decreased eye head, and body movements toward stimuli
- History of falls, injuries (safety issue.)
Memory
The ability of the brain to store and retrieve information
Amnesia
Loss of memory
Types of amnesia
- Retrograde
- Anterograde
Retrograde amnesia
Loss of the past memories, both personal and factual history like events. New memories can still be formed and retained.
S & S vary according to the side of the brain the damage was done on. Either way, memory problems that others report as formerly known information.
Left Side Trauma:Inability to retrieve past personal history, unaware of recent current events.
Right Side Trauma:Inability to remember past persons, places, objects, music, etc:
Manifestations of retrograde amnesia
vary according to the side of the brain the damage was done on. Either way, memory problems that others report as formerly known information.
- Left Side Trauma:Inability to retrieve past personal history, unaware of recent current events.
- Right Side Trauma:Inability to remember past persons, places, objects, music, etc:
Anterograde Amnesia
The past information is retained, the person is unable to remember any new personal or factual information (post trauma).
Manifestations of anterograde amnesia
Vary according to the side of the brain the damage was done on but overall a person would be confused, disoriented, inability to listen, remember new information. They would show signs of behavioral changes.
- Left Side Trauma: Impaired language and semantic memory. Disorientation to time, situation, place, name, and persons.
- Right Side Trauma: Impaired episodic memory (personal history), emotional memory, disorientation (self, person, and place).
Executive Attention Deficits
e.g. ADHD
Inability to maintain sustained attention in order to set goals and recognize when an an object will help them meet a goal. It also manifests with a working memory deficit so the person is not able to remember instructions or information needed to complete a task or guide behavior.
It can be temporary, progressive, or permanent depending on the trauma/cause.
Alterations in Image Processing
The inability to form concepts, categorize, assign meaning, and make generalizations using sensory data. It can be temporary or permanent depending on the trauma/cause. They show the inability to reason and think abstractly, very concrete reasoning is demonstrated, might be delusional.
Sensory Inattentiveness
AKA “Neglect Syndrome”
Inability to recognize sensory input from the dysfunctional side/part of body. An example includes a person who had a stroke with loss of function in right arm, they can’t perceive sensation, eventually the brain stops recognizing the limb all together.
Seizure
Results from a sudden, explosive disorderly discharge of cerebral neurons.
This can involve, motor, sensory, autonomic and psychic clinical manifestations and temporarily altered arousal.
They may not involve all of these manifestations.
Convulsions
The jerky contract-relax movement associated with some seizures
Epilepsy
Seizure activity for which no underlying correctable cause for the seizure can be found.
Causes of seizures
- Hypoglycemia
- Exhaustion
- Stress
- Stimulant drugs
- Environmental stimuli such as blinking lights, odors, and changes in temps.
Classifications of seizures (3)
- Partial
- Generalized
- Unclassified
Partial seizures
Begin locally.
Three types:
- Simple
- Complex
- Secondarily generalized
Simple partial seizure
do NOT include loss of consciousness but may have sensory, motor, psychic our autonomic signs.
Complex partial seizure
includes impairment of consciousness, may be precipitated by simple partial seizure.
Secondary generalized partial seizure
Partial onset but evolve to generalized tonic-clonic seizure
Generalized seizures
Bilaterally symmetric and so not have a local onset. (Grand-Mal seizure)
- Absence
- Myoclonic
- Clonic
- Tonic
- Tonic-clonic
- Atonic
Phases of generalized seizures
- Aura: Partial seizure immediately preceding the onset of a generalized tonic-clonic seizure.
- Prodroma: Early manifestations occurring hours to days before a seizure - warning sign
- Tonic Phase: Muscle contraction with increased muscle tone.*
- Clonic phase: alternating contraction and relaxation of muscles*
- Postictal phase: altered level of consciousness that can last 5-30 min.
* During seizure
Treatment for seizure/epilepsy
Correcting or controlling the cause and, if none is identified, give antiseizure medicine.
Types of data processing deficits
- Agnosia
- Dysphasia
- Acute Confusional States (ACS)
- Dementia
Agnosia
A defect of pattern recognition. A failure to recognize the forms and nature of objects.
-Tactile
-Visual
-Auditory
:generally only one sense is affected.
Although agnosia is associated most commonly with cerebrovascular accidents, it may arise from any pathologic process that injures specific areas of the brain.
Dysphasia
Impairment of comprehension or production of language with impaired:
- Communication
- Comprehension
- Use of symbols
In either written or verbal language is disturbed or lost. It is usually associated with cerebrovascular accident involving the middle cerebral artery or one of its many branches. It results from dysfunction in the left cerebral hemisphere, usually the frontotemporal region.
