Altered Consciousness Flashcards
Components of Sensorium
• Consciousness
• Attention span
• Orientation to time, place and person
• Fund of information
• Insight, judgement and planning
• Calculation
Aware that you are aware
Sensorium
Recognize our awareness of self and environment
Sensorium
Functions of Sensorium
Proposes various actions and their consequences
• Directs motor system in behaviors for personal survival and satisfaction
• Allows us to experience life as a conscious process with a past, present and future to respond appropriately
Registers current internal and external contingencies
Relates current internal and external stimuli to our memories and to our future hopes and desires
Invests the streams of afferent stimuli with emotion, determines their significance and assigns priority that results in neglect or attention
Exteroceptors
Eyes ears nose tongue skin
Proprioceptors
Vestibule muscles tendons
Interceptors
Thoracicoabdominal viscera
State of full awareness of self and environment and normal responsiveness to external stimulation and inner needs
Consciousness
2 elements of consciousness
Arousal (Wakefulness)
Awareness (Content)
Problems with arousal (wakefulness)
Integrity of ascending reticular activating system (ARAS)
Problems with awareness (content)
Integrity of cerebral cortex
Quality and coherence of thought and behavior
Awareness (content)
Ascending pathway to cerebral cortex
Brainstem reticular formation > ascending projections system > thalamus > diffuse thalamocortical projection > cerebral cortex
Fully responsive to a thought or perception and indicates by behavior and speech the same awareness of self and environment as that of the examiner
Normal Alertness
Attention to and interaction with immediate surroundings
Normal Alertness
Normal alertness may fluctuate during
the day from keen alertness to deep concentration
Inability to think with customary speed, clarity and coherence
Confusion
• Impaired judgement and decision making
Confusion
Confusion
Most often due to a process that affects the whole brain such as
Encephalopathies and dementia
Test for confusion
• Recall events
• Defect in use of working memory
• Serial subtraction or spelling backwards or digit span and backwards
• Impaired registration
May incorporate clouded interpretation of internal and external experience, and an inability to integrate and attach symbolic meaning to experience
Apperception
Degree of confusion varies from hour to hour
• Least pronounced in morning, increases as the day wears on, peaking in early evening hours
Sundowning
“to go out of the furrow”
Delirium
Severe inattentiveness, altered mental content and sometimes hyperactivity
Delirium
Characterized by misperception of sensory stimuli often with hallucinations
Delirium
Delirium disorientation order
Time
Place
Person
• Inability to sustain a wakeful state without application of external verbal stimuli
• Some degree of inattentiveness and mild confusion coupled with drowsiness that improves with arousal
• Decreased mental, speech and physical activity
• Patient shifts positions naturally and without prompting
• Lids droop, may snore, limbs relaxed
Drowsiness
Lt. “to beat against or blunt”
• Mental blunting
• Mild to moderate reduction in alertness, accompanied by a lesser interest in the environment
• Slower response to stimulation
• Nonpainful physical stimulation
Obtundation
Lt. “to be stunned”
• Deeper state than drowsiness
• Patient can be roused only by vigorous and repeated painful stimuli and usually repeated stimulation is required to sustain arousal
• Responses to spoken commands are either absent, curtailed or slow and inadequate
• Reduction or elimination of natural shifting of positions
• Eyes are displaced slightly out and up which is same as in sleep
Stupor
verbal stimulation
Or command
Drowsiness
light, physical, nonpainful
stimulation
Obtundation
Stupor noxious stimuli
Trapezius squeeze
Sternal rub
Nail bed pressure
Suborbital pressure
Gk. “deep sleep or trance”
• Incapable of arousal by external stimuli or inner need
• In lighter stage, corneal, pupillary and pharyngeal reflexes can be elicited
• In deepest stage, no meaningful or purposeful reaction of any kind is obtainable and corneal, pupillary and pharyngeal responses are diminished
Coma
Patients who, after recovery from coma, return to a state of wakefulness without cognition
Persistent Vegetative State
Eyes-open permanent unconsciousness with loss of cognitive function and awareness of the environment but preservation of sleep-wake cycles and vegetative function
Persistent vegetative state
