Lecture: coma and consciousness Flashcards
Define consciousness
State of full awareness of the self and one’s
relationship to the environment (depends on prior experience)
Components include: level of consciousness, self awareness and content of consciousness
GCS of coma patient?
8 or below
What is the most common cause of mild traumatic brain injury?
Most common form of TBI 22:1 • Does not require LOC • Evidence of head impact • GCS 13-15 • Neurosurgical intervention not required • Common in sport • Cumulative effect • Medicolegal implications Does not require reduced arousal, but awareness if affected.
Describe key features of coma.
- Unresponsiveness
- Eyes closed
- Does not respond to stimuli
- No awareness of outside or self
- Graduation in depth of coma but no arousal cycle
- Self limiting
define brain dead
irreversible coma. Permanent absence of all brain functions including brain stem reflexes.
How must suspected brain dead patients be assessed?
- Two experienced examiners
- Off all sedation
- Normal temperature and electrolytes
- When above criteria cannot be met imaging can be use (cerebral perfusion scan)
Define a minimally conscious state?
Patient unable to follow instructions or communicate BUT appears to have awareness of the environment.
Define vegetative state
- Patient with complete unawareness of self and environment
- Cannot communicate
- Preserved sleep wake cycles
- Complete or partial preservation of hypothalamic and brain stem autonomic functions
Describe permanent vegetative state
A vegetative state that is irreversible
Diagnosis is made over a period of time and is based on the degree of certainty that recovery will not occur.
Based on probability based on time and is not absolute.
Describe neuropathology of vegetative state.
- Recovery of arousal in unresponsive patient
- Autopsy of 49 patients, 35 blunt TBI, 14 non TBI
- Diffuse axonal injury most common (71%)
- Thalamus abnormal in 80% - 96%
- Ischaemic damage, haematomas
- Non TBI ischaemia in 64%, thalamus always
- Either subcortical white or thalamic lesions
Describe locked in syndrome
state of alert wakefulness associated with paralysis and inability to speak. Patient can possibly communicate with eye movements and blinking
Describe akinetic mutism
A condition characterized by decreased motor responses and paucity of speech. Caused by injury to the mesial frontal region of the brain (e.g., from traumatic brain injury, hydrocephalus, Creutzfeldt-Jakob disease).
Lesions in frontal cortex, cerebellum, cingulum.
Patient with upper pontine damage response to painful stimuli?
extension
Patient with upper midbrain damage response to painful stimuli?
flexion
Uncal herniation symptoms?
pupil dilatation then oculomotor failure