Types of dysphasia
- Expressive
- Receptive
Not as important to know:
-Transcortical (can’t repeat/recite, but can understand)
Acute Confusional States
Transient disorders of awareness that result from cerebral dysfunction caused by drug intoxication, metabolic dosorders, nervous system disease/trauma/surgery
- Delerium
- Hypokinetic confusional state
Delerium
Associated with overactivity of nervous system; causes hyperconfusion
- occurs in critical care units or following surgery or withdrawal
- this will improve over time/lasts 2-3 days
Manifestations of delirium
- difficulty concentrating
- restlessness
- irritability
- sleep problems
- poor appetite
Hypokinetic confusional states
Underactivity of nervous system.
Occurs in people with fever or metabolic disorders
Manifestations of Hypokinetic Confusional States
- Forgetfulness
- Sleep a lot
Dementia
Progressive failure of cerebral functions. Doesn’t go away. Caused by neuro degeneration, compression, atherosclerosis and trauma; also associated with genetic pre-dispositions including alzheimer and Huntington disease
Decrease in:
- Orienting
- Memory
- Language
- Judgement
- Decision making
Alzheimer disease
one of the most common causes of severe cognitive dysfunction in older persons and the leading cause of dementia
Exact cause unknown
•Linked to three genes with mutations on chromosome 21
•Formation of neuritic plaques containing a core of amyloid-beta protein, creation of neurofibrillary tangles, and degeneration of basal forebrain cholinergic neurons with loss of acetylcholine.
Manifestations of Alzheimer
- Insidious, forgetfulness, and emotional upset •Becomes more forgetful over time
- Memory loss gradually increases
- Loses the ability to concentrate
- Loses the ability to problem solve
- Judgment deteriorates
- Behavioral changes
- Mood swings
Alterations in Cerebral hemodynamics
An injured brain reacts with structural, chemical, and pathophysiological changes that are called secondary brain injuries. Critical features of these changes include alterations in cerebral blood flow, intracranial pressure and oxygen delivery.
Cerebral blood flow (CBF)
Blood flow to the brain is normally maintained at a rate that matches metabolic needs of brain
Cerebral perfusion pressure (CPP)
70-90mm Hg; pressure required to perfuse cells of the brain
Cerebral Blood volume (CBV)
The amount of blood in the intercranial vault at a given time.
Can fluctuate depending on needs of brain at the time
Cerebral Oxygenation
Critical factor; measure by oxygen saturation in the internal jugular vein
Alterations in cerebral blood flow may be related to three injury states
- Inadequate cerebral perfusion (cerebral oligemia)
- Increase intercranial Pressure (with normal perfusion)
- Excessive cerebral blood volume (cerebral hyperemia)
Normal intracranial Pressure
1-15 mm Hg
Increased Intracranial Pressure (IICP)
May result from an increase in
- Intracranial content (tumor growth)
- Edema
- Excess CSF (Cerebrospinal fluid)
- Hemorrhage
- IICP necessitates an equal reduction in volume of the other cranial contents.
- The easiest thing for the brain to get rid of to make more room is remove CSF
- If removing the CSF doesn’t work, cerebral blood volume and blood flow are altered
Four stages
Stage 1 of Increased Intracranial Pressure (IICP)
Vasoconstriction and external compression of venous system in attempt to decrease pressure.
- Compensatory response begins
- So the Actual ICP may not change if compensatory mechanism is successful
Stage 2 of Increased Intracranial Pressure (IICP)
Continued expansion of intercranial content. There is an increase in ICP that may start to exceed brain’s ability to adjust
S/S- subtle & transient:
- confusion
- restlessness
- drowsiness
- pupillary
- breathing changes
Stage 3 of Increased Intracranial Pressure (IICP)
ICP now has an effect on arterial pressure; the brain tissues begin to experience hypoxia and the patient’s conditions begin to rapidly deteriorate.
S/S:
- widened pulse pressure
- bradycardia
- small sluggish pupils
- decrease levels of arousal
Stage 4 of Increased Intracranial Pressure (IICP)
Brain tissue shifts (herniates) from area of high pressure to a compartment of lesser pressure
- When it shifts, the brain tissue’s blood supply is compromised– leads to more ischemia & hypoxia
- Small hemorrhages develop in the brain tissue as well as obstructive hydrocephalus
Cerebral edema
Increase in fluid content of brain tissue
Occurs after brain insult from:
- Trauma
- Infection
Types of cerebral edema
- Vasogenic edema*** most important
- Cytotoxic (metabolic) edema
- Interstitial edema
Vasogenic edema
Caused by increased permeability of the capillary endothelium of the brain after injury to vascular structures.
Edema starts at the vascular site of injury and spreads from there.
Manifestations from vasogenic edema
- Disturbances of level of consciousness
- Severe increase of ICP
Cytotoxic edema
Caused by toxins that directly affect brain’s cellular elements of the brain that transport K+ and Na+ in the brain.
Damage to cell membranes=loss of potassium/increased sodium creates swelling.
Interstitial edema
Seen mostly with noncommunicating hydrocephalus.
Edema caused by movement of spinal fluid.