37 - Coma Flashcards
Define hypersomnia
excessive sleepy but normal congnition on awakening
Define coma
eyes remain closed even after vigorous stimulation
Define obtundation
mental blunting
define abulia
awake but apathetic (lobotomized)
define akinetic mutism
silent, alert, seemingly immobile. No mental activity with vigorous stimulation
Define vegetative state
no awareness or meaningful interaction with environment
What lesion of the midbrain would cause insomnia? Narcolepsy?
rostral midbrain lesions cause insomnia
caudal midbrain lesions cause narcolepsy
What is the function of the reticular gray concerning coma?
important for arousal
Will a lesion of the upper pons cause coma if the midbrain and thalmus are fine?
yes. upper pons lesions can cause coma even without thalamic or midbrain injury
What is primary sleep initiator? How?
VLPO. deploys GABA to inhibit wake centers
How can you differentiate metabolic and structural comas by looking at the pupils?
pupil reflex is last to go in metabolic coma, but FIRST to go in structural
If a coma patient has elevated vital signs: structural or psychogenic coma?
structural elevates vitals.
Psychologic has normal vitals
What is first sign of both central and transtentoral herniation?
Cheyne stokes
What causes the flexor response (decorticate)?
response to pain due to loss of corticol control of brainstem motor centers
What causes extensor (decerebrate) posturing?
response that arises after loss of the red nucleus and rubrospinal tract in midbrain
What is perfect score on glasgow?
- above 12 is a good prognosis
What parts of the brain mediate consciousness?
Arousal = ascending arousal system of rostral brainstem Content = corticol circuits
How can you distinguish structural from metabolic comas?
metabolic: non-focal signs (lateralizing signs like hemiparesis absent)
head CT negative
pupils STAY reactive even as brainstem functions lost.
Asterixes, multifocal myoclonus/tremor, uremia, liver failure, hypoxia
Stupor and coma reversible.
What is immediate treatment for coma patients?
stabilize vitals (ABCs)
stabilize neck
determine history
empiracal D50, thiamine naloxone (opiate OD)
What are the two componenets of consciousness?
arousal (sleep-wake cycels) and content (awareness)
What is the most common coma causing lesion?
paramedian tegmental area lesions, just ventral to aqueduct of Sylvius
What are signs of a central herniation?
reduced consciousness, small reactive pupils, decorticate psoturing (flexor), cheyne-stokes respirations, eventual midbrain failure
What are sources of endogenous toxins for metabolic encephalopathy?
uremia and hepatic failure
