Arousal, Coma and Unconciousness Flashcards
define arousal
state of wakefulness
define consciousness
arousal + context
- awareness of both self and the external environment determined by a motor response to internal or external stimulus
define coma
total absence of awareness of both self and external environment
- severest impairment of arousal
- inability to obey commands, speak, open eyes to pain
GCS 3-8
What are the three components of GCS?
Eye opening
Best Verbal Response
Best Motor Response
What is the highest and lowest GCS score?
- lowest = 3
- highest = 15
What are the subdivisions of eye opening?
1 = none 2 = to pain 3 = to speech 4 = spontaneous
What are the subdivisions of best verbal response?
1 = none 2 = incomprehensible sounds 3 = inaapropriate 4 = confused 5 = oriented
What are the subdivision of best motor response?
1 = none 2 = extension 3 = abnormal flexion 4 = flexion to pain 5 = localises to pain 6 = obeys commands
What is the anatomy underlying coma?
- both cerebral hemispheres and/or brain stem ascending reticular activating system is grossly impaired
What is required for arousal and awareness?
What is required for cognition and consciousness?
- functioning reticular activating system
- intact cerebral cortex
What is the main component of the ascending reticular activating system (ARAS)?
What are its inputs?
What are its outputs?
- central tegmental tract
Inputs = vestibular nuclei, ascending pain pathways. If upside down or in pain –> wake up
Outputs = to hypothalamus thalamus and hence cerebral cortex
Where does ARAS extend to and from?
Extends from caudal medulla to rostral midbrain
What is required of the cerebral hemispheres to result in coma with an intact brainstem?
- widespread dysfunction of both hemispheres
- often drugs
Give examples of acute altered status of conciousness
- clouding of consciousness = attention lack, slow thinking, confusion, memory loss, drowsiness
- delirium = + disorientation and hallucination
- stupor = sleep-like state
Give examples of chronic altered state of conciousness
- dementia = mental function, memory, comprehension, speech
- hypersomnia excessive drowsiness and intermittent wakening
- vegetative state = after TBI, no evidence of concious intelligence
What are the causes of coma?
- lesions causing diffuse brain dysfunction
- supratentorial mass lesions causing BS compression
- infratentorial lesino causing BS compression
- intrinsic lesions of BS itself
- psychiatric states that may mimic comatosed states
What GCS define coma?
1-8
Describe the oculocephalic reflex when concious and unconscious
- conscious - eyes move with head as its rotated
- unconcious - eyes remain in original position, slowly rotate to new mid position
What is the oculovestibular reflex/caloric stimulation
- put cold water into ear
- eyes should move the that side
What is the abnormality in decorticate response?
Hemisphereic dysfunction –> abnormal Flexion of arms
extension of legs
What is the abnormality in decerebrate response?
Decorticate by to upper brains the
–> abnormal extension of arm and leg
What is abnormality in flaccidity?
- pontine medullary damage
What pattern of breathing do those locked-in show?
Why?
- patient breathing automatically
- not corticospinal tract to adjust
What pattern of breathing do those with ondines curse show?
- can be voluntarily but will stop or hypoventiliate when asleep