vegetative syndrome of unconscious awakening persists for - months after nontraumatic brain injury = persistent
3
vegetative syndrome of unconscious awakening persists for - months after traumatic brain injury = persistent
12
Causes of persistent vegetative state
Anoxia - Ischemia - worst prognosis
• Metabolic or encephalitic coma
• Head trauma
MRI of Persistent Vegetative States
global brain atrophy but thalamic and basal ganglia were disproportionately affected
atrophy of white matter with secondary ventricular enlargement
thinning of corpus callosum
• Cortex is diffusely injured or disconnected from thalamus
Automatism
Swallowing
Grimacing
Grunting
Moaning
Motor activity
Primitive postural and reflex movement
Vegetative State Laboratory Test EEG
lack of normal change in background EEG activity during and immediately after stimulating the patient
Neuroimaging of Laboratory test
progressive and profound cerebral atrophy
State of coma in which brain was irreversibly damaged and has ceased to function, but pulmonary and cardiac function could still be maintained by artificial means
Brain Death
State of complete unresponsiveness to all modes of stimulation, arrest of respiration and absence of all EEG activity for 24 hours
Brain Death
person is dead if the brain is dead and that death of brain may precede the cessation of cardiac function
Brain Death
Brain Death features
Absence of all cerebral functions
Absence of all brainstem functions inc spongy respiration
Irreversible
Absence of cerebral function
• Deep coma
• Total lack of spontaneous movement and of motor and vocal responses to all visual, auditory and cutaneous stimulation
Absence of brainstem function
• Loss of pupillary response
• Loss of corneal, oculocephalic, oculovestibular (caloric testing), gag and cough reflex
• Absence of facial movement to noxious stimuli
• Absence of cerebrally mediated movement to noxious stimulation of extremities
Apnea Test is the destruction of
Medulla
Abnormal Apnea Test
Pa CO2 = 60mmHg
Destruction of the medulla
Apnea Test
• Unresponsiveness of medullary centers to high carbon dioxide tension
Apnea Test
Apnea Test
Absence of tachycardia in response to
Atrophine
Apnea Test
Damaged Vagal Neurons
Confirms cerebral death
• Electrocerebral silence, flat or isoelectric EEG
EEG
- lack of contrast pacification during 4VA
• Digital subtraction angiography (DSA)
used to rule out reversible cause
Toxicology screening
hypothermia or intoxication with sedative-hypnotic drugs and immediately post cardiac arrest
Isoelectric EEG w/ preserved brainstem reflexes
GCS Year
1978
GCS is by
Graham Teasdale and Bryan Jennett
• Scale used to objectively describe the extent of impaired consciousness in all types of acute medical and trauma
Glasgow Coma Scale
3 aspect of GCS
Eye Opening
Verbal Response
Motor Response
GCS P Year
2018
GCS P by
Paul Brennan
Gordon Murray
Graham Teasdale
Mild TBI
13-15
Moderate TBI
9-12
Severe TBI
3-8
GCS-P of severe TBI
1-8
Alteration in sensorium
Trauma
Infectious
Metabolic
Nutritional
Vascular
Neoplastic
Trauma sample
epidural/subdural/subarachnoid/intracerebral
Infectious sample
meningitis, encephalitis, brain abscess
Mass lesion/neoplastic
neoplasm, abscess, hematoma, granuloma, cyst
Vascular sample
cerebral infarction/hemorrhage/SAH
Focal Lesion
mass lesion, infarction, hematomas
Multifocal Lesion
Multiple tumors, mass lesions
Diffuse lesion
Metabolic endocrine, toxic encephalopathy
Causes of alteration in consciousness
Structural
Functional
-discrete lesion ex. hematoma
-widespread destructive changes of the hemispheres
- increased ICP
Structural
metabolic, toxic, nutritional d/t neuronal failure in the cerebrum and RAS
Functional
Destructive lesion immediately within thalamus or midbrain
Direct damage to ARAS
Interruption of thalamocortical impulses or generalized destruction of cortical neurons
Widespread bilateral damage to cortex and cerebral white matter
Disturbance in higher intellectual functions
• Seizure
• Language problem
• Behavioral, personality and mental changes
• Contralateral hemiparesis with
Babinski
• Contralateral hemisensory deficit
• Visual field deficit
Cerebrum
•CROSSED MOTOR/SENSORY SYNDROME
• Ipsilateral cranial nerve deficit
• Contralateral hemiplegia with Babinski
• Contralateral hemisensory deficit
Brainstem
Truncal ataxia
• Limb ataxia
Cerebellum
Behavioral and personality changes may be the initial presentation
• Acute confusional episode
• Delirium
• Alteration of consciousness
• Generalized seizures
• FND are usually absent but if present, they are bilateral
Encephalopathy
Causes of alteration in consciousness
Primary brainstem lesion
Bihemispheral lesion
Secondary brainstem compression
Encephalopathy
