Ch.16 Flashcards
(46 cards)
ALTERATIONS IN COGNITIVE
SYSTEMS
Consciousness
* State of awareness of oneself and the environment
* Arousal
* State of awakeness
ALTERATIONS IN AROUSAL
- Structural
- Divided by location
above or below
tentorial plate
- Divided by location
- Metabolic
- Psychogenic
- Coma is produced by either:
- Bilateral hemisphere damage or suppression
- Brain stem lesions or metabolic derangement that
damages or suppresses the reticular activating system
ALTERATIONS IN AROUSAL Clinical manifestations
- Level of consciousness changes
- Pattern of breathing
- Posthyperventilation apnea (PHVA)
- Cheyne-Stokes respirations (CSR)
- Pupillary changes
- Oculomotor responses
- Motor responses
- Vomiting, yawning, hiccups
BRAIN DEATH (TOTAL BRAIN
DEATH)
- Body can no longer maintain internal homeostasis
- Brain death criteria:
- Completion of all appropriate and therapeutic procedures
- Unresponsive coma (absence of motor and reflex
responses) - No spontaneous respirations (apnea)
- No ocular responses
- Isoelectric EEG
- Persistence 6 to 12 hours after onset
CEREBRAL DEATH
- Cerebral death (irreversible coma) is death of the cerebral hemispheres exclusive of the brain stem and cerebellum
- No behavioral or environmental responses
- The brain can continue to maintain internal
homeostasis - Survivors of cerebral death:
- Remain in coma
- Emerge into a persistent vegetative state
- Progress into a minimal conscious state (MCS)
- Locked-in syndrome
ALTERATIONS IN AWARENESS
Selective attention:
* Ability to select from available, competing environmental
and internal stimuli
* Sensory inattentiveness
* Extinction
* Neglect syndrome
* Selective attention deficit
* Memory
* Amnesia
* Retrograde amnesia
* Anterograde amnesia
* Executive attention deficits
* ADHD
* Image processing
SEIZURES
- Syndrome versus disease
- Sudden, transient alteration of brain function caused by an abrupt explosive, disorderly
discharge of cerebral neurons - Motor, sensory, autonomic, or psychic signs
- Convulsion
- Tonic-clonic (jerky, contract-relax) movements associated
with some seizures
- Tonic-clonic (jerky, contract-relax) movements associated
- Epilepsy: a seizure activity with no underlying
cause
SEIZURES Etiologic Factors
- Cerebral lesions
- Biochemical disorders
- Cerebral trauma
- Epilepsy
SEIZURE types
- Partial seizures
- Simple (without impairment of consciousness)
- Complex (with impairment of consciousness)
- Secondary generalized (partial onset evolving to
generalized tonic-clonic seizures)
- Generalized seizures
- Absence
- Myoclonic
- Clonic
- tonic-clonic
- atonic
- Unclassified epileptic seizure
SEIZURES types con.
Aura
* A partial seizure experienced as a peculiar sensation preceding onset of generalized seizure that may take the form of gustatory, visual, or auditory experience or a feeling of dizziness, numbness,
or just “a funny feeling”
Prodroma
* Early clinical manifestations, such as malaise, headache, or sense of depression, that may occur hours to a few days before onset of a seizure
Tonic phase
* State of muscle contraction
Clonic phase
* State of alternating contraction and relaxation of muscles
Postictal phase
* Time period immediately following cessation of seizure activity
DATA PROCESSING DEFICITS
- Agnosia
- Dysphasia
- Aphasia
Agnosia
Tactile, visual, auditory, etc.
Dysphasia
- Expressive dysphasia
- Nonfluent; cannot find words, difficulty writing
- Occlusion of one or several branches of left middle cerebral
artery supplying inferior frontal gyrus
*Receptive dysphasia - Fluent; can produce verbal language but it is meaningless, with inappropriate words, similar sounds or meaning substituted for correct words
- Occlusion of inferior division of left middle cerebral artery
- Transcortical dysphasia
- Ability to repeat and to recite. Speech is fluent but the words make no sense. The individual cannot read or write and has impaired comprehension.
- Occlusion of left middle cerebral artery of left internal carotid
artery
Aphasia
Inability to communicate (more severe form of dysphasia)
ACUTE CONFUSIONAL STATES (ACS)
- Transient disorders of awareness that result from
cerebral dysfunction- Secondary to drug intoxication, metabolic disorder, or nervous
system disease - Delirium
- Secondary to drug intoxication, metabolic disorder, or nervous
Delirium
- Hyperkinetic-acute state of brain dysfunction associated with right upper middle temporal gyrus or left temporal occipital junction disruption and several neurotransmitters are involved
- Difficulty in concentrating, restlessness, irritability, insomnia, tremulousness, and poor appetites. Completely inattentive and perceptions are grossly altered in full state.
- Hypokinetic-More likely to be associated with right sided frontal basal ganglion disruption
- Associated with under activity, (fevers or metabolic disorders), or under the influence of depressants. Decrease mental function, specifically alertness, attention span, accurate perception, interpretation of the environment and reaction to the
environment. Forgetfulness is prominent and the individual
dozes frequently.
DEMENTIA
- Progressive failure of cerebral functions that is not
caused by an impaired level of consciousness - Losses:
– Orientation
– Memory
– Language
– Judgment
– Decision making
ALZHEIMER DISEASE (AD)
- Familial, early and late onset
- Nonhereditary (sporadic, late onset)
Theories: - Mutation for encoding amyloid precursor protein
- Alteration in apolipoprotein E
- Loss of neurotransmitter stimulation of choline
acetyltransferase - Neurofibrillary tangles
- Senile plaques
- Diagnosis is made by
ruling out other causes of
dementia
ALZHEIMER DISEASE (AD) Clinical Manifestations
– Forgetfulness
– Emotional upset
– Disorientation
– Confusion
– Lack of concentration
– Decline in abstraction,
problem solving, and
judgment
CEREBRAL HEMODYNAMICS
- CBF-Cerebral blood flow
- The brain is normally maintained at ta rate that matches local metabolic needs of the brain
- CPP-Cerebral perfusion pressure (70-90mm hg)
is the pressure required to perfuse the cells of the
brain - CBV-Cerebral blood volume is the amount of blood in the intracranial vault at a give time
- Cerebral oxygenation-is the critical factor and is measured by oxygen saturation in the internal jugular vein
INCREASED INTRACRANIAL
PRESSURE (IICP)
- Normal 1to 15 mm Hg
- Caused by an increase in intracranial content
– Tumor growth, edema, excessive CSF, or hemorrhage
Stage 1 - Attempt to further decrease IICP
Stage 2 - Continued expansion of intracranial content. May see episodes of confusion, restlessness, drowsiness, and slight pupillary and breathing changes
Stage 3 - Brain tissues being to experience hypoxia and hypercapnia, condition rapidly deteriorates.
Stage 4 - Brain tissue shifts (herniates) form the compartment of greater pressure to a compartment of lesser pressure. Causing further ischemia and hypoxia in the herniating tissues.
CEREBRAL EDEMA
- Increase in the fluid (intracellular or extracellular)
within the brain - Types:
- Vasogenic
- Cytotoxic
- Interstitial
Vasogenic
- The blood brain barrier is disrupted and plasma proteins leak into the extracellular spaces, drawing water to them and increasing the water content of the brain parenchyma.
- Starts in area of injury an spreads
Cytotoxic
- Toxic factors directly affect the cellular elements of the brain
parenchyma, causing failure of the active transport systems - Cells lose potassium and gain larger amounts of sodium. Water follows by osmosis and the cells swell